青海省西宁地区绵羊住肉孢子虫感染情况调查研究

为了掌握青海省西宁市及其辖属区县绵羊住肉孢子虫的感染强度并明确感染类型。通过随机采集供往西宁市辖属区县各市场、超市及摊贩的屠宰后绵羊不同部位肌肉组织,进行压片镜检、染色切片观察和形态学鉴定;选取虫体含量高的羊心肌和膈肌样品,提取基因组DNA以线粒体细胞色素C氧化酶亚基I(Cox1)基因设计引物进行PCR扩增并测序比对。西宁市辖属区县绵羊住肉孢子虫感染率为82.5%,平均感染强度7.67,从寄生部位上看,膈肌感染率最高(75%),其次是心肌(67.5%)、舌肌(57.5%),食道肌未见有感染。所检虫体边缘肌肉组织较疏松,虫体囊壁分为两层,原生囊壁与次生囊壁均结构平整无突起皱褶等特殊性结构,经PCR扩增出长度为905 bp的目标片段,测序后在GenBank上进行序列比对,其与已公布的羊柔嫩住肉孢子虫的同源性达98%,最终鉴定为羊柔嫩住肉孢子虫。初步明确青海西宁地区绵羊感染主要以羊柔嫩住肉孢子虫(Sarcocystis tenella)为主,且西宁市感染率高于中国绵羊住肉孢子虫感染的平均水平。建议加强青海省西宁地区羊住肉孢子虫实验室检测及调运、屠宰检验检疫力度,保证上市羊肉类产品卫生质量,保障公众的身体健康和饮食安全。

Investigation on the Infection of Sarcocystis ovis in Xining of Qinghai Province

In order to find out the infection intensity and type of Sarcocystis ovis in Xining of Qinghai Province, different parts of muscle tissues of slaughtered sheep were randomly collected from markets, supermarkets and vendors in districts and counties under the jurisdiction of Xining. Microscopic examination and staining section observation were conducted for morphological identification. Genomic DNA extracted from myocardial and diaphragm samples of sheep with high worm content was taken for PCR amplification and sequencing analysis of mitochondrial cytochrome C oxidase subunit 1 (Cox1) gene. The results showed that in Xining, the infection rate of Sarcocystis ovis was 82.5%, and the average infection intensity was 7.67. In terms of parasitic sites, the highest infection rate was found in diaphragm (75%), followed by that in myocardium (67.5%), tongue (57.5%), while no infection was found in esophageal muscle. The muscle tissue at the edge of the worm was loose, and the cyst wall of the worm was divided into two layers. The structure of the primary and secondary cyst wall was flat, without protrusion and wrinkle. The 905bp target fragment was amplified by PCR and the sequence was aligned in GenBank. The homology between the target fragment and the published sequence of Sarcocystis tenella was 98%. So it was identified as Sarcocystis tenella. In conclusion, this research preliminarily clarified that the main infection of sheep in Xining of Qinghai Province is Sarcocystis tenella, and the infection rate in Xining is higher than the average level in China. We suggest that the laboratory detection, transportation and slaughter inspection and quarantine of Sarcocystis ovis in Xining of Qinghai Province should be strengthened, to ensure the sanitary quality of mutton products in market and the health and food safety of the public.