Non specific serological reactions in the diagnosis of bovine brucellosis: experimental oral infection of cattle with repeated doses of Yersinia enterocolitica O:9.
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 decrease till the day of slaughter (D76). Y. enterocolitica O:9 was not isolated from organs collected at slaughter. No clinical symptoms were observed. Hyperplasia of intestinal lymph formations was the sole microscopic lesions observed. Five animals showed a serological reaction against Brucella antigens in at least one of the following tests: Rose-Bengal test, complement fixation test, tube agglutination test or indirect ELISA (iELISA) tests. Only one animal showed a high level of serological response and a positive reaction 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 serological reaction and faecal Y. entercolitica O:9 shedding observed in herds showing false positive serological reactions in brucellosis.
Garin-Bastuji
B
B
OIE Reference Laboratory for Brucellosis, Maisons-Alfort, France. b.garin@alfort.cneva.fr
Hummel
N
N
Gerbier
G
G
Cau
C
C
Pouillot
R
R
Da Costa
M
M
Fontaine
J J
JJ
D000372:Agglutination Tests / Q000662:veterinary; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000097:blood; D002002:Brucella / Q000276:immunology*; D002006:Brucellosis / Q000175:diagnosis / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D015169:Colony Count, Microbial; D003168:Complement Fixation Tests / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005189:False Positive Reactions; D005243:Feces / Q000382:microbiology; D005260:Female; D005456:Fluorescent Dyes / Q000032:analysis; D012395:Rose Bengal / Q000032:analysis; D015009:Yersinia Infections / Q000175:diagnosis / Q000662:veterinary*; D015008:Yersinia enterocolitica / Q000276:immunology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D005456:Fluorescent Dyes; D012395:Rose Bengal