Infectivity Model Verification Studies - Annual Report, 1983

摘要

Texas Tech continued in 1983 to determine the level at which nitrogen dioxide increases susceptibility to respiratory infection and to determine the immune mechanism(s) that are most affected. A previous, frequently cited report by Ehrlich and Henry (1968) indicated that exposure to 0.5 ppm NO2 for three months depressed host resistance to Klebsiella pneumoniae infection. Texas Tech's studies during 1981 and 1982 failed to verify these results; furthermore, no excess mortality was found after Klebsiella pneumoniae challenge in mice exposed to up to 1.5 ppm NO2 for three months. During 1983, the results of using a dose-response bacterial challenge confirmed that exposure to 1.5 ppm NO2 for up to three months does not increase susceptibility to infection with Klebsiella pneumoniae. It was also noted that this level of exposure to NO2 does not increase susceptibility to an aerosol challenge with mouse-adapted influenza virus. The Texas Tech studies tend to suggest that NO2 does depress host resistance to bacterial infection at a level of exposure greater than 1.5 ppm, that the effect is transient rather than enduring, and that the target cell may be the alveolar macrophage.