Insects Flashcards
Mosquitoes are members of the _________ family?
Culicidae
Mosquitoes are part of an important genera, and include?
Aedes, Anopheles, Culex, Culiseta, and Psorophora.
Mosquitoes are voracious?
Blood feeders.
Mosquitoes breed in?
Water
Mosquitoes feed on? (female vs male)
Females: blood.
Males: nectar, plant juices, and other liquids.
Mosquitoes can transmit disease such as?
Malaria, yellow fever, and dengue in humans, as well as a vector for Dirofilaria immitis and Equine Viral Encephalitis.
Mosquitoes are also vectors for?
West Nile Virus (encephalitis or brain inflammation) which can affect:
-humans, horse, birds, as well as dogs & cats, but in these cases the infection is usually inapparent or mild.
Treatment for mosquitoes usually involves?
Environmental measure such as insecticides, larvicides, or using various species of fish as biological controls.
Control of mosquitoes includes?
- Eliminating standing water from property.
- Removing vessels that may collect rainwater & become breeding grounds.
- Keep watering troughs clean by changing water often.
- Use of mosquito dunks in ponds.
- Commercial repellants such as coils that are burned to produce a smoke that repels.
- Mosquito traps that mimic mammals by emitting CO2, heat, and moisture.
What are some common mosquito repellants?
-DEET, permethrins, and oil of citronella.
For large animals such as cattle?
Mosquitoes
Topical applications such as sprays and repellants are not very effective.
For small animals, especially dogs?
Mosquitoes
Some topical applications also repel and kill mosquitoes (K9 Advantix - Imidacloprid/permethrin).
Flies
Overview
- Class: Insecta
- Order: Diptera
- Generally NOT host specific.
- Lay eggs, hatch into larva, then become adult.
- Some species lay eggs in organic material, filth, wounds, standing water, on the host, etc.
Flies
Tabanus spp.
- Horsefly, deerfly
- Females feed aggressively on blood; bite is painful.
- Can transmit equine infectious anemia, anthrax, tularemia, anaplasmosis.
- Breed in standing water.
- Diagnosis: ID of adult fly.
- Treatment: Commercial fly repellants repeated at intervals.
Flies
Hypoderma spp.
- Common cattle bot fly.
- Larvae can be found in stomach.
- Larvae migrate through flesh, cause weight loss & decrease value of hides.
- Migrate to esophagus or spinal column before forming warbles on the back.
Flies
Hypoderma spp.
Cysts or “warbles” form….
Around the larvae, which undergo two molts (second and third stage).
- The warble stage lasts 4-8 weeks.
- Finally, third stage larvae emerge through the breathing holes, drop to ground, and pupate.
- Flies emerge from pupae in 1 to 3 months depending on weather conditions.
- Adult flies, which do not feel live <1 week.
- The life cycle is complete in one year.
Flies
Hypoderma spp.
Adult flies do not?
Sting or bite, but they are an annoyance to cattle.
Flies
Hypoderma spp.
Diagnosis / Treatment
Diagnosis: Warbles on back of cattle.
Treatment: Pour-on organophosphates (coumaphos, famphur, fenthion); ivermectin.
Flies
Gasterophilus spp.
- Bot fly
- Very common, most horses are infected with Gasterophilus larvae (in the stomach).
- Flies lay eggs on horse which are ingested (July-Sept); larvae develop & remain in stomach over winter; in spring they are passed out & develop into adults.
- Flies buzzing around are annoying to cattle, horses.
Flies
Gasterophilus spp.
Diagnosis / Treatment
Diagnosis: Yellow eggs on hair of legs, face; at necropsy larvae are at pyloric or cardiac region of stomach.
Treatment: Carbon disulfide, dichlorvos, ivermectin, removal of eggs as soon as they are laid.
Flies
Oestrus ovis
- Sheep nasal bot fly.
- Adults lay eggs around nasal area; larvae migrate to sinuses.
- Causes nasal discharge & difficulty in breathing, excessive sneezing.
- Adult flies are annoyance to sheep.
