Inhibition of iEhrlichia canis/iand iBabesia canis/itransmission among ticks fed together on dogs vaccinated with Bm86 antigen

摘要

GAVAC (Heber Biotec S.A, Havana, Cuba) is a commercially available vaccine developed with the Rhipicephalus (Boophilus) microplus Bm86 recombinant antigen. Bm86 is a “concealed” antigen that is present in the plasmatic membrane of tick gut epithelial cells with unknown function so far. It is well known that after vaccination in the last fifteen years in Cuba, there was a significant decrease of babesiosis (Babesia bovis and Babesia bigemina) and anaplasmosis (Anaplasma marginale) in cattle. A reduced transmission capacity of ticks fed on tick-immune animals and humans has been reported for several tick-borne pathogens. Recent experiments have demonstrated that an anti-tick vaccine may contribute to the control of tick-borne pathogens not only by decreasing the exposure of susceptible hosts to ticks, but also by reducing the vector capacity of ticks. In this study, the potential of Bm86 vaccination to interfere with pathogen transmission among ticks was evaluated by using as experimental model the brown dog tick Rhipicephalus sanguineus and the tickborne Babesia canis and Ehrlichia canis pathogens. Dogs, vaccinated and not vaccinated, were infested with pathogen-infected ticks and noninfected nymphs of R. sanguineus. After feeding, the pathogen transmission to newly molted adults from co-feeding uninfected nymphs was studied by conventional PCR and qPCR. Results suggest that the anti-Bm86 antibodies could be able to block the transmission of B. canis and/or E. canis from infected to non-infected ticks.