Effects of Infection of Eimeria tenella, E. acervulina, and E. maxima upon Salmonella typhimurium Infection in Chickens

Three experiments were conducted to examine whether Salmonella typhimurium infection is enhanced by concurrent infection with Eimeria tenella, E. acervulina, or E. maxima. There were two groups in each experiment: birds infected with a daily oral dose of approximately 1 X 10(4) cfu of S. typhimurium for 5 days after coccidial infection and birds infected with S. typhimurium alone with the similar exposure schedule. Chickens were necropsied 7, 10, and 14 days after coccidial infection. The numbers of S. typhimurium in the contents of ceca and small intestine were counted, and numbers of chickens positive for S. typhimurium in the liver and bile were examined. In E. tenella infection, the S. typhimurium counts in the ceca and small intestine of concurrently infected chickens were significantly greater than those of birds infected with S. typhimurium alone. In E. acervulina infection, the S. typhimurium counts in the ceca of chickens killed 14 days after E. acervulina infection and the numbers of birds positive for S. typhimurium in the ceca of chickens killed 10 and 14 days after E. acervulina infection were significantly greater than those of chickens infected with S. typhimurium alone. In E. maxima infection, the numbers of birds positive for S. typhimurium in the ceca and liver of chickens killed 7 days after E. maxima infection were significantly greater than those of birds infected with S. typhimurium alone. Results of this study indicate that infection with E. acervulina or E. maxima is able to enhance S. typhimurium infection in chickens.