Red Fox with Mange

Red Fox

On June 27 construction workers in Marlboro, MA had an unexpected visitor – a juvenile male red fox. Unfortunately, this was no ordinary fox – he was thin and weak, with severe crusting of the skin on his face, eyelids, and feet. With the help of animal control, he was brought to Tufts Wildlife Clinic where he was found to be alert but quiet and cooperative for examination and blood collection. The fox was very thin at only 6 pounds, probably because his crusted eyelids prevented him from seeing well enough to find food (Fig. 1). His bloodwork was consistent with malnutrition and parasite infestation, but he was negative for heartworm disease (yes, foxes can get heartworm too!). Microscopic examination of scrapings of the crusted skin around his ears and feet confirmed the doctors’ suspicion – the fox had sarcoptic mange.

Red Fox with mangeSarcoptes scabe
Figure 1. Juvenile red fox with severe sarcoptic mange. Photograph by Karen Donahue, CVT. Figure 2. Sarcoptes scabei, photograph by Dr. Michael Dryden, DVM, Kansas State University, used with permission.

Sarcoptic mange is caused by Sarcoptes scabiei (Fig. 2), a microscopic mite that burrows under the skin of many animals, including dogs, foxes and humans. It can cause severe itching, crusting and inflammation of the skin. Sarcoptic mange is a highly contagious disease most effectively transmitted by direct contact. Luckily for us, the mite does not survive off the host in the environment for more than a few days. Human infection with Sarcoptes scabiei is called “scabies” and usually goes away in healthy individuals without treatment, unlike infection in wild animals. Young or debilitated animals are more susceptible to disease because their immune systems aren’t functioning at full strength. Most of the foxes with mange seen by Tufts Wildlife Clinic are young, usually less than a year old. Sarcoptes mites have a preference for the skin on the face, ears and feet. In the wild, animals quickly become malnourished as the crusting around their eyes and face impairs their ability to see and find food. Secondary skin infections are common as the crusts start to crack and bleed. Without treatment, many wild animals with mange die of starvation and exposure.

Thanks to the compassion of the construction workers, “our” mangy fox was saved just in time. A treatment plan was initiated to treat the mange, secondary infections, remove the crusting around the face, and start the fox on a nutritional diet. Ivermectin and selamectin were used (at different times) to treat the mange, antibiotics were given for the skin infection, and a non-steroidal anti-inflammatory medication was administered for pain and inflammation. The crusting around the eyes was so severe that it was not possible to tell if the fox even had eyes for several days. Warm compresses and an antibiotic ointment were applied to the area every day. The fox was quite weak at first so it wasn’t difficult to restrain him for these treatments. He eagerly ate his other medications in his food.

Red Fox recoveringRed Fox better
Figure 3 (Left). Six days after presentation. Figure 4 (Right). 11 days after presentation. Photographs by Karen Donahue, CVT.

Five days after presentation, the crusting and inflammation had subsided enough to see the fox’s eyes (Fig. 3), revealing another, much more serious problem. The inflammation and crusting of the skin had caused the upper eyelids to roll inward, toward the eyes. This resulted in the eyelashes and eyelids rubbing on the cornea (surface of the eye). This condition is called “entropion” and can be caused by genetic factors (as seen in certain purebred dogs, including the Shar Pei, cocker spaniel and mastiff) or by disease that changes the conformation of the skin. In this case, the entropion caused corneal ulcers that led to bilateral iridial prolapse. This means that the ulcers were so deep that the iris (the colored part of the eye) was able to bulge out in both eyes. Iridial prolapse is a serious condition that may result in rupture of the eye and subsequent blindness. Fortunately, the Tufts Ophthalmology Service enjoys seeing our wild patients and agreed to see our fox for a consultation. The fox was started on an antibiotic eyedrop in addition to an ointment to keep the pupil dilated and treat inflammation within the eye. The fox continued to eat well and seemed to improve more each day (Fig. 4 ).

Red Fox operation
Figure 5. Dr. Stefano Pizzirani performing surgery to correct the entropion. Photograph by Jonathan Babyak.

Almost one month after arriving at Tufts Wildlife Clinic, it became clear that the entropion in the left eye was not going to resolve even though the skin around the eyes was back to normal. Veterinary ophthalmologist Dr. Stefano Pizzirani performed a surgery to correct the entropion in the left eye (Fig. 5). By removing a sliver of skin from the upper lid and sewing the edges together he was able to fix the eyelid into a more normal position. The entropion in the right eye had corrected itself when the skin healed.

After his surgery, the fox continued to receive topical eye medications because the eyes remained at risk for infection or worse, rupture. It is at this time during a course of therapy that one must weigh the risks and benefits of treatment for a wild animal. Although it would have been ideal to medicate the eyes four to five times a day, the stress of being handled often outweighs the benefit of the medication. And, the more one handles a fox that doesn’t want to be handled, the greater the risk for rupture. After discussing the options with Ds. Pizzirani and Dr. Chris Pirie, the ophthalmology resident, it was decided to restrain the fox just once a day for medications and keep our fingers crossed.

The fox continued to improve. He gained weight and grew a lush, healthy coat. During the day he was given access to our outdoor carnivore pen so he could get some exercise, splash in a pool, and hear the sounds of nature (Figures 6 and 7). On September 14, almost 11 weeks since arrival, the fox was pronounced healthy! What else to do but let him go, right? Wrong. As mentioned earlier, this was a young fox; he was probably born just the past spring. Red foxes usually stay with or near their mother until they are 10 months old, practicing their hunting skills under supervision. This fox should have been with his mother and was too young to release back into the wild without any “preparation” for living life as a wild fox.

The decision was made to transfer the fox to a licensed wildlife rehabilitator who could keep him in a large outdoor enclosure and prepare him for life in the wild. He continued to improve and, after one month with the rehabilitator, was successfully released back into the wild.

Red fox eatingred fox in outdoor pen
Figure 6 (Left). The fox nibbles on a fish in his outdoor enclosure. Figure 7 (Right). Red fox in outdoor carnivore pen at Tufts Wildlife Clinic. How beautiful he looks now! Photographs by Malory Wade.

Thanks to generous donations, we are able to provide medical care to wildlife in need. Please consider a donation today and be a part of something special — the opportunity to give wildlife a second chance at life and help protect our natural world.