Periodic infectivity of Plasmodium gametocytes to the vector. A review.

Frank Hawking, in 1966 postulated that in synchronous malaria infections, the brief period of infectivity of gametocytes was timed to occur when the vector bites. Since this early work, numerous studies had contributed to confirm and explain this phenomenon with bird, rodent and primate Plasmodium. Data on the periodic production of gametocytes, the duration of their maturation, the effect of the schizogony on the infectivity and the circadian bioavailability of gametocytes provide some more informations on the periodic Plasmodium gametocyte infectivity to the vector. This paper is intended to be a review of contributions on the "Hawking phenomenon" and to summarize the principal causal hypotheses. The conclusion stresses the practical consequences for experimental studies and epidemiological surveys.