Authors: ADOSINDA MARIA COELHO, MARIA DE LURDES PINTO, JUAN GARCIA DIEZ, ANA CLAUDIA COELHO
Abstract: Trás-os-Montes e Alto Douro, in the northeastern region of Portugal, previously exhibited the highest brucellosis prevalence in the entire small ruminant population of Portugal. Consequently, a vaccination program of the whole population with Brucella melitensis Rev-1 was carried out from 2001 to 2004, and further compulsory Rev-1 vaccination of 3- to 6-month-old lambs and kids was carried out between 2005 and 2007. The prevalence of brucellosis decreased by 71.42% in 2004, with a 2-fold decrease occurring from 2005 to 2007. The reduction of brucellosis prevalence was statistically significant (P < 0.001) according to flock size. By species, brucellosis prevalence decreased 14.5-fold in sheep and 5.5-fold in goats in 2004. Regarding flock constitution, it decreased by 77% for pure flocks and 73% in mixed flocks in 2004. Regarding the animals involved in production, brucellosis prevalence decreased during the 7-year period. It was concluded that Rev-1 vaccination of the whole population was effective in decreasing brucellosis prevalence. These results contribute to the scarce information available regarding the effect of Rev-1 vaccination on different characteristics of flocks. They may be used to improve the efficiency of brucellosis eradication programs within livestock management.
Keywords: Brucellosis, Brucella melitensis Rev-1 vaccination, prevalence, sheep, goat
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