October 2017

The foX-Files...the truth is out there

A passerby saw a strange-looking carcass on the side of the road and pulled over for a closer inspection.  Convinced that he had found the mythical creature El Chupacabra, he brought it into the local veterinary diagnostic laboratory for identification.  At necropsy, widespread alopecia, dermal inflammation, and thick, hyperkeratotic crusts were evident. The animal was identified as a red fox, not the legendary El Chupacabra.  A skin scrape of an area of inflamed dermis revealed the following organism:​​​

What's your diagnosis?

Answer

This parasite is the mange mite of red fox, Sarcoptes scabiei var. vulpis. It is well-known to cause severe disease causing high mortality rates in red fox, coyotes, and wolves, and is often responsible for stark declines in population densities. Red fox can develop overwhelming hypersensitivity reactions due to the presence of this parasite, leading to extreme inflammation, crusting, and alopecia. This response leaves fox vulnerable to adverse environmental conditions and secondary infections. The mite can be readily identified based on its sarcoptiform shape and long unjointed pedicels (stalks) terminating with caruncles (suckers).