Canine Distemper Killing Gray Foxes

Since last April, Ralph “Bud” Matthews has trudged the Santa Ana Mountains north of Mission Viejo three times a week in search of foxes. But in recent weeks, his research on the gray fox has taken an unforeseen and tragic turn.

The foxes, already imperiled by urban development, are facing a new threat.

Matthews, nearing completion of his master’s thesis at Cal State Fullerton, has determined that canine distemper is killing the gray fox of Modjeska Canyon. And even as it claims the gray fox, Matthews and authorities warn, the disease also could endanger any dog in the vicinity that has not been vaccinated against canine distemper within the past year.

The significance of Matthews’ findings was underscored March 25, when two distemper-ridden gray foxes were deposited at the doorstep of local animal-control facilities.

“These came from Santiago Canyon, just up the road from Modjeska Canyon, and they were wandering around, slobbering all over the place,” said Richard H. Evans, chief of veterinary services for the Orange County Health Care Agency. “They were brought in by passersby who thought they had rabies, which is an easy mistake to make. But it was definitely canine distemper.”

The gray fox once roamed the campus of Cal State Fullerton as well as the Anaheim Hills, Matthews said, but has been losing its fragile hold to relentless urban sprawl.

In Matthews’ study, he set 80 traps that led to nine foxes being captured. Of those, he collared seven with radio transmitters that cost $250 apiece. Two of the seven were found dead in March, the victims of distemper.

Of the five remaining foxes carrying radio transmitters, none has been found, Matthews said. And for the first time since the study began, their radio signals have vanished, leading him to conclude that they too died of distemper.

Last week brought another strange development in what has been a perilous time for foxes in California. Animal-control officials in the Bay Area’s Marin County reported that 233 foxes and raccoons have been found dead since Jan. 1, the victims of what state fish and game officials said is canine distemper.

Last month alone, authorities reported 45 dead foxes, said Jolie Levine, spokeswoman for the Marin County Humane Society. “In March of last year, we only had five,” she said.

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Foxes in the Bay Area are showing the same symptoms as the two deposited on Evans’ Orange County doorstep: wandering about aimlessly, an eerie absence of fear in the presence of humans, and profuse foaming from the mouth.

When contacted, officials in Los Angeles, Ventura, Riverside and San Diego counties said last week that the incidence of distemper in their regions has been no higher than normal, although officials in San Diego reported distemper killing more skunks than usual in March.

So far, only foxes and raccoons have died in Marin County, Levine said, “with not a single case” reported among stray or domestic dogs.

Nevertheless, Bay Area and Orange County authorities are urging pet owners to take “serious precautions.” Some canine diseases can be transmitted simply by a dog sniffing an infected animal, Levine said.

Levine and other animal-control officials say last year’s heavy rains led to bumper broods of wildlife throughout the state. Those animals are now grown and, she said, may be crowding the ecosystem.

So, whatever disease appears to be claiming the foxes’ lives--in Northern and Southern California--may be “part of the natural order of things,” Levine said.

Veterinary chief Evans, who completed his master’s thesis on canine distemper among wildlife, said the sudden turn in Matthews’ Orange County study is hardly unusual.

A highly contagious disease that attacks an animal’s central nervous system, canine distemper is 90% fatal among wildlife, he said, but less so among domestic pets which, through evolution, have developed better resistance. Unlike rabies, with which it holds similar properties, distemper cannot be transmitted to humans.

“It’s basically a dog disease that is transferred easily to certain species of wildlife--coyotes, all species of foxes, even raccoons and skunks, which are actually quite susceptible,” said Evans, who documented one outbreak near St. Louis, Mo., in 1981 that claimed 10,000 animals in a four-month period.

Canine distemper has been more common in the foothills of Orange County in recent years, Evans said. He recommended that the guardians of domestic dogs promptly get them vaccinated against distemper and have them revaccinated if the dogs have not received a “booster” shot within the past year. Otherwise, he said, their lives are at risk.

“The problem is one of spread,” Evans said. “We’d like to make sure that every dog in the region is vaccinated and protected.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Distemper Facts

WHAT IS IT?

Canine distemper is a contagious, airborne virus of dogs and wild animals. It is not the same as rabies or feline distemper.

* Skunks, gray foxes and raccoons are the main wildlife carriers.

* It is not a disease of humans or cats.

* It spreads through nasal contact with infected animals.

* Mostly puppies and young dogs are affected.

* About 50% of cases are fatal.

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SIGNS / SYMPTOMS

Symptoms appearing within seven to 14 days of infection:

* Lethargy

* Loss of appetite

* Dazed, confused behavior

* Discharge from eyes, nose

* Circling, convulsions

* Wild animals show no fear of humans

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PROTECT YOUR PET

Because of high immunization rates, distemper outbreaks in urban areas are rare. In rural areas, where dogs often are not immunized, outbreaks are more likely.

* Always immunize dogs.

* Isolate puppies from other young dogs until fully immunized.

* Re-immunize as recommended by veterinarian.

* Dogs should get booster shots if they have contact with wildlife.

Source: Humane society and World Book Encyclopedia