Trypanosoma vivax em bovinos no estado do Rio de Janeiro

• Autor(a) principal: Costa, Renata Vit?ria Campos
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/4987
• topic: Trypanosoma vivax; Bovino; Tripanossom?ases; Bovine; Trypanosomiasis; Medicina Veterin?ria

Trypanosomiasis is a disease caused by species of the genus Trypanosoma. In cattle trypanosomiasis is caused by Trypanosoma vivax that originates in tropical Africa, where the disease represents an obstacle to the development of livestock. The spread of disease to the Americas occurred during European colonization in the 1830s, and the displacement of the herds and the adaptation of the parasite to mechanical transmission by hematophagous flies allowed the spread of this parasite. In Brazil, T. vivax infection in cattle was reported for the first time in the State of Par?, in 1944, and the presence of the parasite has been reported in several states. This study aimed to report the epidemiological and clinical-pathological aspects of T. vivax natural infection in cattle in the state of Rio de Janeiro. Sixteen foci of Trypanosoma vivax infection were diagnosed in cattle in 13 municipalities in the state of Rio de Janeiro between April 2016 and October 2018. Of these, 12 outbreaks were studied based on epidemiological data, clinical-pathological signs and laboratory tests. Clinically affected animals presented anemia, decreased appetite, significant decrease in milk production, progressive weight loss, weakness, reproductive abnormalities, diarrhea and neurological signs. In some animals the picture evolved to death. The laboratory diagnosis (parasitological, molecular, necropsy and histopathological examinations) was performed on 284 whole blood samples and tissues collected from 280 cattle. Parasitological exams performed on leukocyte - layer smears were positive in 25 samples from six of the 12 foci studied. Molecular diagnosis using conventional polymerase chain reaction (cPCR), carried out on whole blood samples, detected 46 positive samples in five of the 12 foci and in seven other positive samples in tissue fragments collected. The cPCR presented high diagnostic sensitivity when compared to parasitological methods. Of the 12 cows that died, nine presented neurological signs and, on histological examination, inflammatory alterations were found mainly in the central nervous system and heart, characterized by meningoencephalitis and multifocal myocarditis; in the central nervous system of the animals these lesions occurred with greater intensity in the brain in relation to the marrow. Trypanosomiasis in bovine herds in the state of Rio de Janeiro is of concern because of its potential to cause economic losses and, due to the lack of specificity of clinical signs, laboratory tests are fundamental to elucidate the diagnosis.