Veterinary Parasitology

Front 1

What is an Obligate Parasite?

Back 1

Depend on their Hosts to maintain themselves within the environment

Front 2

What is an Facultative Parasite?

Back 2

Parasites can complete their life cycle w/o a period of parasitism

Front 3

What is a temporary parasite?

Back 3

Parasites that have one or more NONparasitic stages that live away from the host.

Front 4

What is a permanent parasite?

Back 4

Parasites complete their entire life cycle on a single host

Front 5

What is highly host specific vs low specificity?

Back 5

High host specificity = parasites are restricted to one host species
Low host specificity = can infect a wide range of host species

Front 6

Charactoristics (6) of an "ideal" parasite

Back 6

1. recognises host site
2. maintains its position
3. Utilizes host nutrients
4. Adapts to physio-chemical conditions at site
5. minimizes host immune response
6. Life cycle is synchronized with one of host

Front 7

Definitive Host

Back 7

host in which the parasite undergoes sexual reproduction

Front 8

Intermediate (secondary) host

Back 8

host other than final host that the parasite must infect to complete its life cycle (ANY REPRO IN THIS HOST IS ASEXUAL)

Front 9

Transport host

Back 9

host in which there is no parasite development but serves to distribute parasite into environment (NOT ESSENTIAL FOR COMPLETION OF LIFE CYCLE)

Front 10

Paratenic Host

Back 10

similar to transport hosts but limited parasite development (CYCLE CAN BE COMPLETED IN ABSENCE OF THIS HOST) (ALSO NOT AN OBLIGATE PART OF LIFE CYCLE)

Front 11

Disease host

Back 11

host in which disease is observed

Front 12

Accidental host/incidental/dead-end host

Back 12

some parasite development but no transmission

Front 13

Reservoir host

Back 13

host that maintains infxn in an environment, usually to the detriment of domestic livestock or man

Front 14

Direct Life Cycle

Back 14

parasite has a cycle of development in ONE DEFINITIVE HOST and the infective form is usually external, environmentally resistant, nonparasitic form.

Front 15

Types of direct life cycles (3)

Back 15

1. all stages parasitic
2. single non-parasitic stage
3. more than one non-parasitic stage

Front 16

Indirect Life cycle

Back 16

parasite needs to cycle btwn at least TWO different types of hosts to complete its life cycle. (THERE IS ALWAYS ONE DEF HOST AND ONE I. HOST)
-infective forms can be non-parasitic, parasitic or both

Front 17

Types of Indirect life cycles (3)

Back 17

1. predator-prey cycles (carnivore def host and herbivore as i. host)
2. Vertebrate - invertebrate cycle (def host always vertebrate and i.host is invertebrate)
3. Vector-borne parasites (flies adn ticks are the vector)

Front 18

Cons to having an I. Host

Back 18

-added complication for LC (life cycle)
-Reduces overall chance of success
-need for compensatory asexual repro in I.host

Front 19

Pros to having an I. Host

Back 19

-I.Host increases the range of the parsite in time and space
-Exploit transient environments
-Isolation from host extinction

Front 20

How do ticks remain on host?

Back 20

lipo-protein salivary secretion acts as glue to host epidermis and dermal collagen

Front 21

Host reactions to ticks (immunological)?

Back 21

In rxn to salivary secretion= inflammation followed by development of aquired immunity
-Delayed type 4 dermal hypersensitivity but type 1 immediate hypersensitivity involoved
-Effect of rxn = pruritis

Front 22

What results due to pruritis associated to tick bites?

Back 22

-excessive grooming
-vesiculation of epidermis to push tick off
-graqnuloma of dermis which cuts off bld to tick
-accum of eosinophils - poisons tick

Front 23

Host Reaction to ticks (overall cost)

Back 23

-Pruritis
-Stress
-Anorexia
-Anemia
(also hide damage, teat damage, paralysis)

Front 24

Psoroptic Mites Location

Back 24

ON SKIN SURFACE -penetrate outer layers of epidermis and feed on inflammatory exudate

Front 25

Sarcoptic Mite Location

Back 25

IN EPIDERMIS

Front 26

Demodectic Mite Location

Back 26

SUPERFICIAL TO EPIDERMIS BUT WITHIN THE HAIR FOLLICLE

Front 27

Dermanyssid Mite Location

Back 27

SUPERFICIAL AND TEMPORARY

Front 28

Trombiculid Mite Location

Back 28

FEED LIKE TICKS

Front 29

PSOROPTES OVIS
-what is it?
-where is it found?
-what does it cause?
-Survival?

Back 29

-most serious ectoparsatic infection in UK livestock
-doesn't burrow in epidermis but remains at base of hairs
-pierces skin with chelicerae
-exudate and scabbing takes place
-mites found around scabs and on wool (fomites)
-pruritis is intense, spreads quite quickly
-May survive off host for several days or weeks

Front 30

What are chelicerae?

Back 30

piercing mouthparts

Front 31

What are chelae?

Back 31

scissor like structures at the end of chelicerae

Front 32

Effective control of PSOROPTES OVIS?

Back 32

-tx of both infected livestock and either disinfection or 2-4 week vacating of contaminated enclosures and fomites.

Front 33

Common name of PSOROPTES OVIS?

Back 33

SHEEP SCAB

Front 34

Common name of PSOROPTES CUNICULI?

Back 34

RABBIT EAR CANKER

Front 35

PSOROPTES CUNICULI
-Where does it infect?
-What does it infect?

Back 35

-mange of auditory canal in rabbits can also infect horses

Front 36

Larval stages of ticks and mites?

Back 36

three pairs of legs

Front 37

Nymphs and Adult stages of ticks and mites?

Back 37

four pairs of legs

Front 38

Body Design of Ticks and Mites?

Back 38

-head, neck, thorax fused
-antennae and mandible absent
-Mouthparts: palps, chelicerae, hypostome
-together with basis capituli forms a capitulum or gnathosome

Front 39

Common name for CHORIOPTES OVIS?

Back 39

Cattle Scab

Front 40

CHORIOPTES OVIS
-who does it infect?
-What is seen with infxn?

Back 40

-cattle, sheep and (horses rarely causing severe effects)
-epidermal pustulation and thickening and wrinkling of skin
-horse lower legs where there is hair

Front 41

Common name for OTODECTES CYNOTIS?

Back 41

canine or feline otitis

Front 42

OTODECTES CYNOTIS?
-who does it infect?>
-what is seen with infxn?

Back 42

-common parasite of cats and dogs, increased amts is when dz is seen
-cerumen forming heavy waxy and crusted exudates blocking auditory canal
-pruritis is severe!

Front 43

What do Sarcoptic Mites feed on?

Back 43

keratinocytes within outer layers of epidermis

Front 44

Sarcoptic Mites create skin reactions that lead to...

Back 44

-acanthosis (thickening of stratum spinosum) and
-Hyperkeratosis (thickening of stratum corneum)
-self trauma due to excessive grooming

Front 45

SARCOPTES SCABIEI
-who it infects?
-what is seen with infxn?

Back 45

-common for pigs in UK and dogs (can infect cattle, sheep,fox and humans)
-papules form and skin thickens
-immediate and delayed dermal hypersensitivity to feces
-vigorous grooming and self trauma
-secondary rash may occur

Front 46

NOTOEDRES CATI
-host?
-what is seen with infxn?

Back 46

-cats around head and ears
-pruritis is intense and leads to self trauma
-rare in uk

Front 47

KNEMIDOCOPTES MUTANS
-host?

Back 47

-poultry
-skin under scales of legs become inflammed leads to distortion and lameness

Front 48

KNEMIDOCOPTES GALLINAE

Back 48

-poultry
-infests skin at base of feathers leads to depluming itch

Front 49

KNEMIDOCOPTES PILAE

Back 49

-ornamental cage birds
-infests the skin of the cere, head, neck, wings and feet
-leads to scaly face

Front 50

On examination how can you distinguish between mange mites?

Back 50

Look at Pretarsi

Sarcoptes and Notoedres: long unsegmented pedicel (stalk)

Psoroptes:
pretarsus has a long 3 segmented pedicel

Front 51

Describe body structure of Demodex?

Back 51

tiny, wormlike mites with short, stubby legs

Front 52

What Demodex species are found on the human face?

Back 52

D.folliculorum and D.brevis

Front 53

Demodex disease?
-where?
-what happens?

Back 53

-commensal on mammal species normally found without dz
-infestations transfer from mom to offspring
-live in hair follicles
-remain external to epidermis
-infestations localized due to nodules incasing thousands of mites
-occasionally infestation becomes severe and cause dz

Front 54

What is a danger of demodex (secondary)?

Back 54

Immune deficiency

Front 55

WHat host is infected by demodex?

Back 55

-dogs
-cattle and goats (ruins hides)

Front 56

TROMBICULA AUTUMNALIS?
-who
-when
-how

Back 56

-cats, dogs and humans
-edinburgh = summer
-parasitic ONLY AS LARVAE
-small with six legs
-adult free living
-attach to host in passing (as with ticks)
-use stylostome
-cause intense pruritis

Front 57

What is a stylostome?

Back 57

salivary feeding tube that can be secreted

Front 58

CHEYLETIELLIDAE

Back 58

-infests cats, dogs and rabbits
-alot of dandruff produced
-C.blakei (cat fur mite) easily transferred to humans.

Front 59

what distinct feature allows for recognition of cheyletiellidae?

Back 59

big palpal claws, M-shaped gnathosomal peritremes and comblike tarsal appendages

Front 60

What species of Cheyletiellidae is a risk to humans?

Back 60

C.blakei easily transferred from cats to humans

Front 61

What species are bloodsucking mesostigmatid mites that parasitize birds?

Back 61

Dermanyssus Gallinae
Ornithonyssus sylviarum

Front 62

D. Gallinae
-host infects?
-how does it infect?
-what is seen with infxn?

Back 62

-red mite of poultry, infests poultry houses
-Mites are free living and crawl onto poultry and feed rapidly on blood
-Feeding site becomes inflamed and pruritic
-leads to loss of productivity
-can infect workers of poultry houses too

Front 63

ORNITHONYSSUS SYLVARIUM
-host?

Back 63

-northern fowl mite similar to D.gallinae YET remains on its poultry host

Front 64

ORNITHONYSSUS BACTI

Back 64

-infests rodents and can cause problems in animal houses
-also can infect cats due to hunting (short lived infxn)

Front 65

What are DERMATOPHAGOIDES MITES? (Acarus and Glycophagus)

Back 65

-house dust mites
-cause asthma in humans via inhalation of feces in fomites
NONE of allergy causing mites are parasitic it is the protein from the dust and dead bodies

Front 66

LAMINOSIOPTES CYSTICOLA

Back 66

-endoparasite of poultry
-forms nodules in lungs, peritoneum and abd.
-no clinical dz seen but carcass is downgraded

Front 67

PNEUMONYSSUS AND CYTODITES

Back 67

-respiratory mites

Front 68

TRIXACARUS CAVIAE

Back 68

-infects g.pigs
-sarcoptic type mite
-causes acanthosis and hyperkeratosis..and death

Front 69

Scab and mandatory tx??

Back 69

-had probs in past with failed attempt to eradicate sheep scab using pesticides
-now mandatory tx abandoned
-Private good now (farmer pays)
as opposed to public good (management by govt)
-incidence of scab increasing throughout UK

Front 70

Important things to remember about P. Ovis?

Back 70

-resevoir can exist on cattle
-fomites can exist infected for up to 2 weeks
-Mites reproduce very rapidly (10 day cycle) at all seasons!!
-Have limited powers of dispersal

Front 71

How do Arthropods evade Immune Reactions of their hosts?*****************

Back 71

-blood sucking arthropods: saliva=anesthetic (so not felt right away) also antigenic material in glue along with proteo

Front 72

What is Malpighian tubules and who has them?

Back 72

Excretory organs branch off from gut
-Larval insects

Front 73

What kind of metamorphosis does Mites and Ticks have?

Back 73

All Have Incomplete Metamorphosis

Front 74

Mite development?

Back 74

-Larval stage develops into a nymph
-usually several nymph stages
-Mostly all stages are parasitic
-All stages are found on host
(moulting, mating and egg production)

Front 75

Tick development?

Back 75

-Larva develops into the nymph stage
-ONLY ONE nymph which then develops into adult
-Each stage feeds on a different host
-When feeding is complete engorged tick falls off to moult
-egg laying also occurs on the ground
3-HOST Cycle

Front 76

Arthropods as Vectors of Pathogens:
1. Mechanical Transmission

Back 76

-flies with spongy mouthparts
-move from host to host
-no involvement of pathogens with the LC of the vector or development within the vector

Front 77

2. Biological Transmission

Back 77

-movement from gut to mouthparts of pathogen and then transferred from one vert host to another

Front 78

What is moulting?

Back 78

-in order to grow from egg to adult, arthropod must shed its exoskeleton and grown a new larger one

Front 79

What is Anaplasmosis?

Back 79

-caused by Boophilus tick (and biting flies)
-dz Anaplasma Marginale rickettsia

Front 80

What is Babesiosis?

Back 80

-Babesia protozoa transmitted by:
Boophilus
Rhipicephalus
Ixodes ticks

Front 81

What is Cowdriosis?

Back 81

Ehrlichia ruminantium rickettsia
transmitted by:
Amblyomma ticks

Front 82

What is Ehrlichiosis?

Back 82

Ehrlichia species transmitted by:
several ticks

Front 83

What is Theileriosis?

