Valley Fever (Coccidioidomycosis) Statistics

Valley fever is reportable in the following states: Arizona, Arkansas, California, Delaware, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Dakota, Ohio, Oregon, Rhode Island, South Dakota, 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.

The case numbers reported here are those reported in the annual Summary of Notifiable Infectious Diseases, published in CDC’s Morbidity and Mortality Weekly Report. Numbers reported by individual states might differ slightly from those reported here because of differences in the timing of reports or surveillance methods.

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

• The number of susceptible people exposed to the fungus Coccidioides because of travel or relocation to endemic areas
• Environmental factors such as temperature and rainfall, which can affect the growth of the fungus and how much of it is circulating
• The way cases are being detected and reported

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.⁴ The number of coccidioidomycosis-associated deaths each year has been fairly stable since 1997.⁴

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,⁵,⁶ archeological workers,^7–10 solar farm workers,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.