This study aims to evaluate the dynamic of simultaneous infection with Haemonchus contortus and Haemonchus placei in sheep, with emphasis on evaluation of the competition or crossing between these two species. In the first trial, six animals (group 1) received 2,000 infective larvae (L3) of H. placei, on day zero and 11 days later the same animals were infected with 2,000 L3 of H. contortus. This difference in time of infection was planned to allow both species to reach patency simultaneously. Faecal cultures with samples from each lamb of group 1 were used to produced L3, which were used to infect animals of groups 2A (n=6) and 2B (n=6). All animals of groups 1, 2A and 2B were sacrificed at 50, 42 and 84 days post-infection (D.P.I.), respectively, for identification of parasite species and to evaluate the production and establishment of hybrid parasites. In the second trial, one group of lambs (n=16) were artificially infected with 4,000 L3 of H. placei and another group (n=16) with H. contortus. These animals were allocated on a "clean" pasture in February 2014, where they grazed together during 392 days. To evaluate the infection evolution, lambs of each experimental group were sacrificed periodically throughout the trial, with the last five sheep of each group being slaughtered in February 2015. In addition, tracer lambs were placed on the paddock to access pasture contamination. In both trials, after the sacrifice, the parasites were recovered for further molecular analysis.
News published in Agência FAPESP Newsletter about the scholarship: