Valley Fever in Dogs: Symptoms and Causes

Valley Fever in Dogs
Photo by Jamie Street

Valley Fever is a fungal infection that causes inflammation of the lungs and sinuses, resulting in coughing, sneezing, fatigue, fever, and sometimes pneumonia.

Dogs are at higher risk of developing valley fever because they spend time outdoors, where the fungus thrives.

Here, we’ll discuss everything to know about valley fever in dogs, ranging from the symptoms, causes, and treatments.

Dogs are susceptible to Valley fever because their immune systems aren’t as strong as humans. So, they can develop serious complications even after being exposed to the fungus.

If you live near areas where the fungus grows, you should take precautions to prevent exposure. There are three ways to treat valley fever in dogs: prevention, treatment, and control.

Prevention involves keeping your dog away from areas where the fungus thrives. Treatment consists in administering antibiotics to reduce the risk of infection. However, control involves removing the source of fungal spores from your yard.

What is Valley Fever?

Valley Fever, also known as desert rheumatism, is a disease caused by Coccidioides Immitis, a tiny fungus. This fungus grows best in the soil where there are high levels of humidity and warm temperatures.

In addition to being found throughout the Western United States, it is common in desert regions of Mexico, Central America, South America, and Australia.

Infections usually occur when people breathe dust containing the spores into the lungs, which has several symptoms.

These symptoms typically go away within 2 weeks without treatment. However, untreated infections can lead to pneumonia or even death.

The Centers for Disease Control and Prevention estimates that about 50 million Americans are infected yearly. Most cases occur in Arizona, California, Nevada, New Mexico, Texas, Utah, and Colorado.

Most people do not know they have been exposed to the fungus because the signs and symptoms are similar to those associated with flu and cold viruses. 

Valley fever doesn’t only occur in humans; they occur in dogs too. But how do you know when your dog has contracted this disease? Well, there are symptoms to look out for.

Symptoms of Valley Fever in Dogs

The most common form of valley fever in dogs is the primary form. This occurs when the fungus enters the lungs and begins growing inside the air sacs, known as alveoli.

As the fungi grow, they produce a substance called beta-glucan. Beta-glucan is like a sponge that sticks to cells lining the lung walls causing them to swell up and fill with fluid.

When this happens, the dog develops difficulty breathing and coughing. Sometimes the dog coughs up blood and sometimes coughs up mucus. If left untreated, the swelling can cause the lungs to collapse.

Another type of valley fever is the disseminated form. This occurs when fungal organisms travel to other body parts such as the kidneys, liver, heart, brain, or eyes.

Dogs affected by this valley fever may show signs of depression and loss of appetite. They may also experience seizures or blindness.

Here are a few other symptoms your dog could experience:

  • Dry Cough
  • Sneezing
  • Fatigue
  • Eye inflammation
  • Persistent Fever
  • Lethargy
  • Vomiting
  • Weight loss
  • Diarrhea
  • Difficulty Breathing
  • Pneumonia

You can help protect your dog against valley fever by taking steps to avoid exposing him to the fungus. Keep your dog indoors during times of heavy rainfall, especially if he’s outside playing.

Also, clean up any dirt around your home so your dog won’t track the fungus into your house. And ensure that it takes antifungal medications always.

How Does This Disease Spread in Dogs?

Valley fever in dogs spreads through the air via airborne particles called conidia. Conidia are tiny structures on the surface of the fungus that allow it to be transmitted between animals and plants.

When animals breathe in the conidia, they enter their body and germinate inside cells. The germinated conidia then grow into mature fungi, which cause valley fever.


If your dog lives near an area where this fungal infection is common, your veterinarian may recommend diagnosing your dog with valley fever for treatment.

The vet may want to run a fungal antibody blood panel (titer) to see if there is any evidence of exposure to the disease.

If your dog has symptoms besides lethargy, vomiting, diarrhea, and fever, it might need additional blood testing and diagnostic x‑rays of its chest.

If your dog has traveled to an endemic region for valley fevers, you must inform your vet about this travel experience. Even if your dog shows no signs of being exposed to valley fevers, it may still carry them.

Treatment for Valley Fever in Dogs

Treatment of Valley Fever in pets usually involves taking an oral dose of an antifungal drug twice daily for several days. This helps prevent further growth of the fungus in the lungs.

Although many pets feel better after starting therapy, the prognosis depends upon how far the disease has progressed.

If the fungus has spread throughout the body, the chances of recovery decrease dramatically. Some pets will require lifelong administration of antifungals, even though the symptoms have resolved.

Prevention of Valley Fever in Dogs

As mentioned earlier, to reduce your risk of getting valley fever in your pet, keep your dog away from areas where the fungus grows. It would help if you also took precautions to limit your dog’s exposure to the fungus.

For example, don’t let your dog play outdoors during periods of heavy rain. Clean up any dirt around your property, so your dog doesn’t track the fungus into the house.

Frequently Asked Questions

Is my dog at risk for valley fever?

Yes! Your dog can get valley fever just like people do. Some veterinarians believe your dog could be more likely than humans to develop valley fever because of their lifestyle. A study published in the Journal of Veterinary Internal Medicine showed that dogs who live in rural areas were more likely to test positive for coccidioidomycosis than those living in urban areas.

Can my dog give me this disease?

No. Valley fever isn’t contagious among people. However, your dog can become infected by inhaling the fungus spores.

How can my dog contract valley fever?

Coccidioidomycetes are microscopic organisms that can infect both people and animals. They’re most commonly seen in the soil of arid regions, but they can also grow in damp environments such as caves, mines, and other places where water collects. These fungi enter the respiratory tract through inhalation, causing pneumonia-like symptoms.

How long does it take for my dog to recover from valley fever?

It takes anywhere from one week to three months for your dog to fully recover from valley fever. During this time, your dog needs to stay on a course of antifungal medication. The length of treatment depends on how severe the infection was when it began.

What kind of tests can I perform to diagnose valley fever in my dog?

Your veterinarian may order blood tests to determine whether your dog has been exposed to the fungus. They may also use radiographs to look for damage caused by the fungus inside your dog’s lungs.


Valley fever is a fungal infection that affects people and dogs. However, dogs are most likely to contract it than humans, and valley fever in dogs can be terrible.

Fortunately, there are ways to treat your dog if they have it. We hope you found this article knowledgeable enough to help your dog get through valley fever.

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