We investigated a blastomycosis cluster among humans and canines in a neighborhood in Wisconsin, United States. We conducted interviews and collected serum specimens for Blastomyces antibody testing by enzyme immunoassay. Although no definitive exposure was identified, evidence supports potential exposures from the riverbank, riverside trails or yards, or construction dust.
Keywords: United States; Wisconsin; blastomycosis; disease outbreaks; fungi; serology; zoonoses.