Headlines - Hantavirus Infections in Burgundy and Franche-Comté

Four species of hantavirus circulate on the European continent, causing hemorrhagic fever with renal syndrome (HFRS) in humans. These fevers are caused by the Puumala virus, which was first identified in France in the 1980s. The reservoir is a wild rodent, the bank vole, but other reservoirs are possible. Infection occurs through inhalation of dust contaminated by the excreta of infected animals. HRSF varies in severity, ranging from flu-like symptoms—sometimes accompanied by severe muscle pain, transient visual accommodation disorders, thrombocytopenia, and mild kidney involvement—to severe kidney failure, which most often has a favorable outcome. The case fatality rate ranges from 0.5% to 15% depending on the virus. In France, the most affected regions are in the northeast, from the Nord-Pas-de-Calais region to Franche-Comté, with 40% of cases occurring in the Ardennes Mountains. Since 2001, the number of cases recorded by the National Reference Center has typically been around sixty, with epidemic peaks in certain years (129 in 2003, 253 in 2005, and 127 in 2007).While Burgundy is relatively unaffected (a few cases per year), Franche-Comté is significantly more affected, with 33 cases in 2005, 18 in 2007, and 34 in 2010. The most affected departments in Franche-Comté are Jura and Doubs.Prevention relies on controlling risk factors primarily linked to the handling of woodpiles—especially indoors—and to dry sweeping of premises that have been unoccupied for a long time, particularly if they are built in or near forests, as well as on controlling wild rodents, whose proximity to humans constitutes the main risk factor. Under certain climatic conditions, rodent proliferation promotes the survival and transmission of the virus, with infection rates in captured rodents reaching up to 60%. Thus, rodents could serve as a sentinel population for predicting the risk of an epidemic outbreak. Variations in the number of human cases appear to be directly linked to the dynamics of rodent infection and their population dynamics.