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652 Cards in this Set

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What is a parasite?
Eukaryotic organism that is metabolically dependent on another animal (host) during one or more stages of its life cycle
What is the difference between definitive and intermediate host?
Definitive (final) host is where parasite attains sexual maturity. Intermediate host serves as a temporary but necessary environment for completion of the immature stages of the life cycle
What is a paratenic host?
Host not needed to complete life cycle but utilized as vehicle for reaching a necessary host
What is a vector?
Arthropods or other invertebrates which seve as hosts and carriers for parasites (may be intermediate or transport host)
What is a reservoir host?
Infected animals which serve as a source of infection for others (include all infectious agens, not just parasites)
What is sylvatic reservoir?
A wild animal reservoir
What is a prepatent period?
What is a patent infection?
Period after infection before production of eggs, cysts, etc. in definitive host
Patent infection: mature infection (reproductively speaking)
What are parasitologic priniciples?
1) Under natural circumstances animals have parasites. In large animals we aim for control, in companion animals for elimination
2) Parasitic infection is not equivalent to disease. Immunity often prevents disease but not infection
3)Stress make animals more susceptivle to parasitic infection and parasitic disease
4)Antiparasitic drugs are only one part of the treatment. Use more than 1 method to control a parasitic infection (integrated pest management)
Phylum Arthropoda divides into what 2 classes?
Insecta: fleas, lice, flies
Arachnida: ticks, mites
What 3 types of names do drugs have?
Chemical, Generic, and Trade. We typically only study generic names.
What is a withdrawal period?
The length of time that a food animal or product must be withheld from entering the food chain following treatment with a drug
What is an extra label use?
Use of an approved drug in a manner that is not in accordance with the approved label directions
What types of arthropod control agents exist?
Pesticides (kill outright or interfere with growth and development)
Biological control
Physical control
What agency are most pesticides (if not all) are regulated by?
EPA: Environmental Protection Agency
What agency regulates pesticides against internal parasites?
FDA: Food and Drug Administration
What is the disadvantage of pyrethrins in terms of residual activity?
They are botanicals, natural, so they are quickly metabolized
What is the mode of action of pyrethrins?
They disrupt Na/K ion transport in nerve membranes. This paralyses organism. It's a quick knock down, but they can recover
What is the advantage of pyrethrins (other than killing parasites)?
They also have repellent activity
What synergists are pyrethrins often used with?
Synergists like piperonyl butoxide
What is the spectrum of action of pyrethrins?
Many species
How toxic are pyrethrins? What are the side effects of pyrethrin toxicity?
Pretty safe. If toxicity occurs: salivation, diarrhea, vomiting, ataxia, convulsions, death.
Whom should you NOT give pyrethrins to?
Nursing puppies or kittens less than 4-weeks-old
Toxic in fish.
What are synthetic pyrethrin-like compounds? What advantages do they have over pyrethrins?
Pyrethroids are more potent, longer lasting. (Note: pyrethroids end with -trin and -thrin with few exceptions)
Who should NEVER be treated with Pyrethroids?
What is the disadvantage of pyrethroids over pyrethrins?
Higher risk of toxicity
What is the mode of administrations for pyrethroids and pyrethrins?
Topical: dusts, sprays, shampoos, spot-ons
Environmental: pyrethrOIDs
What is the other name for Macrolides? What were they originally? What were they marketed for originally?
Macrocyclic Lactones originally were fermentation products of soil microbes. Were first marketed as dewormers only.
Which two groups can you divide macrolides into?
Avermectins (ivermectin, doramectin, selamectin, eprionomectin)
Milbemycins (milbemycin, moxidectin)
What is the mode of action of macrolides?
They are endectocides: bind to glutamate -gated chloride channels leading to hyperpolarization of nerves and muscles
What is the spectrum of action of macrolides?
Macrolides are effective against many arthropod species and some worms
How persistent are macrolides in animals?
They are lipophilic, which helps keep them in animals longer (may be weeks depending on formulation and drugs).
What are modes of administration of macrolides?
Oral, spot-ons, injection, feed additives
Some macrolides are used as plant pesticides and in roach products.
What two types of neonicotinoids are there?
Imidacloprid and Nitenpyram
What is the spectrum of action of Imidacloprid?
Fleas, lice, plant pests
What is the mode of action of imidacloprid and nitenpyram?
Imidacloprid binds to postsynaptic nicotinic acetylcholine receptors in insects
What is the toxicity level of imidacloprid and nitenpyram?
Low toxicity because mammalian receptors are different.
How long does imidacloprid persist in animal?
Persists for weeks
What is the metod of administration of imidacloprid?
topical, enironmental for plants. May also be used orally such as Capstar.
What class of pesticides does nitenpyram belong to?
What is the spectrum of action of nitenpyram?
What are the main differences between imidacloprid and nitenpyram?
Imidacloprid persists for weeks, while nitenpyram acts fast and gone. Imidacloprid is administered topcally, nitenpyram is administered orally.
What class of pesticides do spinosyns belong to?
Spinosyns are macrolides, but work more like neonicotinoids
What is the mode of action of spinosyns?
They activate nicotinic acetylcholine receptors, but separate receptors from the ones neonicotinoids activate.
What is the spectrum of action of spinosyns?
What is the toxicity level of spinosyns?
Low toxicity
How long do spinosyns stay in the animal?
How are spinosyns administered?
What class of pesticides does Fipronil belong to?
What is the spectrum of action of Fipronil?
Insects, ticks, mites
What is the mode of action of Fipronil?
Fipronil binds to GABA receptors, inhibits flux of Cl inons into nerve cells, resulting in hyperexcitability
What is the toxicity level for Fipronyl?
Low: doesn't seem to bind to mammalian receptors. CAN be toxic to some birds, reptiles, fish, and rabbits
How long does Fipronil persist in an animal? Where is it stored?
It is stored in hair follicles, sebaceous glands, and released onto skin, so can persist for weeks (?)
How is Fipronil (phenylpyrazole) administered?
Topically (Frontline)
What class of Pesticides does Amitraz belong to?
What is the spectrum of action of Amitraz?
Ticks and mites
What is the mode of action of Amitraz?
Amitraz inhibits monoamine oxidase
What is the toxicity level of amitraz?
Low in everyone except horses
What species should NEVER be treated with Amitraz? What are the symptoms of amitraz toxicity in these species?
Horses.: Lethargy, hypotension, mydriasis, hypothermia, vomiting
How long does amitraz persist in an animal?
What is the method of administration of amitraz? What are some products that contain amitraz?
Products: preventic collar, tactic (pesticide for food animals).
What class of pesticides does Metaflumizone belong to?
Semicarbazones. (It's a new member)
What is the spectrum of action of metafumizone?
What is the mode of action of metaflumizone?
Blocks Na channels in axons, prevents neurotransmission
What is the toxicity level of metaflumizone?
How long does metaflumizone persist in an animal?
Weeks. It is distributed in hair coat.
What is the method of administration of Metaflumizone?
What is the spectrum of action of organophosphates?
Many arthropods
What is the mode of action of organophosphates?
Acetylcholinesterase inhibitors.
What is the main problem with organophosphates? What are the symptoms of it?
Toxicity. SLUD: salivation, lacrimation, urination, diarrhea
Respiratory failure
Chronic neurotoxicity
Which species should not be treated with organophosphates unless specifically labeled for them?
What is the mode of administration of organophosphates?
Systemic absorption from topical products. Administered on animal, environmentally
How long do organophosphates persist in an animal?
Newer ones can persis for several weeks
How can you identify organophosphates by a chemical name?
It contains -phosphate
(fention, chlorpyriphos, dichlorvos, diazinon, tetrachlorvinphos)
What class of pesticides is similar to organophosphates?
Carbamates. Don't combine them with OPs!
How toxic are carbamates compared to organophosphates?
Not as toxic.
How can you recognize carbamates in a product?
Generic name usually contains "carbamate"
"Sevin" dust is the only one in common veterinary use.
What is the other name for chlorinated hydrocarbons?
What is the most famous chlorinated hydrocarbon? What are some other examples of chlorinated hydrocarbons?
DDT is the most famous
Lindane, dieldrin, aldrin, methoxychlor.
What is the mechanism of action of chlorinated hydrocarbons?
Inhibit Na/Ca flux--interfere with depolarization and repolarization of membranes
Why are most chlorinated hydrocarbons unavailable in the US?
Concerns about environmental persistence and some toxicity
What is the draw back of lime sulfur? What is its advantage?
It is safe, but smelly. Not used much anymore
What are some of the repellents?
DEET, Picardin: oil of lemon eucalyptus
What are some natural products? What are their drawbacks?
D-limonene, herbal preparations. Drawback: little efficacy or toxicity data.
What two drugs are the examples of insect development inhibitors (IDI)?
What is the mechanism of action of IDIs?
Chitin synthesis inhibitors
What is the mechanism of action of Insect Growth Regulators (IGRs)?
