Newsletter June 2016
News for Cat Adopters and What is Dog Mange?
Cats and FIV
For many years, we have been testing cats that are being adopted for two viruses – feline leukemia and feline immunodeficiency virus. The verdict if a cat was positive for either virus was that it couldn’t be rehomed unless it could be an only cat, kept inside. The other option, and one used a lot, is euthanasia.
We now know that cats with FIV are not that much of a risk. A recent study (check this link) shows that cats with FIV do not transmit it to other cats that easily.
This is a quote from the report.
Housing of FIV positive cats in shelters and foster home and adoption of these cats to private homes frequently poses a conundrum to cat welfare workers, as these animals are frequently healthy and have normal lifespans, but could have the potential to transmit the disease to FIV seronegative cats present in the shelter or housing situation. Another concern is the frequency of vertical transmission of FIV from seropositive queens to their kittens. In both situations, FIV positive cats and seronegative cats exposed to them may be euthanized without good reason. It is generally known that FIV is commonly transmitted between cats via bite wounds, and FIV may also be transmitted through parenteral routes. Mucosal transmission between individuals is relatively inefficient compared to feline leukemia virus or human immunodeficiency virus (HIV).
In the first portion of this study (shelter 1), 138 cohabiting cats, all spayed and neutered, were followed over a period of years. Initial testing demonstrated that 130 cats were FIV seronegative and 8 were FIV seropositive. Only one of the FIV negative cats went outdoors, and this particular cat was also aggressive towards the other cats but no skin wounds were noted on cats he engaged with. Cats in this shelter, a privately owned rescue in a house operated by a single caregiver, had unrestricted access to each other. They had no history of FIV vaccination and shared litterboxes, food, water, dishes, and bedding. The second round of retrovirus testing was performed on 45 of the seronegative cats and 5 of the seropositive cats at a median 28 months after the first (range 1 month-8.8 years) showed no changes in the results. At median 38 months after the first test (range 4 months-4 years) 4 of the seronegative cats and one of the seropositive cats had maintained their original status.
Dogs and Mange
Scabies (Sarcoptes Mite Infestation)
Sarcoptes mites live in the surface layer of the skin. They create tiny tunnels as they burrow, eating their way through the skin and depositing eggs. This is primarily a disease of dogs, but occasionally these mites may infest cats. Sarcoptes mites cause an extreme itch even though the skin may look clinically normal. This mite is picked up by contact with infested animals, usually of the same species. Because it's so contagious, we often see it as a kennel epidemic.
There are two ways to diagnose scabies. The first is with a skin scraping. A scalpel blade is used to scrape off the superficial skin layer. The debris is examined under a microscope to look for mites. The best places to scrape are the edges of the ear and the elbows.
However, even if mites are present, it may not be easy to find them because they are highly mobile. It is for this reason that many veterinarians use the second method. They treat suspect cases with one dose of ivermectin or the medication Revolution. If the itch goes away, it suggests the pet had scabies. This approach allows diagnosis and treatment in one step.
Demodex (Demodectes Mite Infestation)
The demodectic mite is ubiquitous in dogs, and to a certain degree, in cats. All puppies are infested shortly after birth from their mothers. The mite moves from the skin of the mother to the pup's muzzle while he is suckling. The same is assumed to occur in cats.
Though Demodex is present in the hair follicles of every dog, we don't see epidemics of demodectic mange because most dogs mount an immunity to the parasite, which keeps it in check. Notice I didn't say get rid of it. An older dog that has lived his entire life without signs of Demodex can develop symptoms of mite infestation if cancer, Cushing's disease, or any other immunosuppressive disease compromises his immunity.
Demodex can be diagnosed with a skin scraping, but deep scrapings are needed to find these mites that are located at the bottom of hair follicles. Because they don't scurry around, they are easier to find than Sarcoptes mites.
Puppies can develop localized Demodectic mange, which is characterized by a small patch of hair loss with scaly skin, usually on the head. I rarely treat these cases. Instead, I rely on the puppy's immunity to take care of it. As the pup matures, so will his immune system.
Sometimes Demodex infestations spread to involve the legs and eventually the rest of the body. If a dog develops generalized Demodex, you know that the dog's immunity is poor; he can't mount an adequate immune response to the mites.
Often the areas with mites become secondarily infected, so the skin becomes itchy, inflamed, and may emit an unpleasant odor. Dogs with the generalized form of Demodex may need treatment with antibiotics, specialized shampoos, and of course, specific medication to kill the mites. This used to be an extremely frustrating and difficult condition to manage. Newer medications are giving some dohgs relief.
Dog suffering from demodectic mange.
Demodectic mite under the microscope.