PLASMODIUM-VIVAX - FREEZE-FRACTURE STUDIES ON THE ULTRASTRUCTURE OF THE SPOROZOITES WITHIN THE SALIVARY-GLAND OF THE MOSQUITO ANOPHELES-STEPHENSI

Freeze-fracturing has been used to study the ultrastructure of the spo rozoites of the malarial parasite Plasmodium vivax within the salivary gland of the mosquito Anopheles stephensi. The architecture of the pe llicular complex of the salivary gland sporozoites was essentially the same as that reported for the intraoocystic forms, but the outline of cross-fractured P. vivax sporozoites was more flattened and crescent shaped as opposed to the circular outline described for the intraoocys tic sporozoites. The salivary gland sporozoites of P. vivax also exhib ited apical rosettes and a cytosome connected to a food vacuole, two u nique structures not previously reported for malarial sporozoites.