Increasing Incidence of Blastomycosis Infection in Vermont

BACKGROUND: Blastomycosis is an invasive infection caused by the ubiquitous fungus Blastomyces. The clinical presentation ranges from limited cutanenous infections to pneumonia and disseminated disease. Endemic areas in the United States include: midwestern, south-central, and southeastern states; yearly incidence is <0.3 cases per 100,000. Diagnosis is based on recovery of the organism on fungal culture. A urine antigen test is available for the detection of blastomycosis which has a sensitivity of 92.9% and specificity of 79.3%. Anecdotally, an increasing number of patients are presenting to the University of Vermont Medical Center (UVMMC) with disseminated blastomycosis – an area in which the fungus is rare. We hoped to determine the incidence of blastomycosis in Vermont over a 10-year period and examine the sensitivity of the urine antigen in our patient population. METHODS: After IRB approval, medical record numbers of all patients who had BD-glucan, blastomyces urine antigen, culture, or pathology positive for blastomyces during a 10-year period (2006–2016) were obtained. Chart review completed for all patients with diagnosis of blastomycosis. Data collected on demographic characteristics: zip code, comorbidities, site of infection, HIV, BD-glucan, blastomyces urine antigen, fungal culture, and treatment duration. RESULTS: Forty-one blastomycosis cases were found; 39 cases in Vermont residents. The incidence rate Vermont was 0.7 cases per 100,000. Mean age was 49 years, 60% of patients were male. Most patients had pulmonary (37%) or disseminated infection (37%). 17% of patients had localized cutaneous disease, bone and joint infection (7%) or CNS disease (2%). Urine antigen was positive in 78% overall, and in 90% with disseminated infection. Three deaths, none attributed to blastomycosis. CONCLUSION: Vermont appears to have a higher incidence than what has been reported in the US overall. This increase may have to do with better reporting and testing rather than a true increase in disease. Most common disease presentation was localized pulmonary or disseminated disease. Urine antigen sensitivity ranged from 78% (overall) to 90% (disseminated disease). This appears consistent with what has been reported in other studies, but is lower than the overall reported sensitivity. DISCLOSURES: All authors: No reported disclosures.