Attempted treatment of tigers (Panthera tigris) infected with Microsporum canis.

An outbreak of dermatophytosis caused by Microsporum canis occurred in tigers (Panthera tigris) at an exotic felid sanctuary in 2003. In an attempt to find an effective, practical, safe, and affordable method for controlling this epizootic, a clinical treatment trial was conducted. Nonalopecic tigers were studied to address the inapparent carrier state observed at the facility. The efficacy of three topical and environmental treatment combinations of a 2% lime sulfur solution and a peroxide-based cleaner were evaluated in nonalopecic, culture-positive tigers (n = 18) housed in four separate enclosures. Lime sulfur solution was applied topically to all of these animals. As a control, nonalopecic but culture-positive tigers (n = 6) housed in two other enclosures were not treated. Environmental treatments included lime sulfur solution (n = 1), a peroxide-based cleaner (n = 1), and no treatment (n = 2). All solutions were applied at 2-wk intervals for seven treatments. The 2% lime sulfur solution treatments were unsuccessful in resolving infections in most tigers. Lime sulfur was effective in suppressing environmental fungal growth immediately posttreatment, whereas the peroxide-based cleaner was not effective. A follow-up survey of all study tigers and their enclosures was conducted 2 yr later, at which time 22 of 24 tigers (92%) had attained resolution, defined as two sequential negative hair cultures. Review of the culture results during the clinical trial and follow-up study suggests that nonalopecic dermatophytosis in tigers that are housed outdoors may not warrant aggressive individual or environmental treatment, as the infection may clear with time.