Non specific serological reactions in the diagnosis of bovine brucellosis:experimental oral infection of cattle with repeated doses of Yersinia enterocolitica O : 9
B. Garin-bastuji et al., Non specific serological reactions in the diagnosis of bovine brucellosis:experimental oral infection of cattle with repeated doses of Yersinia enterocolitica O : 9, VET MICROB, 66(3), 1999, pp. 223-233
Eight heifers were orally infected with 4 x 10(9) colony forming units of a
field cattle strain of Yersinia enterocolitica O:9 in a capsule, 5 days a
week, for about 9 weeks (day 0-day 64 (D0-D64)). The faecal shedding of Y.
enterocolitica O:9 began on D5 for seven out of the eight challenged cattle
with a high level of excretion during the first month, followed by a decre
ase till the day of slaughter (D76). Y. enterocolitica O:9 was not isolated
from organs collected at slaughter. No clinical symptoms were observed. Hy
perplasia of intestinal lymph formations was the sole microscopic lesions o
bserved. Five animals showed a serological reaction against Brucella antige
ns in at least one of the following tests: Rose-Bengal tests complement fix
ation test, tube agglutination test or indirect ELISA (iELISA) tests. Only
one animal showed a high level of serological response and a positive react
ion in the dithiothreitol-microagglutination test. The observed variability
in terms of individual sensitivity to the Y. enterocolitica O:9 infection
is in agreement with the low individual prevalence rate and the transient s
erological reaction and faecal Y. enterocolitica O:9 shedding observed in h
erds showing false positive serological reactions in brucellosis. (C) 1999
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