Valley fever is seen in dogs that spend time in the low desert regions of the southwestern United States. While healthy adult dogs may experience no symptoms of valley fever, puppies, senior dogs, and dogs with a compromised immune system may show symptoms ranging from coughing to painful joints. In today's post, our Clearlake vets explain what valley fever is, how to identify it, and how it is treated.
What is valley fever?
Coccidioidomycosis is a condition seen in dogs and people that goes by a number of different names, including valley fever, desert rheumatism, San Joaquin Valley fever, and California disease.
Valley fever is caused by a fungus called Coccidioides immitis that lives in the soil and thrives in particular desert climates.
In the United States, Coccidioides immitis can be found in the low desert regions of Arizona, New Mexico, Texas, and California.
How is valley fever spread?
Valley fever is spread through the inhalation of Coccidioides immitis (fungal) spores. When the spores are inhaled by your dog, they grow into spherules within the lungs.
If your dog has a strong and healthy immune system the body will 'wall off' the spherules and your pet will remain asymptomatic (no symptoms of valley fever).
However, if your dog is very young, old, or has a compromised immune system, the spherules will continue to grow until they eventually burst, releasing hundreds of endospores which can spread throughout the lungs and other parts of your pet's body where the cycle will begin again.
Fortunately, valley fever is not contagious between dogs.
How common is valley fever in dogs?
In California, the number of reported valley fever cases has been greatly increasing in recent years, having tripled from 2014-2018. From 2018–2022, between 7,000 and 9,000 cases have been reported each year.
What are the early signs of valley fever in dogs?
In the early stages, when the spherules are contained within the lungs, symptoms of valley fever typically include fever, dry cough, decreased appetite and lethargy.
Once the fungal spores have reached other parts of your dog's body more diverse symptoms may appear such as painful swollen joints, persistent fever, weight loss, eye inflammation, and blindness. In some very rare cases, if the fungus reaches the brain, valley fever can result in seizures.
If your dog is displaying symptoms of valley fever it is essential to seek veterinary care as quickly as possible to avoid serious health complications.
How does a veterinarian diagnose valley fever in dogs?
If your dog has recently visited an area where the fungus is known to frequent, your veterinarian may suspect your dog has valley fever. In order to diagnose your dog properly, your vet will run a number of tests to determine how your dog's internal organs look. Your vet will probably run a blood test (there is a specific valley fever blood test, also called a cocci test), and they may also get chest x-rays to see how the lungs are doing.
Sometimes tests are negative early in the infection, especially the valley fever blood test, and they may need to be repeated in 3-4 weeks to establish the diagnosis.
Is valley fever curable in dogs?
When diagnosed and treated early, many dogs recover well from valley fever. Dogs diagnosed with valley fever after the disease has spread to other parts of the body are more challenging to treat, and in some cases the disease becomes life-threatening.
What is the treatment for valley fever in dogs?
Antifungal medications are the primary treatment for valley fever in dogs. How long your dog will need to take these medications will depend upon the severity of your pup's condition.
In most cases, antifungal medications will need to be administered for six to 12 months, with an improvement in symptoms often being seen within a week or two. When valley fever has spread to other parts of the body, your dog may need to continue taking antifungal medications for life.
Some of the most common antifungal medications used to treat valley fever in dogs include ketoconazole (Nizoral®), itraconazole (Itrafungol® and Sporanox®), and fluconazole (Diflucan®).
How do I prevent my dog from getting valley fever in the first place?
Because the fungus that causes Valley Fever lives in dry, desert soil, the most common places for infection include Arizona, California, Utah, Texas, and Nevada. Luckily, there are several steps you can take to protect yourself and your pet from contracting Valley Fever.
- Avoid non-landscaped areas and limit your dog's roaming to well-kept parks.
- Take walks in paved areas and keep your dog on a leash.
- If your dog likes digging, avoid desert areas.
- If your home is in a desert area, keep your pet inside for a reasonable amount of time during the summer.
- Learn to recognize the signs of valley fever and contact your vet immediately if your dog exhibits any symptoms.
Is there a vaccine for valley fever?
There is a vaccine available to immunize your pets against Valley Fever. This will make it much safer for dogs to roam in yards and other dog-safe outdoor areas.
If you live in an area where the condition is common, it’s best to vaccinate your pup on the recommended schedule — likely once or twice a year after the initial dose and booster. There are minimal side effects, and the hope is the vaccine will be approved for manufacture within the year.
If you don’t live in an area with valley fever, it’s important to stay aware of any changes that could happen over time. Climate change increases the infection rate, possibly causing a vaccination need in the future.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.