Nephropathia epidemica in Norway: description of serological response in human disease and implication of rodent reservoirs.

In search for the Norwegian nephropathia epidemica (NE) agent, lung sections from small rodents and sera from human patients have been tested by indirect fluorescent antibody technique (IFAT). A cytoplasmatic antigen reacting with patient sera and a Korean hemorrhagic fever (KHF) reference antiserum was found in the lungs of 6 bank voles (Clethrionomys glareolus) from 2 different locations. Antibodies reacting with vole lung antigen (NE agent) and KHF agent in A-549 cells were detected in sera from 35/57 patients clinically suspected of having NE. Specific IgM antibodies were usually detected in "early" obtained sera. Positive sera had considerably higher titers against NE than KHF agent. One serum had an IgG titer of 160 against NE, but no detectable KHF antibodies. One patient had an atypical disease. Two NE patients must have been infected north of the distribution area for Cl. glareolus, suggesting the existence of other reservoir animals.