Effects of infection with Eimeria tenella upon Salmonella typhimurium infection in the gnotobiotic chicks. Scanning electron microscopic study.

The gnotobiotic chicks infected with Eimeria tenella received an oral inoculation of Salmonella typhimurium 4 or 8 days after E. tenella infection. Chicks were necropsied one day after the salmonella infection. In the experiments 1 and 2, there were two groups; birds infected with S. typhimurium alone and birds infected with a combination of E. tenella and S. typhimurium. The number of S. typhimurium in the cecal contents was significantly greater in the concurrent infections than S. typhimurium infection alone. The S. typhimurium counts in the cecal wall of gnotobiotic chickens killed 5 days after E. tenella infection were significantly greater than those of chickens infected with S. typhimurium alone. In the experiment 3, the scanning electron microscopic study was made on damage of cecal mucosa. There were four groups; uninfected birds as control, birds infected with E. tenella, birds infected with S. typhimurium and birds infected with a combination of E. tenella and S. typhimurium. No damage was observed on the cecal mucosa of both the control and the S. typhimurium infection alone. The concurrent infections caused greater damage on the cecal mucosa than did the E. tenella infection alone.