Effect of O. intermedium concentration and heat inactivation on the percentage of female Lu. Longipalpis containing a Leishmania infection. (A) Two concentrations of O. intermedium of 106 (OD 0.02) and 107 CFU mL-1 (OD 0.2) were used to feed groups of sand flies prior to Leishmania infection. Control group were fed on 7% sucrose only before infections. Three independent experiments were carried out. Fisher’s Exact Test:* P ≤ 0.0001. (B) Effect of feeding heat inactivated (HI) O. intermedium (107 CFU mL-1) on subsequent Leishmania percentage infection of females. Infection rates from individual sand fly midguts from 3 independent experiments. Fisher’s Exact Test: *P ≤ 0.0001.