Juvenile hormone analogs
What two drugs are the examples of IGRs?
What is the spectrum of action of IDIs and IGRs?
Many insects depending on product
What is IDIs and IGRs toxicity?
How long do IDIs and IGRs persist?
Some products persist for months
What is the method of administration of IDIs and IGRs?
Topical and Environmental
Give examples of Biological control
Pheromones in traps
Use of parasitic wasps and other predators
What is parasitoid?
Organism that is parasite early in development but that finally kills the host during or at the completion of development (e.g. Wasps)
What is target-site resistance?
Genetic difference in the molecular target of the drug so drug doesn't bind; amplification of target gene
What is metabolic resistance?
Increased inactivation or removal of drug
What is behavioral resistance?
Avoidance of pesticide
What are the important factors in determining how fast the resistance will develop?
Dose of drug
Drug formulation
Human factors (outdated drugs, etc.)
Size of refugia
How do you minimize resistance?
Maximize use of non-pesticide controls
Don't use unnecessarily
Use appropriate dose and route of administration
Rotate pesticide use
What order are fleas? What are their general characteristics?
Wingless, laterally compressed, complete metamorphosis
What is the most common flea of cats and dogs?
Ctenocephalides felis felis
How many stages of C. felis are spent off host?
3 out of 4 stages are spent off host. Only adults are on host.
What environment do off-host stages prefer?
warm and very humid
One female can lay up to how many eggs? How soon do they hatch?
Up to 1000. Usually hatch in a few days.
What does C. felis larva eat?
Eat organic debris, but require flea feces
How long do they stay in larval stage?
About 1 week
How long does C. felis stay in pupa stage?
If warm and humid, it takes 5 days to get to an adult. Can stay in pupa for a few months.
What is the minimal life cycle of C.felis?
Egg hatching: 2 days
Larva: 6 days
Pupa: 6 days
TOTAL: about 14 days
Where do fleas overwinter?
Your house, reservoir hosts
How do you diagnose C felis?
Adults in large numbers, flea dirt
What is the characteristic distribution of fleas on an animal?
Tailhead, thighs, abdomen, neck
What are clinical signs of C. felis presence?
extreme pruritus, flea hypersensitivity, allergy to flea saliva components
What are some other medical problems associated with C. felis?
Vectors of tapeworms
Vectors of Bartonella henselae (cat scratch disease)
Give examples of ADULTICIDES for flea control.
Natural products
Give examples of LARVACIDES for flea control.
If you have to choose a collar with a pesticide, which should you choose for flea control?
Flea collars with IGRW
Give examples of environmental flea control
Mechanical: vacuum where pet spends most time
Sprays and foggers: IGR, IDI
What are some other hosts of C. felis? How adaptable is C. felis?
Ferrets, humans, confined calves, goats
C. felis is highly adaptable
How would you treat host other than cats/dogs? What are the dangers to humans?
In ferrets, treat with cat parasiticides
Treating animals may increase human bites.
What fleas are the vectors of plague in SW US?
Rodent fleas
Name a human flea
Pulex irritans
What flea is a stick tight flea of poultry?
Echidnophaga gallinacea
Are fleas generally species-specific?
Yes, generally they are, but C. felis is highly adaptable
What parasites belong to order Phthirapter?
What are general characteristics of lice?
Small, wingless, dosroventrally flattened. Often white or gray, some brown.
Do lice undergo complete metamorphosis?
No, they do not.
What type of lice belongs to Anoplura?
Sucking lice
What type of lice belongs o Mallophaga?
Biting/chewing lice
Where do lice spend their entire lifecycle?
On host
Where do you find lice eggs?
Glued to feathers/hairs
What is the minimum lifecycle length for lice?
Minimum 3 weeks
How do you transmit lice?
Direct transmission by contact or fomites
How host-specific are lice?
VERY host-specific. Cannot survive long off the host.
When would you see lots of lice on an outside animal? Why?
In winter. Longer hair coat, more stressed animals
What are clinical signs of lice infestation?
Pruritis, hair loss, poor haircoat--common
Anemia, debilitation, disease vectors
What species commonly have lice (but not severe)?
Food animals
Wild birds
Wild mammals
Can be in rodents
What species do not usually have lice but can easily get and transmit them?
What species do not commonly have lice unless not well-cared for?
Small animals
How do you diagnose lice?
Lice and eggs on host
Predilection sites
What drugs would you use to treat lice infestation?
Depends on host:
Is it hard to kill the adults? What about eggs? How should you approach this?
Adults are easy to kill, drugs don't kill eggs. Repeat treatment in 2 weeks or use products with long residuals; treat all animals
What are the examples of human lice? Are they zoonotic?
Small animals cannot give you lice.
Pediculus: head and body louse
Phthirus: pubic louse (crabs)
What order do flies belong to?
What are the characteristics of this order?
Diptera. 1 pair of membranous wings with some exceptions, compete metamorphosis
What are the problems that flies introduce?
Fly worry
Disease transmission
Parasitism by larval flies
Name non-biting flies
Musca domestica
Musca automalis
Where does musca domestica lay its eggs?
In decaying organic material
What is the lifecycle of muscla domestica?
2 Weeks lifecycle
What gender is parasitic in musca autumalis? What do they eat?
Females are parasitic. Eat secretions.
Where does musca autumalis lay its eggs?
In fresh manure
Who does musca autumalis choose as its host?
Primarily ruminants, horses
What's the importance of musca autumalis?
Irritation (tearing, inflammation)
Bovine pinkeye (Moraxella bovis) mechanical transmission
Name biting flies
Haematobia irritans
Stomoxys calcitrans
What is the common name for Haematobia irritans?
Horn fly
What are predilection sites for H.irritans?
Back and ventrum of cattle, horses. Resident parasites
Where does H. irritans lay its eggs?
In fresh manure
What is the importance of Haematobia irritans?
Irritation, decreased production
What is the common name of Stomoxys calcitrans?
Stable fly
What is the lifecycle of Stomoxys calcitrans?
Visits animal 1-2X/day; lays eggs in decaying manure
What are predilection sites of S. calcitrans?
legs, flanks
What is the importance of Stomoxys calcitrans?
Fly worry
Fly bite dermatitis
What is the common name for Family Tabanidae? What do they look like?
Horse and deer flies.
Big with big eyes, stout body
Deer flies often striped wings
Where do horse and deer flies lay their eggs?
Near water
What is the importance of tabanidae flies?
Fly worry
Mechanical vectors of disease
Where do mosquitoes lay their eggs?
In water
What is the importance of mosquitoes?
Fly worry
Disease vectors
What species do blackflies and buffalo gnats belong to?
They belong to Simulium spp.
What is the lifecycle of simulium flies?
Lay eggs in RAPIDLY moving water
What is the importance of simulium flies?
Fly worry
Fly-bite dermatitis
Disease vectors
What are predilection sites of simulium flies?
Horse and dog ears
What are common names of Culicoides spp.?
No-see-ums, midges
Where do culicoides lay their eggs?
Larvae aquatic or in moist sil, humus
What is the importance of culicoides?
Fly worry
Mostly a clinical problem in horses
Sweet itch: fly-bite allergy
What are the elements of fly control in large animals?
Get rid of manure, fed through pesticides
Use wasps/traps
Dust bags, back rubbers
Ear tags-cattle
What are the elements of fly control in Horses?
Repellants and sprays
Physical barriers
What is the definition of Myiasis? What are the two types of myasis?
Any infection due to the invasion of the tissues or cavities of the body by the larvae of dipterous insects.
Two types: Cutaneous and Internal
Predominantly what flies are responsible for cutaneous myasis?
Blow flies and flesh flies
Where do cutaneous myasis flies lay their eggs?
Decaying organic mater, wounds, body secretions, maggots eat necrotic tissue
What is the prevention of cutaneous myasis?
Wound spray in fly season
Castrate/dehorn before fly season
What is the official name of Screwworm fly? What part of the world is it common in?
Western hemisphere
How is cochliomyia different from other cutaneous myasis flies?
It lays eggs in living tissue
What should you do if cochliomyia is suspected?
Notify regulatory vets, send samples.
What are some common names for internal myasis fly larvae?
Bots, grubs, warbles
Are adults of internal myasis flies dangerous? What do they look like?
They don't feed, and look like bees (hairy). Host animals actively avoid them.
Describe Gastrophilus spp lifecycle
Eggs laid on legs, face
Migrate in gums/tongue
Move to stomach for 10-12 months
Pass out in feces
Pupate on ground
What stimulates Gastrophilus to hatch out of eggs?
Warm air stimulates larvae to hatch
What are the clinical signs/significance of gastrophilus?
Not very significant
Rarely ulceration or perforation
Sometimes lesions in mouth
See eggs on legs
What do you treat gastrophilus with?
Ivermectin, Moxidectin (macrolides)
Warm water on legs so eggs would hatch.
