Infectivity titration of hemorrhagic fever with renal syndrome virus: use of immune adherence hemagglutination for detection of virus growth.

Serial dilutions of hemorrhagic fever with renal syndrome viruses were inoculated into Vero-E6 cells in microplates. After 2 weeks of incubation, infected cells were disrupted by freezing and thawing, and virus antigens were detected by immune adherence hemagglutination. The infectivity titers of the virus as determined by this method were in close agreement with those obtained by the immunofluorescent antigen endpoint method. Then, a neutralization method was established. Japanese hemorrhagic fever with renal syndrome isolates, strains SR-11 and TR-352, were found to be distinct from Hantaan virus, strain 76-118, by the neutralization test.