TEMPORARY LOSS OF PLASMODIUM GAMETOCYTES INFECTIVITY DURING SCHIZOGONY

Experiments with P. y. nigeriensis and Anopheles stephensi fed through a membrane showed that gametocytes infectivity was impaired by the addition of hemolysed serum to parasitized blood. The same phenomenon occurred when mouse hemoglobin, bovine hematin or hemolysed mouse blood were added to normal serum. In vivo, when A. stephensi was fed on a mouse infected with a synchronous strain such as P. vinckei petteri, gametocytes lost much of their infectivity at the time of schizogony and recovered it a few hours later. This phenomenon should be taken into account when experiments on gametocytes infectivity or transmission are performed. These results confirm the involvement of toxic and non specific, rather than immunological, factors in the blockage of gametocytes infectivity.