CONTROL OF BOOPHILUS-MICROPLUS POPULATIONS IN GRAZING CATTLE VACCINATED WITH A RECOMBINANT BM86 ANTIGEN PREPARATION

Current methods for the control of cattle tick Boophilus microplus inf estations are not effective and the parasite remains a serious problem for the cattle industry in tropical and subtropical areas, Recently, we developed a vaccine against B. microplus employing a recombinant Bm 86 (rBm86) antigen preparation (Gavac(TM), Heber Biotec) and it was sh own to induce a protective response in vaccinated animals under contro lled conditions. Here we show that, under field conditions in grazing cattle, the vaccine is able to control B. microplus populations. Two p arasite-free farms were employed for the study. In the first farm, ani mals were vaccinated with the recombinant vaccine, while, in the secon d, animals received a saline injection in adjuvant. After immunization , animals were artificially infected and the infestation rate was reco rded. Over the 33 weeks of the experiment, the infestation rate was lo wer in the vaccinated group compared with the control group. At the en d of the experiment it was necessary to use chemicals in the control f arm after serious losses in production and animals.