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Valley fever takes an animal toll, and pets rely on the same treatment as people

Reporting on Health Collaborative

(Published Monday, November 19th, 2012 04:27PM)

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Valley fever takes an animal toll, and pets rely on the same treatments as people

The first valley fever victim that Dr. Demosthenes Pappagianis remembers was Mbongo -- a gorilla at the San Diego Zoo

"I was a kid in San Diego at the time and saw the article in the newspaper," recalled the veteran researcher on the animal's 1942 death from the disease, also known as coccidiomycosis. "I didn't know what cocci were at that time, but I knew that a gorilla at the zoo had died."

Zoo animals, pets and animals in the wild contract coccidioidomycosis the same way people do, by inhaling spores from a fungus that thrives in soil, particularly in California's Central Valley, Arizona and throughout the Southwest.

"We all get it from breathing the spores and not being coughed on by a sick person or dog," said Dr. Lisa Shubitz, a veterinarian and associate research professor at the University of Arizona.

Valley fever affects an estimated 150,000 people every year throughout the country and played a role in the deaths of more than 3,000 people between 1990 and 2008, according to one study. The scope of the disease's animal toll isn't known, but veterinarians in Bakersfield and Arizona said it's an illness that they routinely see.

Valley fever has been found in everything from sea otters and llamas to primates and cattle. Domestic animals are often treated with the same drugs that humans are prescribed.

Research that aims to save and improve human lives may also benefit animals. And research also suggests that some animals become infected with valley fever but never become sick, similar to the many covert valley fever cases in humans.

Yet research funding for developing treatments and vaccines for both people and animals remains limited.

"We only get one crack at (a study). We have to do it right the first time because there's very little money being put into the problem," Shubitz said.

Funding for animal research is so scarce that treatment for animals really depends on developments in treatments for humans, Shubitz said.

Pappagianis, a professor and valley fever researcher at the University of California, Davis, pointed out that medications are often tested on animals before tried on people.

"The veterinary side of things is absolutely vital for development of knowledge," Pappagianis said.

And just as a vaccine could fight valley fever in humans, veterinarians said a vaccine could be a huge help to combat the disease in animals.

"I think a vaccine would advance care of dogs more than any other single thing that we could do," Shubitz said.


An animal history

The first valley fever case discovered in an animal was uncovered in 1918 in a cow slaughtered in San Diego, according a study published in The American Journal of Pathology in 1948.

Gradually the disease was identified in other animals. A canine case was spotted in a female Great Dane in Tucson, Ariz., in the early 1940s, the study recounted. Valley fever was found in wild animals, including in a dolphin and sea lions, usually when they were spotted debilitated or dead, Shubitz said.

Some animals appear to boast strong resistance to the disease, while others do not. Alpacas and llamas are prone to valley fever but hard to treat because their digestive system doesn't absorb the medication well, Shubitz said.

Cattle actually are very resistant, while monkeys and other primates are highly susceptible, Pappagianis said.

Employees at the San Diego and Phoenix zoos and the Reid Park Zoo in Tucson said the illness still comes up at their facilities.

"Thankfully, it is a disease that is rare at the San Diego Zoo. Treatment is dependent on the species, but typically treatment requires months of oral antifungal medication taken daily," Yadira Galindo, a spokeswoman for the zoo, wrote in an email.

Dr. Alexis Moreno, senior veterinarian at the Reid Park Zoo, said primates and bears are sensitive to the disease, but she has also seen it in otters and lions and consulted on cases in tapirs in California.

"It's obviously a chronic concern," Moreno said.

The disease is usually treated with fluconazole -- the same medication routinely used in people. Moreno said she hasn't had an animal die from valley fever during her six years at the zoo.


Valley fever and man's best friend

Veterinarians in Bakersfield and Arizona said they know to look for the illness in dogs because it's so prevalent in their areas. The symptoms often include lethargy, weight loss, fever and coughing. A dog may limp if the disease has spread to its bones.

As with people, the disease may be confined to the respiratory system or disseminated to other areas of the body. If valley fever is to blame for a dog's maladies, a chest X-ray usually reveals enlarged lymph nodes, said Dr. Roger Paulson, veterinarian at Stine Veterinary Hospital in Bakersfield.

A diagnosis is definitive if a blood test confirms valley fever, Paulson said.

