Rabid fox could signal outbreak


On March 23, a rabid fox attacked a dog one mile south of Magdalena. The dog, which had not been vaccinated against rabies, was euthanized.

This latest case of rabies in Magdalena may signal the arrival of a new strain of the virus in Socorro County, one that could put more livestock and pets at risk of contact with infected animals, and consequently pose a bigger menace to humans than the more common bat or skunk rabies strains, according to Paul Ettestad, New Mexico state public health veterinarian.

“There are various strains of rabies; most strains are perpetuated within species,” he said. “Bats infect other bats, and a bat may expose a dog or cat, for example. But we don’t see dog-to-dog transmission of bat strains of the virus.”

If a bat exposes a fox to bat rabies, it’s also a random occurrence, he said. Although the fox may infect another fox, it also will be an isolated incident. But if the fox strain of rabies is present in Socorro County, several other foxes are also likely infected, which presents a serious public health problem.

“The Arizona gray fox strain of rabies has been in Arizona for awhile and also in Grant, Hidalgo and Sierra counties,” he said. “If it’s now in Socorro County, that means it’s spread north and east. More fox-to-fox cases means more interaction (of rabid animals) with pets and livestock. Those animals expose a lot of people (to rabies). Rabid foxes are extremely aggressive and will attack people, dogs, cats, cows and horses.”

A fox can attack an unvaccinated outdoor pet or a horse, giving it a little nip on the nose that heals without anyone knowing, he said. But now the animal is infected with the deadly rabies virus.

The problem is that livestock don’t often exhibit the classic signs of rabies — aggressive behavior and foaming at the mouth. Rabid horses typically seem depressed or lame, he said. Many times, the horse drools and has trouble swallowing, making its handlers think that something is stuck in its throat.

“They think there’s a piece of baling wire or something caught in its mouth,” Ettestad said. “They reach in to see what’s in there.”

Before long, several people have been exposed to the rabies virus present in the animal’s saliva.

Then all of the exposed people have to go through the anti-rabies inoculations at a cost of several thousand dollars, not to mention the emotional trauma of having to undergo a series of shots over the course of months, he said.

That’s the best case scenario — when the owner calls a veterinarian in to solve the problem. If the horse doesn’t get veterinary care, the owners may just bury it without a second thought or it may die unseen out on the range.

Then those people will most likely come down with rabies — a disease with an almost 100 percent fatality rate.

Maybe because of the unspecific symptoms, more human rabies cases result from contact with rabid horses and cows than dogs or cats, said Dr. Dean Wilkinson, a local veterinarian and owner of Animal Haven Veterinary Clinic.

Even though few horse owners vaccinate their animals against rabies, veterinarians think it’s a worthwhile safety precaution.

“It’s definitely worth it to get your horse vaccinated,” Ettestad said. “I think with the situation in Socorro County, it’s a good investment. For the past few years, the fox population has been low, perhaps because of distemper, but they cycle up and down. If the fox population goes up, rabid foxes may show up in Hop Canyon or in the bosque and could spread up and down the river valley.”

Tissue samples from the rabid fox in Magdalena have been sent to the Centers for Disease Control in Atlanta for further analysis, he said, but the results won’t be known for a few weeks.

Any observations of unusual behavior in foxes or other mammals should be reported to the New Mexico Department of Health. A state infectious disease epidemiologist is available 24/7/365 at 505-827-0006 to answer questions and take reports.