BOVINE BRUCELLOSIS VACCINES: EFFICACY, EFFECTS OF VACCINATION AGE AND IMMUNE RESPONSE
T lymphocytes, memory cells, vacinal effectiveness, systematic review and meta-analysis, challenge
Bovine brucellosis is an infectious and contagious zoonosis that affects animal health and public health. The disease can spread very quickly, because one of its routes of transmission is through aerosols, a form that infects animals and humans, in addition to direct contact, either through placental remains and abortion, or indirectly, by products of animal origin, such as milk, cheese and derivatives. The objective of these studies was to evaluate the fluctuation of the animals’ T lymphocytes against the in vitro challenge with irradiated Brucella abortus γ; find the best age for vaccination of calves, in the range of 3 to 8 months of age, considering the immune response, production of cytokines, immunoglobulins and the generation of memory cells; and, by means of a systematic review and meta-analysis, recalculate the effectiveness of the two most usual vaccines today, being S19 and RB51. As a result it was found that the fluctuation of T lymphocytes exists, but it is small. However, combined with the results obtained in relation to age and vaccination, it is possible to infer that the puberty animals, from 5 months of age, tends to respond better to both vaccines. The systematic review gave support to state that vaccinated animals are about 5 times more likely to be protected against brucellosis compared to unvaccinated animals, regardless of the vaccine used. Thus, it is possible to conclude that vaccination should remain the most important measure of disease control and prevention in herds where brucellosis exists, and should be carried out on young animals, between 3 and 8 months, preferably between 5 and 8 months of age.