What do hypoderma bovis and lineatum cause? What are their common names?
Myasis. Common names: cattle grubs, warbles, heel flies
What is the lifecycle of Hypoderma?
Esophagus/spinal cord for 2-4 months
Migrate to SC tissue on back
Make a bump with hole 5-8 weeks
Pupate on ground
How do you diagnose hypoderma?
Adults gadding (running away)
What spp does hypoderma affect?
Cattle, occasionally goats and horses
How do you treat/control hypoderma?
Systemic treatment
Avoid treatment when larvae in spinal cord/esophagus
What are the dates between which you should NOT treat hypoderma in VA?
November 1st--March 1st
What is the name of spp. for rodent bot flies?
Cuterebra spp
What animals does cuterebra spp affect?
Rodents, rabbits
What is the lifecycle of cuterebra?
Eggs laid near burrows or along trails.
Larva picked up by rodent, rabbit
Develops in SC cyst
Pupate on ground
Dog/cat can pick up larvae
Where is cuterebra nodule found on animal?
Head and neck
How do you treat cuterebra?
Remove carefully (enlarge hole, pull out)
Antibiotics as needed
Can humans get cuterebra?
Yes, occasionally
What are the dangers of cuterebra?
Infrequently abberant migration (big problems in brain)
Oestrus is a parasite of what spp?
Small ruminants
Where does Oestrus spp larvae go in an animal?
Nasal passages and sinuses causing nasal discharge
What is the family of bloodsucking flies? What do they look like?
Diptera Hippoboscidae. Adults have flat looking body
What is Hippoboscidae called in sheep and goats? What other animals are hosts?
Wild birds
What do tsetse flies transmit?
What do Phlebotamine flies transmit? What is their common name?
Sand flies
Transmit Leishmania --infections worldwide
What is the scientific name for bed bugs? What do they do?
Come out at night and suck blood
What do Triatomid bugs transmit? What is their common name?
Transmit Chagas disease caused by Trypanosoma cruzi
What are the 4 stages of ticks and mites lifecycle?
All stages on host
What is the difference in the number of legs in nymphs, adults, and larvae of ticks and mites?
Nymphs, adults: 8 legs
Larvae: 6 legs
What 2 parts is body of aracnids divided into?
Capitulum (gnathosoma)
Idiosoma (rest)
What are the parts of Capitulum in mites/ticks?
How are mites transmitted?
Via direct contact/fomites
What is "mange"
General term to describe mite infestiaon
Name Sarcoptic mites
Name Psoroptic mites
Name mites other than sarcoptic and psoroptic mites
Mesostigmatid mites
Trombiculid mites (Chiggers)
What is the difference between sarcoptic and psoroptic mites?
Sarcoptic mites have short last 2 pairs of legs, are burrowing mites, and are more round, 3 weeks lifecycle
Psoroptic mites are more oval, are surface dwellers, and have longer legs, 2 weeks lifecycle
How would you diagnose sarcoptic mites?
Skin scraping of periphery
May find mites or eggs on fecal exam
What sarcoptic mites are most common in dogs in US?
Sarcoptes scabei var canis
What are clinical signs of Sarcoptes scabei?
Hairless areas or thin hari, intense pruritus, aloecia, thickened wrinkled skin
Secondary bacterial infection, self-inflicted trauma
What is the treatment/control of canine sarcoptes?
Treat all animals
Use Macrolides
Enironmental treatment
Are sarcoptes mites zoonotic?
Yes. Lesions in areas of contact, but humans also have their own sarcoptes
What other economically important species have sarcoptes?
Swine. Lost production in young pigs
Old sows are carriers
Eradicable from closed systems with macrolides
In what species is sarcoptes rare?
It is rare in ruminants and horses
In what species can sarcoptes cause serious disease?
What is the rare sarcoptic mange of the cat?
Notoedres cati
Where do you see lesions associated with Notoedres cati?
On head and neck similar to sarcoptes
What species of sarcoptic mites cause mange in birds?
Knemidocoptes spp
Where do you see lesions associated with Knemidocoptes spp?
Nonfeathered portions
White, crusty honeycomb
It can be a serious progressive disease
How would you treat Knemidocoptes?
With Macrolides
What other species have sarcoptic mites?
Many. Genus name varies. Examples are:
guinea pigs
What are three species of psoroptic mites?
How do you diagnose psoroptic mites?
By skin scraping except ear mites
What psoroptic spp are responsible for a highly contagious severe mange in ruminants?
Psoroptes ovis
How important is Prosoptes ovis mange in the US?
Eradicated from sheep in US; Cattle infections are treated and may not be reported.
Notifiable illness
How do you treat Psoroptes ovis mange?
With Macrolides and treat all animals
Is Psoroptes ovis zoonotic?
Yes, handlers can get lesions
What psoroptic mite is primarily an OTIC parasite of rabbits?
Psoroptes cuniculi
Is Psoroptes cuniculi found in other species?
Yes, occasionally in alpacas, goats, and rare in horses
Who does Chorioptes mites affect?
Occasionally in horses, but more common in ruminants
What are clinical signs of choriptes mites?
Lesions on legs (feet) (espeically featherd horses)
Tailhead in cattle
What is a common EAR mite of dogs, cats, and ferrets?
Otodectes cynotis
What are clinical signs of Otodectes cynotis?
Otitis externa-may be with intense pruritus
Coffee grounds in the ear
How do you diagnose Otodectes cynotis?
Ear swab, otoscope
How do you treat Otodectes cynotis?
Clean ears
Miticide (macrolides, pyrethrins)
What mite causes canine mange and is rare a problem in other hosts?
Demodex spp
What does Demodex look like?
A cigar with legs
What is the lifecycle of Demodex?
It lives in sebaceous glands and/or hair follicles.
Has many hosts; highly spp specific. Infected early from dam, most asymptomatic
Demodex in large numbers causes what clinical signs?
Interferes with follicles, gland function
Can lead to inflammation, secondary infection
What are the two forms of Demodex canis?
Localized form: some pups (3-10 months of age), small hairless lesions, nonpruritic, 90% resolve
Generalized form: progressive spread from localized in pups, also adult onset
What are general clinical signs of Demodex canis?
What dogs are more susceptible to Demodex canis?
Purebred shorthaired dogs
How do you diagnose Demodex canis?
Skin scraping-squeeze first
Eggs and mites in feces
What do you use to treat Demodex canis?
Don't breed
Do other spp have Demodex?
Localized rare in cats
Generalized even more rare in cats
In ruminants: non-pruritic pistules
Might be in humans
What spp of mites have common name of "Walking Dandruff"?
Cheyletiella spp
How important is Cheyletiella in dogs,cats, rabbits?
Infrequent surface mite
What are the clinical signs of Cheyletiella?
Often few signs, can show scurfy dandruff, pruritus
How do you diagnose Cheyletiella?
Scotch tape, brushings
How do you treat/control Cheyletiella?
Environmental control
Is Cheyletiella zoonotic?
Yes, in areas of contact
What mites are closely related to ticks and look more like small ticks?
Mesostigmatid mites
What are the examples of mesostigmatid mites?
Ornithonyssus sylvarium
Ornithonyssus spp
Dermanyssus gallinae
What is a northern fowl mite? What is its lifecycle and what is its significance?
Ornithonyssus sylvarium: avian bloodsucking mite
Entire life cycle on host
Can cause decreased weight gain, egg production
What is the main problem with Ornithonyssus spp of rodents?
They can cause problems in humans
What is a red poltry mite? Is it zoonotic? How do you diagnose it?
Dermanyssus gallinae: parasite of poultry and wild birds; bloodsucking AT NIGHT
Diagnose by finding red or black mites in environment during the day
Can be pest to people
What is the name for chiggers and harvest mites?
Tromboculid mites
What is different about Trombiculid mites from other mites?
Only larvae are parasitic, they are orange or red. Attach for several days
What are clinical symptoms associated with Trombiculid mites? What is the treatment?
Intense pruritus after mites are gone
Treatment symptomatic
What type of parasites are worms? What are two phylums we're most concerned with?
Metazoan parasites
Phylum Platyhelminthes
Phylum Nematoda
What are two classes of Phylum Platyhelminthes?
Class Cestoda
Class Trematoda
What Phylum is limited importance in domestic animals?
Phylum Acanthocephala
Does host immunity eliminate worms?
No, only controls them
What government agency approves anthelmintics? Can products be used off label?
FDA approves drugs for various species
Products can be used off label in valid veterinarian-client relationship
What are some members of Benzimidazoles drug group?
What are some members of Imidazothiazole Tetrahydropyrimidines drug group?
What are some members of Macrolides drug group?
What are some members of Isoquinolones drug group?
What is the member of Cyclic depsipeptide drug group?
What is the difference between side resistance and cross resistance?
Side resistance: if resistant to one member of a group, resistant to all
Cross resistance: Occurs when resistance to one group confers resistance to another group
How can you tell anthelminic drug belongs to Benzimidazoles or probenzimidales group?
