Can Haemonchus placei-primary infected naïve lambs withstand Haemonchus contortus infections?

An experiment was conducted with the objective of evaluating whether a 5000 L3 larvae Haemonchus placei primary infection, a less pathogenic parasite species for sheep, could attenuate highly pathogenic Haemonchus contortus infections in lambs. Thirty nine 6-month-old lambs were divided in three primary-infection groups: (HcPI) H. contortus-primary infected lambs, (HpPI) H.