The invasion of salmonella typhimurium into the cecal wall of chickens infected with Eimeria tenella

Abstract

The effect of concurrent Eimeria tenella and Salmonella typhimurium infections on the invasion of S. typhimurium into the cecal wall of chickens were studied. In the experiment 1) groups were composed of birds infected with a daily dose of 1 X 10(3) to 1 X 10(5) S. typhimurium for 5 days and birds infected with S. typhimurium as the same manner one day after having been infected with 20,000 E. tenella oocysts. Chickens were killed 7, 10 and 14 days after coccidial infection. The ceca were examined bacteriologically. The number of S. typhimurium in the cecal washings and cecal wall and the number of chickens positive for S. typhimurium in the ceca were significantly greater in the concurrent infections than in the S. typhimurium alone. In experiment 2) groups were composed of birds infected with E. tenella and S. typhimurium in the same manner as experiment 1) and birds infected with 2 X 10(6) to 2 X 10(7) S. typhimurium for 5 consecutive days. Chickens were killed 7, 10 and 14 (or 15) days after coccidial infection. The distribution of S. typhimurium in the ceca was examined by fluorescent antibody technique. In coccidia-infected chickens, intense, specific fluorescence was noted in the epithelia destructed by coccidia, around the coccidial oocysts parasitized in the epithelial cells, and in the lamina propria and submucosa. In S. typhimurium alone-infected chickens, specific fluorescence was also found in the epithelia, lamina propria and submucosa, but was only limited in the lumen and on the surface of epithelial linings. The results indicated that the invasion of S. typhimurium into the cecal wall was enhanced by E. tenella infection in chickens.