If you live in the desert states in the southwestern part of the United States, you may assume that you’ve had valley fever at some point and just didn’t know it. Valley fever was first discovered in the San Joaquin Valley in California. Valley fever is commonly found in south and central California, Arizona, New Mexico, Texas, and the southern parts of Utah and Nevada. It is also found south of the U.S. in portions of Mexico, Central and South America. In the U.S., between 50,000 and 100,000 people develop valley fever each year.
Valley fever, which has the medical name coccidioidomycosis, is an infection caused by fungus that lives in the soil in the desert southwest. When the soil is disturbed, the fungus can become airborne which means it can be inhaled when we breathe. People who live in areas where the fungus is found have a high risk of catching the infection, but anyone who visits the desert southwest can catch valley fever.
Once the fungus enters the lungs, it causes an infection that can mimic the symptoms of the flu. Symptoms include:
• Fatigue
• Coughing
• Chest pain
• Fever and headaches
• Join pain
• Rashes
Most cases of valley fever are mild. Because these symptoms are common to a number of illnesses, over 60 percent of people who catch valley fever never know they had the infection. Most of these people recover without need for any medical treatment, although symptoms can linger for as long as six months.
In approximately 5 percent of people with valley fever, pockets of the fungus form nodules in the lungs. These nodules show up as patches approximately one to one-and-a-half inches in diameter and may resemble lung cancer on a chest x-ray. Doctors may need to perform more invasive tests such as removing part or all of the nodule to determine whether or not it is cancer.
A small percentage of people develop a more serious form of valley fever that spreads (disseminates) to other parts of the body. In these cases, the fungus can escape from the lungs and form lesions in the skin, bones, or joints. The most serious form of disseminated valley fever causes meningitis which is an infection that can spread from the spinal fluid into the brain.
People who visit the desert southwest then return home with the infection may be at higher risk of misdiagnosis. Because valley fever is a regional condition that is rarely seen outside the southwestern states, doctors in other parts of the United States may not be as familiar with the symptoms or appropriate treatment for the condition. Symptoms, if they develop, typically show up between 15 and 21 days after the fungus is inhaled. A blood test can be done to test for the antibodies the body makes to fight off the infection.
There is no vaccine or other way to keep from catching valley fever if you are in an area where the fungus is found. People who are in good health are generally able to recover from the infection quickly. People who have a compromised immune system are more prone to catch valley fever. This infection cannot be spread from an infected person to another person. The only way to catch valley fever is by inhaling the fungus that has been living in the soil. The good news is that once you have valley fever, you will be immune to the infection for the rest of your life.
People are not the only ones susceptible to valley fever. Many animals, including dogs, cats, cattle, horses, and some zoo animals also catch valley fever. Most are able to recover from the infection on their own, but some may need to be treated with antifungal medications. A small number of animals are not able to recover from the infection.
Sources:
U of A Valley Fever Center for Excellence
National Institutes of Health: PubMed Health
Directors of Health Promotion and Education