【作者】 白丽丽；

【导师】 陈德坤； 宋长绪；

【作者基本信息】 西北农林科技大学 ， 预防兽医学， 2008， 硕士

【摘要】 2001年以来,我国大部分养猪密集地区都会出现“猪无名高热症”,该病发病率和死亡率都很高,并且发病迅速,对养猪业造成了极大的危害。2006年6月份以来在我国南方主要养猪省份都爆发了该病。该病的病原复杂,至今尚存在争议。本研究就此开展工作,获得以下结果:1.初步弄清了2004-2006年期间广东省4个地区PRRS和2005-2007年期间广东省4个地区猪伪狂犬病分布以及流行特点。2.分别采用培养的犬肾细胞(MDCK)、猪肾细胞系(PK-15)、仓鼠肾细胞系(BHK-21)、非洲绿猴肾细胞(Marc-145)分离到了1株PRV野毒及4株PRRSV毒株;对4株PRRSV分离株的高变区E片段基因进行的分子克隆证明它们均在基因水平发生了变异;动物试验发现,分离到的PRV野毒株在昆明系小鼠上引起的症状比在猪引起的临床症状更为典型。但该毒株攻击猪后所产生的病理组织变化很典型。这些结果表明,广东省“猪无名高热”不是由单一病毒引起的疾病。3.克隆到了PRV GDSH株gE基因,对其进行了测序。该序列与GeneBank上公布的gE基因序列比对分析表明,PRV GDSH株gE基因序列与Ea株亲缘关系为99.9%。;克隆到了4株PRRSV广东分离株E片段基因,对其进行了测序。该序列与GeneBank上公布的E片段基因序列比对分析表明,4株PRRSV广东分离株均发生了变异,但从遗传进化树看四株PRRSV广东分离株并未发生较大程度的偏离,它们均来自同一分支。更多还原

【Abstract】 Pig high fever disease swept China in most intensive pig faming area since 2001. The high morbidity and mortality rates of this disease greatly imperilled the pig farming industry. However, the complexity of possible trigger pathogens is still under dispute. In this study, materials from high fever-prone areas are isolated, cultured in several cell lines, and analysis by molecular epidemiology survey. Our results show that:Serological results of PRRSV and PRV in Guangdong Province. In the samples which collected from 2004 to 2006 in Pearl River Delta, northern, western and eastern earas of Guangdong Province, the total PRRSV positive rate is 48.5 percent. Among them, specimens in the Pearl River Delta region have the highest positive rate of 22.0 percent, while specimens in Western Guangdong have the lowest rates of 15.9 percent. Northern and eastern parts of Guangdong have a positive rate of 19.4% and 18.9% seperately, which stands in the middle of the four provinces. All the data suggeste that porcine reproductive and respiratory syndrome virus is widespread in farms of Guangdong Province, which advises strengthen measurements to be taken to prevent and control the infection.Separation of PRV GDSH virus strain. A suspicional pseudorabies virus (PRV) strain, which isolated from a pig farm in Sihui Guangdong, was amplified by PCR, and measured by infectivity and animal test. It showed typical pathological changes in canine kidney cells (MDCK), Pig Kidneys cell lines (PK-15), and hamster kidney cells (BHK-21). TCID50 in MDCK cells is 10-8/0.1 mL; 56℃30 minutes inactivation; virus inoculated mice and pigs get a typical pseudo-rabies symptoms, itching to death; PCR DNA which isolated from the virus infection in mice with specific primers gets typical 262 bp fragment of Pseudorabies GD virus genes. All the data show that the isolated virus belong to pseudo-rabies virus, which is then named GDSH strain. PRV from the pathogen has proved to be widely spread in Guangdong Province.PRV g-E gene cloning and sequence analysis. Results showes that virus from the Sihui Guangdong pig farm contains a PRV wild strain, named GDSH strain here. The PCR product of this virus is about 1.7 kb, and the homology of its nucleotide sequence is about 98.3% to 99.9% to other PRV strains. Compared with PRV Ea, the homology reaches 99.9 percent. In conclusion, PRV isolated in Guangdong did not mutate remarkbly.更多还原