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.