It end with -azole
Except Probenzimidazole (Febantel)
What Benzimidazole is no longer marketed?
What Benzimidazoles and Probenzimidales are approved for BOVINES in the US?
Hint: TOFA was a good cow
What Benzimidazoles and Probenzimidales are approved for OVINES in the US?
Hint: AT sheep
What Benzimidazoles and Probenzimidales are approved for CANINES in the US?
Hint: Keep OFF my dog
What Benzimidazoles and Probenzimidales are approved for EQUINES in the US?
It's TOF to be a horse
What Benzimidazoles and Probenzimidales are approved for FELINES in the US?
What Benzimidazoles and Probenzimidales are approved for CAPRINES and SWINE in the US?
FaT Goats and Pigs
What is the mode of action of Benzimidazoles and Probenzimidales?
They bind to parasite tubulin and prevent microtubule assembly; also have some secondary effects on enzymes
What precaution should be taken when giving Benzimidazoles and Probenzimidales to small animals?
Benzimidazoles and Probenzimidales need to stay around to work, so Fenbendazole has to be given with food in small animals.
Rumen and cecum act as reservoirs.
How should Benzimidazoles and Probenzimidales be administered?
Orally; poorly water soluble
What are MEAT withdrawal times for Benzimidazoles and Probenzimidales?
Days to weeks
Albendazole is 27 days (longest)
What are MILK withdrawal times for Benzimidazoles and Probenzimidales?
Fenbendazole: NO milk withdrawal
Others NOT approved for lactation
What is the spectrum of action of Benzimidazoles?
Nematodes: adults
Most larvicidal if given over longer periods of time
What Benzimidazoles also have activity against tapes and flukes?
How safe are Benzimidazoles? What are the precautions?
Usually very safe
Some contradictions in early pregnancy
Albendazole in ruminants
Febantel in dogs
What species do you see most Benzimidazole resistance in?
Small ruminants
Cattle (just starting)
Levamisole is used in what spp?
Ruminants, pigs
Pyrantel is used in what spp?
Horses, dogs, cats, pigs
Morantel is used in what spp?
Cattle, goats
What is the mode of action of Levamisole, Pyrantel, and Morantel?
They are Cholinergic agonists: depolarizing neuromuscular blocking agents
What is the mode of administration of Levamisole, Pyrantel, and Morantel?
Oral and Injection
What is MEAT withdrawal time of Morantel, Pyrantel, and Levamisole?
What is the spectrum of action of Levamisole, Morantel, and Pyrantel?
Adult nematodes
Pyrantel used for horse tapes in the past
How safe are Levamisole, Pyrantel, and Morantel?
Pretty safe
Levamisole is the one associated with most problems
What worms have known resistance to Levamisole?
Small ruminant strongylids
What worms are resistant to Pyrantel?
Horse strongylids, ascarids
What are Macrolides called based on their method of killing the worms?
What effects do Marcolides exert on worms?
Multiple effects on somatic and pharyngeal muscles, also affect reproduction
Which group of Macrolides: Avermectins or Milbemycins are more lipophilic, and, thus, have better residual activity?
What are withdrawal times for MEAT for Macrolides?
0-Weeks depending on product
What are withdrawal times for MILK for Marcolides?
Eprinomectin-no withdrawal
Moxidectin-no withdrawal
Others can't be used
What is the spectrum of action of Macrolides?
Adult nematodes
Good larvicides
How safe are Macrolides? What is mammalian toxicity related to? What are the signs of toxicity?
In general, wide safety margin
Toxicity related to GABA
Signs: dilated pupils, ataxia, confusion, depression, collapse
What breed of dogs should NOT be given high doses of Ivermectin? Why?
Sensitivity due to mutation in MDR1 gene
What Macrolide should not be administered at higher doses in foals and debilitated horses?
What is the environmental effect of Ivermectin?
Activity against arthropods delays processing of fecal material and may have effect on pasture ecology
What type of worms are Praziquantel and Epsiquantel used to treat?
Tapeworms and flukes
What is the mode of action of Isoquinolones?
Tetanic contraction of muscles, probably related to changes in permeability of tegument to calcium
How safe are isoquinolones?
What is used to treat adult heartworm?
Arsenicals: Melarsomine
What drug acts on energy metabolism in protozoa and electron transport in helminthes?
Nitroheterocyclic drug-Nitazoxanide
What medication is used to treat liver fluke in ruminants?
What medication available OTC is mostly used for ascarid nematodes? How does it work?
Paralyzes worms, anticholinergic
What phylum is the most successful of all worms?
Nematoda: major plant and animal parasite spp.
What is the largest nematode?
Placentoma gigantissima from placenta of sperm whale
Describle the body of a typical nematode
Body surface made of cuticle
Several layers, contains collagen-like material
Cuticle may form spins, ridges, alae
Body wall consists of cuticle, hypodermis, and longitudinal muscles
Fluid filled (hemolymph) body cavity-pseudocoel
Describe Nematode nervous system
Ganglia with longitudinal nerve cords in between
Papillae--tactile receptors
Acetylcholine and GABA neruotransmitters
On what do nematodes feed? What does their mouth look like?
Blood, cells, mucus, intestinal contents.
Buccal capsule-->pharynx(esophagus) important in taxonomy
What does nematode digestive system look like?
Intestine-single layer of absorptive cells
Excretory anus in female
Cloaca in male
Describe general nematode reproductive system
Most are dioecious
Some are parthenogenetic
Females are bigger
Males have 2ndary sexual structures used for ID
Females release eggs or larvae
Describe general nematode developmental stages
4 molts (ecdysis):
Cuticle restricts growth
Stages in between molts are: L1-L5(preadult)
Adults follow L5 with no molt
What are orders of nematodes we studied?
What is the superfamily of order Ascaridida?
Ascaridoidea (roundworms)
Describe Ascarids in general
Large, stout-bodied, adults found in small intestine usually, feed on lumen contents, host fluid
Don't attach
Laral migratory phase in definitive host is common
Females very prolific, eggs in fresh feces, unembryonated (single cell), thick shell highly resistant to environmental conditions
Larva develops, remains in egg
Development to infective stage 2-4 weeks usually. Infective stage L2.
What is the most common parasite of confined pigs?
Ascaris suum
How does pig gets infected with Ascaris suum?
It ingests eggs from the environment
Eggs hatch in sm. intestine
Hepatic portal system to liver
Bloodstream to lungs, molt
Coughed up, swallowed
Mature in sm. intestine
What is the prepatent period for Ascaris suum?
6-8 weeks
What causes liver condemnation in pigs infected with Ascaris suum?
Larvae in liver causes inflammation/fibrosis.
Gross anatomy: "milk spots"
Regresses in 4-6 weeks
What are some problems associated with Ascaris suum larvae in lungs?
May cause cough (thumps)
Can increase susceptibility to other pathogens
What are some problems associated with Ascaris suum larvae in small intestine?
Decrease food utiization
Slow growth
Rarely may block bile ducts
Rarely may cause obstruction/perforation
How is Ascaris suum diagnosed?
By fecal exam (eggs)
(Females produce thousands daily)
Are Ascaris suum eggs immediately infective when passed in feces?
NO. Require about 3 weeks to become infective, can last for years in soil.
When does immunity to Ascaris suum develop?
During period of initial infection
In what pigs do you see most losses/disease associated with Ascaris suum
In young pigs
What would you do to control Ascaris suum?
Sanitation and fecal removal
-Pressurized steam
-Hot lye water
How would you treat Ascaris suum?
Emphasis on prefarrowing sows, premarket pigs
Can other species of animals get Ascaris suum by ingesting eggs?
Yes. Respiratory disease outbreaks in calves have been reported. It is also similar to A. lumbricoides--human ascarid
What is a human ascarid similar to A. suum of pigs?
Ascais lumbricoides
Infects 1/3 of world population
Occasionally in US, usually in kids, SE
What is a common ascarid of horses?
Parascaris equorum
What is the lifecycle of Parascaris equorum?
Like A. suum:
Lungs 1 week post infection
SI approximately 2 weeks post infection
Prepatent period 11-14 weeks
What are pathologic changes in horse's lungs associated with Parascaris equorum?
Mechanical damage: increased by immune response
Increased susceptibility to pathogens
Nasal discharge
Unthrifty, poor condition
May have permanent effects in severe cases
What can very heavy infection with Parascaris equorum lead to? What's the treatment?
Perforation or impaction (uncommon)
May require surgery
Poor prognosis
What age group of horses is most susceptible to Parascaris equorum?
Foals and yong horses
Immunity develops, adults rarely have patent infection
What measures of control do you implement against Parascaris equorum?
Eggs require 2 weeks to become infective, so remove manure
5% phenol disinfectant solution for cleaning stalls
How do you treat Parascaris equorum infection?
