The Geographic Distribution of Dimorphic Mycoses in the United States for the Modern Era

Patrick B. Mazi, John M. Sahrmann, Margaret A. Olsen, Ariella Coler-Reilly, Adriana M. Rauseo, Matthew Pullen, Julio C. Zuniga-Moya, William G. Powderly, Andrej Spec

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Background. The dimorphic mycoses (DMs) of the United States—Histoplasma, Coccidioides, and Blastomyces—commonly known as endemic mycoses of North America (in addition to Paracoccidioides) are increasingly being diagnosed outside their historical areas of endemicity. Despite this trend, the maps outlining their geographic distributions have not been updated in more than half a century using a large, nationwide database containing individual-patient–level data. Methods. This was a retrospective analysis of >45 million Medicare fee-for-service beneficiaries from 1 January 2007 through 31 December 2016. Diagnoses of histoplasmosis, coccidioidomycosis, and blastomycosis were defined by International Classification of Diseases, Ninth/10th Revision, codes. The primary outcome was the incidence of histoplasmosis, coccidioidomycosis, and blastomycosis for each US county. Clinically meaningful thresholds for incidence were defined as 100 cases/100 000 person-years for histoplasmosis and coccidioidomycosis and 50 cases/100 000 person-years for blastomycosis. Results. There were 79 749 histoplasmosis, 37 726 coccidioidomycosis, and 6109 blastomycosis diagnoses in unique persons from 2007–2016 across 3143 US counties. Considering all US states plus Washington, DC, 94% (48/51) had ≥1 county above the clinically relevant threshold for histoplasmosis, 69% (35/51) for coccidioidomycosis, and 78% (40/51) for blastomycosis. Conclusions. Persons with histoplasmosis, coccidioidomycosis, and blastomycosis are diagnosed in significant numbers outside their historical geographic distributions established >50 years ago. Clinicians should consider DM diagnoses based on compatible clinical syndromes with less emphasis placed on patients’ geographic exposure. Increased clinical suspicion leading to a subsequent increase in DM diagnostic testing would likely result in fewer missed diagnoses, fewer diagnostic delays, and improved patient outcomes.

Original languageEnglish (US)
Pages (from-to)1295-1301
Number of pages7
JournalClinical infectious diseases : an official publication of the Infectious Diseases Society of America
Issue number7
Early online dateNov 11 2022
StatePublished - Apr 1 2023

Bibliographical note

Publisher Copyright:
© 2023 Oxford University Press. All rights reserved.

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't


Dive into the research topics of 'The Geographic Distribution of Dimorphic Mycoses in the United States for the Modern Era'. Together they form a unique fingerprint.

Cite this