Brucellosis 2003 proceedings - PHIDIAS

Poster Session
is difficult to obtain a good vaccine coverage in young animals under 8 month old, as
Argentinean regulation states.
84- EFFICACY OF S-RB51 VACCINE IN ADULT CATTLE.
L. Samartino 1 , M. Fort 2 , S. Conde 1 , E. Salustio 1 . (1) INTA. Centro de Ciencias Veterinarias, Buenos
Aires, Argentina. (2) Estación Experimental Anguil, La Pampa, Argentina.
Strain B. abortus RB51 (S-RB51), was developed to protect cattle for
brucellosis and the level of protection was comparable to S-19 (Am. J. Vet. Res.
1996: 57, Am. J. Vet. Res. 1998: 59). Besides, the S-RB51 do not induce the
production of antibodies even if it is applied multiple times ( Prev. Vet. Med. 2000:
45). In this experiment we study the efficacy of S-RB51 applied for adult cattle which
were calf vaccinated either with S-RB51 or S-19. Four groups of cattle were
established: A:23 cows were vaccinated with S-19 and revaccinated with S-RB51. B:
21 cows were vaccinated with S-RB51 and revaccinated with S- RB51 C: 28 cows
were vaccinated with S-19 and revaccinated twice with S-RB51 D: 12 cows were not
vaccinated. All animals were challenged in the middle of pregnancy with 2.1x10 7 B.
abortus strain 2308 intraconjuntivally Serological studies were done using BPA, 2
ME, CFand ELISA tests. Bacteriological studies were performed from aborted
foetuses, vaginal swabs and milk. All cows vaccinated and revaccinated with S-19
became seropositive but they remained negatives when were vaccinated and
revaccinated with S-RB51. The number of abortions were 4, 3, 3 and 6 in groups A,
B, C and D. Strain 2308 was recovery from 6, 5, 8 and 10 cows for the same groups
and CF titres (1/40) were detected in 6, 6, 10 and 12 cows respectively 6 months
post-challenged. These animals were considered infected. According to these results
we did not see any differences in the efficacy among these combination of vaccines,
however protection given by the vaccines was much better in groups A, B and C than
the control group.
85- ATYPICAL POST-VACCINATION SEROLOGICAL RESPONSE IN COWS
REVACCINATED WITH Brucella abortus RB51 IN ENDEMIC BRUCELLOSIS
AREAS OF MÉXICO.
E. Díaz-Aparicio 1 , B. Arellano-Reynoso 1 , E. Herrera 1 , M. Leal 2 , and F. Suárez-Güemes 2 . (1) Instituto
Nacional de Investigaciones Forestales, Agrícolas y Pecuarias. México-Toluca Km. 15.5, Cuajimalpa,
México, DF. 05110. México. (2) Facultad de Medicina Veterinaria y Zootecnia Universidad Nacional
Autónoma de México. México.
It is know that RB51 vaccination does not induce antibodies, that interfere with
diagnosis, due to this fact, any positive reaction is considered as infection, however,
we observed in cattle revaccinated with RB51, animals without infection, that were
serologically positive. The aim of this work was to elucidate which antibodies were
present in these animals with an “atypical” response. Sera samples were collected
from an infected dairy herd, ten sera from each group were used, RB51 vaccinated
groups: 1 card (CT) and rivanol (RT) negative; 2 CT positive, RT negative; 3 CT
and RT positive (1:50 or 1:100); 4 CT and RT positive (1:400). RB51 revaccinated
groups: 5 CT positive, RT negative; 6 CT and RT positive (1:50 or 1:100). Positive
group with B. abortus isolation, and negative non-vaccinated group. All vaccinated
Brucellosis 2003 International Research Conference
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