Macrolides (larvicidal)Fenbendazole (larvicidal)

Resistance to Ivermectin, Pyrantel
What is the typical control program for Parascaris equorum in horses?
Treat at 8 weeks monthly to 6 months
What is the common name for ascarids in small animals?
"arrowhead worms" because they have cervical alae
What is the most common ascarid of dogs in the US?
Toxocara canis
15% of shelter dogs
18% in Southeast
What is the lifecycle of Toxocara canis?
Basic pattern of hepatotracheal infection
May also go through somatic migration, where animal becomes a somatic reservoir
What is the age group of dogs susceptible to hepatotracheal migration?
Most often occurs in dogs less than 3 months of age. Less likely in older dogs
What type of larval migration is prefered by Toxocara canis in older dogs?
Somatic migration
What happens to somatic reservoir of Toxocara canis in pregnancy?
Somatic reservoir gets reactivated day 40-45 of pregnancy. Parasites are present in puppy liver at birth.
What is the prepatent period of Toxocara canis?
3 weeks
What are other routes of infection of Toxocara canis (other than transplacental and from ingesting eggs)?
Transmammary: less important
Transport hosts: rodents, birds, earthworms
Dam may get infected through coprophagia
What are clinical signs of Toxocara canis?
Most are seen in puppies:
potbellied appearance
Poor hair coat
Failure to gain
Diarrhea and constipation
Death in some heavy infections
How do you diagnose Toxocara canis infection?
Fecal exam
What is the public health importance of Toxocara canis treatment?
Zoonotic to children
What do you treat Toxocara canis with in puppies/dogs?
Pyrantel in young puppies
Many heartworm preventatives
Treat others as needed
What would you do for control of Toxocara canis?
Remove feces every day
Wash surfaces with 1% bleach solution (strips away sticky coat, but doesn't kill)
What is the most common parasite in cats similar to Toxocara canis in dogs?
Toxocara cati
What are the routes of infection with Toxocara cati in cats?
Transport hosts
Transmammary transmission
How do kittens get Toxocara cati?
It is transported through milk, and kittens should be treated
How do Toxascaris spp differ from Toxocara spp?
Parasites of dogs, cats, wild animals
Much less prevalent
Not prenatal/transmammary transmission
What are clinical symptoms of Toxocara canis in HUMANS?
Visceral larva migrans (larva anywhere)
Ocular larva migrans (larva in eye)
What are the symptoms of Toxocara canis visceral larva migrans in HUMANS?
Respiratory signs
Rarely encephalitis
Risk factors: age, pica
What are the symptoms of Toxocara canis ocular larva migrans in HUMANS?
More common than VLM
Partial loss of vision
What are the risk factors for Toxocariasis?
Socioeconomic group
Non-metrapolitan area
Dog ownership
What is a raccoon ascarid that causes visceral larva migrans in many species? What are clinical signs of this parasite?
Baylisascarid procyonis
Severe CNS signs with several fatalities in children
Could Baylisascarid procyonis cause a patent infection in dogs?
What is the method of control of Baylisascarid procyonis?
Treat captive raccoons
What ascarid affects pandas?
Baylisascarid schroederi
Are ascarids in cattle a big problem in the US?
No, but may be important worldwide.
What are the signs of ascaridida infections in birds? Are they common?
Common in wild and free range birds
Weight loss
Ruffled featheres
Family Anisakidae of Superfamily Ascaridoidea are parasites of what animals?
How do marine animals get infected with Anisakidae?
By eating fish
Can humans get Anisakidae? If yes, what can you do to prevent it?
Yes, they can by eating raw, pickled fish
Larvae try to leave GI tract-very painful
Larvae killed by:
-freezing for 24 hours at -20C
How often should puppies with Toxocara canis be treated to prevent shedding?
Every 2 weeks starting at 2 weeks of age.
What are superfamilies belonging to the order Strongylida?
What are morphologic characteristics of Strongylida order?
Bursate nematodes
-modified cuticle used in reproduction
Buccal capsule variable in size and shape
Adults are blood or tissue feeders
What is general lifecycle of Srongylida?
Direct lifecycle: fecal-oral
Most members produce simiar eggs: oval, thin, shell, ball of cells inside (morula)
L1 develops in egg, hatches, develops to L3 eating bacteria in environment, retains cuticle of L2 as protective sheath.
What do larval development and survival depend on?
Local climate
Dessication is most important negative factor. Temperature tolerance vaires with spp, but extremes are bad
What are factors that promote development of L3 from egg?
What are factors that promote survival of L3?
Egg-->L3: Warm temperature (50F min), moisture

L3 survival: cool temperature, moisture
What is the name of larval stage that becomes dormant for variable time period (L3 or L4), also called "arrested development"?
What makes larva undergo hypobiosis?
Proportion of arrested larvae increases during the time of year when survival of larvae on pasture is lowest
What are general charachteristics of Trichostrongyloidea family?
Small thread-like worms
ID based on male bursa and spicules
Buccal capsule is small
GI parasites
1 lungworm genus
Important ruminant parasites
What is the general lifecycle of Trichostrongyloidea family?
Definitive host ingests L3. No migration in host from GI except lungworm.
Parasitic gastroenteritis in ruminants or HOT complex is due to what 3 genera of Trichostrongyloidea family?
What are two less important genera of Trichostrongyloidea family?
What is the brown stomach worm of cattle and sheep?
Ostertagia ostertagi--cattle
Ostertagia circumcincta--sm. ruminants
What is the pathogenesis of Ostertagia ostertagi?
Cattle ingests L3 from pasture
Larvae enter gstric glands for minimum of several days
Emerge into lumen, become adults
While in gastric gland, facilitate cell dedifferentiation, hyperplasia, nodule formation, decreased pepsin production, high pH of Abomasal lumen
What is the minimal prepatent period of Ostertagia spp?
Minimum prepatent period: 3 weeks.
Maximum 4-6 months
What are the clinical sings of Ostertagiasis?
Light infection: no effect
Moderate infection:
-decreased production
Heavy infection:
-anorexia/weight loss
hypoprotenemia (bottle jaw)
What is the difference between type 1 and type 2 syndromes caused by Ostertagia?
Type 1: result of accumulation of worms to pathogenic theshold; many animals are affected, mid to late grazing season; few fatalities; diarrhea, wt. loss
Type 2: follows resumption of development by large number of hypobiotic larvae; few animals affected; when arrested larva emerges; high proportion of deaths; acute, severe diarrhea, dehydration
How fast does immunity to Ostertagia develops in cattle?
Gradually over several grazing seasons
What is the most important helminth of small ruminants in eastern US and the world?
Haemonchus contortus
What is bovine equivalent of Haemonchus contortus of small ruminants?
Haemonchus placei
What are characteristics of Haemonchus spp?
Abomasal blood sucking parasite
If you can see worms in ruminant abomasum, it's Haemonchus
What is Haemonchus contortus life cycle?
Prepatent period 2-3 weeks
Very prolific
Likes warm weather, humidity
Winter hypobiosis in US
What are clinical signs of Haemonchus spp infection?
Anemia (NOT diarrhea)
Failure to gain wt/wt loss
Bottle jaw
What is the stomach/abomasum spp of Trichostrongylus genus?
What is its host range?
Trichostrongylus axei
-rarely pig
What is the clinical sign of Trichostrongylid axei in heavy infection?
What Trichostrongyloidea spp infect small intestine of ruminants?
Cooperia spp.
How is Nematodirus spp different from other Trichostrongyloidea superfamily spp?
Eggs are uniue
N. helvetianus in calves on lots may be pathogenic
What Trichostrongyloidea superfamily spp are parasites of trachea and bronchi?
Dictyocaulus spp.
What genus is the parasite of trachea and bronchi in cattle?
Dictyocaulus viviparus
What genus is the parasite of trachea and bronchi in small ruminants?
Dyctyocaulus filaria
What genus is the parasite of trachea and bronchi in horses?
Dyctyocaulus arnfeldi
In what geographical location Dyctyocaulus spp are most important?
Northern Europe (US too hot and dry in summers)
What is the lifecycle of Dyctyocaulus?
L3 larvae migrate from intestine to lungs
Females lay eggs that hatch immediately
Larvae coughed up, swallowed, passed in feces
Eggs, larvae, and adults cause verminous pneumonia
What are clinical signs Dyctyocaulus?
How is Dyctyocaulus diagnosed? How is it treated?
Baermann exam for lavae
Treated with most anthelmintics
What is the typical history of horse with Dyctyocaulus?
Grazing with donkeys
Uncommon infection, hard to diagnose
What is Trichostrongyloidea superfamily parasite of pigs?
Pathologic lesions similar to Ostertagia
What is the important parasite of grouse?
Trichostrongylus tenuis
What egg can be easily confused with Trichuris eggs?
Eucoleus (Capillaria)
Is Trichurius common in cats?
No. It's very rare, but may be present in cats in FL
What is the parasite of bladder of dogs and cats?
