Potentiation of langat virus infection by lead intoxication--influence on host defenses.

Pathogenesis was studied in mice with moderate levels of lead intoxication after Langat virus infection. Both lead chloride and lead nitrate increased mortality by 40--50%. This increase was associated with decreased in vivo interferon and neutralizing antibody synthesis. The increased mortality was associated with enhancement of viral growth in peripheral tissues as evidenced by early appearing and long-lasting high titer viremia following lead intoxication. This resulted in early penetration of blood brain barrier and led to much higher virus titers in the brain. The data strongly suggest that lead increased mortality following infection by complex means, the most important being the enhacement of encephalitogenic potential of Langat virus.