Given the block in transmission by mosquitoes infected with the trp1(-) or trp1(-)mCh knockout parasites, we investigated the number of sporozoites in the midgut, hemolymph and salivary glands over time. In mosquitoes infected with wild-type parasites, midgut sporozoites start to egress from oocysts 11–12 days post infection; hence their numbers in the midgut decrease over time, while the numbers of hemolymph and salivary gland sporozoites slowly increase (Figure 3A). This evidence concerns the gene PMCH and infection.