Back 83

Theileria protozoa transmitted by:
Rhipicecphalus +
Hyalomma ticks

Front 84

What is Tick Toxicosis?

Back 84

-Hyalomma ticks feeding on cattle, sheep and camels

Front 85

What is Dermatophilosis?

Back 85

-Amblyomma ticks cause immune suppression in cattle
-this facilitates sever skin diseases due to Dermatophilus congolensis bacteria
-Not due to transmitted pathogen

Front 86

Life Cycle:
3-stages of Tick development?

Back 86

Associated with feedings:
1.larva to nymph
2.nymph to adult
3. reproduction of adults

Front 87

What is transstadial transmission?

Back 87

-pathogen has to get from vert host to vert host via tick so: must get into feeding larva or nymph and survive until larva or nymph in next stage feed on vert host

Front 88

What is transovarial transmission?

Back 88

if pathogen passes from infected mother to eggs and then to larvae
-also called vertical transmission

Front 89

What pathogen is related to transovarial transmission?.

Back 89

Babesia

Front 90

All tick borne pathogens are transmitted biologically? what does that mean ?

Back 90

They have an essential developmental cycle to complete within the tissues of the tick
**Few can be transmitted without any development*

Front 91

Are ticks hardy? survival?

Back 91

Yes in between feedings can live up to year or more if nymph or adult
-pathogens live for a long time in tick and thus ticks are imp reservoirs of infxn

Front 92

What is the common name of Ehrlichiosis?

Back 92

Tick Borne Fever

Front 93

What species is affected by Tick Borne Fever?

Back 93

-sheep mainly but also cattle and deer

Front 94

What is TBF caused by?

Back 94

MAINLY: -rickettsia Ehrlichia phagocytophila

also:
-Anaplasma phagocytophilum

Front 95

How is TBF transmitted?

Back 95

Ixodes ricinus ticks

Front 96

Signs of dz of TBF

Back 96

-lambs: pyrexic 5 days and immunity suppressed
-Ewes that are naive may abort
-Rams that are naive may become infertile

Front 97

What does E.phagocytophila do? (TBF)

Back 97

-infects neuts and other white cells
-can remain in carrier state (low) for several yrs
-ticks are reservoirs for infxn (deer too)

Front 98

When E.phagocytophila is inside the tick what happens? (TBF)

Back 98

-infects immune cells and develops and replicates in salivary glands
-at time of tick feeding, it becomes an infective form in salivary gland

Front 99

How long does the infective stage last for TBF inside the tick?

Back 99

-lasts from one stage to another over one year

Front 100

What species support tick production which thus allows TBF to spread?

Back 100

sheep and deer on rough hill pastures or woodlands
-ticks require high humidity in leaf litter layer above soil

Front 101

Control of TBF

Back 101

making sure young NOT WEANED lambs are exposed to infection via ticks--> develop good immunity with few clinical signs
--thus lambs will be fully susceptible to infection but have good resistance to clinical ehrlichiosis

Front 102

What is Enzootic Stability? (endemic stability)

Back 102

stable high level of infxn with ensuing immunity but low levels of dz.

Front 103

Ticks can feed all year but are more active in Springtime. What problems does this cause?

Back 103

Lambing, naive lambs that become infected after weaning or
-Naive older stock very important due to infertility or abortion

Front 104

How to prevent problems (TBF)?

Back 104

-fencing to prevent sheep from getting into ticky areas
-also do not put naive adults onto ticky pasture
-NO VAX avail but tx with abx

Front 105

What is another name for Canine Ehrlichiosis?

Back 105

Tropical Canine Pancytopenia

Front 106

k-9 Ehrl is caused by?

Back 106

Ehrlichia canis

Front 107

k-9 Ehrl is transmitted by?

Back 107

Rhipicephalus sanguineus (dog tick)

Front 108

What does K9 Ehrl dz cause?

Back 108

-severe haemorrhage and can be fatal
-residual infections occur in dogs for years

Front 109

Problematic areas for K9 Ehrl?

Back 109

Quarantine kennels in UK
-lg number of dogs moving in and out without quarantine rules

Front 110

What is another name for CANINE BABESIOSIS?

Back 110

CANINE MALIGNANT JAUNDICE

Front 111

What is k9 babes caused by?

Back 111

-Babesia canis
-Babesia gibsoni

Front 112

What is the vector / transmission route? (k9 bab)

Back 112

-same as k9 ehrlic
Rhipicephalus sanguineus
also:
-Dermacentor marginatus

Front 113

What does the infection of k9 bab cause?

Back 113

haemolytic anemia
-infected erythrocytes clump in capillaries and cause brain strokes
-dual infection with E.canis and B.canis can occur

Front 114

What results if a dual infxn of E.canis and B.canis?

Back 114

E.canis: inhibits erythropoesis while
B.canis: clumps erythrocytes
Together the infxn is compounded

Front 115

Therapeutic agent for k9 bab?

Back 115

Imidocarb and a vaccine in france called "pirodog"

Front 116

Risk of spread for k9 bab?

Back 116

same as with k9 ehrl:
traveling dogs and quarantine kennels

Front 117

Looping Ill infects what species?

Back 117

Sheep mainly
but also cattle, pig, horse, dog, deer and grouse

Front 118

Pathogen is looping ill virus. How is it transmitted?

Back 118

Ixodes ricinus ticks
Transstadially
-no complex development in tick BUT the virus replicates in salivary glands

Front 119

What is seen with looping ill dz?

Back 119

Sheep: pyrexia for several days then virus invades CNS if immunity fails neuro probs and paralysis, sometimes death
Hoggs most susceptible

Front 120

How long is tick infected with looping ill as a vector?

Back 120

FOr life therefore is a reservoir of infection

Front 121

Control of looping ill?

Back 121

Immune suppression from TBF predisposes looping ill severity therefore control methods involve:
-endemic stability as with TBF
-along with colostrum from immune dams protects lambs (immunity is sterile therefore sheep aren't a reservoir)
-there is also a vaccine available

Front 122

What is another name for Tick Pyaemia?

Back 122

Cripples

Front 123

What kind of dz is Tick Pyaemia?

Back 123

tick associated dz.
-Ticks are not vectors of causative agent

Front 124

What causes Tick Pyaemia?

Back 124

-Bacterium Staphyloccus Aureus

Front 125

How does Tick Pyaemia infect?

Back 125

Staphy proliferates systemically when lambs are immunosuppressed by E. phagocytophila
-Heavy infestations of ticks --> suppresses immunity

Front 126

What is seen with Tick pyaemia?

Back 126

-infection becomes systemic
-abscesses occur in many internal organs
-main clinical signs are abscesses in joints and brain leading to "crippling"

Front 127

How to control Tick Pyaemia?

Back 127

Much connected to that of TBF. !!!!!
-PROBLEM: Sufficient tick to ensure endemic stability of TBF are likely to cause a higher incidence of pyaemia
THEREFORE: difficult to control both
Pyaemia is more serious economic loss to farmer
Thus concentrate on pyaemia by good management to reduce lambs to stress so not hurt by Ehrlichia induced immune suppression.

Front 128

What is Endemic instability?

Back 128

challenge of infection is low, thus there are many susceptible hosts in the population --> gives risk of an epidemic with many patent infections if there is sudden contact with a new source of infection
-opposite of endemic stability

Front 129

What is premunity?

Back 129

resistance to infection established after an acute infection has become chronic and which lasts as long as the pathogen remains in the host (babesiosis)

Front 130

What is Carrier state?

Back 130

infection with pathogen in a state where it is not patent or easily found but can still be transmitted back to vectors feeding on the host

Front 131

What is a Reservoir host?

Back 131

host with carrier infection may also be known as carrier host

Front 132

What causes Borreliosis?

Back 132

Spirochete bacterium Borrelia Burgdorferi

Front 133

How is the bacterium for Borreliosis transmitted?

Back 133

Ixodes ricinus larvae and nymphs that feed on mice, voles, squirrels and birds

Front 134

What are the natural hosts of borreliosis?
What hosts aren't the natural hosts yet it can survive in?

Back 134

natural hosts: mice, voles, squirrels, and birds

Can survive in and cause dz in: human, dogs, sheep

Front 135

What is the common name for Borreliosis?

Back 135

Lyme Disease

Front 136

Control Options for Tick Borne Disease (8):

Back 136

1. None - rely on endemic stability and host resistance
2. Acaricide tx intensly
3. Acaricide tx strategically
4. Stock and pasture management (hostile environment for ticks)
5. Breed for resistance (cattle)
6. Drugs to tx transmitted pathogens
7. Live parasite vaccines
8. Synthetic antigen vaccine against the pathogen or the tick.

Front 137

Body Design of Lice

Back 137

-no wings
-flattening dorso-ventrally
-strong claws and spines to hold onto host

Front 138

Lice are in the order of...

Back 138

Phthiraptera

Front 139

Suborders of Lice

Back 139

Anoplura (sucking lice)

Ischnocera and Amblycera (chewing lice)

Front 140

Where do lice live? Host finding?

Back 140

-ectoparasites
-spend whole life on host w/transfer to others via close contact
-Lice prefer rough, dark surfaces

Front 141

Use of antennae? (lice)

Back 141

-well developed antennae to locate feeding sites by warmth and smell.

Front 142

Life cycle of lice

Back 142

-develop from egg to larva through several nymphal stages to sexually mature adults
-All active stages look similar
-Only lasts around 2 weeks duration

Front 143

What kind of metamorphosis do lice have?

Back 143

incomplete metamorphosis

Front 144

Lice feeding and reproduction?

Back 144

-Feed in small meals
-Females continuously lay eggs 10/day

Front 145

Which species of lice produce asexually?

Back 145

Bovicola - by parthenogenesis

!!Great advantage -don't have to find mates in low density populations!

Front 146

How do lice survive against host defences?

Back 146

-strong legs with curved claws to move thru and grip tightly to the pelage (hard to groom out)
-eggs glued onto pelage of host and eggs are resistant to dessication or grooming

Front 147

Are lice host specific?

Back 147

Yes highly host specific.
-sessile ectoparasites --> specialized digestion and feeding on specific tissues.

!!ANother great advantage because it allows evolving saliva and feeding mechanisms so specific to evade host immune system!

Front 148

LINOGNATHUS VITULI
-what type of feeder?
-host?
-Where on host?
-any identifiable features?

Back 148

-Anoplura (sucking)
-cattle
-head, neck, dewlap
-long nose

Front 149

BOVICOLA BOVIS
-type of feeder?
-host?
-where located?

Back 149

-Ischnocera (chewing)
-cattle
-top of head, neck, shoulders, back and rump

Front 150

HAEMATOPINUS EURYSTERNUS
-type of feeder?
-host?
-where located?
-identifiable features?

Back 150

-Anoplura (sucking)
-cattle
-base of horns, ears, eyelids
-short nose

Front 151

SOLENOPOTES CAPILLATUS
-type of feeder?
-host?
-where located?

Back 151

-Anoplura (sucking)
-cattle
-head, neck and dewlap
-little blue louse

Front 152

LINOGNATHUS OVILLUS

Back 152

-Anoplura (sucking)
-sheep
-head, ears, and neck

Front 153

Linognathus pedalis

Back 153

-anoplura (sucking)
-sheep
-hind legs to crutch
-!!!Adapted to low temps and can survive on pasture for up to one week!!

Front 154

Bovicola ovis

Back 154

-Ischnocera
-sheep
-whole body

Front 155

Haematopinus Asini

Back 155

-Anoplura
-horse
-mane, base of tail, fetlock - will spread over whole body

Front 156

Damalinia Equi

Back 156

Same as Haematopinus asini except Ischnocera

Front 157

Haematopinus suis

Back 157

-Anoplura
ONly pig louse

Front 158

What is pediculosis?

Back 158

Lice infestation of cattle

Front 159

Predisposition to dz of lice?

Back 159

Winter housing, or Dense housing of sheep, cattle and pigs predisposes for dz and easy spread

Front 160

Clinical signs of heavy infestations of lice?

Back 160

-pruritis
-anaemia
-loss of BCS
-wool loss due to excessive grooming
-"white powder" look on hair (eggs)
-or if hair parted can be seen crawling if large enough

Front 161

Hide damage due to lice infestations?

Back 161

fleck and spot on cattle hides

-due to granuloma formation at site of delayed dermal hypersensitivity rxn to the antigenic saliva

Front 162

Felicola subrostratus

Back 162

-Ischnocera
-cat
-only cat louse

Front 163

Linognathus setosus

Back 163

-Anoplura
-dog

Front 164

Trichodectes canis

Back 164

-Ischnocera lice
-dog
-Intermediate host of the tapeworm of dogs (Dipylidium caninum)

Front 165

Clinical signs of lice on dogs and cats:

Back 165

pruritis that leads to restlessness and excessive grooming
-can be seen in hair

Front 166

Lipeurus caponis

Back 166

-Ischnocera
-birds
-base of wing and tail feathers
-"wing louse"

Front 167

Cuclotogaster heterographus

Back 167

-Ischnocera
-birds
-"head louse"

Front 168

Menacanthus stramineus

Back 168

Amblycera (chewing)
-chicken
-skin of breast, thigh and around anus
-"chicken body louse" or "yellow body louse"

Front 169

Menopon gallinae

Back 169

-Amblycera
-bird
-"shaft louse"

Front 170

Clinical signs of lice in birds:

Back 170

L.caponis and M.stramineus cause worst probs.
-blood drawn
-inflammation
-pruritis
-Loss of BCS
-restlessness
-depluming

Front 171

What kind of metamorphosis do fleas have?

