Two winters ago, Ogden, now 42, saw his first red fox, living in a den under a pile of old leaves and suffering from advanced mange, and it stopped him in his tracks. “There was no fur on it.

Notoedric mange is different from sarcoptic mange. The latter, caused by the mite Sarcoptes scabiei, occurs primarily among red foxes and coyotes. Questions exist regarding the host specificity of ...