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Valley Fever (Coccidioidomycosis) Statistics

Valley Fever 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, 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.

Number of reported Valley fever cases

Number of reported coccidioidomycosis cases,1998-2015
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
2014 5,624 2,243 156 209 8,232
2015 7,622 3,053 198 199 11,072

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

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

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,5,6 archeological workers,710 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.


  1. CDC. Increase in Reported Coccidioidomycosis – United States, 1998-2012, MMWR 62(12);217-221.
  2. Valdivia L, Nix D, Wright M, Lindberg E, Fagan T, Lieberman D, et al. Coccidioidomycosis as a common cause of community-acquired pneumonia. Emerg Infect Dis. 2006 Jun;12(6):958-62.
  3. Chang DC, Anderson S, Wannemuehler K, Engelthaler DM, Erhart L, Sunenshine RH, et al. Testing for coccidioidomycosis among patients with community-acquired pneumonia. Emerg Infect Dis. 2008 Jul;14(7):1053-9.
  4. Huang JY, Bristow B, Shafir S, Sorvillo F. Coccidioidomycosis-associated Deaths, United States, 1990-2008. Emerg Infect Dis. 2012 Nov;18(11):1723-8.
  5. Crum N, Lamb C, Utz G, Amundson D, Wallace M. Coccidioidomycosis outbreak among United States Navy SEALs training in a Coccidioides immitis-endemic area—Coalinga, California. J Infect Dis. 2002 Sep 15;186(6):865-8.
  6. Standaert SM, Schaffner W, Galgiani JN, Pinner RW, Kaufman L, Durry E, et al. Coccidioidomycosis among visitors to a Coccidioides immitis-endemic area: an outbreak in a military reserve unit. J Infect Dis. 1995 Jun;171(6):1672-5.
  7. Loofbourow JC, Pappagianis D, Cooper TY. Endemic coccidioidomycosis in Northern California. An outbreak in the Capay Valley of Yolo County. California medicine. 1969 Jul;111(1):5-9.
  8. Petersen LR, Marshall SL, Barton-Dickson C, Hajjeh RA, Lindsley MD, Warnock DW, et al. Coccidioidomycosis among workers at an archeological site, northeastern Utah. Emerg Infect Dis. 2004 Apr;10(4):637-42.
  9. Werner SB, Pappagianis D. Coccidioidomycosis in Northern California. An outbreak among archeology students near Red Bluff. California medicine. 1973 Sep;119(3):16-20.
  10. Werner SB, Pappagianis D, Heindl I, Mickel A. An epidemic of coccidioidomycosis among archeology students in northern California. N Engl J Med. 1972 Mar 9;286(10):507-12.
  11. Wilken JA, Sondermeyer G, Shusterman D, McNary J, Vugia DJ, McDowell A et al. Coccidioidomycosis among Workers Constructing Solar Power Farms, California, USA, 2011-2014. Emerg Infect Dis. 2015 Nov;21(11):1997-2005.
  12. Schneider E, Hajjeh RA, Spiegel RA, Jibson RW, Harp EL, Marshall GA, et al. A coccidioidomycosis outbreak following the Northridge, Calif, earthquake. JAMA. 1997 Mar 19;277(11):904-8.
  13. Williams PL, Sable DL, Mendez P, Smyth LT. Symptomatic coccidioidomycosis following a severe natural dust storm. An outbreak at the Naval Air Station, Lemoore, Calif. Chest. 1979 Nov;76(5):566-70.