Blastomycosis Could Become Endemic in Upstate New York

An increase in cases of blastomycosis in upstate New York over the past decade suggests that it is becoming endemic, although it is not yet a reportable infection in the state, according to findings from a study in the Centers for Disease Control and Prevention publication Emerging Infectious Diseases.¹ "Because of the lack of recognition of blastomycosis as an emerging infection, diagnosis and treatment are often delayed," Laura Ramirez, a 2027 MD candidate at Albany Medical College in New York, and colleagues observe.

The investigators point out that reporting of blastomycosis to health departments is required by only 5 states: Arkansas, Louisiana, Michigan, Minnesota, and Wisconsin. Blastomycosis is considered endemic in regions surrounding the Ohio River Valley, Mississippi River Valley, and the Great Lakes, and findings from this study suggest that it is increasing to that level in areas along the Mohawk River.

Ramirez and colleagues conducted a retrospective review of patients diagnosed with blastomycosis in the hospital and infectious disease clinic of one medical center in Albany in the period between January 2000 and December 2024. The incidence distribution was mapped using patient postal zip codes. The investigators compiled clinical characteristics, distinguishing pulmonary and disseminated infections, and noted radiologic features, diagnostic methods, and treatments.

The investigators identified 54 patients with a confirmed diagnosis of blastomycosis during the study period. Diagnosis could be established by real-time polymerase chain reaction, positive culture result, or histopathology and cytopathology findings consistent with the diagnosis. The most common diagnostic method was biopsy for specimen collection, obtained in 42 patients, and more than 1 diagnostic method was used in 52% of patients. Almost all patients, the investigators note, were initially misdiagnosed, most commonly with community-acquired pneumonia or malignancy.

"Diagnosis of blastomycosis requires a high index of clinical suspicion, particularly in patients with pulmonary infections and extrapulmonary lesions," Ramirez and colleagues advise. "Such patients often have no notable underlying conditions."

The investigators found the number of blastomycosis cases rose during the study years, with the most pronounced increase in 2024, representing 24% (13 of 54) of the total for the 2 decades. They note that cases were distributed over multiple counties in the region. None of the patients reported travel to known endemic areas, consistent with contracting the infection in their local region. More than half (57%) of the patients had no identifiable underlying conditions.

Disseminated infection was present in 54% of patients, and isolated pulmonary involvement was in 46%. There were no apparent differences between them in clinical characteristics, radiologic features, diagnostic methods, or treatment; however, the groups were too small to distinguish by statistical analysis. Most patients (47; 87%) were hospitalized, whereas 7 (13%) were managed as outpatients.

"The cases described in this study reflect a single medical center, suggesting that the data are probably a fraction of the actual disease burden in the region and that the true incidence might exceed official estimates," Ramirez and colleagues indicate.

"Given that nearly all patients in this cohort initially had misdiagnoses and that New York is not currently considered an endemic region, most patients experience a delay in diagnosis and appropriate treatment," they report.

Reference

1. Ramirez LE, Kostowniak C, Kumar J, Chaturvedi S, Ramani A, Chopra A. Emerging endemic area for blastomycosis, New York, USA, 2000–2024. Emerg Infect Dis. 2026;32(3). doi:10.3201/eid3203.251306