Hemorrhagic Fever with Renal Syndrome in Yugoslavia: Epidemiologic and Epizootiologic Features of a Nationwide Outbreak in 1989

A nationwide epidemic of hemorrhagic fever with renal syndrome (HFRS) occurred in Yugoslavia in 1989. Sera from 609 hospitalized patients, from all six Republics (Bosnia and Hercegovina, Croatia, Macedonia, Montenegro Serbia, Slovenia) and two Provinces (Kosovo and Vojvodina), who had signs and symptoms suggestive of HFRS, and sera and lung tissues from 544 small mammals belonging to 13 species were studied for evidence of hantavirus infection. Of the 226 patients with serologically confirmed HFRS, 182 resided in Bosnia and Hercegovina or in Serbia. The severity of disease differed from region to region, with an overall fatality of 6.6% (15/226). Patients from southern Yugoslavia tended to have more severe disease and exhibited two types of antibody patterns, while approximately equal numbers of clinically severe and mild cases of HFRS were registered in central Yugoslavia, where four types of antibody patterns were found. Two of these antibody patterns suggested the existence of hantaviruses which are antigenically distinct from those reported to date. Two seasonal peaks of disease, one during the summer and the other in late autumn, were found. Hantaviral antibodies and/or antigens were detected most often in the yellow-necked mouse (Apodemus flavicollis) (88/189), the wood mouse (Apodemus sylvaticus) (28/146), the striped field mouse (Apodemus agrarius) (10/64), the bank vole (Clethrionomys glareolus) (36/63), the house mouse (Mus musculus) (14/29), and the Norway rat (Rattus norvegicus) (14/21). Five other species of rodents and insectivores were infrequently infected.