Back 171

Complete

Front 172

Host finding for fleas?

Back 172

-live partly off host
-can remain in the host's nest or housing
-jump onto the host to feed
-once on host tend to remain there

Front 173

Environments preferred by fleas:

Back 173

-warmth, CO2, smell and movement of host -specific to adults
-most are not highly host specific

Front 174

Reproduction and life cycle of fleas:

Back 174

-Eggs layed continuously 10-15/day, drop into host housing
-larvae remain in nest and feed on organic debris and on dry droppings of adult fleas which contain bld
-fully developed larva becomes a pupa which metamorphoses into the adult

Front 175

Survival against host defenses (fleas)

Back 175

-very strong back legs for mobility
-rows of spines and strong leg claws to hold and move
-flattened shape permits rapid travel thru hair without being groomed out

Front 176

Flea feeding:

Back 176

feeding is rapid and small meals repeated to provide for small batches of eggs

!!Also rapid feeding avoids local hypersensitivity rxns in dermis!

Front 177

Ctenocephalides

Back 177

-common flea
-felis and canis but can also infest goat and sheep in tropics
-cat flea most common

Front 178

Spilopsyllus cuniculi

Back 178

-rabbit flea
-can be picked up by cats and dogs when hunting
-tranmits myxoma virus --> myxomatosis in rabbits

Front 179

Ctenocephalies is an intermediate host for:

Back 179

both felis and canis species harbor immature stages of:
Diplyidium caninum (tapeworm of cats and dogs)
-Flea larvae ingest the oncosphere stage of tapeworm and then fleas are ingested by cat or dog when grooming

RARE: B/C the pathogen manages to survive the insect during complete metamorphosis

Front 180

Why are fleas not true vectors when it comes to D. caninum?

Back 180

Transmission does not occur via the active feeding of the flea

Front 181

Best way to control tapeworm?

Back 181

is to control both the tapeworm but also the fleas and lice that transmit it

Front 182

Clinical signs associated with fleas:

Back 182

-mild pruritis
-restlessness to groom
-flea bite allergies can arise

Front 183

Name two main types of chicken fleas

Back 183

1. Ceratophyllus gallinae
2. Echidnophaga gallinae

Front 184

Best control of lice and fleas:

Back 184

-good hygiene on farm and domestically
-antipest cleaning
-pasture management
-good hygiene with indoor or intensive housing (most at risk)

Front 185

Flies:
-Class?
-Order?
-Metamorphosis?

Back 185

-Insecta
-Diptera
-Complete metamorphosis

Front 186

Life Cycle and Reproduction of Flies?

Back 186

-Eggs
-Larvae (legless maggots or in aquatic environment)
-3 or 4 larval stages
-pupal stage
-adult

Front 187

Reproduction rate for flies?

Back 187

-repro rate is high with repeated batches of eggs of several hundred per female
-Breeding is in a favourable season and may be several weeks only
-!!CAn exploit temporary resources if needed!! (r)

Front 188

What is larviparous?

Back 188

larvae develop one at a time within a female to produce fully mature larvae which are laid at sites where they immediately pupate

Front 189

What flies are larviparous? What is the benefit to doing this?

Back 189

TseTse Flies and Keds

-low repro rate but high survival rate (b/c larvae are protected inside adult)
-!!! these exploit stable resources!! (k)

Front 190

Host Finding capabilities of flies?

Back 190

-Complex antennae: highly adapted to searching for hosts by perceiving warmth, Co2 and smell

-Daytime feeders have eyesight capable of discriminating hosts after located via smell

Front 191

What Flies are daytime feeders?

Back 191

Horse flies
Tsetse flies

Front 192

Survival Against host defenses (flies):

Back 192

-adult blood feeding flies are rapid feeders
-active flying and accurate host flying allows for rapid feeds

Front 193

What special charactoristic for defense does larvae of Myiasis flies have?

Back 193

-provoke hypersensitive rxns in skin BUT have an impermeable cuticle to provide protection.

Front 194

Musca autumnalis

Back 194

-face fly
-doesn't attack skin
-feeds on secretions from eyes, nose and mouth
-CAUSES NUISANCE - can disrupt grazing and create fly syndrome in cattle

Front 195

Hydrotaea

Back 195

-head fly
-Feed at eye secretion and at wounds on heads of sheep
-capable of abrading skin to feed on serum and bld

Front 196

Haematobia

Back 196

-horn fly
-cattle
-spend all time as adults on and around cattle
-Mouthparts are piercing proboscis
-occur in large numbers on the backs of cattle
CAUSE NUISANCES

Front 197

Tabanidae
(Tabanus, Haematopota, Chrysops)

Back 197

-Large complex mouthparts
-Painful Bite during bld feeding
-Crude wound
-Not in high density in UK
-Persistant biting leads to lack of BCS/production
-Larvae occur in wet soil/mud

Front 198

Melophagus Ovinus

Back 198

-Sheep ked
-Fly adapted for ectoparasitic life
-No wings, so is mistaken for ticks
-Adult holds onto wool and feeds on bld
-Heavy infestations=loss of production

Front 199

Culicoides

Back 199

-biting midges
-Habitat = bogs (larvae breed)
-Painful feeding
-Sheep, cattle, horses
-common in NW scotland

Front 200

Describe mouthparts of Culicoides

Back 200

-complex like a miniature version of those of a tabanid

Front 201

Culicoides reaction on horses:

Back 201

Severe immediate hypersensitive reaction called: sweet itch

Front 202

Stomoxys

Back 202

-stable flies
-modified piercing skin and feeding on blood

Front 203

Control of Nuisance and biting flies:

Back 203

Partially achieved via:
pour-ons
sprays
ear tags
attractant/bait systems

Front 204

What is myiasis?

Back 204

infestation of live flesh of vertebrates with maggot larva of Diptera flies
-very severe form of parasitism

Front 205

Types of myiasis:

Back 205

Facultative - maggots can survive on carrion

Obligate - parasitically adapted that fly has to infest correct species of live host at the correct site on host

Front 206

Lucilia

Back 206

-blowflies
-facultative myiasis (blowfly strike)
-attracted to protein food sources for egg laying
(carcasses, bld on wounds, soiled wool)
-Maggots hatch at such sites and invade existing wounds via: 1. lacerating mouthparts on existing wounds or 2. proteolytic enzymes in saliva
Results in: toxemia from ammonia and bacterial septicemia in combination leads to death

Front 207

Which Lucilia is the main problem in the UK?

Back 207

Lucilia sericata
Lucilia cuprina
"greenbottle flies"

-warm summers allow higher populations to build up

Front 208

-Hypoderma bovis
-Hypoderma lineatum

Back 208

-Warbles
-Obligate Myiasis
-Eggs laid on legs of cattle
-Larvae hatch and invade the host via hair follicles
-Larvae burrow thru muscle and viscera and end up as mature larvae along the back
-Emerge as larva, drop off and pupate

-Cattle recognize and panic when see adult flies and injure themselves

Front 209

-Gasterophilus
-Oestrus ovis

Back 209

-stomach bot of horses
-nasal bot of sheep

Front 210

Factors favouring eradication of warble fly in 1970's

Back 210

-fly has repro strategy of low production with high survival (get rid of low production may rid of all that survives)
-only one life cycle per year
-summer distinct season of adult activity
-larvae only occur on cattle No wild reservoir hosts
-cattle unable to escape attention of farmer
-Adults have limited dispersal capacity

Front 211

Tx of warbles

Back 211

ivermectin main tx now
-attempt at 5 year eradication scheme but failed

Front 212

Name the vector:
1. African Horse Sickness (virus)
2. Bluetongue (virus)
3. Equine Encephalitis viruses

Back 212

1. Culicoides (fly)
2. Culicoides
3. Mosquitos

Front 213

What flies are vectors?

Back 213

-Adults and usually females (females take repeated bld meals to support production of eggs)

Front 214

Transmission of pathogen using flies as vectors require:

Back 214

INTRA-STADIAL TRANSMISSION
pathogen must get into the vector at one bld meal then back to its mammal host at one of the next few meals within a few weeks.

Front 215

(flies)IF the transmission is mechanical then...

Back 215

it is rapid without development in vector

Front 216

(flies)Extrinsic incubation period of the pathogen

Back 216

if pathogen has a biological development in the vector then this must be fitted into the short period of feeding activity.

Front 217

(flies)Intrinsic incubation period of the pathogen

Back 217

time in the mammalian host from initial infection to a patent state of disease

Front 218

(flies)If transmission is biological then...

Back 218

biological route has to fit the egg laying and feeding cycle of the vector

Front 219

Explain gonotrophic cylce of mosiquitos and Culicoides midges:

Back 219

-take one large bld meal then rest and develop eggs
-After eggs are laid, female takes another meal
-cycle repeats 5-10 times
-Each feed after the first is an opportunity for the pathogen to be transmitted

Front 220

Flies as vectors vs. Ticks as Vectors...

Back 220

-Pathogens getting into ticks have only 1-2 opportunities of onward transmission at the future feedings (via transtadial rte)
-Yet can remain in the vector from months to years between bld meals
-With transovarial transmission (babesia) ticks can remain infected for several generations starting from one initial infection

Front 221

Flies as vectors vs ticks as vectors continued....

Back 221

-tick vectors can act as long term reservoirs
-Fly vectors cannot (pathogen must survive a carrier state infection in mammal hosts)

Front 222

Flies as vectors...

Back 222

-Fly populations are seasonal except in tropics where they feed all the time (this is why more fly borne diseases in tropics)
-Although climate warming may allow spread to temperate regions

Front 223

Feeding mechanisms of flies that aids in them acting as vectors:

Back 223

1. Musca flies and blowflies (Calliphora) have spongy mouthparts on which bacteria are transmitted mechanically (Moraxella bovis)
2. Tabanid flies - have complex cutting to produce bld flow which is taken up by sponge mouthparts and thus transmission of pathogens such as Trypanosoma evansi is transmitted mechanically
3. Mosqitoes have fine piercing mouthparts that transmit Dirofilaria immitis nematodes via saliva.

Front 224

How is Keratoconjunctivitis Transmitted?

Back 224

bacterium Moraxella bovis is transmitted by: Musca species and Hydrotaea
How: feed on lachrymal secretions at the eyes of cattle

Front 225

How is Mastitis Transmitted?

Back 225

Bacterium Corynebacterium pyogenes transmitted by: Htydrotaea

or Streptococcus species transmitted by: Musca species

Front 226

Bluetongue Virus

Back 226

-cattle (reservoir host, show little dz) and sheep (show dz)
-Culicoides
-warmer weather may influence midges
-vaccine avail

Front 227

Rift Valley Fever


African Horse Sickness and Bluetongue (horses)

Back 227

-Mosquitos


-Culicoides
-common in tropics with warmer weather may move
-vaccine avail

Front 228

Leishmaniasis

Back 228

-Leishmania species of protozoa transmitted to dogs by: Phlebotomus species of sandflys
-ingested by sandfly
-develop in fly gut to proliferateve promastigote forms which invade esophagus and mouthparts directly
-these are the infective forms for dogs

Front 229

Transmitted by:
1. West Nile Virus
2.Trypanosomiasis (protozoa)
3. Leismaniasis (protozoa)

Back 229

1. Anopheles (mosqito)
2. Glossina (tsetse flies in Africa) or Tabanids and Stomoxys in Africa, s.america or S.E.asia
3.Phlebotomus sandflies

Front 230

Internal Parasites have one or more non-parasitic stages in their Life Cycle. These can be either:

Back 230

1. dormant stages
2. free living

Front 231

Economic impact of internal parasitism:

Back 231

-reduced productivity due to subclinical infections
-Reduced productivity due to clinical dz
-cost of tx or prevention
-death of animals and loss of capital investment

Front 232

Host specificity of internal parasites:

Back 232

Most are HIGHLY host specific - limiting themselves to a single host genus or species and often within a particular site

Front 233

Internal parasites that can infect a wide range of hosts and are not highly host specific:

Back 233

Toxoplasmosa and Cyrptosporidium

Front 234

2 Types of Parasitic lifecycles for internal parasites:

Back 234

1. Direct/Monoxenous
2. Indirect/Heteroxenous

Front 235

What is Direct/Monoxenous Life cycle?

Back 235

LC is completed in an individual of a single host species
-Infective stage is non parasitic and environmentally resistant form

Front 236

What is Indirect/Heterxenous Life Cycle?

Back 236

Needs to infect two or more different types of hosts to complete life cycle
-Hosts are usually taxonomically unrelated (ie carnivore/herbivore or vert/invertebrate)
-Often has distinct phases of development in each host type

Front 237

Definitive/Final host

Back 237

one host in a direct lifecycle
or
host in which sexual reproduction takes place in indirect life cycle

Front 238

Intermediate host

Back 238

host in an indirect life cycle where any reproduction is entirely asexual

Front 239

Vector

Back 239

Arthropod that transmits a parasite between vertebrate hosts

Front 240

Transport host

Back 240

-NOT essential part of life cycle
-organisms such as flies or earthworms which take up parasite without any parasitic developement in host

Front 241

Paratenic host

Back 241

-NOT essential for life cycle
-as in transport host but limited parasite development (ie migration in host tissues)

Front 242

Disease Host

Back 242

the host in which the disease is seen

Front 243

How to internal parasites get into host?

Back 243

1. Mouth- mainly ingested (food or drink)
2. Skin (either direct skin penetration or indirect via blood sucking arthropod vector)
3. Iatrogenic -contaminated needles
4. Repro tract - coitus
5. Transplacental
6. Transmammary

Front 244

Strategies of Internal parasites for dealing with Hosts Immune response:

Back 244

1. inhabitating lumen of hollow organs
2. camo by mimicking host antigens
3. Changing antigens at diff stages in development
4. inhibiting parts of host immune system
5. rapid repro b4 immune response becomes effective

Front 245

Internal Parasites:
Methods of feeding (4)

Back 245

1 Passive absorption thru outer surface
2. Browsing on gut contents
3.Tissue feeders
4. blood feeders

Front 246

Two types of reproduction seen in internal parasites:

Back 246

1. Asexual
2. Sexual

Front 247

Asexual reproduction

Back 247

used to increase # of individual parasites within the host
(binary fission, shizogony)

Front 248

Sexual Reproduction

Back 248

repro using mating types, separately sexed individuals (dioecious) or doubly sexed individuals (monoecious)

Front 249

Environmental Control of Internal parasites (4)

Back 249

-stocking densities (high =bad)
- Pasture management
-Transport stress leads to egg output
-Selective breeding/genetic manipulation

Front 250

Protozoa

Back 250

-unicellular organisms

Front 251

4 Main groups of Protozoa

Back 251

1. Rhizopods
2. Ciliates
3. Flagellates
4. Sporozoan Protozoa

Front 252

Parasitic Rhizopods:
-where do they feed
-Life cycle
-Location within host
-Reproduction

Back 252

-"amoeba like"
-move via pseudopodia
-Extracellular
-feed via phagocytosis
-Cycle between Trophozoite and cyst forms
-Predominantly asexually
-Direct Life cycles

Front 253

Parasitic Ciliates
-How do they move
-Where do they feed
-Location within host
-Reproduction
-Life cycle

Back 253

-Move using cilia
-Extracellular
-Feed on particulate matter using cytosome
-Cycle between trophozoite and cyst form
-Asexual via binary fission and sexual via conjugation
-Direct Life cycles

Front 254

Parasitic Flagellates
-how do they move
-how do they feed
- Reproduction
-Life cycle

Back 254

-Move using flagellae
-Feed by uptake of soluble nutrients thru cell membrane or flagellar pocket
-Cycle between trophozoite and cyst forms (some exist solely as trophozoites)
-Asexual reproduction
-Most are extracellular with a few intracellular species (living in Macrophages)
-Extracellular species have direct life cycles
-Intracellular species transmitted being vector borne

Front 255

Sporozoan Protozoa
-where are they located
-Reproduction
-Life cycles

Back 255

-Intracellular
-Distinct phases of asexual and sexual repro
-Gives rise to many morphologically distinct forms
-Asexual repro - schizogony
-Sexual repro -fusion of dissimilar gametes --> gives rise to environmentally resistant oocysts
-Either Direct or Indirect Life cycles

Front 256

Coccidia

Back 256

Sporozoan Protozoa subgroup
-Intracellular gut phase with both sexual and asexual repro --> oocyst
-Direct or Indirect Life Cycles

Front 257

Coccidia with direct life cycles:

Back 257

infect gut cells of single host

Front 258

Coccidia with Indirect Life cycles:

Back 258

-Cycle between two host types
-Often based on prey - predator relationships
-Sexual or asexual repro takes place in def host (carnivore)
-Gives rise to oocysts
-In the I. Host only asexual repro takes place
-Gives rise to tissue cysts which lie dormant within soft tissue (muscle) until eaten by def host

Front 259

Haemosporozoan Protozoa

Back 259

-Intracellular bld protozoa infecting either erythrocytes or lymphocytes
-Transmitted by arthropods (ticks or insects)

Front 260

What is an oocyst?

Back 260

-spore phase of certain protists, such as Cryptosporidium and Toxoplasma.
- can survive for lengthy periods outside a host and is very resistant.

Front 261

What is a cyst?

Back 261

-a closed sac having a distinct membrane and develosion on the nearby tissue.

Front 262

What is schizogony?

Back 262

Reproduction by multiple asexual fission
-multiple nuclear divisions inside an infected cell
-cell division which each part turns into an indiv parasite
-merozites emerge - break out of infected cell to go attack other cells

Front 263

What Internal Parsites live in:
1. Brain
2. Lungs
3. Blood

Back 263

1. Toxo, Tapeworm Larvae
2. Lungworm, Tapeworm Larvae
3. Babesia

Front 264

What internal parasite lives in:
1. Muscle
2. Small Intestine
3. Large Intestine

Back 264

1. Toxo, Protozoan cysts, Tapeworm larvae,
2. Nematodes, Adult Tapeworms
3. Nematodes, coccidia

Front 265

What internal parasites live in:
1. Abomasum
2. Liver
3. Foetus

Back 265

1. Nematodes
2. Liver Flukes (trematodes)
3. Toxoplasma

Front 266

Why are Protozoa with Direct Life Cycles Important?

Back 266

1. Infections often lead to death of host
2. Infections lead to decreased productivity and welfare
3. Controlling them costs money and can lead to consumer resistance
4. Some are zoonotic

Front 267

Where do protozoa with direct life cycles complete their life cycle?

Back 267

complete life cycle in a single host

Front 268

What is their feeding and reproduction schedule?

Back 268

-they usually alternate between feeding (trophozoite) and repro stages (cysts and oocysts - environmentally resistant).

Front 269

What is a trophozoite?

Back 269

the activated, feeding stage in the life cycle of protozoan parasites

Front 270

What body systems are protozoa with direct life cycles associated with? (majority)

Back 270

Body systems that have access to outside such as the gut and the repro tract

Front 271

Where are protozoa with direct life cycles found within host?

Back 271

Extracellular in lumen of hollow organs usually motile with cilia or flagella (gut, vagina, uterus)
-CAN be located inside host cells but the extracellular stages are used for infection

Front 272

Describe Extracellular Monoxenous Protozoa

Back 272

-large, motile protozoa
-DLC -direct life cycle !!
-cyucle btween parasitic trophozoite and non parasitic forms (cysts)
-Infect digestive or repro tract

Front 273

Entamaoeba
-What is it?
-Host affected?
-cycle summary

Back 273

-Extracellular gut protozoa (DLC)
-Rhizopod parasite
-Dogs
-Trophozoite forms in gut, cysts pass out in feces to infect other dogs

Front 274

Balantidium
-What is it?
-Host affected?
-cycle summary

Back 274

-Extracellular gut protozoa (DLC)
-Ciliate protozoa
-Pigs but also humans
-Trophozoite forms in gut and cysts pass out in feces.
!! ONly causes dz if present in very large numbers

Front 275

Giardia
-What is it?
-Host affected?
-cycle summary

Back 275

-Extracellular Gut protozoa (DLC)
-Flagellate protozoa
-Young dogs and cats
-Trophozoite forms in gut and cysts pass out in feces
!!Easily dispersed by water "beaver fever"

Front 276

Trichomonas
-What is it?
-Host affected?
-cycle summary

Back 276

-Extracellular Gut protozoa (DLC)
-Flagellate
-Birds (esp game birds and pigeons)
-Two forms: esophageal or intestinal
-No cyst forms
-Contamination due to water supplies normally

Front 277

Histomonas
-What is it?
-Host affected?
-cycle summary

Back 277

-Extracellular gut protozoa (DLC)
-Flagellate
-Turkeys and game birds
-"blackhead"
-Flagellate form found in gut, amoeboid form in liver, no cyst form
-Transmitted via the eggs of the common Nematode: Heterakis Gallinarium
-Causes ulceration and necrosis of cecal mucosa and liver

Front 278

Trichomonas foetus
-What is it?
-Host affected?
-Where in host affected?
-control

Back 278

-Extracellular protozoa that affects Repro system
-Flagellate
-Lives in vagina and prepuce, can migrate to uterus and cause abortion
-Cattle
-Control via restricted breeding/AI

Front 279

Trypanosoma equiperdum
-What is it?
-Host affected?
-Result of infection?
-Control

Back 279

-Extracellular protozoa affecting Repro system (DLC)
-Flagellate
-related to pathogen: Vector borne Trypanosomes
-Causes VTD dourine in horses and donkey
-Results in infertility
-ONLY UK protozoan parasite with statutory testing regime
-control via control breeding

Front 280

What are the most important Intracellular Monoxenous protozoa (gut dwelling)?

Back 280

Coccidia

Front 281

Name some features of coccidia:

Back 281

-Very sm! intracellular!
-Principally found in Digestive tract
-Pass thru sporozoites, merozoites, gametes, and oocyts

Front 282

How do coccidia get into host?

Back 282

-Infective form (oocysts) picked up from environment
-Enter host cell by invagination of host cell membrane so that parasite is separated from the host cell cytoplasm by a parasitophorous vacuole

Front 283

Describe the reproduction stages of coccidia:

Back 283

-Distinct, sequential phases of asexual followed by sexual reproduction -- this results in oocyst formation
-Multiply using mutiple nuclear division to increase their numbers very rapidly at several stages in the life cycle (shizogony)

Front 284

What is a sporozoite?

Back 284

-cells that infect new hosts
-sporozoites eventually burst, releasing merozoites into the bloodstream.

Front 285

What is merozoite?

Back 285

-->a daughter cell of a protozoan parasite.
-Merozoites are the result of asexual reproduction (schizogony, merogony).
- In coccidiosis, merozoites form the first phase of the internal life cycle of coccidian.

Front 286

Life cycle of Coccidia

Back 286

-Direct life cycle
1. Oocyst shed in feces
2. Unsporulated oocyst = non infectious
3. Over several days and requiring oxygen = Sporulation takes place
4. Result is sporulated oocyst that is infectious
5. oocyst is swallowed and enters gut
6. Excystation - oocyst releases sporocysts
7. Sporocysts release sporozoites
8. Sporozoites invade gut cells
9. Trophozoite
10. Schizont
11. Merozoites are released from Schizont
12. Male and Female Gametes now rise from Merozoite
13. Create Developing oocyst that will be shed in feces

Front 287

Eimeria sp.
-What is it?
-host infected?
-Host specific?

Back 287

-Principal cause of Coccidiosis
- Poultry and Farmed rabbits, but seasonally affects lamb and cattle
-Highly host/site specific
-Sporulated oocyst contains four sporocysts each containing 2 sporozoites: 8 sporozoites/sporulated oocyst

Front 288

Eimeria sp. and Poultry
-# of species
-control

Back 288

-17 species can infect poultry
-control via good hygiene to prevent build up of infective oocysts (medicated feeds, vaccines, etc)

Front 289

Caecal Coccidiosis in poultry is caused by:

Back 289

Eimeria tenella

Front 290

Intestinal coccidiosis in poultry is caused by:

Back 290

E. necatrix
E. brunetti
E. mitis
E. maxima
E. acervulina

Front 291

These 3 species cause what dz?
-E. ovoinoidales
-E. bakuensis
-E.Crandallis

Back 291

-Ovine coccidiosis
-unweaned lambs 4-8wks old
-Affect small intestine
-Lambs become infected by oocysts passed by chronically infected adults and go on to shed more oocysts rapidly

Front 292

These 2 species cause what dz?
-E. zuernii
-E. bovis

Back 292

-Bovine coccidiosis
-cattle less than one year old
-infect the cecum and colon

Front 293

These 3 species cause what dz?
-E. stiedae (bile duct)
-E. flavescence (intestine)
-E. intestinalis (intestine)

Back 293

-Rabbit coccidiosis
-wild rabbits can act as a reservoir for farmed rabbits

Front 294

What is Isospora sp?

Back 294

-Form of coccida with direct life cycle
-usually non pathogenic but high levels may give rise to diarrhea
-OOCYSTS might be confused with other protozoa such as TOXOPLASMA

Front 295

What is the main difference between Eimeria and Isospora?

Back 295

-Isospora
Oocyst - 2 Sporocyst - 4 sporozoites

-Eimeria
Oocyst - 4 sporocysts - 2 sporozoites

(opposite)

Front 296

What are the hosts infected with Isospora?

Back 296

Mainly dogs, cats and pigs:
Dogs
I. canis and I. ohioensis
Cats
I. felis and I. rivolta
Pigs
I.suis

Front 297

What is cryptosporidium?

Back 297

-Coccidia with direct life cycle
-Pathogen of young animals (calves) also zoonotic
- Fecal contamination of meat
-Dangerous for immunosuppressed patients

Front 298

Infection route of cryptosporidium?

Back 298

-Parasite develops at jxn between BB and cytoplasm gut epithelium cells
-Produces small sporulated oocysts (immediately infective) which then...
a). initiate another cycle of asexual reproduction in the same host or
b). are shed from the body via feces.

Front 299

Why are protozoa with Heteroxenous Life Cycles important?

Back 299

-cause abortion in sheep,cattle and humans
-cause fetal abn in humans
-cause neuro dz in dogs and horses
-cause of meat condemnation in abbatoirs

Front 300

General features of protozoa with indirect life cycles:

Back 300

-all belong to group of coccidia
-intracellular w/in parasitophorous vacuole
-Alternate cycles of sexual and asexual repro with oocyst formation
-Final and I. host
-Life cycle based on predator (final host): prey (I. host)

Front 301

What development takes place in the Final host involving protozoa with indirect life cycles (coccidia):

Back 301

-Limited to gut producing oocysts that infect the intermediate host

Front 302

What development takes place in the intermediate host involveing protozoa with indirect life cycles (coccidia):

Back 302

-Initially in gut followed by extensive tissue migration of tachyzoites
-Finally resulting in tissue cysts containing bradyzoites which are the infective form for final host.

