BAKERSFIELD — Zoo animals, pets and animals in the wild contract coccidioidomycosis -- valley fever -- the same way people do, by inhaling spores from a fungus that thrives in soil, particularly in the 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 toll the disease has taken on animals isn't known, but veterinarians in Bakersfield and Arizona said it's an illness they routinely see.
Valley fever has been found in sea otters and llamas, 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. It 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 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.
Dr. Demosthenes Pappagianis, a professor and valley fever researcher at the University of California at Davis, pointed out that medications are often tested on animals before they are tried on people.
"The veterinary side of things is absolutely vital for development of knowledge," Pappagianis said.
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.
First animal case: 1918
The first valley fever case discovered in an animal was uncovered in 1918 in a cow slaughtered in San Diego, according to a study published in the American Journal of Pathology in 1948.
Gradually the disease was identified in other animals.
Some animals appear to boast strong resistance to the disease, 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 are very resistant, but primates are highly susceptible, Pappagianis said.
The disease is usually treated with fluconazol, the same medication routinely used in people.
Veterinarians in Bakersfield and Arizona said they know to look for the illness in dogs because it's so prevalent in those 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, a veterinarian at Stine Veterinary Hospital in Bakersfield.
A blood test can confirm valley fever, he said.
But Dr. Thomas Willis, a veterinarian and owner of San Joaquin Veterinary Hospital in Bakersfield, said the tests aren't 100 percent accurate and at times generate false negatives. He recalled two cases in which the tests were negative, but the animals were still given antifungal treatment and it 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 could be passed to humans, like rabies.
At one point, researchers estimated 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, 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 of 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.
Paulson said the advent of a generic fluconazole has made treating valley fever much more affordable.
"People love their pets, but people put a limit on what they can spend on them," he said.
A question of money
While vets said there isn'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 that need to be vaccinated for rabies and distemper.
Some veterinarians said they were skeptical that a vaccine will be developed because of the cost.
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 avoid the fungal spores if you live in an endemic area like the valley, Shubitz said.