Effects of Newcastle disease virus (NDV) on infection of adult mice with the Thogoto-like Ar-126 arbovirus.

Inoculation of mice with Newcastle disease virus (NDV) alters the course of infection with the Thogoto-like arbovirus Tho-Ar-126. The Tho-Ar-126 content of liver, spleen, and lymph nodes was approximately 10 times greater in mice treated with NDV 24 h before infection; the mortality was somewhat increased, but liver damage (as indicated by serum transaminase levels) did not seem to be potentiated. Lymphocytopenia was observed in NDV-inoculated mice, and in the spleen and lymph nodes the proportion of lymphocytes susceptible to lysis by anti-theta (a marker for thymus-derived lymphocytes) was markedly decreased in these animals. This suggests that NDV potentiates infection by Tho-Ar-126 through its action on thymus-derived lymphocytes.