Notes from the Field: Increase in Coccidioidomycosis - California, 2016

Area of Science:

• Infectious Diseases
• Mycology
• Epidemiology

Background:

• Coccidioidomycosis (Valley Fever) is caused by inhaling Coccidioides spp. spores, endemic in the southwestern U.S., particularly Arizona and California.
• Infections typically present as self-limited, influenza-like symptoms but can progress to severe pulmonary or disseminated disease, including meningitis.
• Individuals at higher risk for severe outcomes include those of African or Filipino descent, pregnant women, older adults, and immunocompromised persons.

Purpose of the Study:

• To analyze the incidence trends of coccidioidomycosis in California.
• To identify significant increases in case numbers and rates in recent years.

Main Methods:

• Utilized data from healthcare providers and laboratories reported to the California Department of Public Health.
• Calculated incidence rates per 100,000 population based on the estimated year of illness onset.
• Analyzed case data from 1995 to 2016, with a focus on the recent surge in 2016.

Main Results:

• Annual incidence rates ranged from 1.9 to 8.4 per 100,000 from 1995 to 2009.
• A substantial increase was observed starting in 2010 (11.9 per 100,000), peaking in 2011 (13.8 per 100,000).
• Following a decrease from 2012-2014, incidence rose again in 2016 to 13.7 per 100,000, with 5,372 cases—the highest annual total recorded in California.

Conclusions:

• California experienced a notable increase in coccidioidomycosis incidence in 2016, reaching record case numbers.
• The findings underscore the persistent and potentially increasing public health burden of Valley Fever in California.
• Continued surveillance and public health interventions are crucial for managing coccidioidomycosis in endemic areas.