An outbreak of dermatophytosis caused by Microsporum canis occurred in tigers (Panthera tigris) and humans at an exotic cat sanctuary in the fall of 2003. A facility-wide survey determined at least 48 of 103 (46%) inhabited cages were contaminated with M. canis. Transport cages and office furniture also cultured positive. Contaminated cages were inhabited by all species of felids maintained on the property, including tigers, lions (P. leo), a liger, clouded leopards (Neofelis nebulosa), black leopards (Panthera pardus), cougars (Felis concolor), bobcats (Felis rufus), and domestic cats (Felis catus).
A preliminary clinical trial with a 2% solution of lyme sulfur (LymDyp, DVM Pharmaceuticals Inc., Miami, Florida 33137) was conducted. Each cat in six contaminated enclosures housing multiple animals was cultured and assigned to one of four treatment groups or two control groups. Lyme sulfur solution was applied topically, via sprayers, to each cat in treatment Groups 1 – 4, every 2 wk for a total of seven treatments. In addition, the enclosure for treatment Group 1 was treated topically with lyme sulfur, at the same concentration applied to the cats, and the enclosure for treatment Group 2 was treated topically with Oxyclean® (Orange Glo International, Inc, Littleton, Colorado 80161), a peroxide based disinfectant, at a concentration of 28 mg/L (4 oz per gallon) of water. Cats in treatment Group 3 were moved to an uncontaminated enclosure after the third treatment. The enclosure for treatment Group 4 was not treated. The control cats (six individuals in two enclosures) were not treated. Samples were obtained from each individual and each enclosure every 2 wk, prior to any treatment. Mycologic cure was defined as failure to isolate M. canis in two sequential hair cultures.
Only three individuals attained mycologic cure, one of which later cultured positive. All three individuals were in treatment Group 4. Despite no specific environmental treatment in this group, the environmental cultures became negative after the 4th treatment.
Preliminary conclusions of this study include: 1) Tigers appear to be more sensitive than other species of cats on the property and seem to develop a carrier state similar to that seen in domestic Persian cats;1 2) treating the outdoor environment may not be necessary in controlling an outbreak; and 3) topical treatment with 2% lyme sulfur every 2 wk is not successful in treating tigers infected with M. canis. Future studies are planned to examine topical and systemic combination therapies.
1. Lewis, D. T., C. S. Foil, and G. Hosgood. 1991. Epidemiology and clinical features of dermatophytosis in dogs and cats at Louisiana State University: 1981–1990. Vet. Dermatol. 2: 53–8.