Eimeria tenella Infection Induces Recrudescence of Previous Salmonella enteritidis Infection in Chickens

Four experiments were conducted to examine the effect of Eimeria tenella infection on the recrudescence of Salmonella enteritidis in previously infected chickens. Significant recrudescence of cecal colonization in the birds challenged with E. tenella was observed at 3 wk after S. enteritidis infection in Experiment 1, at 3 and 4 wk in Experiment 2, and at 3, 4, and 5 wk in Experiments 3 and 4. The recrudescence was indicated by .81 to 6.31 logs increase in cecal S. enteritidis counts and by higher percentages of ceca that were culture-positive. The possible prolonged cecal S. enteritidis shedding from chickens infected with coccidia into the environment might be important for the perpetuation of S. enteritidis infectious cycle. Except for Experiment 1, in which a significant higher culture-positive rate of the liver was detected in the coccidia-infected group, no significant difference of culture-positive rate of liver and spleen between the treatments was observed. The recrudescence of previous S. enteritidis infection caused by E. tenella infection was obviously related to the initial S. enteritidis dose size and time of exposure to coccidia.