Infectious Diseases

VALLEY FEVER: Coccidioidomycosis

Coccidiodomycosis! That’s a thousand dollar word, isn’t it! What is it, anyway? It’s the medical term for San Joaquin Valley Fever, or Valley Fever for short. The San Joaquin Valley is an area located in central California extending from Sacramento south to Bakersfield and includes the cities of Lodi, Modesto, and Fresno, and all of Yosemite National Park. It has the dubious distinction of being one the first areas in the U.S. where Coccidioidomycosis was seen. In the early 1900’s investigators in this area noted a high frequency of a flu-like illness that lasted much longer than normal. It became known as San Joaquin Valley Fever and was called that until the 1950’s when the cause and mode of transmission were discovered.

Valley Fever, as it is now called, is a fungal illness of the lungs. The spores of the fungus Coccidiodes immitis live in the soil not only in central California but all over the Southwest from West Texas to south central Washington. The greatest concentrations lie in New Mexico, Arizona, California, and parts of Mexico, areas that have mild winters and arid summers. The spores of this fungus grow in the ground like a mold. Any disruption of the soil releases these spores into the air where they may be carried hundreds of miles. People who have jobs that expose them to dust—farmers, road construction workers, ranchers, archeologists, and military personnel on field exercises—are at particular risk. It is very difficult to avoid breathing in the fungus if you live in dusty places where Coccidioides is common in the environment.

While not everyone who is exposed to Coccidioides becomes sick, anyone who inhales the spores is at risk of infection. People over age 60 are the most common sufferers, but diabetics, pregnant women, people with weakened immune systems, and people of Filipino or African heritage are also susceptible. Anywhere from one to three weeks after exposure, patients may develop fever, chills, fatique, chest pain, cough, night sweats, headaches, joint aches, and a red, spotty rash. The rash of Valley Fever is made up of painful red bumps that later turn brown and are found on the lower legs, arms, chest, and back. In more severe cases, pneumonia and lung nodules occur and are seen on chest X-rays or CT’s.

Valley Fever presents in three forms. They are:

Acute Coccidioidomycosis: the symptoms discussed above appear acutely. The duration of the illness varies from weeks to months depending on its severity. It may resolve without treatment.

Chronic Coccidiodomycosis: When initial infection does not resolve completely, fever, cough, and chest pain persist, and weight loss, blood-tinged sputum, and lung nodules develop. The disease is then classed as chronic.

Disseminated Coccidioidomycosis: the most serious form where infection spreads from the lungs to other parts of the body—skin, bones, liver, brain, heart, and meninges (membranes around the brain and spinal cord). This is considered a serious, life-threatening condition.

Diagnosis is made by a history of travel to endemic areas, exposure to dusty air, and one’s general health state. Physical exam and chest imaging (X-ray or CT) are helpful, but the most conclusive test is a blood analysis for the antigens and antibodies of Coccidioides. Finding evidence of these proteins in the blood coupled with clinical findings and history confirm the diagnosis. Skin testing is also done. Coccidioides antigen is injected into the skin to see if a reaction occurs. A raised red bump developing at the injection site is a positive result. The absence of a raised bump is a negative reaction. A positive result merely means one has been exposed to the fungus at some time, but if the patient has previously had a negative skin test and is now testing positive, you can be certain his/her current illness is Valley Fever.

Most cases of Valley Fever resolve without treatment, but resolution is painfully slow taking several months. Many cases are treated with oral anti-fungal drugs such as fluconazole for a period of 3-6 months. More severe cases may require hospitalization and more aggressive anti-fungal therapy. Disseminated Coccidioidomycosis patients are at risk of death, especially those who develop meningitis. They require lifelong anti-fungal treatment.

Most people make a full recovery, but a small percentage develop long-term lung infections that can take years to resolve. Valley Fever is not contagious from person to person. About 10,000 cases of Valley Fever are reported every year, and the CDC reports that from 1990 to 2008 (18 years) there were 3,089 coccidioidomycosis-related deaths in the U.S., or fewer than 200 per year. Compared to 80,000 deaths from the flu in 2017 alone, that doesn’t sound like much. But Valley Fever stats were taken from just six states and flu stats from all fifty. The death toll from the flu in just six states would still be approximately 10,000 patients per year, a much higher number. That’s not meant to lessen the significance of Valley Fever; not at all. And those who suffer from its prolonged effects would agree it’s just as troublesome as many other more common disorders.

So, when you’re traveling the southwestern United States, especially the San Joaquin Valley of central California, be aware of the risks around you. Avoid dusty fields, road construction areas and building sites, and consider wearing a mask during a dust storm. Or better yet, stay inside. The old saying about “an ounce of prevention…” is very pertinent here.

Dr. G’s Opinion: I’ve never seen a patient with Valley Fever. Practicing in Indiana where the disease is not found isolates one from the experience. But after living in Arizona for two years and speaking to patients who have had it, Valley Fever, though far less common, is a disease not to be ignored. People who have it are sick and stay sick for months. The potential for significant, long-term effects is very real and should concern all physicians who treat the disease. Treating patients long term until they are completely well requires patience from both the doctor and the individual. But as with any infectious disease, taking the preventive measures listed above is the best approach.


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