Front 303

What is tachyzoite?

Back 303

an asexual stage of rapid growth

Front 304

Sarcocystis
-What is it?
-Hosts?

Back 304

-Protozoa with Indirect LC
-Highly host specific host pairings
-dog: sheep-->S.bovicanis and
S.cruzi

-cat:sheep--> S.ovifelis and S.tenella

-Cattle:human-->S.bovihominis

Front 305

Life Cycle of Sarcocystis?

Back 305

-Final host: passes oocysts in feces
-I.Host: ingests oocysts
-Sporozoites hatch out
-Invade endothelial cells of capillaries of gut
-Asexual repro in gut endothelium
-Parasite then enters lymphocytes in bldstream
-carried to soft muscle sites and penetrate muscle
-Tachyzoites take place
-Sarcocysts form and fill with many slow growing bradyzoites
-Final Host ingests I.Host
-Bradyzoites are then released into gut of final host
-invade sub-epithelial cells
-differentiate into gametes
-sexual repro and fertilization
-give rise to thin walled oocysts
-Passed out in feces
-Oocysts are passed sporulated therefore are immediately infective
-contain 2 sporocysts each with 4 sporozoites

Front 306

What clinical signs are seen in Final host with Sarcosystis?

Back 306

-Signs rarely seen
-Occasional mild diarhea

Front 307

What clinical signs are seen in I. Host with Sarcosystis?

Back 307

sheep and cattle:
-condemnation of meat
-Anorexia
-Fever
-Anemia
-Wt loss, hair loss, BCS loss

Horse:
-Equine protozoal myeloencephalitis (neuro prob)
-caused by S. neruona
-horses ingest oocysts but are dead end hosts

Front 308

What is the major species of Toxoplasma of vet imp?

Back 308

T. gondii

Front 309

What is dangerous about T. gondii?

Back 309

-Intracellular but has the ability to develop in most cell types

Front 310

Who is the host for T. gondii?

Back 310

Final host: Cat
I. Host: mouse

**However can infect wide range of dead end hosts (including humans)

Front 311

What is different about the life cycle of T. gondii?

Back 311

Can be completed in the final host with absence of I. host
-Bradyzoites can develop in either final or i.host
-Both final and I. host can become infected by ingestion of tissue cysts and oocysts.

Front 312

Describe the "natural" cat and mouse cycle of T. gondii?

Back 312

-Infected cat pass oocysts in feces
-mice ingest oocysts
-sporozoites invade gut macrophage cells
-multiply and give rise to tachyzoites
-they invade other macrophages or are carried to other sites via blood and lymph
-eventually form bradyzoite cysts which remain in tissues until ingested by cat
-once mouse ingested, multiplies in gut wall
-gives rise to oocysts in 3-10 days
-oocysts passed unsporulated
-in 24 hrs: 2 sporocysts contain 4 sporozoites

**cats can also become infected by eating other cats or ingesting oocysts**

Front 313

What is the strange behavior associated with T.gondii?

Back 313

Bradyzoite cysts remain in mouse until ingested, may move to brain where they affect natural "cat avoidance" behavior
--> this increases a parasites chance of transmission

Front 314

How do un-natural hosts become infected with T.gondii?

Back 314

-ingest oocysts or bradyzoite cysts accidentally

Front 315

What are risks if food animals ingest oocysts of T. gondii?

Back 315

-bradyzoite cyst formation in muscles - danger if uncooked and eaten (humans)

-ingestion of oocysts and bradyzoite cysts by non feline carnivores (humans, dogs) can also lead to tissue migration and cause:

-abortion, fetal damage, visual disturbances, neurological symptoms

Front 316

What is seen when T.gondii is found in the definitive host? (cats)

Back 316

-most infections pass unnoticed
-fatalaties rare, usually involves infection of CNS, liver, lungs etc
-wt loss, fever, uveitis, anorexia, seizures, ataxia
-Transplacentally infected kittens usually die

Front 317

How can sheep become infected with T.gondii?

Back 317

-ingesting oocysts from pasture or feed contaminated with cat feces

Front 318

What clinical signs are seen in sheep infected with T.gondii?

Back 318

-If infected during early stages of pregnancy - abort
-Outcome depends on stage of pregnancy when infection aquired
-Abortion only associated with tachyzoite stage
-VAccine avail but is live so poses risk to vaccinator

Front 319

How do humans become infected with T.gondii?

Back 319

-ingesting oocysts from cat feces (cleaning, gardening, litter pan etc)

Front 320

WHo is at the highest risk for T.gondii (humans?)

Back 320

-early stage pregnancy
-immuno suppressed individuals (aids, transplant)

Front 321

Neospora Caninum
-Hosts?
-Morphologically similiar to...

Back 321

-Definitive host: dog
-Intermediate host: herbivores
-Morphologically similar to T.gondii
-Causes abortion and neonatal death in cattle, sheep, goats, and horses
-paralysis in puppies

Front 322

What are Vector borne protozoa?

Back 322

transmitted by one vertebrate host to another by an ARTHROPOD (vector)

Front 323

Vectors are....

Back 323

Blood sucking arthropods : TICKS AND FLIES

Front 324

What are Haemoprotozoa?

Back 324

-vector borne protozoa that have forms that develop in the blood of the vertebrate host at some point

Front 325

What Reproduction cycle takes place where in vector borne protozoa?

Back 325

-Asexual repro in both vert host and vector
-Sexual repro only takes place in vector

Front 326

What is Cyclical or Biological Transmission?

Back 326

-parasite must undergo a period of developement within the vector before it can be passed on to another host

--> this means that most vector: parasite relationships are highly specific
-Allows a good control point!

Front 327

What is NON cyclical or Mechanical Transmission?

Back 327

-some vbp can also be transmitted directly between hosts without any development in vector

Front 328

What does it mean by Iatrogenically transmitted?

Back 328

-transmission through use of contaminated needles
(mass vaccination or blood transfusion)

Front 329

Babesia sp
-what are they?
-transmission by?
-main hosts?

Back 329

-vbp - Intra-erythrocytic
-transmitted by Ixodidae
-highly host specific
-Mainly cattle in UK, but also sheep, goats, deer and dogs
(cattle forms can infect immunosuppressed humans)

Front 330

Trypanosomes sp
-what are they?
-transmission by?
-main hosts?

Back 330

-vbp - extracellular haemoflagellates
-Transmitted by: Tabanids and Sheep keds (biting flies)
-cattle and sheep (maj dz prob in tropics)
-in UK trympanosomes = nonpathogenic

Front 331

Malaria sp
-What are they?
-transmission by?
-Main hosts?

Back 331

-vbp - intra-erythrocytic
- transmitted by biting flies
-Affect wild and captive birds

Front 332

Leishmania sp
-What are they?
-Transmitted by?
-Main hosts?

Back 332

-vbp intracellular
-transmitted by sandflies
-dogs (not endemic in UK)

Front 333

Name two species of Babesia that affect cattle in UK:
-transmitted by?

Back 333

1. B.divergens
- "small" species
-mainly found on edge of rbc
-most pathogenic in UK
-Transmitted by Ixodes ricinus

2. B. major
-"large" species
-seen inside rbc "paired"
-transmitted by: Haemaphysalis punctata (tick)

Front 334

Transmission of B.divergens is mainly dependant upon...

Back 334

Where the vector Ixodes ricinus is located

Front 335

Principal problems facing B. divergens in the UK (3):

Back 335

1. tick can take up to 3 years to complete life cycle
2. each stage in life cycle feeds only once
3. ticks often inactive for long periods (winter)

Front 336

What strategies have B. divergens evolved to in order to maximize its potentinal for transmission? (3)

Back 336

1. Parasite repro synchronized to feeding behavior of tick

2. ability to be transmitted to a vertebrate host by each stage in the tick life cycle

3. ability to be passed between sequential stages in the tick life cycle without encountering another infected host.

Front 337

Principal features of Helminths?

Back 337

-multicellular
-multi organ
-endoparasites
-all reproduce sexually via eggs
-have a range of morphologically distinct larval stages

Front 338

Name the three main groups of Helminths:

Back 338

1.Platyhelminths (flatworms)
2.Nemathelminths (roundworms)
3.Acanthocephala (thorny or spiny headed worms)

Front 339

Name two classes of Platyhelminths:

Back 339

1. Trematodes
2. Cestodes

Front 340

Trematodes
-body shape?
-life cycle/hosts?

Back 340

-unsegmented, leaf like
-one or two suckers for attachment to host
-simple blind gut with single opening

-Direct OR indirect life cycles
-I. Host = invertebrates (mollusc)

Front 341

Cestodes
-body shape?
-life cycle/hosts?

Back 341

-segmented
-tape like
-can be up to several meters long
-distinct head (scolex) with hooks and suckers for attachment to host
-Gut is absent
-Nutrients via diffusion

-Indirect life cycles
-Vert or Invert can be I.host

Front 342

Name the class of interest in the Nemathelminthes?

Back 342

Nematodes

Front 343

Nematodes
-body shape?
-life cycle/ hosts?

Back 343

-cylindrical, tapering from either end
-shape maintained by fluid filled cavity
-true gut with mouth and anus
-Individuals are either MALE OR FEMALE

DIRECT OR INDIRECT LIFE CYCLES
-Invert hosts = I. host

**paratenic hosts and transport hosts imp!!

Front 344

What is the prominent feature of Acanthocephala?

Back 344

-spiny proboscis aka thorny or spiny head worms
-very few of vet importance!

Front 345

Where do helminths live?

Back 345

-can be found in most body systems of vertebrates either as adults or larvae
-some move around the body (migration)
before they find the final position and start reproduction (predilection site)

Front 346

Why are helminths important?

Back 346

1. production losses due to
-competition for nutrients
-damage to body systems
-death

2. Animal welfare
-companion animals
-food animals

3. Public health (zoonosis)

Front 347

Helminth rate of reproduction?

Back 347

large amounts of eggs (several million per day)
-all sexual reproduction but some can also carry out asexual repro and at cost to host!

Front 348

Forms of Helminths: (sexual maturity)
1. larvae
2. Adult

Back 348

1. sexually immature
2. sexually mature

Front 349

Monoecious

Back 349

male and female sex organs develop in SAME individual
-usually at different times and not self fertilizing

Front 350

Dioecious

Back 350

-male and female sex organs are found in seperate individuals

Front 351

Definitive Host

Back 351

host where adult sexually active forms are found
-found in direct or indirect life cycles

Front 352

Intermediate Host

Back 352

host where only immature (larval) forms are found
-essential part of indirect life cycle

Front 353

Transport host

Back 353

- host takes up an immature form but does not retain it
- no parasite development takes place in host
-NOT essential part of parasites life cycle

Front 354

Paratenic host

Back 354

-host takes up an immature form and retains it in its tissue
-no parasite development other than larval emergence from an egg
-NOT an essential part of parasite life cycle

Front 355

Another name for a trematode?

Back 355

fluke

Front 356

What are monogean trematodes?

Back 356

-Direct life cycles
-Ectoparasites of fish

Front 357

What are digenean trematodes?

Back 357

-Indirect life cycles
-Endoparasites of vet importance

Front 358

Where are adult flukes found?

Back 358

-Final (vert)host

Front 359

Where are larval stages of flukes found?

Back 359

-can be free living or parasitic within an I. Host

Front 360

How many intermediate hosts can flukes have and what are the requirements?

Back 360

-can have more than one intermediate host in life cycle
-BUT one MUST BE A MOLLUSC

Front 361

What is a miracidium?

Back 361

-Produced by adult flukes
-Infectious form to intermediate (first) host
-Develops from egg

Front 362

What is the simplified life cycle of flukes?

Back 362

-Adult produces egg
-Egg develops into miracidium
-Miracidium infects first I.host
-Inside the snail, the miracidium develops into a sporocyst
-Sporocyst gives rise to a number of redia
-Redia give rise to a number of cercaria
-Cercaria eventually develop into metacercaria forms which are infective for final host

Front 363

Define the following terms:
1. redia
2. cercaria
3. metacercaria

Back 363

All developmental stages in Trematodes
1. produces either more rediae, or cercariae
2. This is somewhat like a small adult, but has a large swimming tail somewhat like a tadpole's (but without a notochord or backbone, as it is not a chordate). It finds and settles in a host, and becomes an adult, or a mesocercaria, or a metacercaria, according to species.
3. A cercaria encysted and resting.

Front 364

What stages of Trematode development are found in all species?

Back 364

Miracidium and Cercarial Stages

Front 365

Fasicola Hepatica
-What is it?
-Host?
-Life cycle?

Back 365

-liver fluke
-ruminants (sheep and goats but also cattle, horses and humans)
-Digenean: with miracidium, sporocyst, redia, cercaria and metacercaria
-Single I. Host : Water snail (Lymnaea truncatula)

Front 366

Effect of F. Hapatica on definitive host:
a) Acute Fasciolosis

Back 366

1. Acute Fasciolosis
-assoc with migration of lg #'s of immature flukes thru liver as a result of ingesting lg #'s of metacercaria.
-Mass migration causes severe damage to the liver paranchyma and can result in death within 1-2 weeks of infection

Front 367

Effect of F. Hapatica on definitive host:
b) Sub Acute Fasciolosis

Back 367

2. Sub Acute Fasciolosis
-assoc w/the ingestions of smaller #'s of metacercaria over a longer period
-appears about 6-10 weeks after ingestion
-Dz damages liver and bile duct

Front 368

Effect of F. Hapatica on definitive host:
c) Chronic Fasciolosis

Back 368

3. Chronic Fasciolosis
-most common
-assoc w/ accum of lg #'s of adult liver flukes in bile duct resulting from ingestion of moderate amounts of metacercaria over a period of time.
- Appears several months after initial exposure and leads to general loss of condition, anemia, submandibular oedema (bottle jaw)

Front 369

What Factors determine epidemiology of F. hepatica?

