Serumprevalence of antibodies against Babesia bigemina were evaluated by the indirect Enzyme-Linked Immunosorbent Assay (ELISA). Sera samples from 532 bovines of nine municipalities in the "Norte Fluminense" mesoregion, Rio de Janeiro state, were analysed. The results showed that 371 (69.74%) were positive by indirect ELISA, of which 32.33% were with a titre of 1:500, 22.56% of 1:1000, 10.90% of 1:2000, 3.38% of 1:4000, 0.38% of 1:8000, 0.19% of 1:16000, and 30.26% were negative. The prevalence analysis was done within three age groups: 1 to 3 years (n= 110), 3 to 6 years (n= 241) and > 6 years (n= 181), of which 73.64%, 69.30% and 67.95% were positive, respectively. According to the breed, 68.47% of beef cattle (n= 444) and 76.14% of dairy cattle (n= 88) were positive. Regarding the sex, 69.82% of the females (n= 497) and 68.57% of the males (n= 35) were positive. There were no significant differences between age groups, breeding types and sexes (P > 0.05). There were significant differences (P < 0.0001) between the prevalence in the municipalities. The infection by B. bigemina in this mesoregion is heterogeneous, and the seroprevalence showed that the region has to be considered enzootically unstable. The epidemiological situation requires serological identification of exposed animals at risk condition for the control of babesiosis.
Seroepidemiology; Babesia bigemina; bovine babesiosis; enzyme immunoassay; "Norte Fluminense"; mesoregion; Brazil
