Who can forget the Great Haboob on July 5, 2011? Beyond all the mess that was left behind to clean up, what else did that big dust cloud give us? It gave the car wash industry a tremendous boost. The Haboob has also blown in concerns over an upsurge in cases of Valley Fever. What exactly is Valley Fever and what does the Haboob have to do with it?
Valley Fever is the common name for Coccidioidomycosis, an infection caused by fungi known as Coccidioides. This fungus is found in the soil in certain lower deserts of the desert southwest including southern Arizona, south and central California, southwestern New Mexico and west Texas. It can also be found in parts of Mexico and Central and South America. The name Valley Fever is actually the shortened older name for Coccidioidomycosis, which was San Joaquin Valley Fever. The association between the disease and the causative agent was made in the San Joaquin Valley in California.
Now what does a dust storm have to do with Valley Fever? As I mentioned above, Valley Fever is caused by a fungus, or mold, that lives in the ground or soil here in the Valley of the Sun. Coccidioides grows as a mold a few inches below the surface of the desert soil. During dry conditions the mold becomes fragile. Even slight air disturbances can fracture the mold into single-cell spores that are 3-5 microns in size and can stay suspended in the air for prolonged periods of time. The spores become suspended in air during times of digging such as landscaping, construction of homes and with big dust storms. Humans, and animals such as dogs, may contract the fungus by breathing when the fungal spores are suspended in the air. Once the spores get into the lungs, they change shape and enlarge sometimes as big as 70 microns or more in diameter. They continue to grow and eventually lead to the clinical infection known as Valley Fever. Once the spore fragments are in the lungs and change shape, they cannot be spread from person to person. Therefore, this is not a contagious disease. This disease can occur after inhaling just one of the single cells. We are expecting to see a dramatic increase in the number of Valley Fever cases following the Haboob-an intense dust storm that surely suspended millions and millions of Coccidioide spores for a prolonged period of time.
The risk of exposure in the endemic areas varies but is highest during dry periods that follow rainy seasons. In Arizona these periods tend to be from May thru July and then again from October to early December. It is estimated that 60 percent of the coccidioidal infections in the US occur in Arizona in the counties of Maricopa, Pima and Pinal.
With all this ominous news, how does one know if they have Valley Fever? Well, the incubation period is typically between 7 and 21 days, meaning clinical disease is apparent 7 to 21 days after exposure. Thinking back to our recent Haboob, individuals would start experiencing symptoms around July 12th to July 26th. But symptoms may remain subclinical for weeks or even months. Many times individuals never even realize they had Valley Fever due to the mild nature of their illness.
Valley Fever typically presents as community-acquired pneumonia with chest pain, fever, difficulty breathing and cough. However, one may have only a day or two of mild coughing or cold-like symptoms with muscle aches and joint pains. Two types of rashes can occur, Erythema nodosum and Erythema multiforme. A common symptom is fatigue that can last for months. The arthralgias, or joint pains, have lead to an alternate name for Valley Fever, “desert rheumatism.” Although most patients have a mild form of the disease the does not require treatment, Valley Fever can be very severe and life-threatening; especially in immunocompromised individuals such as those with AIDS, transplant patients, diabetics, pregnant women, cancer patients on chemotherapy, and patients using high-dose prednisone.
The first step in making the diagnosis of Valley Fever is remembering to consider the possibility that Valley Fever might be present. Physicians and patients need to consider the symptoms that are present and if they follow possible exposure to conditions conducive to contracting the spores. Laboratory findings may be unremarkable but an elevated erythrocyte sedimentation rate, an elevated eosinophil count (part of a complete blood count or CBC) and chest x-ray abnormalities are helpful in making the diagnosis. Serologic testing is available the measures antibody production against the mold. This testing can also be used to monitor disease activity and duration.
If you suspect that you may have Valley Fever, and not everyone will have it, please contact your physician or you can call our office for more information. Stay well and remember, there is a fungus among us.