[Increase of Hantavirus infections in France, 2003]

Hantaviral infections causing hemorrhagic fever with renal syndrome are endemic in North Eastern France. Humans are contaminated by the inhalation of aerosols contaminated by rodent faeces. In February 2003, the National reference centre (NRC) for hemorrhagic fevers detected an increased number of cases. An investigation was carried out to confirm the outbreak and take appropriate control measures.

Cases were collected by the NRC. A case was defined as a person living in France with symptoms compatible with hantaviral infection and a positive blood test both for specific Puumala IgM, and IgG. Clinical information and at-risk exposures during the 2 weeks before onset were recorded.

In 2003, 128 cases were diagnosed (61 in 2002). The median age of patients was 38, 77% were men and 82% were hospitalized. Patients were living in North-Eastern France. Clusters were detected in the Ardennes and Oise districts. Occupation (35%) (in agriculture, forestry, and construction work), manipulation of firewood (35%), gardening (29%), and outdoors leisure (14%) were identified as at-risk exposures in these cases.

An increased number of positive diagnoses of hantaviral infections was confirmed. The location and at-risk exposures of the cases were identical in previous investigations. Exclusion and prevention of rodents' access to houses and avoiding the inhalation of contaminated dust are the only possible prevention measures of hantaviral infections. Information about the disease and its prevention needs to be made widely available to both healthcare professionals and the general population living in endemic areas.