Lecture 20 4/23/24 Flashcards
What are the general characteristics of insects?
-separate head, thorax, and abdomen
-six legs
-0-4 wings
-simple and/or compound eyes
-antennae
-mouthparts
-striated muscle
-chitinous exoskeleton shed periodically
-complete or incomplete metamorphosis
-most are free-living or ectoparasites
What are the general characteristics of lice?
-compressed dorsoventrally
-wingless
-recurved claws for grasping hair/feathers
-small thorax w/ short, stout legs
-eggs laid one at a time
-nits are the eggs; resistant to treatment
-incomplete metamorphosis
-highly species specific
What are the characteristics of Mallophaga lice?
-biting/chewing
-head wider than thorax
-hosts include birds and mammals
What are the characteristics of Anoplura lice?
-sucking
-head more narrow than thorax
-hosts include mammals
Where do all of the lice life stages occur?
on the host
What are the characteristics of Anoplura infestation?
-important cause of anemia and hypoproteinemia
-able to treat w/ injectable systemic treatments
-efficient vectors of diseases such as Rickettsia prowazekii, Borrelia spp., and tularemia
Which species of lice are seen in humans?
-head lice/Pediculus humanus capitis
-body lice/Pediculus humanus humanus
-pubic lice/Pthirus pubis
Why is it important that human lice are not transmitted by animals?
-infected humans must have gotten it from another human
-human lice on animals indicate contact with an infected human
What are the characteristics of Haematopinus suis?
-largest louse species
-found in folds of skin behind ears and between legs
-blood-sucking activity leads to discomfort and irritation
Which species is the Anoplura species of the dog?
Linognathus setosus
What are the characteristics of Linognathus vituli?
-long-nosed cattle louse
-Anoplura of cattle
-treated with ivermectin
What are the characteristics of Trichodectes spp.?
-antennae stick out from head
-Mallophaga
-minor intermediate host of Dipylidium caninum
What are the characteristics of Bovicola spp.?
-seen in livestock
-Mallophaga
-antennae stick out from head
-easily visible three-segment antennae
-cause irritation
What are the characteristics of Bovicola bovis?
-irritation leads to self-barbering
-focal areas of alopecia
-can see nits in fur
-treat with pyrethrin dust
What are the key factors of treating lice in livestock?
-treat ALL animals
-dose to appropriate weights
-read labels; some chemicals can be toxic, and some products should not be used in pregnant/lactating animals
-take appropriate environmental precautions
-observe withdrawal times
-retreat ALL treated animals 10-14 days after first treatment
What are the general characteristics of fleas?
-complete metamorphosis
-laterally compressed
-wingless
-separate head, thorax, abdomen
-6 legs
-hind legs specialized for jumping
-adults are parasitic; feed on mammals and birds with piercing/sucking mouthparts
-juveniles feed on flea dirt
Which fleas are of importance in dogs and cats?
-Ctenocephalides felis (dogs and cats, most common on both)
-Ctenocephalides canis (dogs)
What is the life cycle of C. felis fleas?
-eggs appear 2 days after male and female fleas arrive
-eggs accumulate where host rests
-L1 hatch around day 4
-larvae feed on adult flea feces
-L3 larvae spin cocoons and metamorphose into adults 2 weeks later
-after 3-4 weeks, adults emerge from cocoons
-adults can survive up to 2 months without a host
-once host is found, adults will remain on host and repeatedly feed and reproduce; rarely leaves host on its own
What are the clinical signs of fleas?
-flea allergy dermatitis
-anemia
Which pathogens are vectored by fleas?
-Dipylidium caninum
-Acanthocheilenema (imposter heartworm)
-plague
-Bartonella
How are fleas diagnosed?
-visible fleas/flea comb
-flea dirt
How are fleas treated?
-vacuuming
-remove bedding
-treatment of carpet
-treatment of all pets
Why must adulticide, IGR, and environmental control all be used when treating fleas?
in order to control all stages of the life cycle on the host and in the environment
What are the characteristics of hemiptera?
-true bugs
-two pairs of wings
-triangular shield between the wing bases
-four-segmented antennae
-three-segmented beak
What are the characteristics of hemipteran life cycle?
-development by simple metamorphosis
-can feed on plants, other insects, or suck blood
-predacious reduviids inflict painful bites
What are the characteristics of Reduviidae?
-wings and characteristic three-segmented beak
-Triatominae subfamily is parasitic and feeds on blood of vertebrates
-hide in crevices by day; attack sleeping hosts at night
-incomplete metamorphosis
-transmit Chagas’ disease in the feces
What are the characteristics of Cimicidae/bed bugs?
-oval, dorsoventrally flattened bodies
-vestigial wings
-three-segmented beaks
-disagreeable odor
-simple metamorphosis
-nocturnal, secretive bloodsucking parasites
-hide in crevices during day and attack sleeping hosts at night
-can endure starvation for several months
-not confirmed to spread disease
What are the characteristics of bed bug behavior?
-shelter in cracks in walls
-prefer rough substrate
-have eyes and will react negatively to light
How do bed bugs feed?
-anchor to skin with claws of the legs
-feed from a blood vessel
-completely engorge in 3-10 minutes
