Valley Fever: Symptoms, Causes, Risk Factors, Diagnosis, Treatment, Outlook, Prevention

What is Valley Fever?

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.

Symptoms of Valley Fever

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

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:

• fever
• cough
• headache
• chills
• night sweats
• fatigue
• 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

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:

• skin
• bones
• liver
• brain
• heart
• 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

Chronic Coccidioidomycosis

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
• cough
• blood tinged sputum

Causes of Valley Fever

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.

Risk Factor for Valley Fever

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 Diagnosis

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:

• biopsy
• bronchoscopy with lavage
• spinal tap

Treatments for Valley Fever