MALARIA 



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termed a merocyte. When the merocyte ruptures, these spore-like 

 bodies or merozoites enter a fresh cell and develop as before. 



At the time that the merocyte ruptures it is supposed that a toxin is 

 given off which causes the malarial paroxysm. The cycle goes on by 

 geometric progression from the first introduction of the sporozoite, but 

 it is usually about two weeks before a sufficient number of merocytes 

 rupture simultaneously to produce sufficient toxin for symptoms (period 

 of incubation). This cycle is termed schizogony. 



9. 



FIG. 62. Sexual and nonsexual cycle of malaria, i, Schizonts; 2, merocyte; 

 3, merozoites; 4, macrogamete; 5, microgametocyte; 6, and 7, gametes in stomach of 

 mosquito; 8, microgametocyte throwing off microgametes; 9, microgamete fertilizing 

 macrogamete; 10, vermiculus or zygote; n and 12, zygotes; 13, zygote distended 

 with sporozoites; 14, sporozoites. 



After a varying time, whether by reason of necessity for renewal of 

 vigor of the parasite by a respite from sporulation, or whether from a 

 standpoint of survival of the species, sexual forms (gametes) develop. 

 Some think that sporozoites of sexual and nonsexual characteristics are 

 injected at the same time. It is usually considered, however, that 

 sexual forms develop from pre-existing nonsexual parasites. 



These gametes show two types: the one which contains more pig- 

 ment, has less chromatin, and stains more deeply blue is the female -a 

 macrogamete; the other with more chromatin, less pigment, and staining 