Back 369

Mainly based on availability of viable metacercaria on the pasture.

Influenced by:
-Presence of suitable snail habitats - wet mud, temperate, poorly drained pastures, ditches
-Temperature - excess of 10 degrees for snail manipulation and parasite development (if below 5 then snail activity ceases and fluke eggs fail to hatch)
-Moisture - high levels required

Front 370

When are favourable conditions for F. hepatica found in UK?

Back 370

May to October

Front 371

When are large amounts of metacercaria likely to be present on pasture in the UK?

Back 371

1. Metacercaria from snails infected in Summer will appear on pasture from Aug to Oct
-->these will come from snails which became infected w/miracidia from eggs passed onto pasture during spring/summer or overwintered eggs

2. Metacercaria from snails infected during the winter - appear on pasture between may and June
-->come from snails infected with miracidia from eggs passed previous autumn and have been overwintered by snail.

Front 372

What is a major factor when predicting F. hepatica outbreaks?

Back 372

Climate control/Rainfall seasons

Front 373

How can we control F. Hepatica infection?

Back 373

1. drug tx - use to reduce pasture contamination by fluke eggs or reduce effect of fluke population on host
**Check effectiveness of anthelmintic against immature vs adult stages**

2. Reduce snail populations - drain wet pasture and/or apply molluscicides

Front 374

Dicrocoelium dendriticum
-What is it?

Back 374

-small lancet liver fluke
-internal organs can be seen thru semi-transparent body
-Indirect life cycle with ant and mollusc as I. host and Def host is ruminant

Front 375

How does Dicrocoelium differ from F. hepatica?

Back 375

MIGRATION:
1a. Dicro doesn't migrate thru the liver paranchyma - Both adults and immature forms found in bild ducts.
vs.
1b. F.hepatica immature flukes migrate thru liver, Adults get in bile duct

CLINICAL SIGNS
2a. Dicro - rarely any clinical signs seen due to lack of cuticular spines
vs.
2b. Fasciolosis (sub, acute, chronic)

INTERMEDIATE HOST
3a. Dicro has 2 - Ant and mollosc = thus limiting parasites distribution to where both can be found
vs.
3b. JUST MOLLUSC for hepatica

EGGS and ENVIRONMENT
4a. Dicro adapted for transmission in dry areas:
Miracidium stage stays in egg, and Cercaria is protected in slime ball
vs.
4b. Hepatica: miracidium ciliated and swims to snail foot ... needs moisture

STAGES
5a. Dicro has no redia stage. It has two sporocyst generations instead in the snail
vs.
5b. one sporocyst and one redia stage in hepatic

HOST BEHAVIOR
6a. Dicro metacercaria develop in brain of ant and affect behavior enhancing transmission to final host
vs.
6b. Hepatic - no alternated behavior of host

Front 376

Schistosomes
-What is it?
-Where in host is affected?
-Main host
-I. Host?
-Where are they found (location)?
-How do cercaria enter final host?

Back 376

-Liver fluke
-Found in bld vessels of gut or bladder
-Ruminants
-Separte males and females
-I.Host = water snails
-Cercaria enter final host via the skin
-Imp in tropics and subtropics

Front 377

Paramphistomes
-What is it?
-Where found in host?
-Main host?
-I.host?
-Body shape?
-Life cycle?

Back 377

-liver flukes
-forestomachs
-ruminants (some pigs and horses)
-Conical shape rather than flattened
-I.Host = water snail
-Life cycle similar to F. hepatica

Front 378

What is another name for Cestodes?

Back 378

Tapeworms

Front 379

Where is the adult cestode found?

Back 379

-entire life within gut of host (final host)
-Devoted purely to egg making
-Eggs are voided with feces to environment (thick protective wall)

Front 380

What is the life cycle of Cestodes?

Back 380

INDIRECT CYCLE
-eggs in feces in environment
-ingested by I.host (herbivores/invertebrates)
-Herbivores are eaten by carnivore final host or Inverts are eaten accidentally by final host
-larva develops in I.Host into stage developed for waiting = cyst
-Larva fully develops within final host gut
-eggs then voided in feces

Front 381

What stage of Cestodes does the:
Final host have?
I.Host have?

Back 381

Final: Adult cestode (tapeworm form)

I.Host: Larval cystode : called Hexacanth larvae or onchosphere larvae

Front 382

Disease seen with Adult cestodes in final host:

Back 382

-little dz unless shortage of food (competes with host for nutrients)
-ulcers at pt of attachment

Front 383

Disease seen with Larval Cestodes in I.host:

Back 383

Acute dz: invation of CNS, cyst in liver

Front 384

Describe the Adult Structure of Cestodes:

Back 384

-adapted to live in sm intestine
-scolex has ring of hooks or suckers to stay attached
-Moving down from neck of scolex - proglottids form (flat, white, rectangular)
-Tape all the proglottids form is called strobila
-Proglottids are self containing egg units
-Each proglottid is a hermaphrodite
-hundreds of segments
-ones at posterior are voided full of eggs (gravid) or independantly crawl from anus

Front 385

How do adult cestodes obtain nutrients?

Back 385

-no gut
-nutrient derived from digestion process of the host absorbed directly thru proglottid
-flat shape of worm aids in absorption

Front 386

How do larvae absorb nutrients?

Back 386

-no gut
-absorb nutrients from surrounding lymph and tissue fluid

Front 387

What is an oncoshpere?

Back 387

-larva with six hooks found inside an environmentally resistant egg

Front 388

How does the oncosphere get out of the egg?

Back 388

-when ingested by I.host digestive secretions break down wall and larva is released
**At this point it is the hexacanth larva
-It burrows into the gut mucosa and enters the blood or lymph of vertebrate hosts (or body cavity of inverts)

Front 389

Once a cestode is in the hexacanth larval stage where does it go/become?

Back 389

-migrates to favored spot such as muscle and develops into a metacestode.

Front 390

What is the reproduction plan for proglottids?

Back 390

-hermaphrodite with one sex active at a time
-can be cross fertilization btwn worms clost together in the host's gut

Front 391

What is the reproduction stradegy for cestodes?

Back 391

-Massive egg production with low survival rate of eggs

Front 392

While waiting for ingestion of I.host into final host can larvae multiply?

Back 392

-Can multiply to increase chances of infection of final host
-HYDATID cyst is an example of this multiplication

Front 393

Egg containg a larvae is called....

Back 393

onchosphere

Front 394

First larval stage of cestodes is the .....
(it has 6 hooks)

Back 394

hexacanth larva

Front 395

Second and Final larval stage of cestodes is called....

Back 395

metacestode

Front 396

Name 5 types of metacestodes and give examples of each:

Back 396

1. Cystericerus = T.saginata
2.Coenurus = T.multiceps
3. Hydatid = Echinococcus
4.Cysticercoid =D. caninum
5. Stroboliocerus = T. taeniaformis

Front 397

Describe a cysticercus and give an example:

Back 397

-Fluid filled sac with one invaginated protoscolex
-Taenia saginata

Front 398

Describe a coenurus and give an example:

Back 398

-Fluid filled sac (like the cysticercus) with many protoscoleces
-Taenia multiceps

Front 399

Describe a Hydatid and give an example:

Back 399

-Large fluid filled sac containing protoscoleces detached from the cyst wall or forming further small cysts within the main one.
-Echinococcus

Front 400

Describe a Cysticercoid and give an example:

Back 400

-The protoscolex is contained within a solid cyst, these typically form in tape worms with invertebrate hosts
-Dipylidium caninum

Front 401

Describe a Strobilocercus and give an example:

Back 401

-Like a miniture strobila
-Taenia Taeniaformis

Front 402

Taenia
-Final Host
-Intermediate Host

Back 402

Final: Human, Dog, Cat

I. Host: Catte, pig, sheep, rodents

Front 403

Echinococcus
-Final host
-I. host

Back 403

Final: Dogs, Wild canids

I.Host: Ruminants, horses, rodents

Front 404

Monieza
-Final host
-I.host

Back 404

Final: Ruminants

I.host: Mites

Front 405

Dipylidium
-Final Host
-I. Host

Back 405

Final: Dog, Cat

I.Host: Fleas, Lice

Front 406

Anoplocephala
-Final host
-I.host

Back 406

Final: horses

I.Host: Mites

Front 407

What are the two species of Taenia that affect Humans and Cattle/pigs?

Back 407

T. saginata
T. solium

Front 408

What species of Taenia affect Dog and sheep?

Back 408

T. ovis
T. multiceps

Front 409

What is the final host of both T. saginata and T. solium? and what are the intermediate hosts?

Back 409

Final of T. saginata and T. solium = Humans

Intermediate of T. saginata = cattle

Intermediate of T. solium = Pigs

Front 410

Disease associated with both final and i. host for Taenia saginata or solium?

Back 410

Humans (final) = diarrhea and aesthetic problems

Cattle and Pigs (intermediate - with larval) = no known clinical dz

Front 411

How can Larval stages of T. solium affect humans?

Back 411

Poor hygiene leads to humans consuming larval stages
-Cysticercus cysts develop in CNS and eyes
-ZOONOTIC - common prob in tropics

Front 412

What is the general name for the disease caused by infection of humans with cysts of Taenia?

Back 412

cysticercosis

Front 413

What is the best way to control cysticercosis?

Back 413

1. Meat inspection for cysts (cysticercus type) in muscle

2. Human hygiene

3. Prevention of human sewage on fields of vegetables or for cattle pasture

4. Thorough cooking of meat

Front 414

If humans are natural final host where in lies the problem with T. solium?

Back 414

Infection of gut of humans w/ adult tapes of T. solium is part of a natural dz cycle BUT when a human becomes infected with the larval stages (CAUSING CYSTICERCOSIS) = unnatural relationship = zoonotic

Front 415

What is the final host for T. ovis and how are they infected?

Back 415

Dogs harbor T. ovis adults in gut
-get it from eating infected raw sheep meat with larval stages

Front 416

Is there dz seen dogs from T. ovis?

Back 416

-not considered a problem

Front 417

What is ovine cysticercosis and what are its complications?

Back 417

-Infection of sheep meat with cysticercus cyst type of larvae
-Economic loss of sheep meat

Front 418

Best way to control T. ovis?

Back 418

-Tx in dogs in combonation of control of Echinococcus granulosus
-Prevention of access to sheep carcasses

Front 419

How do the final hosts become infected with T. multiceps?

Back 419

-Dogs final host: harbor T. multicep adults
-Get from ingesting infected sheep meat

Front 420

What is the path if T. multiceps is ingested:
-What stage is it ingested at by sheep?
-Where is the predilection site in sheep?
-What develops next?

Back 420

-Onchosphere is larval stage of T. multicep that is ingested
-Penetrates bld stream
-Predilection site = brain
-Coenurus form of cyst 5-10cm develops and effects vision, gait and coordination

Front 421

What is gid?

Back 421

T. multiceps, affects sheep, clinical name for when coenurus cyst develops in brain and effects vision, gait and coordination

Front 422

Echinococcus multilocularis
-What is it?
-Size
-Where is it found? Final host?
-I. Host?

Back 422

-Dog tapeworm and Hydatid dz
-small tapeworm 3-5 proglottids
-Found in gut of dogs and wild canids
-Rodents

Front 423

How do the I. host of E. multilocularis become infected?

Back 423

-infected by eating vegetation contaminated with feces

Front 424

Once I. host is infected with E. multilocularis what is the life cycle?

Back 424

-infection from feces
-larvae develop into HYDATID cysts in rodents
- no harm in either hosts even with extreme #'s

Front 425

How can humans become infected with E. multilocularis?

Back 425

-Hydatid cysts occur in humans from contamination of vegetables from dog or fox feces
or
-direct contamination with dog adult tapes

Front 426

What is the predilection site in humans for E. multilocularis?

Back 426

liver

Front 427

What is the other name for hydatid disease from E. multilocularis?

Back 427

Alveolar Echinococcosis
-cyst grow abn large in humans
-cysts develop alveolar froms and may extend by metastatic budding from original cyst.

Can be life threatening and severe cases only treatable by liver resection or transplant!!

Front 428

Does E. multilocularis occur in the UK?

Back 428

NO - patchy distribution (usa, Central europe, eastwards to japan)

-IMPORTANT PET PASSPORTS FOR DOGS BEING BROUGHT IN TO UK (TAPEWORM CONTROL)

Front 429

Echinococcus granulosus:
-What is it?
-Final host?
-I. host?
-Where is it found?

Back 429

-Cestode - tapeworm
-Final host: dogs
-I. host - ruminants and horses (suffer little clinical dz from cysts)
-found in isolated areas of UK

Front 430

Can E. granulosus infect humans? zoonotic?

Back 430

YES same method as E. multilocularis. EXCEPT
-predilection site is: lung and liver

-Prevention same as with other one

Front 431

What are Anoplocephalan Tapeworms?

