Aerosol stability and respiratory infectivity of japanese B encephalitis virus

Experiments were conducted to examine the aerosol stability and respiratory infectivity of Japanese B encephalitis virus. At 75 degrees F (about 24 degrees C), survival of the virus as aerosol was inversely related to relative humidity. After correction for physical decay, the mean virus half-lives of the virus were 28, 38, and 62 min at relative humiditis of 80, 55, and 30%, respectively. Virus recoveries as aerosol at 4 min aftr dissemination generally exceeded the theoretical limit of 100%, based on the amount disseminated, to suggest that the process of dissemination operated to deagglomerate or release bound virus from the tissue cells in suspension. Swiss-ICR mice and golden Syrian hamsters were highly susceptible to lethal infections after respiratory challenge. Hartley strain guinea pigs and Fisher-Dunning rats, although infected, based on seroconversion observations, survived the infections. Deaths occurred in squirrel monkeys only after exposure to a high aerosol dose of virus (10(6.0) plaque-forming units). Studies of the virus concentration dynamics and histopathological findings in mouse tissues after aerosol challenge supported a hypothesis for direct transport of virus across the foramina of the cribriform plate to the tissues of the central nervous system to produce primary encephalitis.