Soroprevalência e fatores de risco para infecção por Trypanosoma vivax em fêmeas bovinas de corte submetidas à IATF na região norte de Minas Gerais

Abstract

Bovine trypanosomiasis is a disease that burdens livestock in sub-Saharan African countries and Latin America. Trypanosoma vivax is considered the most pathogenic etiologic agent for bovines. T. vivax is a hemoparasite that can normally cause anemia and a persistent febrile state, leading to reduced production, weakness of the affected animals, and eventually death. T. vivax trypanosomiasis is an important reproductive disease of domestic ruminants, causing abortion, estral cycle interruption, retained placenta and perinatal mortality. The aim of this study was to determine the seroprevalence, risk factors and impacts on reproduction associated with Trypanosoma vivax infection in beef cattle females undergoing TAI in the northern region of Minas Gerais through an epidemiological and cross-sectional study, with non-probability convenience sampling. A total of 383 samples of bovine serum from 14 herds were analyzed by indirect immunofluorescence. The data were analyzed using descriptive statistics. Twenty-six samples tested positive for T. vivax IgG antibodies, corresponding to a prevalence of 6.79%. The risk factors that influenced the occurrence of trypanosomiasis were type of exploitation and the practice of vaccination, especially against reproductive diseases. When comparing the reproductive data: pregnancy rate at TAI, final pregnancy rate and gestational loss of the evaluated farms, no statistical difference was observed for any analyzed variable between the positive and negative farms for T. vivax. When analyzing only the positive animals the risk factors that influenced the occurrence of trypanosomiasis were type of breeding, record of abortion in the last 12 months and presence of vectors. It was found that 57.7% of animals seropositive for T. vivax came from properties that had pregnancy rate at TAI and final pregnancy rate below or equal to the median of the group of seropositive animals. The study allowed to prove the expansion of the disease in the northern region of the state of Minas Gerais. The environmental conditions associated with the intensification of breeding and the low adoption of biosecurity measures in rural properties, especially regarding the application of medicines, favored the occurrence of trypanosomosis.