Pearsonema spp (Capillaria in older texts)
How can you diagnose Pearsonema spp? What problem is associated with Pearsonema spp?
Eggs in urine. Do not do free catch sample collection.
May cause cystitis
What Trichinelloidea superfamily spp are common in wild and exotic birds?
Capillaria spp
Can ruminants get Capillaria spp? How important is it in ruminants?
Yes, they can, but it's of NO importance.
What spp are small worms that live in SI of warm blooded animals?
Trichinella spp
What disease is produced by Trichinella spp?
How do Trichinella spp differ from other spp?
Each infected animal is a definitive AND intermediate host
How can humans get infected with Trichinella spp? What are the symptoms?
By eating infected pork
Enteritis from adults
Myalgia, fever, respiratory and cardiac failure
5 larvae/g muscle fatal for humans
What impact did Trichinella spp have on the swine industry?
Enormous impact:
Caused perception that pork is unsafe
Expensive testing conducted in Europe (antibody and microscope tests)
Potential export barrier and perception problem
What is the prevalence of Trichinella spp now? Why has it decreased?
Prevalence is very low
It decreased with introduction of Trichinae herd certification program
What other meat can Trichinella spp be acquired?
From bear meat: most common source of US cases
Bear spp survives freezing
Where can pinworms be found? How widely are they distributed?
Usually small adluts in large intestine
Spp in horses, rodents, ruminants, reptiles, people
Can humans give/get pinworms to people?
NO. Dogs and cats do NOT get pinworms
What order do pinworms belong to?
What is the only pinworm in common domestic spp you see?
Oxyuris Equi in horses
What do Oxyurida eggs look like?
May have polar plug, often flattened appearance on one side
Are pinworms very pathogenic?
No, they are not
What are clinical signs of Oxyuris equi?
"Rat-tailed" appearance to tail
What is the diagnosis for pinworm infection?
"Scotch tape test" for eggs, because they will not be in feces
How do you treat a pinworm infection?
Any modern anthelmintics
Where do most members of order Rhabditida live?
Most are free living nematodes
Only one important genus
What is the only one important genus of order Rhabditida?
StrongylOIDES found in small intestine
What spp of Strongyloides are parasites of humans and dogs?
Strongyloides stercoralis
What spp of Strongyloides are parasites of foals?
Strongyloides westeri
What spp of Strongyloides are parasites of swine?
Strongyloides ransomi
How big are Strongyloides worms?
Very small (6mm)
Are Strongyloides infections common?
How do dogs get infected with Strongyloides?
Skin penetration
What are clinical signs of Strongyloides stercoralis?
Most infections asymptomatic
Diarrhea, bronchopneumonia from migration
Most serious in immunosuppressed dogs and humans
How do you diagnose Strongyloides stercoralis?
Detection of L1 with Baermann exam. (Suspend fecal sample in water, larvae falls down by gravity)
How do you treat Strongyloides stercoralis infection?
Ivermectin is best
What is the primary route of infection with Strongyloides ransomi in pigs?
Primarily transmammary infection
What are clinical signs of Strongyloides ransomi infection?
Neonatal diarrhea
How do you diagnose Strongyloides ransomi in pigs?
Larvated egg in feces
How do you treat Strongyloides ransomi infection?
With Macrolides given to sow prefarrowing
How is Strongyloides westeri transmitted in horses? Is it common?
It is transmitted in milk. Uncommon in well-managed horses
What is the prepatent period of Strongyloides westeri?
About 2 weeks
How do you treat Strongyloides westeri infection in horses?
With Macrolides
Do Strongyloides spp occur in ruminants?
Yes, they do, but rarely cause disease.
Do free living spp of Rhabditida cause problems?
Occasionally, they are opportunistic parasites that invade skin of anima kept on moist, soiled bedding and may cause dermatitis
What are some common characteristics of Order Enoplida Superfamily Trichinelloidea?
Stichosome esophagus
Stichocytes are glandular cells
What is the common name of Trichuris?
What are general characteristics of Trichuris spp(whipworms)?
Whip-shaped body
Anterior end entwined within layer of epithelial cells
Bipolar eggs passed in feces; infective larvae develops in egg (weeks)
Direct life cycle
How resistant to environmental stress are Trichuris spp?
What is one of the BIG THREE helminths in dogs that belongs to order Enoplida?
Trichuris vulpis: canine whipworm
What is the lifecycle of Trichuris vulpis?
2 weeks minimum to develop
Larvae enter gut wall for a few days, emerge and mature
3 months prepatent period
What are clinical signs of Trichuris vulpis infection?
Many infections asymptomatic-like hookworms
Heavy infections may produce clinical disease
Diarrhea: smelly maybe heamatochezia
What age group is most affected by Trichuris vulpis?
Any age. Unlikely in very young dogs.
Superfamily Strongyloidea of Order Strongylida are parasites of what body region?
GI tract
Give general characteristics of subfamily Strongyloidea.
Large buccal capsule: plug feeders
Tend to be bigger than trichostrongyles
What are the most important members of superfamily Strongyloidea?
Common equine strongyles:
Family Strongylidae
-Lg. strongyles (Subfamily Strongylinae)
-Sm. strongyles (Subfamily Cyathostominae)
What are general characteristics of Strongylidae family?
Parasites of equine large intestine
Expect all horses to have some
Produce typical strongylid eggs
What are general characteristics of Subfamily Cyathostominae?
Most numerous and important strongyles in horses and other equids
About 40 spp up to 2cm
General strongylid lifecycles from egg to L3
Do Cyathostomes have shorter prepatent periods than trichostrongyles?
Yes, they do.
What age horses are most susceptible to cyathostomes?
Young horses
Adult horses may be overwhelmed by large numbers
What are general characteristics of Subfamily Strongylinae?
Adults 3-5 cm in length
Make up small proportion of total worm numbers in horses
Larvae usually undergo a migratory phase in the host
Only a few spp in subfamily
What is the most important stage of Strongylus vulgaris?
Larval stages
Following infection L4 migrates through arteries reaches junction of cranial mesenteric artery and aorta
Larvae damage vessels leading to thrombus formation; worms in large thrombus at base of cranial mesenteric and ileo-cecal-colic vessels
Verminous arteritis
What is the prepatent period of Strongylus vulgaris
Mature, prepatent period 6 months after infection
What is the complication of Strongylus vulgaris thrombus formation?
Thrombus can block blood flow; interfere with nerve transmission
Portions of thrombus may break off, block blood flow distally
In severe cases necrosis of portions of bowel occurs
Prominent clinical sign-colic
Are complications of Strongylus vulgaris treatable?
Yes, lesions regress after worms leave or treatment
Adult worms do little damage
What do you treat Strongylus vulgaris infection with?
Macrolides (effective against larvae and adults)
Are other large strongyles a problem in animals?
Not really. Larvae migrate in liver, other tissues and create nodules in wall of liver on return. Mostly noted during necropsy
What spp of Superfamily Strongyloidea are found in cattle, small ruminants, pigs?
Oesophagostomum spp.
Where do Oesophagostomum spp adults live? What is their significance?
In large intestine. Larvae in intestinal mucosa.
They may lead to production losses in heavy infection
What leads to a large nodule formation in case of Oesophagostomum larvae?
Immune response
What is the tracheal parasite of birds of superfamily Strongyloidea?
Gapeworm (Syngamus)
What measures of control would you implement against order Strongylida parasites?
Grazing animals HAVE to be on some kind of control
-Reduce parasite exposure on pasture
-Immunity of the host
What was the biggest failure of the "feed store"?
Development of resistance
Horses: BZDs, pyrantel
Small ruminants: everything
Cattle: emerging
For whom should the safest pasture be reserved?
For the most vulnerable animals
-High performance
Pasture should hav low #s of larvae
What measures can be implemented to increase parasite control on pasture/immunity of the host?
Reduce stocking density
Remove manure (horses)
After grazing pasture, harvest regrowth for hay
Pasture rest
Diversification is good for parasite control
Alternate/mixed grazing
What natural behaviors of domestic animals increase host immunity?
Horses and cattle will not graze around fecal mass
Goats are browsers
Llamas defecate in community piles
How can you use immunity of the host to your advantage?
Cull highly susceptible animals
Select resistant animals
Selective deworming programs
Use less dewormer
Deworm animals that need it most
What elements are you looking for while designing selective deworming programs
Fecal egg counts
Conjunctival mucous membranes
Grouping animals by age, etc.
What deworming products are used most often in CATTLE and SMALL RUMINANTS?
What deworming products are used most often in HORSES?
What order and family do hookworms belong to?
Order Strongylida
Superfamily Ancylostomatoidea
Family Ancylostomatidae
Where do hookworms live?
Small intestine of small animals, ruminants, humans, and others
What is the typical appearance of a hookworm?
Large buccal capsule, teeth or cutting plates. They are BLOODSUCKERS
What is the lifecycle of a typical hookworm?
