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Contributed Papers: Posters
Pathology

INTERACTION OF E. COLI O157:H7 WITH CRYPTOSPORIDIUM PARVUM IN 6-WEEK-OLD LAMBS


Ralph N. Marshall ,Roberto M. La Ragione, Angus Best, Jacqueline A. Marshall, Linda Johnson and Martin J. Woodward. Veterinary Laboratories Agency (Weybridge), Woodham Lane, New Haw, Addlestone, Surrey, UK, KT15 3NB.

Enterohaemorraghic Escherichia coli (EHEC) O157:H7 carriage in ruminants has frequently been reported and deliberate inoculation studies have demonstrated that this pathogen can colonise and persist in cattle and sheep. A recent study from our laboratory has shown that E. coli O157:H7 can colonise 8-week-old conventionally reared goats for up to 29 days post inoculation. Furthermore, high levels of E. coli O157:H7 shedding was associated with a diffuse heavy infection of Cryptosporidia. Abundant, multifocal E. coli O157:H7 associated attaching and effacing (AE) lesions were observed in the distal colon, rectum and recto-anal-junction (RAJ). Cryptosporidium is isolated from farmed animals, including sheep. Since EHEC O157:H7 has been recovered from sheep, the presence of Cryptosporidium in the ovine host may modulate EHEC O157:H7 pathogenesis. Therefore, the purpose of the study to be reported here was to assess any interaction between E. coli O157:H7 and Cryptosporidium parvum in colostrum with-held and conventionally reared 6-week-old lambs. Post mortem (bacteriology/parasitology and immunohistochemistry) and persistence (faecal shedding) data will be discussed for E. coli O157:H7 and Cryptosporidium parvum.

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