Tick fever risk and factors influencing the transmission of Anaplasma marginale, Babesia bovis and Babesia bigemina in cattle properties from Atlantic Forest biome

We studied the immune condition of adult cattle to Anaplasma marginale, Babesia bovis and Babesia bigemina and identified characteristics influencing the transmission of tick fever (TF) agents in properties from the Recôncavo baiano, a region located in the Atlantic Forest biome in Brazil. Blood was sampled from cattle on 28 properties to determine the seroprevalence of antibodies against A. marginale, B. bovis and B. bigemina and define the inoculation rate of B. bovis and B. bigemina on each property. A correlation test was conducted between herd seroprevalences of the TF agents to search for common transmission routes. Relation between characteristics of each property (cattle information, handling practices, tick control practices and acaricide resistance) and A. marginale herd seroprevalence and B. bovis and B. bigemina herd infection rate were explored through comparative analyses. We found seroprevalences over 75% for the three TF agents, being a positive correlation between A. marginale and B. bovis. Variables influencing the transmission of TF agents were genetic composition, use of spray acaricide formulations, use of avermectins and use of fipronil. The present study shows that adult cattle from properties in the Recôncavo baiano region have high seroprevalences for the TF agents meaning that most of the adult cattle are immune and TF outbreaks should not be frequent. We suggest that the principal propagation route of A. marginale in properties from the Recôncavo baiano is tick-borne transmission. Further investigations are necessary to establish risk factors influencing the immunity situation of cattle in the region.