Ectoparasites

1. Ectoparasites

2. Learning Outcomes • List common ectoparasites • Identify common hosts for ectoparasites • Identify signs & treatments for common ectoparasites • List common endoparasites (Recap)

3. Introduction • List as many ectoparasites as you can remember ...

4. Most Ectoparasites are Arthropods. These include: • Fleas • Ticks • Mites & Chiggers • Lice • Flies

5. Fleas Ctenophalidescanis/cati • Both dogs and cats are commonly infested with cat fleas. • They are not host specific and prefer warm & humid environments. • Fleas feed on blood by injecting anticoagulant into the animal to prevent clotting. • The anticoagulant is what causes the allergic response.

6. Fleas Ctenophalidescanis/cati Signs of Fleas? • Flea Dirt • Pruritus (Itching) • Loss of condition • Anaemia • Hair loss

7. In favourable conditions, the lifecycle can be completed in 12-16 days. • Eggs are laid in the hair of animals which fall off into the environment. • Eggs hatch in to larval stages which feed on flea dirt, skin flakes and organic debris. • They undergo 2 moulds, pupate, then emerge as adults.

8. Treatment • Fleas can act as an intermediate host to diseases & parasites so animals & the environment need to be treated with insecticide concurrently. • Flea eggs can lay dormant within the environment for up to 2 years and can be triggered to hatch by heat and movement vibrations from animals (inc. Humans).

9. Ticks • All spp. Feed on the blood from a host. • Larval and adult ticks feed, engorging themselves on blood then drop off in to the environment. • Female ticks then lay eggs in a moist location and then die.

10. Ticks • Signs of Ticks? • Anaemia • Observation • Infection from mouthparts • Ticks should be removed carefully but the potential hosts & environment can be treated with insecticides.

11. Lice • Host specific • Attach to the host using claws & feed on blood. • Can be either biting or sucking depending on whether they have evolved to chew the skin or pierce the skin.

12. Lice • Trichodectescanis= Dog biting louse • Linognathussetosus= Dog sucking louse • Felicolasubrostratus= Cat biting louse • Haematopinusasini= Horse sucking louse • Damaliniaequi= Horse biting louse

13. Lice (Pediculosis) Clinical Signs: • Pruritus • ‘nits’ or lice can be seen. • Anaemia • Poor coat condition • Animals & environment must be treated with insecticide and repeated after 10 days, following the hatching of nits.

14. Mites • Subsuface mites: Live in the dermis and have short legs • Surface mites: Lives on the skin surface and have longer legs.

15. Ear Mites: Otodectescynotis Surface mites that possess suckers to attach to ear canal. Are seen as cream dots in ear wax. Other signs? • Head shaking • Head rubbing • Waxy ears • Smell • Treatment by Acaricidal product

16. Chorioptesequi- Surface mites that affect horses, particularly feathers in heavy horse breeds. • Psoroptesequi/cuniculi– Closely related surface mites that have suckers on stalks. P. equiinfects horses (pruritic dermatitis) while P. cuniculiinfects rabbits (ear infections). • Cheyletiella spp. (Walking dandruff) – Suface mites that infect dogs, cats and rabbits. Can be seen by the naked eye and cause a scurfy coat.

17. Mites: Sarcoptesscabeii • A zoonotic subsurface mite (mange). • Eggs are burrowed in to the host’s skin causing an erythenatous, alopecic dermatitis (usually beginning in the pinna, hock or elbow) spreading across the animal. • Treatment = insecticide.

18. Mites: Demodex spp. • Cigar-shaped surface mite usually present in animals with no ill effects. • Stress or immunosuppression can cause overpopulation. • Can be seen as alopecic dermatitis, usually with secondary bacterial infection. • Treatment = Acaricide

19. Chiggers (Mites): Harvest Mites • Neotrombiculusautumnalis – A surface mite prevelant in late summer/autumn that feed on a host and then drop off. • Result in pruritus & dermatitis.

20. Flies • Some fly larvae are facultative parasites = can infest living animals (but don’t have to) • Others are obligate parasites • Fly strike (myiasis) seen in rabbits & sheep, occasionally in cats & dogs

21. Flies- Life cycle • Adults lay eggs in moist conditions, attracted by odours • Larvae (maggots) hatch rapidly, feed on surface of animal, invade deeper tissue as they grow/moult • Once fully developed larva drops off and pupates • Enzymes secreted on animal to assist tissue breakdown have toxic effects on host leading to depression & anorexia

22. Prevention of fly strike • Careful husbandry prevent build up of faeces • Examine animal at least once daily • Apply larval growth inhibitor = cyromazine (rearguard) • Control flies

23. Treatment of fly strike • Remove maggots • Shave and clean wound • Prognosis good if caught early • Prognosis poor once sever tissue damage occurred- leads to shock and death

24. Flies • Various species of flies bite horses, flies can transmit infections • Hypersensitivity to biting midge called Culicoides spp. Causes severe pruritic dermatitis in summer = sweet itch- tail, head and main more commonly affected • Mosquitoes are vectors of heartworm- Dirofilaria immitis • Sandflies transmit Leishmania spp.

25. Recap • List as many ectoparasites as you can remember ...

26. Recap • List as many Endoparasites as you can remember ...

27. Extension Task • Design a poster for a Veterinary Surgery to inform pet owners about ectoparasites*. • You may choose one type of parasite or generalise. *Pay particular attention to infection control & preventative measures.

28. Learning Outcomes • List common ectoparasites • Identify common hosts for ectoparasites • Identify signs & treatments for common ectoparasites • List common endoparasites (Recap)