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Published: August, 2007; Vol 4, Num 3

 

Valley Fever: 

Summer Hazard in the Southwest

Alternate description

LHSFNA Management Co-Chairman Noel C. Borck

“If you do road or other construction work in Southern California, Arizona, Nevada, New Mexico or Texas, you should be especially concerned about the risk of Valley Fever,” warns LHSFNA Management Co-Chairman Noel C. Borck. “It is a particular problem at this time of year.”

The disease is spread by a fungus that grows naturally in the dry climate of the Southwest. Sixty percent of all cases occur in Arizona. Most infections are in Maricopa, Pinal and Pima counties. In California, a third of all cases occur in Kern county. Throughout the region, incidence rates are highest in the late summer and early fall.

Valley Fever is caused by the Coccidioides immitis fungusthat grows in the soil. It thrives in areas of low rainfall and moderate winter temperatures. Its spores can survive for years even in harsh desert conditions, including drought and extreme heat and cold.

When the soil is disturbed, spores that are present are released into the air where they can be inhaled. Once in the lungs, they continue to multiply and grow for about three weeks before the first symptoms appear.  The presence of the fungus can be confirmed through a blood test or culture. 

Most people who breathe the spores (about 60 percent) develop no symptoms at all. The rest develop flu-like symptoms – cough, congestion, fever, fatigue, body aches and headaches – that can last a month or more. Usually, the disease affects only the lungs, but it can spread through the bloodstream to the skin, bones and the brain. Without treatment, Valley Fever can lead to severe pneumonia, meningitis and even death. However, when properly treated with fungus-killing medications at the first sign of symptoms, most people will recover without problems. Once infected, the body usually establishes a lifetime immunity against future infections.  The disease is not contagious, so it cannot spread from one person to another.

As more people settle in the Southwest, the incidence of Valley Fever is increasing. Nevertheless, because its symptoms are similar to flu and usually resolve themselves without treatment, many cases are misdiagnosed. A recent study in Arizona estimates that more than 30,000 people with Valley Fever are treated annually in the state but only 4,000 are diagnosed with the disease. The Valley Fever Center for Excellence is trying to promote wider understanding of the disease. 

About one in 200 infected individuals develop the more serious and potentially deadly form of the disease. Pregnant women, people with weakened immune systems and those of Hispanic, Asian or African descent are more susceptible to serious complications. Individuals who vacation in Arizona and subsequently develop pneumonia within a few weeks of return to their homes have a one in three chance of a Valley Fever infection.

Because of the disease’s geographically-confined location and its relatively small number of potential victims, the large drug manufacturers have not invested in Valley Fever vaccine research. Efforts to develop a vaccine, however, continue in California where the state has provided sporadic funding in recent years. In Arizona, research continues on medications that can cure the disease. Current drug treatments do not cure the disease but assist the immune system in controlling the fungus, allowing the body to reduce and eliminate symptoms while the treatment continues.

For those who must do construction work where the risk of exposure is high, the best protection is the use of P100/N95 or better respirator. Yet, as MayoClinic.com says, “The few ways of preventing Valley Fever — wearing a mask, staying inside during dust storms, wetting the soil before digging, keeping doors and windows tightly closed — aren't particularly effective.” With few ways to ensure protection, the best advice is to be aware of the symptoms so timely and proper treatment can best be ensured.

A LHSFNA health alert on Valley Fever is available through the Fund’s online publications catalogue.

[Steve Clark]