Typical strongylid egg
Development as for other strongylids
Development best in moist, shaded, slightly sandy loam (doesn't have to be grassy).
What are hookworm spp of CANINES?
Ancylostoma caninum
Ancylostoma braziliense
Uncinaria stenocephala
What are hookworm spp of FELINES?
Ancylostoma tubaeformae
Ancylostoma braziliense
Uncinaria stenocephala
What is the life cycle of Ancylostoma caninum?
Prolific females
Eggs passed in feces
Hatch rapidly in warm weather
L3 formed in about 7 days at 72F
-2 days at 99F
What are the routes of transmission of Ancylostoma caninum?
Skin penetration
Ingestion of larvae
Ingestion of transport host
What is the fate of larvae of Ancylostoma caninum in a dog?
Adult in small intestine OR
Enter intestine wall later emerge OR
Migrate to join somatic reservoir
What happens to larvae of Ancylostoma caninum in somatic reservoir?
Reactivation of arrested larvae
-Migration to mammary gland
Transmammary transmission to puppies (major route)
Transplacental transmission (minor)
-Migrate to small intestine (mechanism for repopulation after treatment)
What are some clinical signs of Ancylostoma caninum?
Anemia, hypoproteinemia
Skin lesions
What age group of dogs is most susceptible to hookworms?
Most adults infected but no disease unless immunocompromised, overwhelmed by parasite numbers, or malnourished
How do you diagnose Ancylostoma caninum?
Must distinguish from other strongylid eggs
Prepatent period depends on infection route (2 wks minimum)
Clinical signs especially in young puppies
How do you treat Ancylostoma caninum?
Canine anthelmintics (except piperazine) effective
Repeat treatment at 2-3 weeks
Many heartworm preventatives effective
What control can you implement for Ancylostoma caninum?
Pick up feces promptly
At least 2X/week
Wash surfaces with 1% bleach, larvae exsheathe, die faster
What is the uncommon hookworm of CATS?
Ancylostoma tubaeformae
How pathogenic is Ancylostoma tubaeformae?
Not as pathogenic as A. caninum; not much skin penetration; don't see heavy burdens in kittens
What is the hookworm of DOGS and CATS in coastal Southern US and south?
Ancylostoma braziliense
Vigrous skin penetrator
What are public health concerns with Ancylostoma?
Larvae can penetrate human skin (especially Ancylostoma braziliense)Produces serrpiginous tracks known as "Cutaneous Larva Migrans"
Occurs most frequently in people with lots of soil contact
Rare cases of adult development in human GI tract (A. caninum)
What hookworm infects DOGS and rarely CATS with more Nothern distribution that tolerates cold weather?
Uncinaria stenocephala
Is Uncinaria stenocephala pathogenic?
Not highly, not much of a skin penetrator.
Mixed infections with Ancylostoma around here
What is a hookworm of ruminants?
Bunostomum spp
What are characteristics/symptoms of Bunostonum spp?
Subtropical and tropical
Skin penetrator, can cause cutaneous larvae migrans
Large numbers can cause severe anemia, death
Describe some general characteristics of superfamily Metastrongyloidea
Different characteristics from other members of the order
-Long, slender adults in lungs and other tissue sites
Usually intermediate host invertebrate or mollusc
Usually diagnose larvae in feces
What is a feline lungworm of superfamily Metastrongyloidea?
Aleurostrongylus abstrusus
What is the intermediate host of Aleurostrongylus abstrusus?
Mollusc plus transport hosts
What are clinical signs of Aleurostrongylus abstrusus?
How do you treat it? How do you diagnose it?
Subclinical to serious respiratory disease
Diagnose by Baermann for larvae
Treat with Ivermectin, long term Fenbendazole
What is a memingeal vessel worm of white tailed deer of the Eastern US, Canada? What is its intermediate host?
Parelaphostrongylus tenuis
Intermediate host: snail
Where is larvae of Parelaphostrongylus tenuis passed?
In feces
What is the pattern of migration of Parelaphostrongylus tenuis?
In deer, migrate from GI up spinal cord to reach brain
Abnormal hosts develop CNS symptoms
Signs range from lameness to paralysis
No definitive antemortem diagnostic test
What is the treatment of Parelaphostrongylus tenuis infection?
High dose anthelmintic, antiinflammatory drugs
What control should you exercise to prevent Parelaphostrongylus tenuis infection?
Exclude deer from pasture
Snail/slug control
Anthelmintic treatment
What is the common name for Haemonchus contortus?
The barber pole worm
Describe general characteristics of order Spirurida superfamily Filaroidea
Parasites of connective tissue, blood vessels, lymphatics, etc.
Adults feed on lymph or plasma
Long slender worms, no distinctive characteristics
usually insect intermediate host
Females produce microfilaria
What is microfilaria?
Larvae less developed than L1
What is the name for CANINE heartworm?
Dirofilaria immitis
What are other definitive hosts of Dirofilaria immitis? What are other hosts of Dirofilaria immitis?
-Califronia sea lions
-Wild canids
Other hosts:
What is the general appearance of Dirofilaria immitis?
Long, thin-females reach 28cm
Found in pulmonary arteries and right heart
What is the life cycle of Dirofilaria immitis?
Adult females produce microfilariae which circulate in peripheral blood
Mosquito consumes microfilariae with blood meal
They develop to L3 in mosquito about 10-14 days in warm weather
L3 deposited at the site of bites
In DH migrates through tissue and abdominal wall to thorax
Reach pulmonary arteries and heart about 70 days after infection, but further development still required
Adult worms and MF productio nabout 190 days after infection
What are some of the uncommon clinical signs of heartworm?
Rarely may see signs of glomerulonephritis, dermatitis
How long can microfilaria survive?
How long can adult heartworm survive?
Microfilaria can survive up to 1 year
Adults can live 5+ years in dogs
How would you diagnose Dirofilaria immitis?
Microfilariae detection
Heartworm antigen test
What are some problems with MF only heartworm testing techniques?
Misses single sex
Only detects patent infections
Misses immune clearance of MF
Misses if on macrolides
How early can you detect a heartworm antigen?
The earliest is 5 months after infection
In low worm burdens antigenemia may not develop until 9 months
When should puppies first be tested?
Interval to first testing of dogs 7 months after birth
Why should you test dogs before starting on preventative?
Adverse reaction possible if microfilariae present
What is the additional procedure you can perform to diagnose heartworm in dogs?
Radiography and other imaging procedures
What is the treatment for heatworm?
-Melarsomine (Immiticide)
Macrolides for microfilariae
Hospitalize dog on the day of treatment
What is the risk associated with heartworm treatment?
Risk of pulmonary thromboembolism
What do Arsenicals treat?
Adult heartworm infection
What are the most common heartworm preventatives?
Macrolides monthly
What do montly macrolide heartworm preventatives treat?
Larvae acquired in the previous 45-60 days
What are additional effects of macrolides in heartworm prevention?
Sterilize adults
Kill microfilariae
Safety net effects
What are safety net effects of macrolides?
Ivermectin over long periods of time:
Growing worms are stunted
Female reproductive tract atrophies
Worm vitality reduced
Prevents or reduces development of disease by gradually clearing infection
The younger the worms, the greater the effect
Can CATS get Dirofilaria immitis?
Prevalence is lower than dogs (5-20% of canine prevalence)
What symptoms of Dirofilaria immitis do cats have?
Many show no signs
Clinically affected animals:
-Respiratory signs
-Exercise intolerance
-Sudden death
Disease occurs with parasite death either as larvae or adults
-Inflammation and thromboembolism
Specifically what causes problems in cats with heartworm disease?
Most problems are from cat response to larvae
May be misdiagnosed as asthma or allergic bronchitis
Heartworm Associated Respiratory Disease (HARD)
What is the diagnosis of heartworm disease in cats?
Rarely MF+
Antigen test maybe negative due to low worm burden
Pre-prophylaxis testing:
-Establishing baseline
Do both antibody and antigen tests
What is the treatment of FELINE Dirofilariasis?
Difficult: arsenicals toxic, risk of thromboembolism; supportive care
What is the other host that can get Dirofilaria?
What can Dirofilaria cause in humans?
Insignificant, may cause radiographic lesions in lungs
What is the parasite of canine SC tissue with no pathogenic importance, but MF can be confusing which can be differentiated microscopically or by antigen test?
Dipetalonema reconditum
What adult worm can be found in horse's nuchal ligament? What is the IH?
Onchocerca cervicalis
IH: Culicoides (midge)
What are clinical problems associated with Onchocerca cervicalis?
Nonseasonal dermititis
Eye lesions
How do you treat Onchocerca cervicalis?
What is the stomach worm of wild animals, dogs, anc cats? What is its IH?
IH: Corpophagous beetles
Is Physaloptera pathogenic?
Not usually, maybe chronic vomiting
How do you diagnose Physaloptera?
