Dust storm raises valley fever issue
Disease risk is dangerous for all mammals
Valley fever, the fungus-caused illness that has unpredictably plagued the American Southwest for decades, threatens the health of not only humans, but of all mammals, including dogs, cats and other pets.
The risk can be especially acute after large dust storms like the one preceding Monday’s thunderstorm unleashes dust lying well below the surface, Desert Veterinary Clinic’s Dr. Cheryl Haugo said.
“Blowing dust storms like last night’s would be great sources, because valley fever fungus lives deep in the soil. It’s not a superficial soil thing,” she said.
Any activities that go beyond the top layer of dirt in the Yuma area escalates the chances of nearby people or animals developing valley fever, she said.
“So (it affects) dogs that dig, dogs that live around road construction. I had one case, it’s probably been about 20 years (ago), where there was road construction in the neighborhood, and the dog got valley fever and the wife of the owner got valley fever. And the wife actually passed away, and the dog survived,” Haugo said.
Haugo called valley fever “pretty common,” and said her office has been monitoring 15 suspected cases of valley fever so far this year. On average it has two sam-
ples tested for the disease per month.
Where humans are concerned, the Arizona Department of Health Services’ website said Yuma County had the lowest rate of reported human cases of valley fever statewide in 2016, at 8.3 per 100,000 residents.
When spores from the fungus are inhaled, infection begins in the lungs, and can then spread into the bones, lymph nodes, the lining of the heart or brain, skin, or almost any other organ.
Dogs make up the majority of veterinary cases of valley fever, with an estimated $60 million spent every year in Arizona by owners of dogs with the disease, according to the Valley Fever Center for Excellence at the University of Arizona’s College of Medicine.
Cats are diagnosed at a much lower rate than dogs, the center’s website says, with about one feline case reported for every 50 canine cases.
“It’s probably because of dogs’ lifestyle more than anything,” Haugo said. “Cats don’t do much deep digging, they’re pretty superficial diggers, and often they’re inside more than dogs. Some cats live their whole lives indoors and they’re hardly exposed at all.”
Protecting humans, dogs or any other animals who go outside is much more difficult, as there are no vaccines available.
It can take weeks for symptoms to show up after a pet has been exposed to valley fever, and the symptoms come in different forms; coughing, fever, weight loss, skin lesions, fatigue, seizures, swelling of limbs, back or neck pain, according to the Valley Fever Center for Excellence.
About 70 percent of dogs who inhale spores from the Coccidiodies fungus that causes valley fever do not become sick because their immune systems can control them, about the same rate as with humans. Some dogs do not show any symptoms for the initial lung infection, only becoming sick when the fungus spreads.
“Any time your dog is experiencing any symptoms for any length of time that aren’t normal for them, they should see their veterinarian and get checked out. And if the veterinarian says, ‘Gosh, I’m concerned about valley fever,’ there’s a blood test that can be run,” Haugo said, though some forms are more difficult to diagnose that way.
Depending on the kind of blood test, it usually costs about $130 to $300, she said.
For cats, skin lesions are the most common symptom, but the disease also appears through weight loss, lack of appetite or energy, coughing, limping or changes in behavior, according to the Center for Excellence.
Cats also tend to conceal illness better, so they are sicker by the time symptoms are noticed.
Because of its unpredictability, treatments for the disease also vary, though nearly all patients are given antifungal medicines such as itraconazole. “But the treatment would definitely be tailored to the patient, and to their symptoms and their target organ.” she said.