Role of enteropathogenic Escherichia coli and turkey coronavirus in severe intestinal disease of young turkeys (poult enteritis-mortality syndrome)

Archived formalin-fixed intestinal tissues, and frozen intestinal contents collected from 12 PEMS flocks in 1998 were used to determine the prevalence of EPEC in PEMS-affected turkey flocks. EPEC isolates were assessed for pathogenicity and ability to reproduce AE lesions in young turkeys. EPEC were associated with 10/12 cases based on light and electron microscopy identification of attaching and effacing (AE) lesions, HEp-2 cell adhesion, fluorescent actin staining (FAS); and presence of E. coli attaching and effacing (eae), shiga-like toxin I and II, and bundle forming pilus genes using PCR procedures. Presence of AE lesions identified by light microscopy agreed with the identification of AE lesions by electron microscopy. HEp-2 cell adhesion and FAS tests were relatively simple methods for screening E. coli isolates. FAS, and presence of eae gene by PCR were two of the best methods for identifying EPEC.; Prevalence of EPEC in PEMS experimentally produced by bird-to-bird passage was determined. Formalin-fixed intestinal tissues, and frozen intestinal contents were examined by utilizing methods for detection of AE lesions and presence of EPEC. Immunohistochemistry was also utilized to detect AE lesions. EPEC were identified in 8/9 cases suggesting a high prevalence of EPEC in PEMS experimentally produced by bird-to-bird passage.; The hypothesis that TCV potentiates EPEC infection was examined experimentally in young turkeys. Turkeys inoculated with EPEC (106, 10 8, or 1010 CFU) did not show intestinal disease and mortality even with 1010 CFU, whereas turkeys inoculated with TCV + EPEC (104, 106, or 108 CFU) showed intestinal disease and high mortality even with 104 CFU. Effects of simultaneous versus 1-week prior inoculation with TCV and EPEC were studied. Intestinal disease and high mortality were only observed in turkeys inoculated with both agents; however, turkeys inoculated with TCV 1-week before EPEC showed most severe disease. TCV proved to promote EPEC shedding, but EPEC did not promote TCV infection. These findings demonstrate a synergistic interaction between TCV and EPEC by which TCV potentiates EPEC infection.