High rates in parts of California and Arizona

Drought. Famartin near Gabbs, Nevada

I remember the first patient I met with Coccidioidomycosis (cok-SID-EEOY-do-my-ko-sis), or Cocci, as we called it. She was stuck in bed. She'd been healthy. She'd recently given birth and had been born in the Philippines - both seemingly meaningless details, but both placed her at risk. She'd lived where cocci was in the soil. She hadn't known. She'd taken a breath and her lungs had filled with the fungus from the soil. That's how this had all started. Now walking was difficult; the infection was in her spine, chipping away at her vertebrae.

Most exposed develop no symptoms of Coccidiodomycosis (Cocci) - also called Valley Fever. Few need medications. Less than 5% become particularly ill. For a small number, it is, however, a devastating disease. Deaths are (stably) rare; fewer than 200 die in the US a year.

The disease comes from the desert. As droughts reduce water available in California, in particular, this disease may be found in a wider area.

The disease is caused by one of two genetically different, but identical appearing, fungi, Coccidioides immitis or Coccidioides posadasii. C immitis is in California. C posadasii is in the American Southwest, especially Arizona (where 60% of infections occur), Northern Mexico and parts of Central and South America. 

Transmission is through inhalation of fungal spores, breathed in through dust. Drought in California may increase the dust that spreads the infection.

Most cases are asymptomatic

Approximately, 150,000 are infected annually in the US. In 60% of cases, there are no symptoms. Immunity is thought to be lifelong. There is no person-to-person spread.

In certain areas like southern Arizona, there is a high incidence - as high as 3% annual incidence among high risk residents in 1985.

Some have symptoms

About 40% of those infected develop symptoms - usually a mild cough and fever 1-4 weeks after exposure. The illness often resembles the flu (fatigue, fever, chest pain with coughing, headaches, rash, sore throat) and is self-limited. In most cases (possibly 95%), symptoms will resolve without treatment, though some recommend treatment.

Coccidioidomycosis may cause up to 15-29% of cases of community acquired pneumonia in parts of Arizona. The disease is under-diagnosed (testing under-performed and symptoms self-resolve). Recorded cases have increased notably from 5.3 cases in 100,000 in 1998 to 42.6 cases in 100,000 in 2011.

More advanced disease

Some cases are more serious. Some have an immunologic, rheumatologic symptoms - fever, joint pain, red rash or red nodular bumps (erythema multiforme and erythema nodosum, respectively).

In rare cases - 1-5% of symptomatic infections or about 0.6% overall - Coccidioidomycosis spreads beyond the lungs, usually through the blood. Disseminated infections can occur in any organ, but most commonly in the skin, joints, bones, and the central nervous system, which can cause meningitis.

Disseminated infections require prolonged treatment with antifungals such as Amphotericin, Fluconazole, or other Azoles. Central Nervous System infections, including meningitis, can require intrathecal shunts or injections for direct drug delivery. Symptoms may relapse.

High Risk

Environmental Risks

Exposure occurs through inhaling spores from the soil. Risk is often work-related, affecting farmers, film crews, construction workers, wildfire firefighters, military recruits, oil drillers and miners - and even college athletes and archaeologists. Earthquakes, such as Northridge in 1994, aerosolize spores. Dust storms, such as during droughts, can lead to outbreaks. Desert communities face higher risks. Prisoners may be at high risk (In Fresno county, California, 1% of population are inmates, 43% of cases occur in inmates).

Minimal exposure can cause infections - such as driving through (or even using a car from) an endemic area. Nonetheless, increased time lived in an affected area increases exposure risk.

Inherent Risk

Some individuals are at increased risk of severe disease. Persons of color have more risk for disseminated disease - most notably those of Filipino descent, but also those of African, Latino, or Native-American descent. Pregnant women (and infants) are at high risk. Immunocompromised individuals are at high risk: persons with HIV, lymphoma and organ transplant patients, diabetics, those on immunosuppressants such as corticosteroids (prednisone) or TNF-alpha (for Rheumatoid Arthritis, Crohns disease, and Psoriasis). Early treatment should be considered in these cases.


This disease may increase as more live in desert areas of Arizona and California. Further droughts, even earthquakes, can lead to increases in disease.

Those who are at high risk because of ancestry, pregnancy, or a weak immune system may wish to avoid high risk activities or even spending time in high risk areas. Staying indoors during dust storms is important.

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