Valley fever, also known as coccidioidomycosis, is an infection caused by the Coccidioides fungus. This fungus is commonly found in soil and dust in the southwestern United States and in parts of Mexico, Central America, and South America. Coccidioides fungus was also recently discovered in central California and south-central Washington.
The spores are most likely to form in warm, wet soils after periods of heavy rainfall. The spores are then stirred into the air by anything that disrupts the soil, such as wind, construction, and farming. People can then contract valley fever by breathing in these tiny, airborne fungal spores.
The fungal infection normally starts in the lungs. In rare cases, the infection can spread to the rest of the body. Some people might also develop a chronic form of coccidioidomycosis. This means the symptoms occur repeatedly for extended periods of time.
Most people who are exposed to the Coccidioides fungi don’t experience any symptoms. When symptoms do occur, they appear within one to three weeks after the initial exposure. The symptoms of valley fever often resemble those of the flu. However, they can vary depending on the severity and type of valley fever contracted. The symptoms also depend on the health status of the person who contracts the illness.
Acute coccidioidomycosis is the most common form of valley fever. It causes symptoms that are similar to those of the common cold or flu. These symptoms include:
- night sweats
- joint pain
- painful rash
Most cases of acute coccidioidomycosis are mild. Symptoms typically go away within a few weeks. In some cases, however, the infection can become more severe and develop into the disseminated or chronic form of coccidioidomycosis.
Disseminated coccidioidomycosis is the most serious form of valley fever. However, it is very rare, accounting for less than one percent of cases. It occurs when the fungal infection spreads from the lungs to other parts of the body, including:
- membranes that surround the brain and spinal cord
Once these organs become infected, the symptoms of valley fever may become more severe. Depending on the parts of the body that are affected, additional symptoms may also develop. These symptoms include:
- skin ulcers
- painful and swollen joints
- decreased appetite
- enlarged lymph nodes
- change in mental state, including irritability and confusion
The coccidioidomycosis infection may become chronic if it doesn’t go away completely. This means that symptoms may return repeatedly or persist for extended periods of time. The symptoms of chronic coccidioidomycosis include:
- low grade fever
- chest pain
- blood tinged sputum
People can contract valley fever by inhaling dust from soil that contains Coccidioides fungus. There are two types of Coccidioides fungus that can cause valley fever: Coccidioides immitis and Coccidioides posadasii. These fungi are present in various parts of Mexico, Central America, and South America. They are also commonly found in the dry desert soils of Arizona, Nevada, Utah, Texas, New Mexico, south-central Washington, and the San Joaquin Valley of central California.
Like other types of fungi, Coccidioides species have a complex life cycle. They grow as mold in soil and develop long filaments, or thin series of cells. These filaments can break off into airborne spores when the soil is disturbed by weather, farming, or construction. The fungal spores are extremely small and can be carried hundreds of miles by the wind. When the spores are inhaled, they can reproduce inside the lungs and perpetuate the cycle of the disease.
You are at risk for valley fever if you live or spend time in an area where Coccidioides fungi are commonly found. Your risk of contracting the infection is even higher if you are in an area where soil containing Coccidioides fungi is often disturbed by weather, farming, or construction.
You have an increased risk of getting the chronic or disseminated form of valley fever if you:
- have a weak immune system
- have diabetes
- are an older adult
- are pregnant
Valley fever is difficult to diagnose solely on the basis of symptoms, as they often mimic those of other diseases and illnesses. To make an accurate diagnosis, your doctor may test a sample of your mucus or blood to check for the presence of Coccidioides fungi in your body. Your doctor may also perform an X-ray to see if there are any changes in your lungs consistent with an infection by Coccidioides.
If you have severe symptoms and your doctor suspects the infection has spread throughout your body, they may order the following tests:
- bronchoscopy with lavage
- spinal tap
Treatment for valley fever may include home care, medication, or surgery, depending on the severity of symptoms.
Most people get better without treatment. To speed up recovery time, however, doctors often recommend home treatments. These can include bed rest, drinking plenty of fluids, and taking over-the-counter pain relievers such as ibuprofen and acetaminophen.
When symptoms don’t improve with home remedies, doctors prescribe antifungal medications to kill the fungus. These drugs are also used to treat the chronic or disseminated form of valley fever. The most commonly prescribed antifungal drugs are fluconazole (Diflucan) and itraconazole (Sporanox). However, voriconazole (Vfend) and posaconazole (Noxafil) may be used to eliminate more serious fungal infections.
In rare cases, surgery may be required to remove the infected areas of the lungs. This is usually only performed for people who have chronic or severe valley fever.
The outlook for people with valley fever depends on their overall health and the type of infection. Most people with the acute form of coccidioidomycosis completely recover without any complications. People with the chronic form also usually recover with treatment, but they may experience relapses in the future.
Though few people develop the disseminated form of valley fever, they are more likely to experience life-threatening complications. People with conditions that affect their immune system are at higher risk of developing the disseminated form. This includes people with HIV or AIDS, patients on active chemotherapy, and diabetics.
Valley fever can’t always be prevented. However, you can limit your exposure to the Coccidioides fungus by:
- wetting soil with water before digging or gardening
- wearing a filtration mask that can filter 0.4 micrometer size particles
- covering open dirt areas around your home with grass or plants
- keeping your doors and windows closed during dust storms or on windy days