Kids, 6-28 weeks of age, infected with 200-1000 infective larvae of meningeal worm (Pneumostrongylus tenuis) of white-tailed deer (Odocoileus virginianus), developed colitis and peritonitis. Bacteroides sp., Bacillus sp., Escherichia coli, Proteus sp. and Enterococcus sp. were found in the peritoneal cavity. Most kids were moribund or dead 4-11 days after infection and frequently the colon had ruptured. Only two kids (of 11) in which the disease was allowed to run its course survived colitis and peritonitis but these two animals developed severe neurologic signs 18 and 38 days after infection. Numerous developing worms and various traumatic and other lesions were found in the central nervous system of kids which developed neurologic signs.