Altered histopathology in protein-deprived mice during Sendai virus pneumonia: evidence for delayed inflammatory response and recovery.

The morphology of the lungs and airway during the course of respiratory infection caused by Sendai virus was examined in normal (20% protein diet) and malnourished (2% protein diet) BALB/c mice. Mortality in normal Sendai-infected mice was 0 compared with 71% in the infected malnourished group. Virus was isolated until day 6 in normally fed mice and until day 9 in the malnourished group. Pulmonary inflammation was largely mononuclear and began in the normally nourished animals on day 3, peaked at day 6, and reverted almost to normal by 30 days. In the malnourished group, inflammation was delayed by about 1 day and fell further behind during the first week. It peaked 10-13 days after infection and was still present with little resolution by day 30. These findings may have relevance to the high mortality of acute respiratory diseases in children of the developing world.