Serumprevalence of antibodies against Babesia bovis were studied by the indirect Enzyme-Linked Immunosorbent Assay (ELISA). Sera samples from 532 bovines of nine municipalities in the "Norte Fluminense" mesoregion, state of Rio de Janeiro, were analysed. The results showed that 484 (90.98%) were positive by indirect ELISA, of which were: 20.30% with a titre of 1:500, 35.72% of 1:1000, 20.87% of 1:2000, 7.33% of 1:4000, 2.82% of 1:8000, 2.63% of 1:16000, 0.56% of 1:32000, 0.75% of 1:64000, and 9.02% 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 98.18%, 90.87% and 86.74% were positive, respectively. There were significant differences (P < 0,05) between the 1 to 3 year-group and other age groups. The young animals are less susceptible to the disease than older animals. According to the breed, 91.44% of beef cattle (n= 444) and 88.64% of dairy cattle (n= 88) were positive. Regarding the sex, 90.54% of the females (n= 497) and 97.14% of the males (n= 35) were positive. There were no significant differences between breeding types and the sexes (P > 0.05). There were significant differences (P < 0.0001) between the prevalence in the different municipalities. The infection by B. bovis in this mesoregion is heterogeneous, although the seroprevalence showed that the region has to be considered enzootically stable. The epidemiological situation requires immunization only of animals coming from other areas.
Seroepidemiology; Babesia bovis; bovine babesiosis; enzyme immunoassay; "Norte Fluminense"; mesoregion; Brazil
