Survey Of Sarcocystis Infection In Slaughtered Pigs From The North Of Henan Province And Their Histopathological Observation

Sarcocystosis in pig is a worldwide anthropozoonosis. Beacause of cysts of Sarcocystis species existed in pork, and make it not be eated. In recent years, it was reported that some of Sarcocystis species was found severely pathogenicity to human and animals. Therefore, Sarcocystosis in pig have a public health significance. In the present study, the epidemiology investigation and identification of Sarcocystis species from slaughtered pigs in the northern regions of Henan were examined to offer a theoretical reference for the animal health supervision work and reduce harm to pig production.A survey of Sarcocystis infection in slaughtered pigs from the north of Henan province by tabletting microscopy. The results showed that2422pigs of1016220pigs were positive for cysts of Sarcocystis species and the average infection rate was2.38%o. Among, the slight infection was69.6%of all positive samples, hyperinfection rate was2.2%and the middle infection was28.1%. These cysts were fusiform, coliform, sickleshaped, elliptic and foliaceous in the muscule of pigs.The Sarcocystis positive samples were collected from the diaphragmatic, vastus medialis, dorsal and psoas from the infected pigs, and examined by paraffin sections (HE staining) to observe pathological changes of muscle tissue and cyst morphologic structure. In the transverse section, most of cysts were round or oval, minor of cysts was irregular. Muscle fibers infected with cysts was found apparent swelling, and structure of muscle tissue encapsulated cyst was fuzzy, the muscle texture can’t be seen. The connection between muscle fibre and normal tissue became not tight. The results of ultrastructure of cysts with the transmission electron microscopy demonstrated that wall of all cysts checked in infected pork were thick, and numerous parallelled cylindrical projections were present in the wall of cysts, and honeycomb- like in longitudinal section. Several filaments beginning with the inner layer parallelly occurred in projections. Basilar membrane extended to the cystic cavity, and the cavity was divided into a plurality of different compartments and consistent with that of S. miescherriana described previously.PCR method based on18S rRNA gene was used to amplify different Sarcocystis positive samples, the obtained sequences were aligned and analysed to further verify which species of Sarcocystis were in these examined porks. The results of phylogenetic relationship analysis confirmed that S. miescherriana was present in herds of pigs in the north of Henan province. These findings suggest that attention should be paid to sarcocystosis in pig farms from Henan province.