Serological evidence of hantavirus infection in laboratory rats and personnel.

Laboratory-acquired haemorrhagic fever with renal syndrome (HFRS) has been reported in many countries. A serological survey of laboratory white rats and of laboratory personnel for antibodies to hantaviruses was conducted in Singapore. Forty-four per cent (143/329) of rats were seropositive by the indirect immunofluorescent antibody test but none had hantaviral antigens in lung tissues. Two of 74 laboratory personnel were seropositive but neither had a history of clinical illness. The high seropositivity rate among laboratory rats led to their replacement with Hantaan virus-free strains. To eliminate the hazard of laboratory-acquired HFRS, regular serological screening of laboratory rats and replacement of infected animals with seronegative stocks should be implemented. High risk techniques with laboratory rats, which are likely to generate aerosols, should be performed in biological safety cabinets. Serological surveillance of laboratory personnel and reporting of suspected HFRS cases are useful in the early detection of hantavirus infection.