“Valley Fever”, an Arizona Disease

You may have heard the term “valley fever”.  Perhaps you have even had the disease.  Most Arizonans have known someone with the disease, or have even had it themselves.  For those of you who have recently relocated to our state: Welcome to one of the most beautiful states in the nation and the area of the highest prevalence of this disease.  Please be aware and informed to protect yourself, and your pets.

What is it?

Valley fever, or coccidioidomycosis, is a fungal disease endemic to the southwest United States and parts of Mexico, South America and Central America.  It is caused by a fungus (Coccidioides species), which lives in the soil.  Arizona is among the areas of highest prevalence.  You can see a map of the regions most affected at: https://www.vfce.arizona.edu/Images/SkinTest.jpg.

How do people and animals get infected?

The fungus reproduces by producing spores which become airborne when the soil is disturbed.  It is by inhaling the spores that most people, and animals, become infected.  Because they like to sniff the ground, dogs are more likely than cats to fall victim to the disease, but it any mammal can become infected.  Changes in temperature and rainfall, as well as dust storms and construction can have an impact on how many individuals are affected each year and what time of year most of the new cases occur.

What are the symptoms?

It takes about 1 to 4 weeks for symptoms of valley fever to appear. Most of the time, only mild flu-like symptoms, or no symptoms at all, are experienced.  However, some individuals, particularly those that are immunocompromised, can succumb to more severe disease.  A persistent cough, often with a fever, is the most common sign of infection.  The cough can be due to pneumonia, or enlargement of the lymph nodes in the chest which press on the windpipe, causing irritation.  The early signs in dogs are similar to those of “kennel cough”.  Pulmonary disease (lung infection) causes symptoms such as:

  • Poor appetite
  • Persistent cough
  • Fatigue
  • Fever

Left untreated, the disease can disseminate.  This means it can spread to other parts of the body. In dogs, the bones of the legs are most commonly affected, but it can affect any organ. Some signs of disseminated Valley Fever include:

  • Limping or swellings in the legs
  • Seizures or other signs of neurologic disease, like back or neck pain and weakness
  • Soft swellings in the skin that ooze fluid and don’t heal
  • Swollen testicles
  • Heart failure (weakness, fainting, coughing, difficulty breathing)
  • Red or cloudy eyes, often with squinting
  • Swollen lymph nodes

How is valley fever diagnosed?

Diagnosis of valley fever is based on the patient’s symptoms, laboratory test results, and radiographic evidence (x-rays).  There is a blood test for valley fever which measures the levels of antibodies the patient has produced against the disease.  The blood test doesn’t detect the organism, but rather the body’s response to it.  So, although it is a valuable test and a great way to monitor the response to treatment over time, it is important for the veterinarian to interpret the test in conjunction with other indicators of the disease.

How can valley fever be prevented?

Unfortunately, there is no vaccine for valley fever at this time (2014).  The best way to protect your pet and yourself is to stay indoors during dust storms and avoid activities that generate dust.  Discourage your dog from digging or sniffing rodent burrows, avoid walking near construction sites, and have a ground cover in your yard that reduces dust, such as grass or gravel.  Despite all these precautions, your pet can still become infected.

Can valley fever be fatal?

Unfortunately, it can be fatal, but most make a full recovery.  The ability to recover from valley fever depends on how early in the disease the treatment is started and other factors such as the patient’s age, and concurrent health problems.

Is it treatable?

Yes.  Once the diagnosis has been established, an antifungal drug can be prescribed.  Fluconazole is the drug most commonly used.  Treatment duration varies from several months to a lifetime, depending on the severity of disease and the organs affected.  Relapses are common, so blood testing before, during, and after treatment are necessary to determine how long to treat and when or if treatment can be safely stopped. All of the available drugs used to treat valley fever have the potential to cause birth defects, so be sure to let your veterinarian know if your dog has been diagnosed with valley fever and might be pregnant.

Is it contagious?

No, valley fever can’t be spread between animals or from animals to humans by coughing.  The infective spores are only encountered in the soil, and not in the body fluids.  However, if an animal has draining sores on the skin, they should be kept bandaged and the bandages should be handled and disposed of carefully and never by immunocompromised individuals. Burial of animals that have died of valley fever should be avoided.

What is the most important thing I should take away from this article?

You should be vigilant, both for the sake of your pet, and yourself.  We want our clients to be well informed, both for their own protection, as well as that of their pets.  If your dog is experiencing a cough that isn’t going away within a week, or has some of the other signs listed above, please come see us.  We want the opportunity to get your friend back to a healthy state as quickly as possible.  As always, we are open to any questions about your pet’s health care, so don’t hesitate to call us with any concerns.

The doctors and staff at K C Animal Hospital