Laboratory-acquired infections with Hantaan virus, the etiologic agent of Korean hemorrhagic fever.

Clinically apparent infections with Hantaan virus, the etiologic agent of Korean hemorrhagic fever, occurred in nine persons exposed to the virus at the Korea University Virus Institute (Seoul) between 1971 and 1979. All were directly related to trapping of wild rodents or work with naturally or experimentally infected wild and laboratory rodents in a designated animal suite. All infections were acquired during the months of November-April, and none was associated with accidental parenteral inoculations. These facts suggested that aerosols produced by chronically infected rodents were the infectious vehicles and that limited air circulation and lowered humidity in the animal rooms during winter months increased the probability of viral transmission. Four persons, including two casual visitors, became ill within four months after the initiation of experimental studies of infections in Wistar rats with Hantaan virus, an occurrence suggesting that this rodent may be a highly infectious host for Hantaan virus.