MICROSCOPICAL AND SEROLOGICAL STUDIES WITH ULTRASTRUCTURE DESCRIPTION OF SARCOCYSTIS SPECIES IN SHEEP IN ASSIUT

Basem Refat Nageib ,Huda Kuraa

doi:10.21608/avmj.2018.168909

Abstract

This study was conducted to determine theinfection rate of Sarcocystis species in sheep in Assiut. A total of 100 slaughtered sheep examined for Sarcocystis, no macroscopic cysts were observed, 93% (93/100) were positive by microscopical examination and 28% (28/100) were positive by using Agar gel diffusion test.Theinfection rate of Sarcocystis had very high significant differences between microscopic examination and Agar gel diffusion test. High statistical significant effect was found on the infection rate of Sarcocystis in different examined muscles of sheep. The highest infection rate was recorded in oesophagus (71%), followed by diaphragm (65%), tongue (58%), skeletal muscles (53%) and heart muscles (43%). The infection rate of Sarcocystis in males was 95.2% (40/42) while in females were 91.4% (53/58) by microscopical examination. Higher infection rate of Sarcocystis were detected in sheep 6 months - 2 years age 95% (38/40) than that of sheep between 2-4 years old 92.7% (38/41) and those equal or older than 4 years 89.5% (17/19). No significant difference between infection and age groups or sex of animals was observed. The use of transmission electron microscope (TEM) allowed the identification of S. tenella and S. arieticanis in sheep in Assiut. Examination of S. tenella cyst wall with TEM showed palisade-like villar protrusions while, examination of S. arieticanis cyst wall showed hair-like villar protrusions parallel to cyst wall.

Highlights

Sarcocystis is one of the most prevalent obligate intracellular protozoan parasites belong to Apicomplexan phylum infecting food livestock such as cattle, sheep and goat (Kia et al, 2011)
Examination of S. tenella cyst wall with transmission electron microscope (TEM) showed palisade-like villar protrusions while, examination of S. arieticanis cyst wall showed hair-like villar protrusions parallel to cyst wall
Sheep are the intermediate host for four species: S. tenella (S. ovicanis) and S. arieticanis that are known as pathogenic parasites, which form muscular microcysts transferred by dogs

Summary

Introduction

Sarcocystis is one of the most prevalent obligate intracellular protozoan parasites belong to Apicomplexan phylum infecting food livestock such as cattle, sheep and goat (Kia et al, 2011). Sarcocystis spp. require two hosts to complete its life cycle; with the sexual cycle in the intestine of a carnivore as a definitive host and asexual cycle in the tissues of an herbivore as an intermediate hosts (Dubey, 1976 and Fayer, 2004). The definitive host is infected due to ingestion of the Sarcocystis infected muscular tissue, which results in the intestinal generation of oocysts (Fayer et al, 2015). Sheep are the intermediate host for four species: S. tenella (S. ovicanis) and S. arieticanis that are known as pathogenic parasites, which form muscular microcysts transferred by dogs. Sheep become infected with the parasite via ingesting sporocysts or sometimes sporulated oocysts existed in the food or water (Dubey and Lindsay, 2006). Natural infections by Sarcocystis in domestic sheep have been investigated in various countries throughout the world, with prevalence ranging from 9 to 100% depending on the detection methodology (Dubey et al, 2015)

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