Journal Article

A Large Community Outbreak of Blastomycosis in Wisconsin With Geographic and Ethnic Clustering

Monika Roy, Kaitlin Benedict, Eszter Deak, Miles A. Kirby, Jena T. McNiel, Carrie J. Sickler, Eileen Eckardt, Ruth K. Marx, Richard T. Heffernan, Jennifer K. Meece, Bruce S. Klein, John R. Archer, Joan Theurer, Jeffrey P. Davis and Benjamin J. Park

in Clinical Infectious Diseases

Published on behalf of Infectious Diseases Society of America

Volume 57, issue 5, pages 655-662
Published in print September 2013 | ISSN: 1058-4838
Published online June 2013 | e-ISSN: 1537-6591 | DOI:
A Large Community Outbreak of Blastomycosis in Wisconsin With Geographic and Ethnic Clustering

More Like This

Show all results sharing these subjects:

  • Infectious Diseases
  • Immunology
  • Public Health and Epidemiology
  • Microbiology


Show Summary Details



Blastomycosis is a potentially life-threatening infection caused by the soil-based dimorphic fungus Blastomyces dermatitidis, which is endemic throughout much of the Midwestern United States. We investigated an increase in reported cases of blastomycosis that occurred during 2009–2010 in Marathon County, Wisconsin.


Case detection was conducted using the Wisconsin Electronic Disease Surveillance System (WEDSS). WEDSS data were used to compare demographic, clinical, and exposure characteristics between outbreak-related and historical case patients, and to calculate blastomycosis incidence rates. Because initial mapping of outbreak case patients’ homes and recreational sites demonstrated unusual neighborhood and household case clustering, we conducted a 1:3 matched case-control study to identify factors associated with being in a geographic cluster.


Among the 55 patients with outbreak-related cases, 33 (70%) were hospitalized, 2 (5%) died, 30 (55%) had cluster-related cases, and 20 (45%) were Hmong. The overall incidence increased significantly since 2005 (average 11% increase per year, P < .001), and incidence during 2005–2010 was significantly higher among Asians than non-Asians (2010 incidence: 168 vs 13 per 100 000 population). Thirty of the outbreak cases grouped into 5 residential clusters. Outdoor activities were not risk factors for blastomycosis among cluster case patients or when comparing outbreak cases to historical cases.


This outbreak of blastomycosis, the largest ever reported, was characterized by unique household and neighborhood clustering likely related to multifocal environmental sources. The reasons for the large number of Hmong affected are unclear, but may involve genetic predisposition.

Keywords: blastomycosis; outbreak; Wisconsin; Hmong

Journal Article.  4321 words.  Illustrated.

Subjects: Infectious Diseases ; Immunology ; Public Health and Epidemiology ; Microbiology

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content. subscribe or purchase to access all content.