[Hemorrhagic fever with renal syndrome]

Puumala hantavirus is the most common hantavirus infection in Western Europe. The causative agent, Puumala virus, is a member of the Hantavirus genus in the Bunyaviridae family. The natural hosts of hantaviruses are chronically, but asymptomatic infected rodents, which transmit the virus to human in their excretions. Puumala virus is carried by the bank vole, clethrionomys glareolus. Hemorrhagic fever with renal syndrome (HFRS) caused by Puumala virus in France or Belgium is very similar to the previously described Nephropathia epidemica in Scandinavia. In most severe cases, the disease is clinically characterized by high fever of abrupt onset, headache, loin or abdominal pains, nausea and vomiting, and occasionally acute and transient myopia. Renal involvement results in transient proteinuria and hematuria and acute renal failure. Except for interstitial hemorrhage in the outer medulla, the renal histopathologic findings are unspecific and include prominent changes in the interstitium with interstitial oedema and inflammatory infiltrates. Thrombocytopenia, mild elevation of liver enzymes, and leukocytosis are typical laboratory findings. Spontaneous complete recovery is the rule. Laboratory diagnosis is primarily based on serology such as indirect immunofluorescence or capture enzyme--linked immunosorbent assays which detect IgM antibodies and an increased level of IgG antibodies against Puumala virus. Viral antigen may be demonstrated in the cytoplasm of renal tubular epithelial cells.