Demodex gatoi-associated contagious pruritic dermatosis in cats--a report from six households in Finland.
BACKGROUND
Demodex gatoi is unique among demodectic mites. It possesses a distinct stubby appearance, and, instead of residing in the hair follicles, it dwells in the keratin layer of the epidermis, causing a pruritic and contagious skin disease in cats. Little is known of the occurrence of D. gatoi in Europe or control of D. gatoi infestation.


METHODS
We describe D. gatoi in 10 cats, including five Cornish Rex, two Burmese, one Exotic, one Persian and one Siamese, living in six multi-cat households in different locations in Finland containing 21 cats in total. Intense pruritus was the main clinical sign. Scaling, broken hairs, alopecia and self-inflicted excoriations were also observed. Diagnosis was based on finding typical short-bodied demodectic mites in skin scrapings, skin biopsies or on tape strips. Other pruritic skin diseases, such as allergies and dermatophytoses, were ruled out. In one household, despite finding several mites on one cat, all six cats of the household remained symptomless. Amitraz used weekly at a concentration of 125-250 ppm for 2-3 months, proved successful in three households, 2% lime sulphur weekly dips applied for six weeks in one household and peroral ivermectin (1 mg every other day for 10 weeks) in one household. Previous trials in four households with imidacloprid-moxidectin, selamectin or injected ivermectin given once or twice a month appeared ineffective.


CONCLUSIONS
D. gatoi-associated dermatitis is an emerging contagious skin disease in cats in Finland. Although pruritus is common, some cats may harbour the mites without clinical signs. In addition, due to translucency of the mites and fastidious feline grooming habits, the diagnosis may be challenging. An effective and convenient way to treat D. gatoi infestations has yet to emerge.
Department of Basic Veterinary Sciences (FINPAR), Faculty of Veterinary Medicine, University of Helsinki, Finland. seppo@patovet.fi
Seppo A M
SA
Saari
Kirsi H
KH
Juuti
Joanna H
JH
Palojärvi
Kirsi M
KM
Väisänen
Riitta-Liisa
RL
Rajaniemi
Leena E
LE
Saijonmaa-Koulumies
D000818:Animals; D000977:Antiparasitic Agents / Q000627:therapeutic use; D017610:Calcium Compounds / Q000627:therapeutic use; D002371:Cat Diseases / Q000188:drug therapy / Q000469:parasitology* / Q000473:pathology; D002415:Cats; D005260:Female; D005387:Finland; D007559:Ivermectin / Q000627:therapeutic use; D008297:Male; D008924:Mite Infestations / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D008925:Mites; D011537:Pruritus / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D012871:Skin Diseases / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D013440:Sulfides / Q000627:therapeutic use; D013885:Thiosulfates / Q000627:therapeutic use; D014052:Toluidines / Q000627:therapeutic use; D016896:Treatment Outcome
D000977:Antiparasitic Agents; D017610:Calcium Compounds; D013440:Sulfides; D013885:Thiosulfates; D014052:Toluidines; C033907:calcium sulfide; C014983:amitraz; D007559:Ivermectin