Development of live attenuated strains of Babesia bovis and Babesia bigemina: preliminary test
DOI:
https://doi.org/10.1590/S1678-3921.pab1987.v22.14698Keywords:
Babesiosis, vaccine, attenuation, bovine passageAbstract
With the objective of developing local strains of Babesia bovis and Babesia bigemina attenuated according to the Australian method, sixteen rapid passages of B. bovis in splenectomized calves and four slow passages of B. bigemina in intact calves were made. A preliminary test of the virulence and antigenicity of these strains in two-year old Hereford steers in the field showed that: 1) the B. bovis strain was of low virulence as the inoculated animals did not present clinical signs of the disease during the vaccine reaction; 2) the B. bigemina strain was still too virulent since three of five inoculated steers presented visible clinical signs, although all recovered spontaneously from the infection; 3) both strains were highly antigenic as all inoculated animals were positive for the indirect fluorescent antibody test and resisted the homologous challenge with the respective virulent strain, while all of the non-vaccinated controls became acutely ill and although properly medicated, one died.