'Valley fever' outbreak reported in US Navy SEALS

Last Updated: 2002-09-27 11:00:04 -0400 (Reuters Health)

NEW YORK (Reuters Health) - A recent outbreak of the fungal infection "valley fever" among US Navy SEALS highlights the potential risk to soldiers and others exposed to the dry, dusty regions where the culprit fungus lives, according to Navy researchers.

The illness, which doctors call coccidiodomycosis, typically has flu-like symptoms, but occasionally can lead to serious lung infection. It is caused by inhaling the soil-dwelling spores of the fungus Coccidioides immitis. In areas where the fungus is endemic--including the southwestern US--activities that turn up the soil, such as construction work and military training exercises, can put people at risk of infection.

In the Navy SEAL outbreak, 10 of 22 men on a training exercise in California's San Joaquin Valley fell ill and tested positive for infection with the fungus.

"This...represents the highest attack rate (45%) ever reported for a military unit during temporary field exercises," according to Dr. Nancy Crum and colleagues at the Naval Medical Center in San Diego, California.

They report the findings in the September 15th issue of the Journal of Infectious Diseases.

The researchers note that although the fungal infection is said to often produce no symptoms, all of the SEALS who tested positive for infection fell ill--with symptoms such as cough, fever, chills and night sweats. This high rate of illness may have to do with the men's "high intensity of exposure," according to Crum's team.

They also point out that the unit's one Hispanic soldier had the most abnormal chest x-ray, which falls in line with the higher risk of severe illness among Hispanics, African Americans and certain other ethnic groups. Smokers, the elderly, pregnant women and people with diabetes or a weakened immune system also have a higher risk of serious illness.

According to Crum and her colleagues, the SEAL outbreak highlights the potential for anyone exposed to the fungal spores to become ill. "Coccidioidal infection should be considered in symptomatic patients who recently traveled to the southwestern United States," they advise.

Preventive strategies in high-risk areas include avoiding outdoor work on windy days, using only enclosed vehicles, wetting soil before digging and setting up campsites on vegetated land.

Valley fever outbreaks have also been linked to soil scattered by earthquakes, dust stirred up in dust storms, and archeological digs.

SOURCE: Journal of Infectious Diseases 2002;186:865-868

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