What is Valley Fever in Pets?
Valley Fever is caused by a fungus that lives in the desert soil in the southwestern United States. The scientific name for Valley fever is “coccidioidomycosis,” but it’s also sometimes called “San Joaquin Valley fever” or “desert rheumatism.” As part of its life cycle, the fungus grows in the soil and dries turning into strands of cells that are inhaled. Once inhaled the spores grow and turn into endo spores. This process continues and spreads the infection in the host until their immune system surrounds and destroys it. Pets show sickness from Valley fever when their immune system does not kill the spores quick enough and they spread in the pet.
How Common is Valley Fever?
Approximately 6-10% of dogs living in Pima, Pinal and Maricopa counties in Arizona will become sick with Valley Fever each year.
Dogs comprise the majority of valley fever cases in animals, however not all dogs who breath in the spores will become sick.
About 70% of dogs who inhale Valley Fever spores are asymptomatic and possibly immune to the disease afterwards.
In October 2019 80% of the pets we tested for Valley Fever at Queen Creek Veterinary Clinic came back positive for the fungus.
If your dog lives or has traveled to desert areas in the United States and begins a dry hacking cough, limp, lose weight, or lose their appetite it is a good idea to test for Valley Fever as these are common symptoms of the disease. Pets with untreated progression of the disease may develop a high fever, hence the name Valley Fever.
Can you prevent Valley Fever?
Currently, there is no way to prevent Valley Fever. You cannot prevent Valley Fever but you can limit the likelihood of exposure by avoiding activities that generate dust such as hiking, digging, sniffing and home construction. It is important to know that Valley Fever is not contagious from pet to pet contact or pet to people contact. It is only spread through inhaling spores directly.
There is a vaccine in development! Once tested and approved this vaccine may be able to prevent Valley Fever or help pets only feel a very mild illness.
Valley Fever Diagnostic and Treatment Protocol
Cocci profile (CBC, Chemistry, T4 Cocci Titer)
Blood work (called a Titer) tends to be important in making the diagnosis for Valley Fever however, occasionally the Valley Fever Titer will show a negative result in pets that are believed to be ill with Valley Fever. Based on presentation and clinical signs radiographs and/or CT may be indicated. This is because Valley Fever can settle anywhere in the body, it is most commonly found in blood, bones or lungs.
Trial of Fluconazole
Fluconazole is a medication used to treat fungal infections, most commonly Valley Fever. A trial of fluconazole should be considered in symptomatic patients based off of blood work results. If the patient shows improvement during the trial of fluconazole, we treat the patient as a Valley Fever patient regardless of titer results.
After 30 days of treatment, blood work will be ran to look for changes in liver values and white blood cells. These values will help us determine severity of the disease, future dosing, additional medications needed, and possibly duration of treatment.
In 3-4 months, your doctor may perform a recheck of the blood work and Cocci (Valley Fever) titer. Blood work will be repeated to monitor values every 4-6 months moving forward. Valley Fever treatment can range anywhere from 6 months to life. Treatment is discontinued when there are no changes in the titer (1:4 ratio or below) for 2 consecutive blood tests in conjunction with a normal CBC and globulins or one or two years with no symptoms. Your doctor will recommend a recheck Cocci (Valley Fever) titer in 3 months after discontinuing Fluconazole, to make sure that it is not returning.