High mortality and growth depression experimentally produced in young turkeys by dual infection with enteropathogenic Escherichia coli and turkey coronavirus.
Six-day-old turkeys were inoculated with turkey coronavirus (TCV) and an enteropathogenic Escherichia coli (EPEC) (isolate R98/5) that were isolated from poult enteritis and mortality syndrome (PEMS)-affected turkeys. Turkeys inoculated with only R98/5 did not develop clinically apparent disease, and only mild disease and moderate growth depression were observed in turkeys inoculated with only TCV. Turkeys dually inoculated with TCV and R98/5 developed severe enteritis with high mortality (38/48, 79%) and marked growth depression. R98/5 infection resulted in attaching/effacing (AE) intestinal lesions characteristic of EPEC: adherence of bacterial microcolonies to intestinal epithelium with degeneration and necrosis of epithelium at sites of bacterial attachment. AE lesions were more extensive and were detected for a prolonged duration in dually inoculated turkeys compared with turkeys inoculated with only R98/5. An apparent synergistic effect in dually inoculated turkeys was indicated by increased mortality, enhanced growth depression, and enhanced AE lesion development. The results suggest that TCV promoted intestinal colonization by R98/5; however, R98/5 did not appear to alter TCV infection. The present study provides a possible etiologic explanation for PEMS.
Guy
J S
JS
Department of Microbiology, Pathology, and Parasitology, North Carolina State University, Raleigh 27606, USA.
Smith
L G
LG
Breslin
J J
JJ
Vaillancourt
J P
JP
Barnes
H J
HJ
D000818:Animals; D001422:Bacterial Adhesion; D004753:Enteritis, Transmissible, of Turkeys / Q000150:complications* / Q000473:pathology; D004926:Escherichia coli / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D006130:Growth Disorders / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D011201:Poultry Diseases / Q000209:etiology* / Q000473:pathology; D014422:Turkeys; D015430:Weight Gain