Parasitology Lecture 4

Front 1

Arthropods characteristics

Back 1

1.75% of all animal species
2.exoskeleton
3.insects=6 legs
4.arachnids=8 legs

Front 2

Phylum Arthropoda

Back 2

1.Blackfly(simulians)
2.Glossina-tsetse fly
3.Psychodidae-sandflies(phlebotamus, Lutzomyia)
4.Culicidae-mosquitoes
5.Reduviids
6.Fleas
7.Lice

Front 3

Subphylum Chelicerata (acarina, Arachnids)

Back 3

1.Ixodidae-Hard ticks
2.Argasidae-soft ticks
3.Human mites
4.Sarcoptes Scabeii

Front 4

Gradual Metamorphosis

Back 4

1.Eggs
2.Nymphs
3.Adults

Front 5

Complete Metamorphosis

Back 5

1.Eggs
2.Larvae
3.Pupa
4.Adult

Front 6

Myiasis

Back 6

1.Dipteran(fly) Larvae invading living animal tissue
2.Facultative-Musca Domesticus
3.Obligatory-Bed bugs(cimex)

Front 7

Bed bugs(cimex)

Back 7

1.7sp for hummans
2.in beds, walls
3.feed at night, no pain
4.NOT a vector

Front 8

Lice(walking birthmarks) characteristics, treatment

Back 8

1.Complete Metamorphosis
2.Mammalian Lice-Anaplura:
-Pediculus Humanus
-Phthirus pubis
3.Adults can surv 10days w/o host, nits last longer
4.Insecticides=pyrethrins, Kwell(resistance occuring)

Front 9

Head vs. body lice
identical but not interbread

Back 9

Head
1.lay eggs on hair shafts
body
1.eggs in seams of clothing(300per life of female)
2.can inc. mass 5000x in 3 months

Front 10

Fleas (Siphonaptera) Characteristics

Back 10

1.Ectoparasites of all warm blooded
2.host preferences, but not exclusive
3.survive unfed-3yrs in humidity

Front 11

Siphonaptera growth

Back 11

1.Complete metamorphosis(3larval instars, pupa)
2.Eggs fall off host, mature->nest

Front 12

Siphonaptera Body

Back 12

1.6 legs
2.Hind pair has resilin(elastic prot) for jumping
3.Legs have hooks for fur

Front 13

Important Fleas

Back 13

1.Pulex irritans
2.Xenopsylla sp.-Rat fleas
3.Tunga penetrans-sand flea/chigger
-penetrates skin, nail base, b/w toes
-painful and irritating

Front 14

Chelicerata types, life stages

Back 14

1.850 important ticks
2.35,000 mites
3.3 life stages
-Larva (6 legs)
-Nymph (1 or more)
-Adult (8 legs)

Front 15

Ticks, types

Back 15

1.Argasids-Soft ticks
2.Ixodidae-Hard ticks

Front 16

Argasids characteristics

Back 16

1.Soft ticks
2.can't see head
3.nocturnal feeders(few minutes)
4.bird ticks

Front 17

Ixodidae characteristics

Back 17

1.Hard ticks
2.can see head, Dorsal scutum(shield)
3.host preferences

Front 18

"Three host" hard ticks

Back 18

1.Female drops off, lays thousands of eggs, dies
2.Gene's organ->waterproof wax
3.Larva(hexapod) absorb water, find host, feed for days, drops off
4.Molts on ground to nymph, finds new host, feeds 4-8 days, drops off
5.Molts to adult, new host, mates, engorges, drops off

Front 19

Ticks Host Finding

Back 19

1.Sense ground vibrations
2.Climbs to top of vegatation
3.Haller's organ(front legs)wave around(questing behavior)
-odors
-temperatures
-CO2

Front 20

Ticks feeding

Back 20

1.Haller's organ helps find spot to bite
2.Chelicerae
-sense ATP
-pierce skin
3.Hypostome-anchor
4.secrete cement
5.engorgement->inc. weight by 200x

Front 21

ticks mating

Back 21

1.blend of phenols secreted by male
2.mate on and off host

Front 22

Ticks as ectoparasites

Back 22

Tick Paralysis
-46 species
-single female tick can cause
-symptoms appear in 5-7 days

Front 23

Mites Lifecycle

Back 23

1.Egg
2.larva
3.2-3 nymph stages
4.adult

Front 24

Mites breathing

Back 24

1.Stigmata(large mites)-trachea branching
2.Astigmata(small)-cutaneous

Front 25

Scabies (genus/characteristics)

Back 25

Sarcoptes Scabei
-adult=250uM long
-causes scabies in humans
-mange in animals

Front 26

Dust mites (species)

Back 26

1.Dermatophagoides Pteronyssinus
2.D. Farinae
3.Euroglyphus Maynei

Front 27

dust mites (characteristics)

Back 27

1.on all continents, every house
2.perfer humid
3.maybe 2700/g of dust
4.reared in lab from electric bear trimmings

Front 28

Insecticides types

Back 28

1.DDT/Pyrethrins
2.Organophosporous & Carbamates
3.Bti

Front 29

DDT/Pyrethrins (origin, target)

Back 29

1.pyrethrins first from flowers, DDT from war
2.Target-Na-volt-gated sodium channel
-block channel and slow nerve conduction

Front 30

Organophosporous & Carbamates (history/target)

Back 30

1.origionally nerve poisons
2.Target=Acetylcholinesterase
-irrev bind serine, stop recycling of acetylcholine

Front 31

Bti

Back 31

1.Bacillus thuringensis
2.make 5 toxin prots during sporulation
-lyse larval midgut cells
3.easily develope resistance

Front 32

Insecticide Resistance

Back 32

1.Point mutations in target
2.detoxifying enzymes