Valley Fever - Coccidioidomycosis

Introduction  Valley Fever (Coccidioidomycosis) is a disease caused by inhaling spores of two fungi, Coccidioides immitis or Coccidioides posadasii.  The disease was originally named “Valley Fever” because of its discovery in California’s San Joaquin Valley, and is prevalent in Mexico, Texas, Nevada, Arizona and the Desert Southwest.  Valley Fever is sometimes called Cocci, Imperial Valley Fever, desert fever, or desert rheumatism.¹  Researchers estimate that of the 4 million Americans living in regions with Cocci in the soil, 80% of them are in southern Arizona.²    It is the 4th most common disease reported to the Arizona Dept. of Health Services. ³  There are estimated to be at least 50,000 new symptomatic cases / year and two thirds are believed to be in Arizona.  Valley Fever has higher regional morbidity & mortality rates than Hanta and West Nile viruses.⁴

Who Gets Valley Fever?  Because the Cocci spores are in the soil, people who live or work in areas with new construction or high winds are more likely to be exposed, as the earth in those places is stirred up.  Highly endemic areas include Maricopa, Pinal, and Pima counties in Arizona.  In fact, the growth and simultaneous construction in Arizona may be contributing to the recent rise in infection rates.  The most susceptible people are those with compromised immune systems.  For example, mortality rates from disseminated Valley Fever infection are higher in individuals with HIV/AIDS.⁵  For reasons that are not well understood, African Americans, Asians, and Filipinos experience more Valley Fever complications, as do smokers, diabetics. Pregnant women in the second and third trimesters are also more prone than the general population to develop disseminated Valley Fever.⁶  Valley Fever is not contagious.  Climatic conditions can also be an important factor.  In Arizona, more infections occur in June - July and in October - December than at any other time of the year due to seasonal changes.⁷  In addition to humans, other animals such as cattle, horses, sheep, coyotes, cata, and even bats can be infected with Valley Fever.  Of special concern is the epidemic of Valley Fever in dogs.  Because of their popularity as companion animals, dogs make up the main group of reported animal cases of the disease.  Veterinarians in areas with endemic Valley Fever are generally trained in treatment of Valley Fever, and research to further the knowledge of canine Valley Fever is ongoing.

Signs & Symptoms Most people (about 60%) who become infected with Valley Fever have no apparent symptoms.   If symptoms do develop, they occur within 3 weeks after inhaling the spores.  Of the 30% who have symptoms, some have mild disease where the disease appears like a mild community acquired pneumonia that may last from weeks to months before resolving. Others, however have prolonged fatigue and may also take months to recover .  Some people who have mild cases never know that they have had Valley Fever.  The most common symptoms are cough, chest pain, fatigue, headache, and fever.  After recovery, most people develop a lifelong immunity against re-infection.  Five to ten percent of those infected experience more severe complications.⁸  In the 1%-2% of patients whose Valley Fever becomes disseminated, the fungal infection may spread from the lungs to the skin, joints, bones, and -in the most serious and potentially fatal complication- to the brain’s protective membranes, called the meninges.  

Diagnosis  Unfortunately, most cases of Valley Fever go undiagnosed and unreported, possibly due to under-testing.  (Only 3,660 out of 30,000 to 90,000 suspected cases were reported in 2004.)  For the patient, it may feel like pneumonia.  If Valley Fever is suspected, the physician should order a blood test.  Chest x-rays, tissue biopsy, sputum cultures, and other diagnostic tools may be used as well.  If a person lives in or has traveled to an endemic area, it is important to consider Valley Fever as a potential diagnosis. ⁹

Prevention & Treatment  Researchers are working to develop a vaccine and progress toward that goal has been made in recent years.   Although there is no currently available "cure," Nikkomycin Z shows promise as a potential therapeutic agent and is being studied at the University of Arizona.  Antifungal medications, such as Ketoconazole, Itraconazole, Fluconazole, Voriconazole, and Amphotericin B are used to mitigate the symptoms of chronic infection; some patients may require long-term (or even lifelong) treatment.  It is recommended that people in areas with Cocci reduce their chances of infection by staying out of blowing dust storms and wearing respirators when doing outdoor work that involves soil disruption.

⁴  Climate and Health: Basic Science and Decision Support for Valley Fever by Andrew Comrie, UA, Dept. of Geography & Regional Development and Dept. of Atmospheric Sciences (comrie@arizona.edu )

• Fungal Infections
• Molds
• Respiratory Diseases
• Valley Fever