Arthropods Pt 3

ANS 389C

what is Order Psocodea also known as?

Order Phtheroptera; lice

historically, lice were grouped into 2 main types. what were they?

• sucking lice (Anoplura) - found only on mammals

• chewing lice (Mallophaga) - the name means “wool eaters”, but this group is not scientifically accurate anymore

scientists now only recognize 4 suborders of Order Psocodea. what are they?

• anoplura

• Rhynchophthirina

• Ischnocera

• Amblycera

anoplura

sucking lice that live on mammals only

Rhynchophthirina

rare lice, found on elephants and warthogs in Africa

Ischnocera

mostly chewing lice on birds, but some species are found on mammals

Amblycera

chewing lice found on birds and some mammals in South America and Australia

all parasitic lice are…

• permanent ectoparasites

• obligate parasites

• host specific

what are parasitic lice called?

Phthiraptera

list some morphological features of Phthiraptera

• small

• various colors

• wingless

• dorsoventrally flattened

• stout legs and claws

what do Phthiraptera feed on?

• dead skin

• feathers

• sebaceous secretions (skin oils)

• blood

most lice have similar ___ _____

life cycles

how many eggs do females lay in a lifetime (about 1 month)?

20-200 eggs

eggs are called _____

nits

where are nits located?

glued to hair or feathers

how many molts do nymphs go through before becoming an adult?

3

what is the total time from egg to adult in lice?

2-3 weeks

describe features of sucking lice

• have piercing mouthparts

• feed on blood

describe features of chewing lice

• have cutting and grinding mouthparts

• feed on skin, hair, feathers, scales, scabs

the level of impact a louse has on a mammal depends on..

the severity of the infestation

(true/false) louse populations can increase dramatically in a short time

true

name some clinical effects of louse infestations

• pruritus

• alopecia

• self mutilation

• weight loss

• anemia

how are lice generally transmitted?

through direct physical contact

when do lice become more active?

in the winter

what family contains the largest of lice in domestic animals?

Family Haimotopinidae

what mammals do Haimotopinidae infest?

cattle, pigs, horses

what family infests cattle, sheep, horses and deer?

Family Bovicolidae

order Siphonaptera are also known as

fleas

what stage(s) of Siphonapteras are parasitic?

adult only

what is the feeding type in Siphonaptera?

obligate blood-feeding

over ___% of Siphonaptera live on mammals

95%

list morphological features of fleas

• dark brown to black

• small, wingless

• bodies are laterally compressed (narrow)

• third pair of legs are very long

why are the third pair of legs on fleas very long?

they are designed for jumping

(true/false) fleas are able to parasitize a range of different hosts

true

do female, or male fleas feed more?

female fleas feed more

what effects can blood feeding have on a host?

• pruritus

• skin inflammation

• anemia

what are the 4 stages that fleas go through?

egg → larva → pupa → adult

describe appearance of flea eggs

oval shaped, smooth

where are flea eggs laid?

on host

when do flea eggs hatch?

they hatch dependent on temperature; could take 2 or less weeks to hatch

describe appearance of flea larvae

maggot-like, brown head, bristles

what do flea larvae feed on?

organic debris

how many times does a flea larvae molt until it pupates?

2

the time for a flea to complete its lifecycle depends on _________ and ________

temperature and humidty

what mammals does cutaneous hypersensitivity reactions occur in?

dogs, cats, poultry

what’s an example of fleas affecting public health in humans?

Bubonic Plague — bacteria called Yersinia Pestis

what family parasitizes many types of mammals and is found worldwide?

Family Pulicidae

what is the name of dog and cat fleas?

Ctenocephalides

arachnids are a diverse group of ______-_______ arthropods

land-dwelling

(true/false) arachnids are usually ominvores

false, they are usually carnivores

do arachnids have antennae or wings?

no

do arachnids have simple eyes or compound eyes (like insects)?

simple eyes

what is the main group of veterinary importance in Class Arachnida?

Subclass Acari (mites and ticks)

list morphological features of Acari

• very diverse

• most are tiny

• body looks sack-like, because segments are fused together

• not clearly divided

how many legs do adult Acari have?

4

what are the names of Acari’s body segments?

• gnathosoma

• idiosoma

parasitic mites largely inhabit the _____

skin

what do parasitic mites feed on?

blood, lymph, skin debris, sebaceous secretions

how do parasitic mites feed?

• puncture skin

• scavenge on skin surface

• feed on wounds

what are mite infestations called?

Acariasis

Acariasis can cause severe skin disease called _____

Mange

what are symptoms of Mange?

itching, hair loss, thickened skin

how long do mites stay on host?

usually their whole life

how are mites spread?

mostly spread by direct contact between animals

mites may be intermediate hosts for ________

tapeworms

what are the 4 stages of a mites life cycle?

egg → larva → nymph → adult

how many legs do mite larvae have? nymphs? adults?

larva - 6 legs

nymph - 8

adult - 8

how long does it take a mite to complete its life cycle?

less than 4 weeks

describe appearance of Family Sarcoptidae

round bodies, flattened ventrally

legs embedded in body (appearance of short legs)

what type of mite burrows into the skin?

Family Sarcoptidae

what genera of Family Sarcoptidae are of veterinary importance?

• Sarcoptes

  • sarcoptic mange

• Notoedres

  • mainly affects cats and rodents

• Trixacarus

  • mange in guinea pigs and dogs

do Psoroptidae burrow into the skin?

no

describe appearance of Family Psoroptidae

oval-shaped bodies

legs are longer than the burrowing mites

what genera is of Family Psoroptidae are of veterinary importance?

• psoroptes

  • psoroptic mange

    • cattle, sheep, rabbits

  • chorioptes

    • mild mange, often on legs and tails

  • otodectis

    • ear mites in dogs and cats

what order within Class Arachnida is a large and diverse group of mites that are found in many environments and varied forms?

Order Trombidiformes

what families in Order Trombidiformes are of veterinary importance?

Demodicidae and Cheyletiellidae

what family contains Genus Demodex

Family Demodicidae

where can Demodex mites found?

in many animals, including humans

where do Demodicidae live?

in hair follicles and sebaceous glands

(true/false) Demodicidae are not host specific

false, they are host specific

what species of Family Demodicidae are of veterinary importance?

Demodex canis and Demodex gatoi

most mites in Family Cheyletiellidae are ________, but some species are _________

predators; ectoparasites

what animals do Cheyletiellidae affect?

dogs, cats and rabbits

can Cheyletillidae be tranferred to humans?

yes

what is another name for Family Cheyletiellidae?

“walking dandruff”

Order Ixodida are also known as…

ticks

ticks are obligate blood-feeding _________

ectoparasites

what do ticks feed on?

mammals and birds

(true/false) ticks are larger than mites

true

how often do ticks feed?

infrequently, with long gaps between meals

what are the 2 families of interest in Order Ixodida?

Ixodidae and Argasidae

Ixodidae (hard ticks)

• have a hard plate (scutum) on their back

• in males, it covers the whole back

• in females, larvae, and nymphs, it only overs a small part so the body can swell during feeding

Argasidae (soft ticks)

• no scutum

• include bird ticks and tampans

what are some symptoms of tick bites?

• irritation and inflammation

• allergic reactions (hypersensitivity)

• anemia (if many ticks are feeding)

• reduced production (weight loss, milk drop)

what can tick saliva cause?

• toxicosis

• tick paralysis

most importantly, ticks are vectors of disease:

• viruses

• bacteria

• Rickettsiae

• protozoa