Plasmodium gallinaceum: fluorescent staining of zygotes and ookinetes to study malaria parasites in mosquito.

We have developed a fluorescent labeling procedure for staining the mosquito stages of Plasmodium gallinaceum. PKH26, a lipophilic dye, is efficiently and permanently incorporated into the membranes of zygotes and ookinetes. Stained zygotes undergo normal development into ookinetes; the stain does not interfere with ookinete mobility or ability to adhere to the mosquito midgut lumen. Stained zygotes and ookinetes are comparable to untreated parasites in their ability to give rise to oocysts when fed to mosquitoes. This technique can be used to study the development of Plasmodium parasites in the complex cellular environment of the mosquito midgut after a blood meal. It may also be adapted to study other parasite-vector interactions.