sporozoite

noun

1. Any of the minute active bodies into which a sporozoan divides just before it infects a new host cell.

   “Ross […] was then able to outline its history within the mosquito: first, as a zygote in the stomach; then as an oocyst in the stomach wall; and finally as a mature sporozoite that reaches first the proboscis and then a human host when the insect bites and squirts its saliva prior to sucking blood.”