[Observation on the development of Plasmodium falciparum in Anopheles dirus]

This paper is a record of our observation on the stages of development of Plasmodium falciparum in Anopheles dirus. The malarial parasites were derived from 5 infected patients living in Guizhou Province and used to infect 8 batches of An.dirus. The morphology of various developmental stages studied under light microscope and their average size were as follows: Microgametes were filament-shaped, 13.31 +/- 2.22 microns; macrogametes and zygotes oval or round, 4.36 +/- 0.59 microns and 3.39 +/- 0.39 microns respectively; ookinetes banana shaped, 13.56 +/- 0.80 microns x 2.90 +/- 0.48 microns; oocysts ovoid or spherical in shape, the smallest one being 7.086 microns in equivalate diameter (2 days old) and the largest one 72.60 microns (11 day old); slender sporozoites measured 10.625 +/- 0.82 microns x 1.179 +/- 1.3 microns. The late sporogonic stage of P. falciparum was observed with scanning electron microscope. The sporozoite buds developed on the surface of the sporoblast bodies, being round or elliptic or irregular-shaped. The anterior end of sporozoites was truncate and sometimes a micropyle could be seen at a distance 1/3 from the anterior end. A description was given of the different characteristics of the macrogametes and zygotes, together with the arrangement of the pigment granules of oocysts.