Aspectos epidemiológicos da tristeza parasitária bovina no Brasil: com ênfase na área limítrofe entre os biomas caatinga e mata atlântica do estado da Bahia

Abstract

The epidemiological situation of Anaplasma marginale and Babesia spp. infections and the occurrence of cattle tick fever outbreaks in bovines of Brazil are reviewed, emphasizing the situation of the border area between the Caatinga and Mata Atlântica biomes of the State of Bahia. To characterize the behavior of the disease in each region of Brazil we reviewed seroprevalence studies, casuistry of Veterinary Diagnostic Laboratories and case reports. Subsequently, based on the cattle diseases diagnosed by the Livestock Development Center of the Federal University of Bahia (CDP-UFBA), a retrospective study was developed reviewing characteristics of the tick fever outbreaks diagnosed between January 2018 and October 2021. Additionally, a prospective study was developed between October 2021 and October 2022, accompanying the occurrence of outbreaks, and applying a survey to the attended producers. In areas of enzootic instability (South region and the Pantanal and Caatinga biomes), ecological conditions interfere with tick Rhipicephalus (Boophilus) microplus, biological vector of the agents of the tick fever in Brazil, development in the environment, causing a decrease or absence of the tick population at certain times of the year. As a result, calves do not acquire immunity because A. marginale or Babesia spp. infection are low or there is absent; these animals will show clinical signs of the disease if they get infected after the first year of age. The anaplasmosis is the most diagnosed disease in the area of influence of the CDP UFBA. In this area, a risk factor associated with the anaplasmosis outbreaks is the application of injectable drugs with high frequency. In Brazil, it is necessary to better understand the risk factors of cattle tick fever in areas of enzootic stability, to develop vaccines against A. marginale and Babesia spp. and use it in regions of enzootic instability and/or in animals that are transported from enzootic instability to enzootic stability areas and determine the importance of mechanical transmission of A. marginale. In the border area between Caatinga and Mata Atlântica in Bahia, it is necessary to recognize the biology of the tick to plan its control and to develop serological studies to identify the epidemiological status of tick fever.