Fine structure of the development of Sarcocystis singaporensis in Python reticulatus from macrogamont to sporulated oocyst stage

Abstract

Three, 4-month old reticulated pythons (Python reticulatus) hatched from eggs laid by a newly caught female from Singapore Island, were fed on muscles of Sarcocystis singaporensis infected Rattus rattus caught in Singapore. Snakes were sacrificed five, six and eight days later. The infected tissues were studied by transmission electron microscope. The present communication summarizes findings on macrogamont and oocyst stages. In the premature stages, rough endoplasmic reticulum consolidate into a large rectangular array; the electron-dense wall-forming-like bodies reveal a laminar structure. Macrogamont parasitophorous vacuoles became filled with granular matrix and electron-dense strands, which later on consolidate into a coat around the fertilized zygote. The oocyst wall is constructed from several formed membranes combined with deposited substance. All development to the sporulated oocyst stage occurs in the mucosal epithelium.

Keywords

• Sarcocystis singaporensis
• Python reticulatus
• macrogamonts
• oocysts
• ultrastructure