Control of laboratory acquired hemorrhagic fever with renal syndrome (HFRS) in Japan.

By the end of 1985, 126 human cases of laboratory acquired hemorrhagic fever with renal syndrome (HFRS) were recorded in Japan. Seroepidemiological studies revealed that laboratory rats exhibited high IFA titers against Hantaan or related viruses at locations where HFRS patients occurred. Laboratory researchers contracted HFRS more frequently than laboratory animal technicians or caretakers, although a laboratory animal caretaker died of the disease. Inhalation of HFRS-virus contaminated air in an animal facility is the likely cause of infection with this virus. Wound infection during animal experiments may be another important route of infection. Infection of laboratory rats can occur by transferring animals from contaminated to other animal facilities. Tissue fragments or cells of transplantable animal tumors are a potential source of spreading the HFRS virus. Eradication of HFRS virus from a contaminated animal facility can be achieved best by elimination of all animals in the room, especially when human HFRS is associated with an infected colony. In some cases, when IFA titers of the sera of the rats tested were low, infection apparently disappeared without instituting any particular control measures other than ordinary procedures for care and management of laboratory animals. HFRS viruses have not yet been eradicated from all animal facilities in Japan. Therefore, serological monitoring of laboratory rats continues.