Flies
Oestrus ovis
Diagnosis / Treatment
Diagnosis: Clinical signs; observe larvae at necropsy.
Treatment: Ivermectin is most effective.
Flies
Cuterebra spp.
- Rodent bot fly.
- Larvae are subcutaneous (penetrate skin) or may be ingested.
- Can infect dogs, cats, rabbits, squirrels, mice (rodents are DH).
- Dogs and cats are abnormal hosts for this parasite; aberrant migrations can involve the head, brain, nasal passages, pharynx, and eyelids (can cause CNS probs if block arterial supply to brain).
- Larvae exist in host for 1 to 2 months; exit through breathing hole, fall to ground, and pupate.
Flies
Cuterebra spp.
Diagnosis / Treatment
Diagnosis: Cutaneous lump w/a breathing hold; large light to dark-red or charcoal larvae with dark spines.
Treatment: careful extraction of larvae (damaging larvae may cause anaphylaxis), antimicrobial treatment of wound.
Lice
Overview
- Compressed dorsoventrally.
- Sensitive to direct light, therefore generally found in darker patches of fur.
- Transmission is usually via direct contact.
- Host-specific & spend entire lifecycle on host; this makes them easier to get rid of.
- Adults will die w/in 5 days off host; however, disengaged eggs may hatch if enviro conditions are right.
Lice Two Groups (suborders)
Anoplura (sucking)
- have elongated head (narrower than thorax).
- claws.
- grayish or red.
- usually larger than mallophaga.
- feed on blood.
Mallophaga (biting/chewing)
- rounded head (as wide or wider than thorax).
- yellowish in color.
- generally more mobile than anoplura.
- feed on dead skin & fragments of hair/feathers.
Lice
Species
Anoplura
- Haematopinus spp. (pigs, ruminants)
- Linognathus setosus (dogs)
- Polyplax spp. (mice, rodents)
Mallophaga
- Felicola subrostratus (cats)
- Trichodectes canis (dogs)
Pediculus humanus capitis (human head louse)
Lice
Signs of Pediculosis
- Intense pruritus.
- Self-infliceted wound from excessive scratching which may become infected.
- Dull, rough hair coat.
- Alopecia.
- Examine fur for adults, nymphs and nits (eggs).
- Can be found on the head, at base of ears, and elbow areas (dark furred areas).
Lice
3 Stage Life Cycle
- Egg/nit
- Nymph
- Adult
Lice
Life Cycle
- Females lay eggs which are glued to host’s hair or feathers.
- Eggs develop in 1 to 2 weeks.
- Total development from egg to adult takes from 3 to 5 weeks.
- Adult lifespan is at least one month.
Lice
Treatment
- Carbaryl, pyrethrins, ivermectin, lindane, coumaphos, diazinon, malathion, rotenone,.
- Medicated dips, dusts, shampoos, sprays.
- Usually treat twice, repeat second treatment in 3 weeks (coincide w/life cycle).
Lice
Control / Prevention
- Disinfect enviro and isolation (do not put animal in enviro where lice infested animal was).
- Keep pets away from animals with lice infestation.
- usually not necessary to treat enviro as lice complete lifecycle on host.
Lice
Other Facts
- Lice (& Fleas) are wingless.
- Lice infest mainly very young or very old/debilitated animals.
Mites
Overview
- Microscopic arthropods; not visible to naked eye.
- Transmission is usually via direct contact.
- Host-specific & site of infestation varies with genera.
- Some species cause mange (cutaneous acariasis)
Mites
Species
- Cheyletiella spp. (dogs, cats)
- Demodex canis (dogs)
- Otodectes cynotis (dogs, cats)
- Notoedres cati (cats)
- Sarcoptes scabiei (dogs)
- Dermanyssus gallinae
Cheyletiella Mites
- Walking Dandruff
- lives on surface of skin, may even be seen on hair.
- Collect w/cellophane tape technique
- Relatively large, can be seen w/hand magnifier, brush hair, place material on dark background.