Back 431

-Do not have predator/prey life cycles
-Final host: herbivore or carnivore
-I. host: arthropod accidentally ingested

Front 432

Dipylidium Caninum
-What is it?
-Size?
-Clinical Effect?
-Control?
-Final and Intermediate Host?

Back 432

Dipylidium Caninum
-Anoplocephalan tapeworms
-20-50cm long
-no clinical affect
-Control: aesthetic reasons, slight risk of human infection, deworming, good hygiene (litter)
-Final: dog or cat
-I. host: Ctenocephalides (flea) and Trichodectes (lice)

Front 433

Life cycle for Dipylidium Caninum?

Back 433

1. larva develop into cysticercoid type of metacestode
2. Insects become infectd by eating the eggs
3. Larva in fleas remain during metamorphosis to infect the adult flea
4. Final host grooms the flea out of coat and ingests the infected flea or louse.

Front 434

Moniezia expansa and M. benedeni
-What is it?
-Hosts affected?
-Life cycle?
- Clinical dz?

Back 434

-Anoplocephalan tapeworm

-M. expansa: adults affect sheep
-M. benedri: adults affect cattle

-I. host: free living mites such as Acarnia/ Oribatidae(occurs in vegetation)

-1. Larval metacestode takes form of = cysticercoid and develops in mites
2. Mites are accidentally ingested with eaten vegetation or hay

- little clinical harm seen

Front 435

Anoplocephala Perfoliata and A. magna
-Adults infect what host?
-I. Host?
-Why are they imp?
-Disease?
-Size?

Back 435

-Anoplocephalan tapeworm

-Final host: horse

-I. host: oribatid mites

-Only tapeworm of horses

-cause ulcers and perforation of gut mucosa

-small 20cm

Front 436

What plan was put into action to prevent Hydatid diseases in humans?

Back 436

-PETS - dogs must be dewormed and deticked prior to entering the UK (24 hrs before)

Front 437

What is the main problem with the plan to prevent hydatid dz from coming in thru PETS?

Back 437

-Deworming with Droncit only kills adult infestations but not the eggs.
-Thus the first defecation after tx could heavily contaminate areas where rodent I. hosts are avail
-Localized endemic could establish if rodents did ingest and then were subsequently ingested by fox.
-THUS FOX CONTROL IS VITAL TO THE PREVENTION AS WELL.

Front 438

What group of internal parasites poses the most threat to the UK?

Back 438

Nematodes

Front 439

Name basic features of Nematodes:
-body design
-Gut design
-Sexes?

Back 439

-multicellular, elongate, unsegmented endoparasites
-shape maintained by a fluid filled body cavity
-external waxy cuticle
-all longitudinal muscles no circular
-simple gut and anus (no differentiation as with Trematodes and Cestodes)
-Seperately sexed individuals (compare with Trematodes and Cestodes)

Front 440

What are the life cycles for Nematodes?

Back 440

-Both parasitic and non-parasitic stages in LC
-Direct and indirect LC
-Indirect cycles= vert and invert hosts (vert is final)

**often paratenic and transport hosts

Front 441

Are nematodes highly host specific?

Back 441

yes

Front 442

How do nematodes feed?

Back 442

Can be BROWSERS or TISSUE FEEDERS or BLOOD FEEDERS

-gut is divided into muscular esophagus and non muscular intestine
- esophagus pumps food thru the intestine against the hydrostatic pressure of the body cavity

Front 443

Describe Browsers (nematodes)

Back 443

-feed on gut contents
-have simple mouth
-sometimes with lips

Front 444

Describe Tissue feeders (nematodes)

Back 444

-feed on gut contents
-have enlarged, cuticular buccal capsule around mouth with cutting plate hooks

Front 445

Describe Blood feeders (nematodes)

Back 445

-feed on gut contents
-feed directly on caplillaries with specialized stylets or by tissue destruction

Front 446

How do nematodes reproduce?

Back 446

-no multiplication in host
# of adults is determined by # of infective forms ingested by host

-Repro is usually sexual with seperate sexes

-Repro is confined to parasitic forms

-Eggs develop in uterus and pass with feces **some are ovo-viviparous

-Egg output can be millions

Front 447

Name the 7 stages of the nematode life cycle?

Back 447

1. Adult - M and F
2. Eggs - pass via feces
3. Five larval stages: L1 -L5

L1 and L2 = free living on pasture

L3 - L5 = parasitic

Front 448

What are the different stages associated with the larvae of nematodes? (4)

Back 448

- free living larvae
- ensheathed larvae
-larvae within eggs
- larvae within host

**INFECTIVE FORM IS USUALLY LARVAE BUT CAN VARY PER SPECIES FOR WHICH EXACT LARVAL STAGE**

Front 449

Where do larval stages continue their development once inside the final host? (nematodes)

Back 449

Either close to site of entry or they migrate to final adult location

Front 450

What are the two forms of migration inside final host for nematodes?

Back 450

1. Hepato-tracheal
-larva migrate from gut thru liver and lungs before arriving back to gut
-Most popular method


2. Somatic - larva
-migrate from gut thru various organ systems arrive back into the gut
-Target organs usually specific to parasite

Front 451

How are nematodes able to survive the UK temperate conditions?

Back 451

-free living larvae are susceptible to freezing and drought
-Therefore have come up with Principal Adaptions:
a. hypobiosis
b. periparturient (spring) rise
c. critical hatching conditions

Front 452

What is Hypobiosis (nematodes)?

Back 452

-Seasonal inhibition of development at a particular larval stage

USUALLY L4 WITHIN HOST

-Assoc. with autumn (unfavorable)

-Larval develop resumed in spring

-This allows overwintering and focus egg production on times when survival of free living forms is more favorable

**not exculsively seasonaly adapted

Front 453

What is Periparturient (spring) rise for nematodes?

Back 453

-Increase in parasite egg production seen around parturition time (sheep)

-Can arise from maturation of autumn inhibited larvae or from increased egg output by adult worms (due to changes in immunity, hormones etc assoc with birthing)

-Strategy aims: to synchronize the availability of infective forms with the presence of susceptible hosts ie YOUNG NAIVE LAMBS

Front 454

What is Critical Hatching conditions? (nematodes)

Back 454

-Larvae hatch from the egg only after a particular combination of weather conditions (ie cold followed by warm)

-Designed to deliver large numbers of infective forms onto the pasture when conditions are most favourable for survival of free living stages

Front 455

How can we control nematodes?

Back 455

1. Anthelmintics
a. Therapeutically
b. Strategically
c. Prophylactically

2. Using vaccines
3. Changing environment (reduce number of larvae on pasture - change location/stock)
4. Using resistant breeds
5. Using nematophagous fungi (reduce larval levels on pasture)

Front 456

What are general features of Browsing nematodes?

Back 456

1. adults = gut parasites
2. adults = simpler mouth with lips to esophagus
3. DIRECT LIFE CYCLES
4. External, non - parasitic larval stages
5. parasitic larval stages are either non migratory or migratory
6. Highly site and host specific

Front 457

What are the 3 basic groups of Browsing nematodes

Back 457

1. TRICHOSTRONGYLES

2. ASCARIDS

3. TRICHINELLA

Front 458

General Features of Trichostrongyle Nematodes:
-Eggs are laid where?
-What forms are free-living and what do they feed on?
-What is the infective form?
-Major animals affected?

Back 458

-Eggs laid on pasture

-L1 and L2 are free living
Feed on bacteria

-L3 within the cuticle of L2 (ensheathed) is infective form - LIMITED LIFE SPAN DOES NOT FEED

-Ruminants (sheep) and horses

Front 459

What is the lifecycle for Trichostrongyle nematodes?

Back 459

1. Eggs give rise to:
2. L1 and L2 free living
3. L3 stage is ensheathed in cuticle from L2 and is infective form
4. L3 exsheaths at site in gut of host due to response of environment
5. L3 penetrates gut mucosa and assoc. glands
6. Grow there and moult to L4 then L5
7. L5 emerges onto gut surface as male or female worm

Front 460

What is the repro strategy and I.D. for trichostrongyle nematodes?

Back 460

Males have copulatory bursa with supporting rays and spicules

Females have charactoristically shaped vulval flaps.

Front 461

Trichostrongylus sp. (PGE)
-infective form?
-description?
-any diff sex ID?
-Where are they found in host?
-What hosts?
-Where does larval development take place?

Back 461

-L3 infective form inside L2
-small and slender
-small bursa in males
-Found in Abomasum or small intesting of poultry and ruminants
-ALL LARVAL DEVELOPMENT TAKES PLACE IN GUT EPITHELIUM

Front 462

Osteragia sp. (Bovine Ostertagiasis)
-what is it?
-description?
-Where is it found?
in what host?
-Differences in life cycle compared to overall plan?
-what causes any clinical dz?
-what is seen with dz?

Back 462

-Trichostrongyle Nematode
-small, reddish brown
-found in abomasum of cattle
-L3>L4 in gastric glands of abomasum
-L4> adult in lumen
-Dz caused by lg #'s of L4 in gastric glands (emergence)
-Leakage of gut proteins into blood and pH changes

Front 463

What are the two types of dz caused by Ostertagia in cattle?

Back 463

1. Type I Ostertagiasis

2. Type II Ostertagiasis

**Seasonal**

Front 464

What causes Type I Ostertagiasis?

Back 464

L3 ingested in Spring/summer and develop into adults that year

Front 465

What causes Type II Ostertagiasis?

Back 465

L3 ingested in previous autumn and underwent hypobiosis in the gastric glands as L4.

Dz comes from mass emergence of larvae in following spring.

Front 466

Nematodirus sp. (N. battus)(Nematodiriasis)
-what is it?
-describe?
-Male ID?
-Where is larval development?

Back 466

-Trichostrongyle Nematode
-long, slender, whitish worm, with twisted body "cotton wool"

-Males have long fused spicules with specific end expansions, with small cephalic vesicle=helps it stick to villi

-Larval development on mucosal surface -->leads to damage of villi and thus diarrhea and dehydration

-L1>L2>L3 all retained within egg **CAN PERSIST FOR UP TO TWO YEARS ON PASTURE

Front 467

What is required for development of larval stages of Nematodirus sp?

Back 467

-Critical hatching temperature for L3 from egg

(usually only one batch of worms per year)

Front 468

How can you prevent nematodiriasis?

Back 468

Forcasting to prevent early year temps to give dewormers to coincide with hatching.

Front 469

Haemonchus sp. (Haemonchosis)
-What is it?
-Where is it found..in host?
- Can it cross infect?
-Males ID
-Females ID
-Dz caused?

Back 469

-Trichonstrongyle Nematode
-Lg blood-feeding worm
-Found in abomasum of cattle, sheep, and goats
-Can cross infect btween sheep and cattle

-Males large bursa
-Females: white ovaries twisted around the blood filled gut "barber's pole"

-Infestations lead to severe bld loss with anemia, wt loss, weakness, fatal hemorrhage gastritis

Front 470

Control Options for Trichostrongyles of Ruminants:
-Aimed principally at limiting pasture contamination of L3 stages by reducing egg output

Back 470

1. Anthelmintic
-effective?
-activity?
-timing?
-frequency?
-resistence?

2. Pasture management
-dose and move to new pasture
-alternate stock grazing
-rotational grazing

Front 471

Ascarids
-Adult description
-Found in what host?
-Infective stage?
-Larval behavior?

Back 471

-Nematodes
-Large white non bursate worms
-Intestines of pigs, horses, poultry, cats and dogs
-L2 either in egg or tissue of paratenic host
-can be migratory (either rte) or non migratory

Front 472

Toxascaris leonina
-what is it?
-migratory?
-Location within what host?
-Dz causing?
-Life cycle?
-control?

Back 472

-Ascarids
-Non migratory
-Sm. intestine CATS AND DOGS
- Patho in lg numbers

-Infection caused by: ingestion of L2 in egg or L2 in tissue of mice (PARATENIC HOST)

-control by dewormer and good hygiene

Front 473

Heterakis
-What is it?
-Location in what host?
-Transport or paratenic host?
-Life cycle?
-Dz causing?

Back 473

"browser nematode"
-Non migratory Ascarid
-Small white worms
-Lg intestine of domestic and wild birds
-Earthworms ingest infective eggs and become transport/paratenic hosts in which L2 migrate into tissues until eaten by bird

-Non pathogenic normally but Aids in transmission of Protozoan Histomonas meleagridis

Front 474

Ascaridia
-What is it?
-Describe it?
-Location in what host?
-Life cycle, transport hosts?
-Major problem caused when?

Back 474

"browser nematode"
-non migratory ascarid
-stout white worms
-sm. intestine of poultry and wild birds
-Earthworms act as transport hosts once eaten eggs - L2 passes thru to gut

-Mainly prob of young birds= hemorrhagic enteritis

Front 475

Ascaris suum
- What is it?
-Migratory or not?
-Describe simply life cycle

Back 475

Migratory AScarid "browser nematode"
**MOdel for HEPATO-TRACHEAL MIGRATION**

1. egg hatches in sm intest.
2. L2 passes to liver
3. In liver moults to L3
4. travels to lungs via bld
5. Then travels back to intestine
6. TWo final moults take place in intestine

Front 476

What is milk spots and describe their significance?

Back 476

In prev infected pigs of Ascaris suum:
-larvae travel to liver and stimulate an immune response
--> results in white spots and leads to meat condemnation

Front 477

What is Ascaris Pneumonia?

Back 477

Lg numbers of larvae of
Ascaris suum traveling thru lungs can give rise to transient Ascaris pneumonia

Front 478

What do Adult Ascaris suum feed on?