But Dr. Thomas Willis, a veterinarian and owner of San Joaquín Veterinary Hospital in Bakersfield, said the tests aren't 100 percent accurate and at times generate false negatives. He recalled two cases where the tests came back negative, but the animals were still given antifungal treatment and the medicine worked.

Exactly how many dogs the disease affects is hard to say. There aren't many diseases that are tracked in dogs, other than severe illnesses that a dog could give to humans, like rabies.

At one point, the researcher estimated that about 6 percent of dogs in Arizona got sick with valley fever annually and that pet owners spent millions of dollars on the costs of diagnostics, follow-up care and medication.

Valley fever affects cats, too, but Shubitz estimated there is about one cat case for every 50 dog cases. In dogs, disseminated valley fever is frequently found in their bones, while it often manifests in cats' skin, she said.

Bobbi Duke lives in northeast Bakersfield, near the Kern River. The disease struck her border collie Lucas and cat Crash within a couple months of each other about six years ago, Duke said.

Lucas just seemed unwell when Duke took him to the vet and he was diagnosed with valley fever, but Crash had a sore on one of his front legs that kept getting bigger. The leg eventually was amputated.

Both animals recovered with several months of medication.

Valley fever also struck her neighbors' dog Nemo. The fungal disease left the 9-year-old Pomeranian listless and coughing last summer.

But Nemo was yappy and friendly on a recent November afternoon, wiggling his puffball body over to whomever would offer him attention. Like people patients, Nemo is given an antifungal medication daily to treat the disease.

Debra Stone, Nemo's owner, said the Pomeranian's medication is much more affordable than the pills the family bought to fight their first bout with valley fever.

The family's initial brush with the disease came in the 1990s, when they were living in another area of Bakersfield and their young Brittany Spaniel, Tanner, came down with valley fever. She survived and lived to the age of 15, but only after a costly course of antifungal medications.

Tanner took two pills a day for about year at the price of $2.50 per pill by Debra's recollection. Today, Nemo's pills cost just $10 for a month's supply.

Paulson, the Stones' vet, said the advent of a generic fluconazole, an antifungal frequently used to medicate valley fever in animals, has made treating cocci much more affordable.

"People love their pets, but people put a limit on what they can spend on them," Paulson said.

Stone said she wishes there was a vaccine for dogs and that she "absolutely" thinks there is a market for one.

"Maybe the vaccine is a little more expensive, but if it's once a year I think it'd be worth it. It'd be cost-effective," she said.


Valley fever's veterinary outlook

While vets said there is''t much money directed to valley fever research in animals, at least one new medication for people has been tested in dogs and Shubitz said there is renewed interested in funding a vaccine for dogs.

The current possibility for a dog vaccine is a mutated live form of the fungus that can't reproduce and has been tested in mice, she said.

The next step would be to fund a dog study, but developing a vaccine could take more than $1 million.

Still, Shubitz thinks it could happen.

"I actually think there's a bigger market for a vaccine in dogs than in humans," Shubitz said. "People spend so much money trying to treat this in dogs they would do anything to try to prevent it."

But a vaccine would have to be affordable and the market for it would be small compared to the number of dogs who need to be vaccinated for rabies and distemper. Though a vaccine could be labeled for use in dogs, Shubitz expects that if one were developed, it could be used in other animals as well.

Some veterinarians said they were skeptical that a vaccine will ever be developed because of the cost.

"We would welcome that from the standpoint of being here in Bakersfield and seeing the amount of cases that we do see," said Willis, of San Joaquin Veterinary Hospital.

The trends in animal valley fever cases aren't tracked so it's hard to say if the disease is on the rise in pets. Dr. Paul Ulrich, veterinarian and an owner of Bakersfield Veterinary Hospital, said dog cases tend to reflect what is happening with human instances in the valley.

Without a vaccine, veterinarians said there isn't much people can do to prevent their pets from developing the illness. Keeping dogs inside on dusty, windy days and trying to dissuade them from exploring rodent holes could help, but there's no way to completely avoid the fungal spores if you live in an endemic area, Shubitz said.

Debra Stone isn't sure where her animals picked up valley fever, but she wonders if Nemo's habit of chasing rabbits under a storage unit this summer could be to blame.

Down the street, Duke said sometimes her neighbors mow the empty lot next door and the dust hangs in the air over her house.

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