Observations on gametogenesis in Plasmodium falciparum from continuous culture

Gametocytes of Plasmodium falciparum were produced in continuous cultures but eventually declined in numbers after 3--4 months in vitro. Their development progressed in a consistent pattern, from small rounded, through triangular, to ellipsoidal, and finally after 8 days to crescentic forms. Morphologic maturity occurred at 8--9 days, but the gametocytes would not exflagellate in vitro, even after 14--18 days of development. Thus, current culture methods cannot produce a continuous supply of functional gametes for further studies.