Back 478

"Browse" on gut contents causing little/no damage

Lg numbers can lead to Loss of BCS and all related

Front 479

Control of Ascaris suum?

Back 479

-dewormers
-good hygiene

-eggs can remain infective for years

Front 480

Name the two important species of Toxocara and thier hosts:

Back 480

Toxocara are migratory Ascarids

T. canis -- dogs

T. cati -- cats

Front 481

Toxocara cani
Infection prior to 3 months of age:
-route of migration
-Important sites

Back 481

Hepato-tracheal migration rte
-L2>L3 moult takes place in lungs
-L3 returns to gut for final two moults to adults

Front 482

Toxocara cani - Infection after 3 months of age
-migration
- Location sites?

Back 482

-L2 migrate to a wide range of tissues including heart, liver, lungs, skeletal muscle
-In these tissues development is arrested (hypobiosis)

Front 483

Toxocara cani becomes arrested in development, what are the two times when it is reactivated?

Back 483

Reactivation leading to:
1. Pre-natal infection
2. Transmammary infection

Front 484

Describe Pre-natal infection when it comes to Toxocara cani:

Back 484

-3 weeks b4 birth L2 becomes activated
-migrates to the lungs of fetus
-here L2 moults to L3 just before birth
-soon after birth larvae migrate to intestine via trachea where they moult to adult

Front 485

Describe Transmammary infection when it comes to Toxocara cani:

Back 485

-Larvae can also be passed to pup via the milk and moult to adults WITHOUT TISSUE MIGRATION PHASE --> VERY UNUSUAL

Front 486

Toxocara canis
-Who can act as paratenic hosts?
-What do heavy infestations lead to?
-What is a principal result of T. canis (infection)
-Control?

Back 486

-rodents and birds containing L2
-Heavy infestations lead to pneumonia and occulsion of gut
-Principal cause of VISCERAL LARVA MIGRANS IN HUMANS (CHILDREN - BLINDNESS)

Front 487

T. cati
-How is life cycle different than T. cani?

Back 487

-somatic migration in adults after ingestion of the L2 in the egg.
-Kittens become infected via TRANSMAMMARY MILK not PRENATAL
-Paratenic hosts important!!
-rare cause of visceral larva migrans

Front 488

Why are paratenic hosts important to T. cati life cycle?

Back 488

Paratenic host play a role in epidemiology.
-->Infections derived from these hosts usually develop directly to adults in the gut WITHOUT MIGRATION.

Front 489

Trichonella spiralis
-What is it?
-who does it infect?
-zoonotic?

Back 489

-Migratory Ascarids - Example of "post adult" migration
-infects wild carnivores or pigs when they eat waste containing infected meat or from tail biting
-yes humans become infected by eating undercooked pork

Front 490

What is the life cycle for Trichonella spiralis?

Back 490

EXAMPLE OF "POST ADULT" MIGRATION

-L1 produced by female
-Migrate from gut
-Become arrested inside cells of skeletal muscle of host
-Muscle is eaten, larval development is resumed in intestine which is completed w/in two days.

Front 491

General features of STrongyle Worms = aka Tissue Feeders
-size
-location
-ID features
-Where do they feed?
-infective form?
-migratory behavior of larvae?

Back 491

-med to lg
-bursate worms of cecum, colon and sm intestine
-WELL DEVELOPED BUCCAL CAPSULE with a range of cutting features such as plates, hooks and teeth
-Feed directly on tissues of gut or blood
-ensheathed L3
-can be migratory or non migratory

Front 492

Chabertia
-What is it?
-Migratory?
-Size
-Host?
-ID features?
-Life cycle?
-Control?

Back 492

-Nematode - strongyle
-non migratory
-ALL STAGES FOUND IN GUT LUMEN OR MUCOSA
-largest nematode
-found in colon of sheep, goat and cattle

-VERY distinctive large bell-shaped buccal capsule

-L3 and L4 deep in mucosa of colon
-L4 found in lumen
-Adults are plug feeders and seldom cause dz in large numbers

-Control same as PGE (deworming and pasture management)

Front 493

Oesophagostomum
-what is it?
-Host?
-ID features?
-Life cycle?
-Control?

Back 493

-Nematode - Strongyle - Tissue feeder
-Ruminants (host)
-Head slightly bent dorsally, variety of cuticular ornamentation

-L3 develops in a fibrous nodule in gut wall
-L4 to adult on gut surface leaving behind charactoristic nodules

-Control dewormers and pasture management

Front 494

Equine Strongyles (equine strongylosis)
-The infection...what is it?

Back 494

Result of infection with a number of diff nematode species but usually tx as single clinical entity.

Front 495

Name the two Major groups of Equine Strongyles?

Back 495

1. Small Strongyles
--> Equine Cyathostomes (Trichonemes)

2. Large Strongyles
-->Strongylus

Front 496

Cyathostomes
-What is it?
-Describe
-Location
-Migratory?
-Clinical dz?
-Control?

Back 496

-1. Small Strongyles
--> Equine Cyathostomes (Trichonemes) - Tissue Feeder

-small, stout warms, L4 is red due to blood (others are white to dark red vary)

-Lg intestine of horses
- Larvae non migratory
-Infection usually well tolerated but increased #'s can lead to enteritis and fibrosis of gut (YOUNG ANIMALS BEWARE)

-Control: dewormer and pasture management

Front 497

Life cycle of Cyathostomes (Trichonemes)

Back 497

-L3 emerges in lumen of sm intes.
-moves to colon--> mucosa
-FIbrous nodule forms around larva
-moults to L4 inside nodule and emerges out to gut surface
-L4 and adults are plug feeders
-L4 sucks blood hence bright red

Front 498

Large strongyle of Horses- Strongylus
-ID feature
-Location and host
-prepatent period?
-infective form?
-migration
-patho
-control

Back 498

-lg buccal capsule
-adults found in lg intestine of horses and donkeys
-long prepatent periods (6-12 months)
-infective form= L3 ensheathed on pasture
-SOMATIC MIGRATION
-patho depends on tissue feeding habits of adults
-difficult to kill with dewormer

Front 499

Three principal species of Strongylus based on larval target organs:

Back 499

1. S. vulgaris
2. S. edentatus
3. S. equinus

Front 500

Describe S. vulgaris
-what it is?
-migration?
-life cycle?

Back 500

-Large strongylus horses
-somatic migration

-L3 penetrates int. mucosa
-moult to L4 in submucosa
-enters sm arteries
-migrates to MAIN MESENTERIC ARTERY
-several months later, moults to L5
-returns to intestinal wall via arterial lumen
-nodules form around the larvae
-nodules rupture releasing adult
-PREPATENT PERIOD 6 MONTHS

Front 501

Patho associated with S. vulgaris?

Back 501

once in main mesentaric artery:
-lesions can develop in artery and its branches arising from thrombus formation with inflammation and thickening of arterial wall

Front 502

Describe S. edentatus
-what is it?
-migration?
-life cycle?

Back 502

-Large strongylus horses
-somatic migration

-L3 penetrates int. mucosa
-travels to LIVER via parenchyma via bld stream
-forms nodules
-moult to L4 in liver
-Leaves liver via hepatic ligaments where the final moult takes place
-L5 travels back to wall of lg intestine
-LG nodule forms and ruptures releasing adult into lumen

PREPATENT PERIOD 11-12 MONTHS

Front 503

Describe S. equinus
-what is it?
-migration?
life cycle?

Back 503

-Large strongylus horses
-somatic migration

-L3 penetrates wall of intestine
-nodules form in MUSCLE LAYERS OF THE GUT
- moult to L4 takes place in nodules
-L4 migrate w/in parenchyma
-reappear in lumen of lg intestine w/out nodule formation

PREPATENT PERIOD 9 MONTHS

Front 504

Hookworms
-what are they?
-where do they infect?
-who do they infect?
-ID shape?
-what type/where feed?
-infective form?

Back 504

-Nematodes - tissue feeders
-sm intestine or colon
-ruminants and dogs
-dorsal bending of head "hook" shape
-blood feeders directly on arterial capillaries of mucosa
-infective form L3 (orally or percutaneously)

Front 505

Ruminant Hookworm - Bunostomum
-what is it?
-size
-where of who
-how infected?
-patho?
-Tx?
-Control?

Back 505

-bld feeder - nematode
-largest nematode
-sm. intestine of ruminants
-orally or percutaneous infection-> followed by migration to gut
-effects masked by other nematode infections
-tx under Ostertagia and Haemonchus and thus get tx anyway
good hygiene (thrive on damp conditions)

Front 506

Unicinaria
-what is it?
-Host?
-how infected?
-control?

Back 506

Northern hookworm of dogs and cats in temperate areas
-oral or L3 penetrates skin causing hypersensitivity rxn in feet
-good hygiene and dewormer

Front 507

Ancylostoma
-what is it?
-Host?
-How infected?
-life cycle imp notes?

Back 507

-Tropical canine hookworm
-dog
-oral or L3 skin penetration
-Larvae migrate to tissues and undergo hypobiosis and then are reactivated during later stages of pregnancy

Front 508

Lungworms
-where are they located?
-how infected?
-life cycle?

Back 508

Nematodes
-Adults in respiratory system
-eggs and larvae passed out in feces
-infection via ingested larvae that migrate from the gut to lungs
-direct or indirect life cycles

Front 509

Dictyocaulus sp (husk)
-What is it?
-description
-Host?
-how infected?
-Life cycle?

Back 509

Lungworm with direct life cycles tissue/blood feeder
-slender, thread like worm
-found in bronchi of cattle, sheep, goats, horses and donkeys (parasitic bronchitis in calves)

-L3 infective form

-penetrates intestinal mucosa and passes to mesenteric LN
-moult to L4 which travels to lungs via bld and lymph
-breaks out of capillary into alveoli
-Final moult in bronchioles
-Adults mature in bronchi

Front 510

What is the repro strategy of Dictyocaulus?

Back 510

-Females produce eggs containing fully developed L1 (ovo-viviparous) which hatch immediately
-migrate up trachea are swallowed and pass out feces

Front 511

What is the feeding strategy of Dictyocaulus?

Back 511

L1 to L3 stages do not feed but are reliant on stored food.

L3 leave fecal pat either by themselves or can be carried distances on spores of fungus PILOBOLUS which grows on feces.

Front 512

Control of Dictyocaulus?

Back 512

Vaccine avail irradiated L3 - less effective realted to earlier challenge resulting from more over-wintered larvae?

Front 513

Syngamus sp. (gapeworm)
-What is it?
-who does it infect?
-size/description?
-ID features?
-infective form?
-Egg survival?

Back 513

Lungworm - tissue feeder - nematode -
-birds
-large reddish
- Male and Female are in copula always Y shaped
-Variety of infective forms:
egg with L3
L3 hatched from egg
L3 in transport host (earthworm, slug, snail or beetle)
-Eggs survive for up to 9 months on soils or years as the L3 is within transport host
-Wild bird populations act as reservoirs for poultry and earthworms

Front 514

Oslerus sp.
-What is it?
-Where is it found? Host?
-Repro?
-Patho?

Back 514

Canine lungworm - tissue feeder - nematode -
- found in upper air passages of domestic and wild dogs
-Adults in nodules at tracheal bifurcation
-Ovoviviparous with larvae in feces

-Heavy infestations result in UR distress esp after exercise

Front 515

Metastrongyles
-What is it?
-Def host/ I. host?
-Life cycle?
-how infected?

Back 515

Obligate, Heterxenous - Lungworms with Indirect life cycles
-Invertebrate as I. host
-Transmission depends on avail of I. host

-Def host: pig
-I. host: earthworm

-Egg containing L1 ingested by earthworm
-Develops thru to ensheathed L3 IN TISSUES OF WORM
-EARTHWORM IS I. HOST NOT PARATENIC HOST OR TRANSPORT HOST

-Pigs becomes infected by eating earthworms
-L3 travel to lungs via lymphatic system

Front 516

Mullerius sp.
-What is it?
-Def host/ I. host?
-Life cycle?
-how infected?

Back 516

Obligate, Heterxenous - Lungworms with Indirect life cycles
-Invertebrate as I. host
-Transmission depends on avail of I. host

-Def host: sheep
-I. host: mollusc

-Adult found in alveolar tissue of sheep
-Gives rise to fibrous nodules
-Ovo-viviparous with L1 passed out with feces
-Infects molluscan I. host thru its feet
-Sheep infected by ingesting snail while grazing.

Front 517

Filarial Nematodes
requirements

Back 517

All have Indirect lifecycles with insects as intermediate hosts

Adults are found in bld system or CT

Larval stages = microfilaria

Front 518

Parafilaria sp.
-what is it?
-hosts?
-life cycle
-how infected?

Back 518

Filarial Nematode - tissue feeders

-Def host: cattle, horses
-I. host: Flies (Musca sp)

-Adults in nodules (verminous) in skin
-no egg stage

-Microfilaria in "bloody" secretions taken up by fly during feeding (NOT BLOOD SUCKING)

-Infect host by L3 breaking out of fly mouthparts and entering skin

Front 519

Dirofilaria sp.
-what is it?
-hosts?
-life cycle
-how infected?

Back 519

-Canine Heartworm - Filarial Nematode - Tissue feeder

-Def host: dog
-I. host: mosquitoes

-Adults found in pulmonary artery and "right" heart.
-Microfilaria circulate in the blood until taken up by mosquito

-After developing in mosquito tissues --> move to salivary glands and are then injected back into the dog via the mosquito saliva injected during feeding