Isolation and characterization of Tula virus, a distinct serotype in the genus Hantavirus, family Bunyaviridae

1 Haartman Institute, Department of Virology, POB 21, FIN-00014 University of Helsinki, Finland 2 Swedish Institute for Infectious Disease Control, S-105 21 Stockholm, Sweden 3 Regional Hygienic Institute of South Moravia, Brno, Czech Republic 4 Finnish Forest Research Institute, FIN-01301 Vantaa, Finland A Vero E6 cell culture isolate of Tula virus (TUL), a hantavirus first detected in European common voles ( Microtus arvalis and M. rossiaemeridionalis ) by RT-PCR was obtained after initial passaging of TUL-infected vole lung samples in laboratory-colonized M. arvalis . TUL was defined as a classical serotype by a cross-focus-reduction neutralization test (FRNT) and was also shown to be distinct from other hantaviruses by haemagglutination inhibition assay. The sequences of S, M and partial L genome segments of the isolate were determined: the S segment was 99·9% identical to the original rodent-derived sequence. Serological evidence for a previous TUL infection was obtained from the serum of a blood donor living near a TUL focus in Moravia, Czech Republic, showing at least a 16-fold higher FRNT titre to TUL as compared to Puumala or other hantaviruses. Received 7 June 1996; accepted 12 August 1996.