Bovine trypanosomiasis in Brazil

Abstract

Trypanosoma vivax is a protozoan that was brought from Africa and is the main etiological agent of bovine trypanosomiasis. This disease has a great importance due to serious economic impact, lack of knowledge of the cattle ranchers about the forms of control and transmission, as well as ineffective treatments. The objective of this study was a review in order to clarify veterinary doctors, academics and rural owners about some characteristics of the disease. The etiologic agent is transmitted mechanically through hematophagous flies of the genus Stomoxys spp. and Tabanus spp., or contaminated needles. Clinical signs involve anemia, emaciation, diarrhea, miscarriages, neurological signs, and mechanisms such as the antigenic variation contribute to the remain of the parasite in bloodstream. The treatment is based on the application of drugs such as diminazene aceturate and isometamidium chloride, but reports of resistance to both drugs were demonstrate. The control involves measures of epidemiological monitoring, vector control, use of bovine breeds resistant to trypanosomes, treatment of affected animals and reduction of their movement. Vaccine development has been ineffective due to the low level of protection and antigenic variations of the parasite.