Feline demodicosis (mites)

Demodex mite infection is commonly reported in the dog, but less common in the cat. When feline demodicosis is diagnosed an underlying cause should be sought as it has been associated with serious disease such feline leukaemia, cancer and diabetes.

Mac Kneipp BVSc MANZCVS October, 2014

Feline demodicosis is caused by three mites; Demodex gatoi, Demodex cati, and an unnamed demodex (Moriello, et al., 2013; Miller, et al., 2013). Identifying which mite(s) is involved is important because they cause different clinical diseases (Chesney, 1988; Tater & Patterson, 2008; Saari, et al., 2009) D. gatoi diagnosis may require multiple superficial skin-scrapings or trial treatment of affected and in-contact cats. D. cati is more likely to be diagnosed by large-area, deep skin-scrapings (Tater & Patterson, 2008). D.gatoi-associated intensely pruritic dermatitis has been compared to other superficial manges, like sarcoptes (Wilkinson, 1983), whilst D. cati causes lifelong follicular demodicosis like canine Demodex canis.

 

D. gatoi-associated dermatitis is an emerging contagious skin disease (Saari, et al., 2009), history and examination of in-contact cats is important (Morris, 1996).

 

D. cati-associated dermatitis can be localized, generalized or ceruminous otitis externa (Scott, 1980). Localized demodicosis often involves the face (Beale, 2012). Two cases were reported on the muzzle of cats treated with inhalant glucocorticoids (Bizikova, 2014). History of medications, particularly glucocorticoid use, is relevant (Tater & Patterson, 2008). Demodex cati is a “classic” follicular-dwelling demodex with infestation starting when the neonate is suckled (Nutting, 1984). The mite can be considered part of the natural feline skin microfauna, having evolved to be immunologically recognized as ‘self’ (Chesney,1989). There is little or no reaction or pruritus (Beale, 2012). Some question whether D cati alone causes clinical disease (Chesney,1989). If dermatitis occurs an investigation of factors that alter the host’s immune system is warranted (L Medleau, 1988). D. cati has been described as an “opportunist dermatosis associated with internal disease” (Muller, 2004).

The search for underlying factors may be more rewarding in feline demodicosis than in canine demodicosis and “history, clinical and laboratory examinations should be directed to this possibility” (Chesney, 1989). D. cati mange has been associated with; feline immunodeficiency virus (J A Neel, 2007), feline leukaemia virus (Guaguere, 1993), neoplasia (Guaguere, et al., 1999) (Johnstone, 2002), cutaneous xanthoma (Vogelnest, 2001), systemic lupus erythematosus (L Medleau, 1988), toxoplasma (Guaguere, et al., 1999), diabetes mellitus (S D White, 1987) and hyperadrenocorticism (Muller, 2004).

In some cases of generalized D. cati demodicosis no underlying disease is found (Miller, et al., 2013; Beale, 2012).

 

CONCLUSION

A diagnosis of D gatoi contagious mange warrants examination of in-contact cats. A diagnosis of D cati demodicosis warrants a careful review for concurrent disease or immunosuppressants; physical examination, thorough history and laboratory tests (complete blood count, serum chemistry, faecal examination, feline leukaemia and FIV testing) as a minimum.

Bibliography

 

Beale, K., 2012. Feline demodicosis: a consideration in the itchy or overgrooming cat. Journal of Feline Medicine and Surgery, pp. 14(3):209-13.

Bizikova, P., 2014. Localized demodicosis due to Demodex cati on the muzzle of two cats treated with inhalant glucocorticoids. Veterinary Dermatology, pp. 25:222-e58.

Chesney, C. J., 1988. An unusual species of demodex mite in the cat.. Veterinary Record, pp. 123, 671-673.

Chesney, C. J., 1989. Demodicosis in the cat. Journal of Small Animal Practice, pp. 30, 689-695.

Guaguere, E., 1993. Demodecie feline. Etude retrospective de 9 cas. Pratique Medicale and Chirurgicale de l'Animal de Compagnie, pp. 28:31-6.

Guaguere, E. et al., 1999. Demodex cati infestation in association with feline cutaneous squamous cell carcinoma in situ: a report of five cases. Veterinary Dermatology, pp. 10:61-7.

J A Neel, J. T. K. C. T. C. G., 2007. Deep and superficial skin scrapings from a feline immunodeficiency virus-positive cat. Veterinary Clinical Pathology, pp. 36:101-104.

Johnstone, I. P., 2002. Doramectin as a treatment for canine and feline demodicosis. Australian Veterinary Practitioner, pp. 32:98-103.

L Medleau, C. A. B. S. A. B. C. S. J., 1988. Demodicosis in cats. Journal of the American Animal Hospital Association, pp. 24:88-91.

L. J. Vogelnest, K. Y. C., 2013. Cutaneous adverse foof reactions in cats: retrospective evaluation of 17 cases in a dermatology referral population (2001-2011). Australian Veterinary Journal, pp. 91(11):443-451.

Miller, W. H., Griffin, C. E., Campbell, K. L. & Muller, G. H., 2013. Muller and Kirk's Small Animal Dermatology7. 7th ed. St. Louis: Elsevier Health Sciences.

Moriello, K. A., Newbury, S. & Steinberg, H., 2013. Five observations of a third morphologically distinct feline Demodex mite. Veterinary Dermatology, 24(E106), p. 460.

Morris, D. O., 1996. Contagious demodicosis i three cats residing in a common household. Journal of the American Animal Hospital Association, pp. 32:350-2.

Mueller, R. S., 2004. Treatment protocols for demodicosis: an evidence based review. Veterinary Dermatology, pp. 15, 75-89.

Muller, A. G. E. D.-R. F. a. B. G., 2004. Three cases of opportunistic dermatoses associated with internal diseases in cats.. In: Veterinary Dermatology. Lyon: Elsevier, p. 15:60.

N. Gabbert, F. B. F., 1978. A Case Report- feline Demodex. Feline Pract, p. 6:32.

Nutting, W. B., 1984. Comparative Topologic Distribution and Histopathology: Demodicidae. In: Acarology VI. Chichester: E. Horwood, pp. 1120-1131.

S D White, J. L. C. F. M. M. G. O., 1987. Generalized demodicosis associated with diabetes mellitus in two cats. Journal of American Veterinary Medical Association, pp. 191:448-450.

Saari, S. A. M. et al., 2009. Demodex gatoi-associated contagious pruritic dermatosis in cats- a reprot from six households in Finland. Acta Veterinaria Scandinavica, Volume 51, p. 40.

Scott, D. W., 1980. Feline dermatology 1900-1978; A monograph. Journal of the American Animal Hospital Association, pp. 16, 331-459.

Tater, K. C. & Patterson, A. P., 2008. Canine and feline demodicosis. Veterinary Medicine, 103(8), pp. 444-461.

Vogelnest, L., 2001. Cutaneous xanthomas with concurrent demodicosis and dermatophytosis in a cat. Australian Veterinary Journal, pp. 79:470-5.

Wilkinson, G. T., 1983. Demodicosis in a cat due to a new mite species.. Feline Practice, pp. 13, 32-35.