Eggs dont' float well-use sugar or sedimentation
What Spirurida spp live in nodules in equine stomach? What are their intermediate hosts?
Draschia and Habronema
IH: stable and house fly
Flies deposit larvae around mouth or other moist areas, larvae cause "summer sore" in other locations that can be mistaken for exuberant granulation tissue, neoplasia
What spp of Spirurida is an "Eye worm"?
Lives in conjunctival, lacrimal sacs
Eggs in tears, eaten by face and some other flies
Several spp infect horses, cattle, dogs
Is Thelazia pathogenic?
Not usually, but may cause conjunctivitis
Treatment: removal
What are general characteristics of phylum platyhelminthes?
Flat mostly, hermaphrodites, definitive host diagnosis-eggs
At least 1 intermediate host
Tapeworm and flukes
What class do tapeworms belong to?
Class Cestoda
Sgmented, relatively long
In GI tract--gutless
At least 1 intermediate host
What 3 region is the body of Cyclophyllideans divided into?
Scolex: suckers/hooks
Neck:region of cell division, gives rise to segments (Proglottids)
Strobila: collective term for all segments (body of tapeworm, oldest segments last)
What two orders does class Cestoda include?
Order Cyclophyllidea
Order Pseudophyllidea
What two classes does phylum Platyhelminthes include?
Class Cestoda
Class Trematoda
What structures does scolex contain?
Attaches to gut wall
What does each segment of a tapeworm have?
All repro organs mature and immature, GRAVID contains fully developed eggs
Maturation occurs as moves down the chain
What do you see in feces of animals with tapeworm infection?
Gravid segments often passed out of host
What is the general name of any larval stage of a tapeworm?
What family do most tapeworms belong to?
Family Taeniidae
What are the three families of order Cyclophyllidea?
What do segments of Taeniidae tapeworms look like?
Square to rectangular in shape
What stages of development of tapeworms are the most important ones for disease and economic loss?
Larval stages
What is the DH of Taenidae tapeworms? What is the IH of Taenidae tapeworms?
DH: predator mammal
IH: hebrivore or omnivore
Do Taenidae eggs always show up in fecals?
May or may NOT be there; fecals often negative
What is the basic metacestode stage of family Taeniidae?
What is and infection/disase caused by cysticercus stage of Taenids called?
Name Taeniid spp with small animal definitive hosts
Taenia pisiformis
Taenia taeniaeformis
Taenia hydatigena
Echinococcus granulosus
Echinococcus multilocularis
What tapeworm is common in SUBURBAN/RURAL outside DOGS? What is the IH and clinical signs?
Taenia pisiformis
Rabbit is an intermediate host
Clinical signs are minimal to none
What is the tapeworm of CATS common in hunting cats? What is the IH and clinical signs?
Taenia taeniaeformis
Small rodent is IH
Inapparent infection
What is the tapeworm of DOGS with ruminants and pigs as intermediate hosts?
Taenia hydatigena
What is the metastode stage of Taenia hydatigena? What does it look like?
Cysticerci attached to peritoneal membranes
May cause confusion at the slaughter house or amongst hunters
What tapeworm of international importance has a DOG/SHEEP cycle?
Taenia multiceps
What tapeworm is of economic importance in Australia and New Zealand (gids)
Taenia ovis
What two tapeworms belong to genus Echinococcus?
E. granulosus
E. multilocularis
How do spp of Echinococcus genus reproduce?
Asexual multiplication in metacestode stage
Are Echinococcus tapeworms zoonotic?
Yes. They are zoonotic
What is the definitive host of Echinococcus granulosus? What is its IH host
DH: Canid
IH: Usually sheep, some strains in horses, camels, humans
What does Echinococcus granulosus form in IH?
UNILOCULAR Hydatid cyst (1 chamber); grows like a balloon
Usually in liver, lung--asymptomatic in IH
What do hydatid cysts of E. granulosus cause in humans?
Hydatidosis: related to location
Treatment often surgical
Widespread globally
What is the tapeworm of foxes, and sometimes dogs and cats? What is the IH?
Echinococcus multilocularis
IH: small rodents (humans)
What is the larval stage of Echinococcus multilocularis?
MULTILOCULAR hydatid cyst, which grows by budding chambers
More difficult to remove surgically than unilocular cyst
Present in Alaska, Europe, Asia, Canada, nothern US
What are two Taenia spp with human DH?
Taenia saginata
Taenia solium
What is the IH of Taenia saginata?
Bovines are IH for Taenia saginata
What is the metastode stage of Taenia saginata?
How do humans get infected with Taenia saginata? What are the symptoms?
Cysticercoids in bovine muscle
Mild abdominal discomfort
Common in many developing countries, uncommon in US
How can you kill cysticerci?
By heating to 56C or freezing to -5C for a week
What is the parasite of humans with pig as an intermediate host? (Humans can also be IH)
Taenia solium
What problem is caused by Taenia solium cysts? What are the clinical signs?
Human cysticercosis in Latin America, Middle East, Asia
Clinical signs develop when cysts die in NS
What is the metacestode stage in non-Taeniad Cyclophyllidean tapeworms?
Cysticercoid: smalll cyst with a single scolex
What is the most common tapeworm of DOGS and CATS transmitted by fleas?
Dipylidium caninum
How do dogs get infected with Dipylidium caninum?
Flea larvae eats eggs, host infected when ingests adult flea
What is the clinical problem associated with Dipylidium caninum? How serious is the infection?
Not really a clinical problem, maybe some perianal irritation
Zoonosis results in uncommon infections in children
What spp of tapeworm infect horses? How do they get infected?
Infection from ingesion of cysticercoid in pasture mites
What spp of tapeworm infect ruminants? How do they get infected?
Infection from ingesion of cysticercoid in pasture mites
What is the most common tapeworm of horses?
Anoplocephala perfoliata
Where do adlut Anoplocephala perfoliata live in a horse?
Cluster at ileo-cecal junction
What is a clinical presentation of Anoplocephala perfoliata?
Usually asymptomatic , but occasionally may cause inflammation and ulceration
What is the diagnosis of Anoplocephala perfoliata?
Difficult to diagnose
Fecals often negative
What do you treat Anoplocephala perfoliata with?
Previously Pyrantel 2X
What do you treat Moniezia infestaion in ruminants with?
How significant are Moniezia spp in ruminants?
Not very
Do birds get tapeworms and do they cause pathogenesis?
Yes, Avian tapeworms can be pathogenic
What type of parasites belong to order Pseudophyllidea?
Tapeworms with at least one aquatic animal
What do eggs of Pseudophyllidea look like in fecals?
Look like fluke eggs, brownish, operculated, passed as eggs, not segments
What is the "zipper tapeworm" with CATS, sometimes DOGS, and wild animals as DH?
How do CATS, DOGS, and wild animals get infected with Spirometra?
Infected by eating amphibians or reptiles
What is a tapeworm of broad fish? What spp can get infected?
Dogs, cats, humans, wild carnivores can get infected by eating fish
What are two orders of class Trematoda?
Digenea: flukes of domestic animals and humans
Monogenea: external parasites of fish, reptiles, and invertebrates
What are some general characteristics of order Digenea?
Leaf shaped, unsegmented, 2 suckers
Mostly 2 intermediate hosts, but first ones is always a snail
Egg operculated produced by adult
What life stage of Digenea order ENTERS an IH snail?
Miricidium: undergoes asexual developmentin several morphologic forms: sporocyst, redia
What is the larval stage of Digenea order that LEAVES the snail?
Cercaria: swims, ingested in land cycles
What is the second larval stage of Digenea order?
Metacercaria: in/on second intermediate host. It's what the DH ingests
What is the name of a liver fluke of RUMINANTS that can also infect dogs, cats, horses, people, and rabbits?
Fasciola hepatica
How important is liver fluke?
Important where occurs
Causes liver condemnation, production losses in ruminants, hepatic disease insmall animals
Where are adults of Fasciola hepatica found? Where are eggs found?
Aduilts in bile ducts
Eggs passed in feces
How do metacercariae get into a definitive host?
They encyst on vegetation, and get ingested by definitive host
What happens to Fasciola hepatica after it gets ingested by definitive host?
It leaves intestine and migrates to liver
Larval migration in the liver (several weeks)
Enter bile ducts and mature
What does Fasciola hepatica cause in cattle?
Cause of chronic poor doing
Anemia, hypoprotenemia
Weight loss, decreased milk production
Immunity gradually develops
What does Fasciola hepatica cause in a sheep?
More severe, may be fatal disease than in cattle
How do you diagnose Fasciola hepatica?
Fecal exam
SEDIMENTATION procedure, not very sensitive
What control would you implement to reduce Fasciola hepatica? How do you teat F.hepatica?
Routine treatment required where common
Treat when transmission is low, worms mostly adults, snails dormant
Albendazole, Clorsulon
Drugs not very effective against larvae
Management: drain, fence out
What part of the country is Fasciola magna important in? What animals have it?