Mites

1. Mites Arthropods-arachnids-acarines

2. Learning objectives • Outline the basic characteristics of mites (morphology, life cycle) • Define the term ‘mange’ • Mites commonly found on farm animals and horses in NZ • Mites commonly found on dogs and cats in NZ • Dermanyssid mites that commonly occur on chickens

3. General characteristics • Microscopic, 100-1000um in length • Mouthparts resemble ticks • Mites that live on skin can be burrowing or non-burrowing, or follicular

4. Mite induced disease • Pathogenic importance varies • Disease of the skin caused by mites is called mange • Most parasitic mites are host specific and do not survive long off the host • Transmission is by direct contact

5. General life cycle • Adult-egg-larva-nymphal stages-adult • Note as with ticks the larva has 6 legs

6. Non-burrowing mites • Long posterior legs • Chorioptes: short pedicles to suckers • Psoroptes: long jointed pedicles

7. Chorioptes bovis • Infests sheep, cattle, horses and goats • Lives on lower limbs, udder or scrotum • Significance is scrotal mange in rams • Causes inflammation of scrotal skin , a rise in temperature and subsequent infertility

8. Chorioptes Bovis

9. Psoroptes ovis • No longer occurs in NZ due to dipping programme • Very important mite as causes sheep scab • Causes intense irritation, can lead to death of sheep • Notifiable disease in NZ

10. Otodectescynotis • Common ear mite of dogs and cats • Causes otitis externa

11. Cheyletiella species • Found on rabbits, cats and dogs • Cause severe dermatitis

12. Walking dandruff

13. Human lesions from cheyletiella

14. Quick quiz • Which mites can be seen with the naked eye? • Name the non burrowing mites of farm animals? • Name the non burrowing mites of cats and dogs? • Which mite is notifiable in NZ? • What are the names of the 4 diseases caused by non burrowing mites?

15. Burrowing Mites • Sarcoptesscabiei • Trixacaruscaviae • Psoregatesovis

16. Sarcoptes scabiei • Infests many species with specific strains • Live in tunnels in skin • Cannot live long off the host • Cause extreme irritation • Common in dogs and pigs ( and man) • Diagnosis can be difficult

17. Sarcoptic mange in dogs • Tends to cause lesions on face, ear edges, elbows • Very very itchy (pruritic) • Can cause lesions on man; considered a zoonosis • Extremely contagious

18. TrixacarusCaviae • Cause mange in guinea pigs

19. Psorergates ovis • Occurs in sheep of fine woolled breeds • Known as the itch mite • Occurs in some properties in South Island.

20. Follicular mites • Species of demodex • Cigar shaped mites, live in hair follicles • In dogs, common in short haired breeds under 2 years • Pups infected from bitch when suckling (not all animals develop mange) • Hair loss, infection as follicles burst • Difficult to cure

21. Demodex • Severe demodex in a pup with secondary infection

22. Mites of poultry and cage birds • Dermanyssussgallinae = red-mite NB lives off host during day and feeds at night • Ornithonyssus species = northern fowl mite and tropical fowl-mite

23. Burrowing mites of poultry and cage birds • Cnemidocoptes species Similar role to sarcoptes in mammals • scaley leg in chickens • depluming itch • scaley face and scaley leg in budgies

24. Summary of mites • Three types: non-burrowing, burrowing and follicular • Mostly live entirely on host • Life cycles all similar • Cause a variety of diseases in different species • Sarcoptes and cheyletiella cause disease in man

25. Quiz • Which ones are burrowing mites? • Which ones are mites of birds? • Which one is a follicular mite? • Which one lives off the host at some point? • Which ones are zoonotic? • Name each mite and say where it would be found (species and site)