Fungal Diseases

Valley Fever (Coccidioidomycosis) Statistics

How common is valley fever?

In states where valley fever is endemic and reportable (Arizona, California, Nevada, New Mexico, and Utah), overall incidence in 2011 was 42.6 cases per 100,000 population and was highest among persons aged 60-79 years (69.1/100,000).¹ In highly endemic areas such as the Phoenix and Tucson metropolitan areas of Arizona, valley fever causes an estimated 15% to nearly 30% of community-acquired pneumonias, but low testing rates suggest that valley fever may be under-recognized.^2,3

Public health surveillance for valley fever

Valley fever is reportable in the following states: Arizona, California, Delaware, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Dakota, Ohio, Rhode Island, Utah, Washington, and Wyoming. State health departments collect information about cases of valley fever and then send the information to CDC. The number of cases each state reports is published in the Morbidity and Mortality Weekly Report (MMWR). Check with your local, state, or territorial public health department for more information about disease reporting requirements and procedures in your area.

Number of reported valley fever cases

Nearly 130,000 valley fever cases were reported to CDC during 1998 to 2012.^1,4 Over 17,000 cases were reported in the U.S. in 2012, more than 70% of which were from Arizona.⁴

Number of reported coccidioidomycosis cases,1998-2012

Year	Arizona	California	Nevada, New Mexico, and Utah	Other states	Total
1998	1,474	719	72	6	2,271
1999	1,812	939	55	20	2,826
2000	1,917	840	67	41	2,865
2001	2,301	1,538	63	30	3,932
2002	3,133	1,727	63	32	4,955
2003	2,695	2,091	55	19	4,860
2004	3,667	2,641	110	44	6,462
2005	3,516	2,885	108	43	6,552
2006	5,535	3,131	140	118	8,924
2007	4,832	2,991	163	149	8,135
2008	4,768	2,597	99	69	7,533
2009	10,233	2,488	147	75	12,943
2010	11,883	4,622	159	129	16,793
2011	16,467	5,697	237	240	22,641
2012	12,920	4,431	211	240	17,802
2013	5,861	3,272	162	143	9,438

The reasons for the overall increase in the number of reported valley fever cases are not entirely known, but could be due to:

Higher numbers of people exposed to the fungus Coccidioides because of increased travel or relocation to endemic areas
Changes in environmental factors such as temperature and rainfall, which can affect the growth of the fungus and how much of it is circulating
Changes in the way cases are being detected and reported

Number of deaths due to valley fever

A recent study found that 3,089 coccidioidomycosis-associated deaths (deaths in which coccidioidomycosis was listed as a primary or contributing cause on a death certificate) occurred in the US during 1990 to 2008, which is an average of fewer than 200 deaths per year.⁵ The number of coccidioidomycosis-associated deaths each year has been fairly stable since 1997.⁵

Valley fever outbreaks

Although most cases of valley fever are not associated with outbreaks, valley fever outbreaks linked to a common source do occasionally occur, particularly after events that disturb large amounts of soil. Past outbreaks have occurred in military trainees,^6,7 archeological workers,^8-11 and in people exposed to earthquakes¹² and dust storms.¹³ If you live in an area with Coccidioides in the environment, contact your local or state health department for the most up-to-date information about outbreaks.