Reduced resistance to experimental viral and bacterial infections of mice treated with polychlorinated biphenyl.

When mice given diet containing 100, 200 or 400 micrograms of polychlorinated biphenyl (PCB) per g, or PCB-free diet for 21 days were inoculated intranasally with influenza virus, the mortality was higher in some groups given PCB than in the control group. When Staphylococcus aureus was inoculated intraperitoneally into mice given a diets with or without PCB, a significant difference was observed in the mortalities in the groups. Subcutaneous injection of S. aureus also caused a larger subcutaneous abscess in the mice given diets containing PCB than in those given control diet. Thus, it is suggested that PCB ingestion reduces host resistance to systemic or local infection with viruses or bacteria.