Dry and windy conditions have not only raised the risk of wildfires in California, but also may have heightened the chance of someone in the great Central Valley developing the fungal infection coccidioidomycosis, or Valley Fever.
It is endemic to the area, particularly in arid months followed by drought. We will probably see an increase in cocci this year, says Kathy Wittman, RN, CIC, infection prevention coordinator for Kaweah Delta Medical Center in Visalia, Calif. The hospital sees about 140 patients annually with the disease in the primary state.
Christi Paradise, RN, CIC, infection control coordinator at Saint Agnes Medical Center in Fresno, Calif., has noted a historical increase in cases when the weather is dry and windy.
However, David Luchini, RN, BSN, division manager of community health at the Fresno County Department of Public Health, reports fewer cases in the first half of 2008: 89, compared with 293 cases in the first six months of 2007.
Between 50,000 and 100,000 people develop symptoms of Valley Fever each year in the United States, with about 35,000 cases occurring in California, according to the state’s Department of Public Health.
The fungus lives in the soil and produces spores. When the soil is dry, dirt near the top loosens, and the wind can pick it up. Construction activity, agricultural work, and natural disasters can disturb the soil. As the spores become airborne, people breathe them in. The warm, moist lungs create an ideal spot for spores to grow.
About 60% of people who contract the disease do not know it, according to the Centers for Disease Control and Prevention (CDC). These people do not develop symptoms. Yet they can still develop a natural immunity to the disease.
For others, the disease presents as a mild, flu-like illness, with fever, cough, headache, rash, and muscle aches, within one to three weeks after exposure. The body fights it off, and most people fully recover within weeks to months. But for some, it may become a chronic lung infection or disseminate and cause a widespread infection, most commonly causing skin lesions, meningitis, and bone and joint infection.
Patients can be affected permanently, and some people die from disseminated Valley Fever, Paradise says.
Who is at risk
Nurses cannot catch Valley Fever from a patient because it is not communicable.
Exposure to the disease is limited to the southwestern United States, Mexico, and parts of Central and South America that meet certain soil and climatic conditions. About 10 to 50% of people living in endemic regions exhibit evidence of exposure to the fungus, says Faisal Aranki, an epidemiologist with the Fresno County Department of Public Health.
Migrant workers and others who toil in the soil, such as construction workers, are at greater risk of developing Valley Fever. If migrant workers came from Mexico and developed natural immunity there, that immunity would hold during their exposure in California, and they are not likely to come down with the disease, Wittman says.
People with a compromised immune system, the elderly, African Americans, Asians, and women in the third trimester of pregnancy are more likely to develop the disseminated disease.
Diagnosis and treatment
Living in an area where providers are aware of cocci infections aids in earlier detection. But people can pick up the infection while traveling in the area and develop symptoms after returning home.
Always find out what the patient has been doing and where the patient has been, Wittman advises.
Providers may order a serological test to check for antibodies against the fungus.
We are looking for a titer that constitutes exposure, Wittman says. It is sent to the University of California, Davis, and when we get the result back, it gives us an idea about how long the person has had the disease and the stage.
Other tests for Valley Fever include a biopsy of the affected tissue or a culture of tissue or body fluids, such as sputum.
You cannot tell by the symptoms, because the symptoms are often vague and nonspecific, Paradise says.
Many cases do not require treatment. For those at risk of developing severe disease, providers may prescribe fluconazole for acute, uncomplicated coccidioidomycosis. The CDC says not enough information exists to determine if treatment of uncomplicated cocci is beneficial or not.
Patients who develop pneumonia in both lungs or systemic disease should receive antifungal therapy, according to the CDC.
It may take months on antifungal therapy before the person can go back to work, Wittman says. She explains that prompt treatment can limit the duration to three to six months, whereas some patients, such as those with comorbidities, may require a year of treatment.
No vaccine exists to prevent Valley Fever. The best prevention methods are steering clear of dust and dry soil. That includes staying inside on windy days, keeping the windows tightly closed, wearing a mask when venturing outdoors, and watering the soil for two or three days before tilling or planting. People at high risk of severe disease should not engage in activities such as gardening that stir up the dirt.
[Valley Fever] is not going to go away, Luchini says. It’s in the soil. It’s pure education and getting into the habit of avoiding being outside on windy days.