Valley Fever

Veterinarians in the Phoenix area are reporting a rise in canine cases of Valley Fever, a potentially deadly fungal disease. As many as 10 percent of dogs living there will contract it. But it’s also a threat throughout the hot, dry climate of the desert Southwest, including Southern California, southwest Texas, New Mexico, Nevada, and Utah. Cases have also been diagnosed in south-central Washington State.

Monsoon season, primarily between June and September, is a time of year that dogs become more susceptible. That’s because the fungus that causes Valley Fever — coccidioides immitis — can come up from the dry ground when it gets loosened by the rains and then enter the respiratory tracts of our canine pets. Any stirring up of the dusty soil can release the fungus into the air.

Most dogs never get sick when they breathe it in, or exhibit only mild symptoms and may not even require treatment. But those with weakened immune systems — very young puppies, old dogs, and those with underlying health conditions — may not be able to fight off the illness without medical intervention. Valley Fever causes everything from a harsh, dry cough to breathing difficulties, fever, lethargy, lameness that stems from bone and joint inflammation, skin ulcers, draining sores, inflammation of parts of the eye that can potentially lead to blindness, and, if the illness hits the nervous system, seizures. In rare cases, it can even cause death.

Diagnosing Valley Fever

A problem breathing may be the initial sign you notice because the fungus hits the lungs first (and sometimes doesn’t travel any further, depending on the immune system response that a dog is able to mount). If you live in the desert Southwest or have traveled there with your dog and notice that your pet is having trouble taking in air or has a dry, hacking cough, get her to the veterinarian as soon as possible. Certainly, any additional symptoms make this trip even more urgent.

In addition to conducting a clinical exam during which the veterinarian will check for such things as swollen joints and lymph nodes, she will draw blood for a complete blood count as well as conduct a urinalysis. She may also check for antibodies to the offending fungus — an indication that the dog has been infected and that her immune system is trying to fight the disease. There are a number of additional screenings that the vet might order as well, including a chest x-ray and x-rays of any affected limbs.

In difficult cases where routine tests might not do the trick, the doctor may take a culture of fluid samples from your dog to isolate and identify the fungus. She may also conduct biopsies or aspirates for microscopic examination of cells, fluid, or tissue samples.

Treatment plan and aftermath

The standard treatment for Valley Fever is to give a dog anti-fungal medication — often for a year or more. A dog with the disease will usually start to feel better within a couple of weeks of starting on an anti-fungal drug, but it can take a very long time to clear the illness from the body. In cases in which the disease has invaded the nervous system and the dog has suffered seizures, medication may be required for life. For a larger dog, the cost of the drug could amount to at least $150 a month.

Dogs can sometimes relapse, but most recover fully.