Estudo da infecção por Babesia bigemina em bovinos de diferentes grupos genéticos em teleóginas de Boophilus microplus proveniente de área endêmica do Estado de São Paulo.

Abstract

The WYBabesia bigeminaWY infection rate and the effects of animal breed on infection were estimated in cattle of different genetic groups raised in the São Paulo State. Blood samples were obtained from 15 cows and 15 calves from the following genetic groups: Nelore, Canchim/Neiore, Angus/Nelore and Simental/Nelore. Blood samples were used to produce thick blood films, for DNA extraction and for determination of packed cell volume (PCV). All DNA samples were submitted to amplification by Polimerase Chain Reaction (PCR) and Nested -PCR using primers specific for WVB. bigemina”. Engorged “Boophilus microplus” females were simultaneously collected from cows and calves, to determine the “B. bigemina” infection rate by microscopic detection and N-PCR. The amplification of parasitic DNA (N-PCR) detected that 100% of animais were positives in all genetic groups. In calves it was possible to detect positive animais by PCR (first reaction). This fact shows that these animais had more DNA of “B. bigemina”, when compared to cows. It was observed an association between the PCV values and animais age. By using N-PCR it was possible to detected 186 (16,9%) infected ticks in calves as well as cows from all genetic groups and again a strong association between age of host and rate of “Babesia” infection on ticks.