LIGHT AND ELECTRON MICROSCOPIC STUDY OF MEROGONY OF EIMERIA SP. INFECTING THE MARBLED TEALS (ANAS ANGUSTIROSTRIS)

Abstract

Two asexual generations were developed before the commencement of the sexual phase. First generation schizont containing 12-16 randomly scattered merozoites masured 19.5 x 16.3 um, supranuclear and ectomerogonic with residual body. Each merozoite being vermiform and measured 7.7 x 2.4 um. The merozoites formation was completed within 48 hours. post-infection (p.i). Meanwhile, mature second generation schizont measured 17.5 x 15 um. It conained 4-20 merozoites, each measured 9.5 x 2.8 um, and the process was completed within 84 hours p.i. The present study showed all changes in the ultrustructural forms associated with the development, starting from uninuclear schizont to multinuclear schizont. The process of merozoite formation, recorded in the present study, termed ectomerogony in which the merozoites developed at the periphery of each schizont. This method is common and recorded among many species of Eimeria. The electron microscope study revealed that the pellicle consists of two membranes, an outer thin unit membrane and an inner complex one usually formed of two membranes. During this stage, the merozoites of the first generation invaded new uninfected epithelial cells. The same events, recorded in the formation of the first generation schizonts and merozoites were carried out in the second generation, except that the second has specific arrangement of merozoites, and it was rich with endoplasmic reticulum. The outer pellicular unit membrane of merozoites was continous enclosing the whole merozoite without interruptions except an invagination at the site of micropore.