Hantavirus pulmonary syndrome outbreak, Brazil, December 2009-January 2010.

An outbreak of hantavirus pulmonary syndrome occurred in the Sobradinho Indian settlement of the Kayabí ethnic group in northern Mato Grosso during December 2009-January 2010. We conducted a retrospective study to clarify the outbreak's epidemiologic and clinical characteristics. Results suggest a relationship between the outbreak and deforestation and farming expansion in indigenous areas.