Studies of Litomosoides carinii by Phase-contrast microscopy: the Development of the Larvae

Abstract

The development of the microfilariae of Litomosoides carinii from the ova, has been studied by phase-contrast microscopy, and recorded with photomicrographs. All stages in the development were obtained by puncturing the uteri of adult female worms at intervals along their lengths, transferring the larvae which emerged onto agar coated slides and allowing the weight of a coverglass to flatten them sufficiently for detailed examination.The head and the tail end of the larva were differentiated at a fairly early stage and about the same time a hook-like structure appeared on the head. Subsequently a body cavity was formed within the larva which was associated with the appearance of highly refractile subcuticular cells. Later this cavity became filled with different types of cells.Throughout its development the larva was enclosed within a membrane which was later stretched by the movement of the larva to form the sheath of the microfilaria. All the microfilariae from the adult female worms, from the pleural fluid, and from the peripheral blood of the large number of infected cotton rats examined, were seen by phase-contrast microscopy to have sheaths.