Gametogony and Sporogony in a Strain of Plasmodium berghei Preserved at Low Temperature

Abstract

A strain of Plasmodium berghei isolated from sporozoites of wild-caught Anopheles dureni and passed by blood transfers to young hamsters retained its gametocyte-producing ability after 310 days at -70 C. The infected blood was preserved by the addition of Alsever''s solution and glycerol. Hamsters infected with the thawed infected blood showed large numbers of gametocytes and exflagellation readily occurred. Batches of Anopheles quadrimaculatus and A. freeborni which fed on these hamsters showed oocyst infection rates of 33.5% and 31.3%, respectively. Freezing of heparinized blood containing P. berghei gametocytes at -70 C without addition of Alsever''s solution and glycerol abolishes and prevents ex-flagellation of micro-gametocytes. The addition of Alsever''s solution with glycerol permits exflagellation of microgametocytes after thawing and preserves the viability and motility of the male gametes.