Our Arizona Veterinarian informed us that our dog has Valley Fever, coccidioidomycosis. This article is to share the information and facts we learned about Valley Fever fungus. Our dog is on Valley Fever antifungal medicine, and his prognosis looks good.

What symptoms made us visit the veterinarian?
- Our dog was eating well but losing weight.
- A few times I caught our pet crying as though he were in pain.
- Something just seemed off with our dog

Canine valley fever originates in a dog as it inhales the coccidioidomycosis fungal spores. These fungus spores are usually found in dirt and in arid areas of the desert. Once inhaled, valley fever spores grow and multiply very rapidly at the first available point in a dog’s body, the lungs.
Symptoms of coccidioidomycosis, valley fever, usually appear between 1 and 3 weeks after exposure to the fungus.
Common Symptoms of Valley Fever in Dogs and Cats
- Fever
- Lethargy
- Lameness
- Dry or moist cough
- Bone swelling/joint enlargement
- Extreme weight loss with muscle wasting
- Enlarged lymph nodes
Most fungi are harmless, but some types like Valley Fever can make you sick. The map below shows areas of the United States that have common cases of Valley Fever in humans and animals.

The fungus spores of Valley Fever begin in the lungs until they grow large enough to rupture, releasing hundreds of endospores. These numerous spores begin a parasitic stage in the tissues and disseminate into the animal’s body. The Valley Fever Fungus can spread to the organs.
The immune system does have the capability to fight off the Valley Fever infection before symptoms can even be realized, but it requires an exceptionally strong immune system to do so.

According to the University of Arizona, about 70% of dogs who inhale Valley Fever spores control the infection and do not become sick. The Valley Fever infection can range from mild to severe.
Canine Valley Fever will begin to affect the dog’s joints if the condition continues to progress. It is very sad when the infection of Valley Fever is so severe in the bones that an animal can no longer move its arms or legs.

It is very important to continue medicating your dog as directed until the veterinarian confirms that the blood tests are negative and tells you to stop medication. If you stop treating Valley Fever too soon, symptoms may recur. Some animals will have to remain on the anti fungal medication for life.

Is Valley Fever contagious from animal to animal, human to human, or animal to human?
NO. Valley Fever is considered a non-contagious disease. Even if multiple animals or humans are affected in the same household, each Valley Fever case was acquired independently.
Recently, I felt swollen glands on our other dog. This week we took him to the doctor for Valley Fever blood tests and x-rays. Already our heart is heavy with our little dog being infected and I can’t yet imagine how crushed we will be if our other dog comes up positive.

A Valley Fever vaccine is under development. Here’s hoping it is developed soon and may be available to prevent Valley Fever or make it very mild.

The Valley Fever Center for Excellence at the University of Arizona is the only academic research institution in the world focused on the study of Valley Fever.