Infecção natural por Trypanosoma (Dutonella) vivax (Ziemmann 1905) em bovinos no Estado do Rio de Janeiro
Trypanosoma vivax, bovino, tripanosomíases.
COSTA, Renata Vitória Campos. Infecção natural por Trypanosoma (Dutonella) vivax (Ziemmann 1905) em bovinos no Estado do Rio de Janeiro 2018. 49 p. Tese (Doutorado em Medicina Veterinária, Patologia Animal). Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, 2018.
This study reports the occurrence of 11 outbreaks of trypanosomiasis by Trypanosoma vivax in cattle in 10 municipalities in the state of Rio de Janeiro. The clinical signs, pathogenesis and epidemiology of the disease were studied from February 2016 to December 2017. In the state of Rio de Janeiro, no outbreaks of trypanosomiasis in cattle were recorded and the commercialization of animals from regions where the disease already been identified as the main cause of occurrence. The Needle sharing management for the application of the hormone oxytocin during milking and the presence of hematophagous flies contributed to the spread of the infection within the herds. The clinical picture was predominantly observed in lactating cows, and the animals clinically affected presented anemia, decreased appetite, significant decrease in milk production, progressive weight loss, weakness, reproductive alterations, diarrhea, neurological signs and mortality. Reduced milk production, loss of animals, spending on medicines and veterinary care, and reproductive diseases were the main causes of economic losses reported by owners. The diagnosis of T. vivax infection was made through the visualization of its morphology and biometry in the parasitological examinations of Buffy Coat and through the polymerase chain reaction (PCR). In the chronic phase of the infection, PCR presented greater diagnostic sensitivity when compared to the parasitological method. Six cows that presented neurological signs and evolved to death were necropsied and histologically presented multifocal lymphohistiocytic meningoencephalitis in the brain and multifocal lymphohistiocytic myocarditis. Trypanosomiasis in dairy cattle introduced in the State of Rio de Janeiro has caused serious economic losses and the warning signal for the diagnosis of this trypanosomiasis can be based on laboratory tests, due to nonspecific clinical signs such as progressive thinning, drop in milk production and anemia, associated with neurological signs, diarrhea and reproductive changes.