- Causes variable degree of pruritus, produce excessive crusting/scaling of dorsal surface of host’s body.
Demodex Mites
- Red mange, elongated (cigar shaped), stubby legs.
- Entire life cycle spent in hair follicles.
- Host specific, considered non-contagious or transmissible.
- Considered non-pathogenic in small numbers, part of the normal cutaneous fauna.
- Inhabits hair follicles & sebaceous glands of dogs, cats & humans.
- Presence of skin lesions w/ numerous mites recovered on skin scrapings is determining sign.
- Localized areas of redness, crusting, alopecia, initially around eye, ears, & mouth.
- Generalized demodicosis may involve much of the body (dermatitis).
- Inherited immune defect may produce demodicosis.
Sarcoptes Mites
Notoedres Mites
- Scabies, sarcoptic acariasis or sarcoptic mange.
- Relatively host specific, spread by direct contact.
- Parasite of epidermis in dogs and humans.
- Severe pruritus, large areas of alopecia, and irritation around eyes, ears, muzzle, & abdomen.
- Recovery from affected animals is difficult, requires multiple, deep (draw blood) skin scrapings.
- Response to treatment often used as diagnosis (if animal responds to treatment, then sarcoptes is confirmed).
Notoedres is feline scabies, similar to above, smaller in size.
Otodectes Mites
- Common ear mite, NOT host specific, readily transmitted between cats & dogs.
- Parasitizes external ear canal of dogs/cats.
- Common cause of otitis externa.
- May be found on other body parts.
- Cause intense irritation, thick dry, black crusts (like used coffee grounds) in ear canal accompanied by pruritus.
- Scratching & shaking head may produce infection & aural hematoma.
- ID with otoscope, microscope exam.
Mites
Life Cycle
4 Stages
Egg–>Larva (6 legs)–>Nymph (8 legs)–>Adult
Complete in 18-21 days.
Mites
Treatment, Control, & Prevention
Dips (once a wk, 4-7 wks), dusts, shampoos, sprays, liquids containing:
- Amitrax (Mitaban)
- Chlorpyrifos
- Lime Sulfur
- Lindane
- Phospmet (Paramite)
- Carbaryl
- Ivermectin (Acarexx), ear mites
- Thiabendazol (Tresaderm), ear mites
- Selamectin (Revolution), ear mites
Mites
Method of collection of sarcoptes, notoedres, and deomodex:
- Scrape skin w/scalpel blade coated w/mineral oil to allow for debris to stick to blade.
- Also apply mineral oil to slide and wipe scalpel blade on miner oil coated slide.
- May use coverslip.
- Examine under microscope (10x).
Mites
Method of collection of otodectes:
- Dip q-tip or cotton-tipped applicator in mineral oil.
- Swab ear & transfer sample onto slide (add more oil).
- Add coverslip & examine under microscope (10x power)
Fleas
Overview
- Fleas feed on the host’s blood.
- They cause digging, scratching (pruritus)
- Allergies (flea bite dermatitis - FAD)
- Are an intermediate host for Dipylidium caninum (flea tapeworm).
- Are zoonotic, carry diseases such as tularemia, plague, etc.
Fleas
Species
- Ctenocephalides canis (rare), dogs & cats.
- Ctenocephalides felis (most common 85-90%), dogs & cats.
- Pulex irritans (human flea).
- Xenopsylla cheopis (rat flea, main carrier of bubonic plague).
- Echidnophaga gallinacea (poultry, aka sticktight flea, hunchbacked appearance, attaches firmly to host).
Fleas
Signs
- Allergy to saliva, some animals hypersensitive, FAD
- Suck blood and can cause anemia, 250 fleas can consume 10% of a 1 lb kitten’s blood.
- Hot spots, self-inflicted moist dermatitis (may start from a flea bite), excessive licking causes irritation (licking removes keratin layer of skin).
- Adults can be found on host, usually abdomen, thighs, tail, head.
- Flea droppings, “dirt” on animal.
Fleas
Life Cycle
4 STAGES
