Blastomycosis Statistics

Rates of infection

Overall, blastomycosis is uncommon. Most cases occur in the United States and Canada. Blastomycosis is reportable in select U.S. states. Data from these states reveal yearly incidence rates of approximately ≤ 2 cases per 100,000 population, although rates may vary substantially within states.1–3 Wisconsin may have the highest incidence of blastomycosis of any state, with yearly incidence rates ranging from 10 to 40 cases per 100,000 people in some northern counties.4

Deaths due to blastomycosis

Two analyses of blastomycosis cases in the United States found that between 8–9% of people with blastomycosis died.3,12 The overall mortality rate for blastomycosis is likely lower than these estimates because these studies did not include patients who had less severe forms of the infection.

Public health surveillance for blastomycosis

Refer to the listing of reportable fungal diseases to see which states require reporting blastomycosis. Check with your state, local, or territorial public health department for more information about disease reporting requirements and procedures in your area.

Blastomycosis outbreaks

Outbreaks of blastomycosis are rare. Blastomycosis outbreaks linked to a common source often involve activities that disrupt soil or plant matter such as construction5,6 or excavation,7,8 or recreational activities near lakes or rivers such as hunting,9 fishing,10 or camping.11 In some outbreaks, identifying a source is challenging, and finding the fungus that causes blastomycosis in the environment is difficult.

  1. Blastomycosis in Wisconsin, 1985–1994. Wis Epidemiol Bull. 1995;16(2):1–5.
  2. Herrmann JA, Kostiuk SL, Dworkin MS, Johnson YJ. Temporal and spatial distribution of blastomycosis cases among humans and dogs in Illinois (2001–2007). J Am Vet Med Assoc. 2011;239 (3):335–43.
  3. Smith DJ, Williams SL, Endemic Mycoses State Partners Group, Benedict KM, Jackson BR, Toda M. Surveillance for Coccidioidomycosis, Histoplasmosis, and Blastomycosis — United States, 2019. MMWR Surveill Summ 2022;71(No. SS-7):1–14.
  4. Benedict K, Roy M, Chiller T, Davis JP. Epidemiologic and ecologic features of blastomycosis: a review. Current Fungal Infection Reports. 2012.
  5. Tosh FE, Hammerman KJ, Weeks RJ, Sarosi GA. A common source epidemic of North American blastomycosis. Am Rev Respir Dis. 1974;109(5):525–9.
  6. Kitchen MS, Reiber CD, Eastin GB. An urban epidemic of North American blastomycosis. Am Rev Respir Dis. 1977;115 (6):1063–6.
  7. Baumgardner DJ, Burdick JS. An outbreak of human and canine blastomycosis. Rev Infect Dis. 1991;13(5):898–905.
  8. MacDonald PD, Langley RL, Gerkin SR, Torok MR, MacCormack JN. Human and canine pulmonary blastomycosis, North Carolina, 2001-2002. Emerg Infect Dis. 2006;12(8):1242–4.
  9. Armstrong CW, Jenkins SR, Kaufman L, Kerkering TM, Rouse BS, Miller Jr. GB. Common-source outbreak of blastomycosis in hunters and their dogs. J Infect Dis. 1987;155(3):568–70.
  10. Klein BS, Vergeront JM, DiSalvo AF, Kaufman L, Davis JP. Two outbreaks of blastomycosis along rivers in Wisconsin. Isolation of Blastomyces dermatitidis from riverbank soil and evidence of its transmission along waterways. Am Rev Respir Dis. 1987;136 (6):1333–8.
  11. Cockerill 3rd FR, Roberts GD, Rosenblatt JE, Utz JP, Utz DC. Epidemic of pulmonary blastomycosis (Namekagon fever) in Wisconsin canoeists. Chest. 1984;86(5):688–92.
  12. Benedict K, Gibbons-Burgener S, Kocharian A, Ireland M, Rothfeldt L, Christophe N, Signs K, Jackson BR. Blastomycosis Surveillance in 5 States, United States, 1987-2018. Emerg Infect Dis. 2021 Apr;27(4):999–1006