The results presented in this study showed clearly that the resistance to Sb(III) does not influence the early-stage development of L. major in sand flies as the infection rate was almost 100% in females infected with both susceptible or Sb(III)-resistant lines on day 2 p. i. In mature infections, heavy parasite loads were significantly more represented in female sand flies infected with both WT strains (LIPA-WT and Liby). Here, LIPA is linked to infection.