Seasonal Fluctuation of Plasmodium falciparum Gametocytaemia.

摘要

Plasmodium falciparum is usually first detected in the peripheral circulation of immunologically naive humans as trophozoites 7-11 d after a successful sporozoite inoculation. The number of parasites multiplies exponentially at each 48 h schizogonic cycle, reaching its highest density 5-8 after initial patency. After this asexual peak has subsided, or about 3 weeks after inoculation, gametocytes, which until then have been absent, suddenly flood the circulation. Large numbers of these persist for about 2 weeks, but thereafter they are relatively rare and show no marked periodicity. Since gametocytes are the sexual stage of malaria and propagate only in the mosquito, transmission of the disease is a direct consequence of their availability. (JES)