My father, Ross Fullmer, was recently diagnosed with a brain mass. The day after he was diagnosed I drove to southeast Idaho from my home in Oregon to spend time with him before he had surgery.
My father has many friends and there was a steady stream of well-wishers in the hospital and at home before his surgery. I was reminded of our strong sportsman’s culture in Idaho as one after another of our friends and relatives visited him reminiscing about the many hours spent hunting, fishing and trapping. One of his friends whom he cut meat with for years has taken up trapping coyotes for their pelts. He commented that he has seen alarming number of both foxes and coyotes with significant hair loss.
While an internet search and a perusal of the Idaho Fish and Game website listed no recent articles on hair loss in coyotes or foxes, our conversation definitely peeked my interest and motivated me to write this article. Extrapolating from my experience with domestic dogs, two likely possibilities for the hair loss is; infestation with mange mites or flea allergy dermatitis. As I have covered flea allergy dermatitis in previous articles I will focus the rest of my comments on mange mites.
There are two general categories of mange in domestic dogs; noncontagious and contagious mange. Noncontagious mange in canids is usually a result of infestation with the mange mite, Demodex cani1. Called demodex or “red mange”, it is by far the most common type of mange in domestic dogs. Demodex mites burrow into the hair follicles which causes hair loss but fortunately for most dogs very little itching.
The mite is normally found on the skin of dogs and many other species including humans. Because demodex mites are normally found in many species they generally only cause disease when there is a malfunction of the immune system. I usually diagnose this condition in puppies between the ages of 3 to 10 months of age because their immune systems are still developing. In my experience infection is rare in adult dogs because their immune systems are generally competent.
In dogs the condition is readily diagnosed with a skin scrapping. Even though treatment is difficult we can typically successfully cure 90% of dogs less than 1 year of age while we are only successful in curing 10% of dogs over 1 year of age. This disparity is due to the fact that the immune system in young dogs will usually mature as he or she ages, eventually naturally controlling mite growth. Unfortunately the immune systems of clinically affected older dogs is usually permanently affected and these pets will require lifelong treatment.
Contagious mange is a result of infestation with the sarcoptic mange mite Sarcoptes scabeii. In contrast to demodex, sarcaopitc mange is readily communicable between animals and can be spread across species boundaries. Susceptible species include, foxes, coyotes, domestic dogs, wild cats, wombats and large hooved stock2. Infection is geographically widespread having been documented in North America, Europe, Australia and Africa2. As sacrcopitc mange is zoonotic it readily infects people causing a rash and intense itching. Fortunately infection in humans is short lived and only lasts for about a couple of weeks, causing intense itching and a great deal of discomfort to infected individuals. The itching is so extreme that affected animals will create wounds with severe secondary infections. Animals also loose enough hair that it makes it very difficult to retain heat during the winter.
Unlike demodex, sarcopitc mange is difficult to diagnose. The mites burrow deeply into the skin and so are difficult to see even after a skin scrapping. Treatment is usually curative as long as the source of infection and be identified.
Regrettably treatment of either types of mange in wild animals is impractical and the disease will naturally run its course without effective intervention. Exceptions to treating wildlife include instances when threatened or endangered species are infected with sarcoptic mange, as entire populations of such animals could be eliminated2.
I have no specific data to confirm the cause of the hair loss in the animals observed by my father’s friend. I suspect of the two conditions discussed, sarcopitc mange is the most likely culprit. If so, hopefully the condition will quickly run its course restoring the population back to a healthy standing.
1. Canine Demodectic Mange Wisconsin Veterinary Referral Center
2. Sarcoptic Mange in Wildlife Rev. sci. tech. Off. Int. Epiz. 21(2) D.B. Pence, E. Euckermann.