DINÂMICA POPULACIONAL DE Rhipicephalus (Boophilus) microplus E NÍVEIS DE INFECÇÃO ESTIMADA POR qPCR DOS AGENTES DA TRISTEZA PARASITÁRIA BOVINA EM ANIMAIS DA RAÇA NELORE E CRUZADOS (ANGUS/NELORE) NO CERRADO

Abstract

Anaplasma marginale, Babesia bigemina and Babesia bovis are recognized in Brazil for causing cattle tick fever, transmitted by the tick Rhipicephalus microplus. Both tick and cattle fever, are responsible for causing direct damage to animal health such as hemolytic anemia, abortion, decreased production and mortality in cattle and indirect damages with inputs and labor to control the tick and treatments for the host. In general, these agents can also persist in cattle herds without clinical signs. This study aimed to correlate the number of ticks to a control polymerase chain (qPCR) of msp5, cbisg and cbosg genes in Brangus and Nellore cattle in the Brazilian Cerrado for 12 months. All animals tested are positive for the presence of A. marginale and B. bigemina, B. bovis was not detected by PCR and qPCR. Brangus cattle carried the highest burden of ticks and A. marginale than Nelore cattle, which had the highest number of B. bigemina copies in the qPCR results. In addition, both breeds did not show statistical differences for weight gain and serology throughout the year. The animals did not show any clinical signs of anaplasmosis or babesiosis during the experimental period, indicating that a low number of ticks may be sufficient to maintain a stable enzootic condition.