华东地区猪圆环病毒2型分子流行病学调查研究
毕业论文关键词：猪圆环病毒2型；Cap蛋白；分子流行病学；遗传变异
Molecular epidemiological investigation of porcine circovirus type 2 in east China in recent years
Abstract： Porcine circovirus type 2 (PCV2) is the main cause of porcine circovirus associated diseases (PCVAD),which result in serious economic losses to pig industry Since 2002. In order to study the genetic variation of PCV2 under the dual pressures of vaccine and antiviral reagents, 12 isolates in East China were sequenced from 2015 to 2016 and analyzed with the isolates collected from 2010-2014 in East China. The results showed that the total positive rate of PCV2 was 36.91% (110/298) in 2005 ~ 2016, the positive rate of PCV2 was 52.70% (39/74) in Anhui and 33.33% (70/210) in Jiangsu. Phylogenetic tree analysis showed that 46 (74.19%) of the 62 PCV2 isolates belonged to genotype PCV2d, 5 strains (8.06%) were PCV2a and 11 (17.74%) were PCV2b. It shows that PCV2 in East China has the tendency to drift from PCV2b to PCV2d. The ORF2 region of PCV2 sequence isolated from this study has its specific amino acid mutation site, and PCV2d isolate has 1 lysine at the end of this region. The results showed that the PCV2 isolates in East China from 2010 to 2016 may have genetic variation due to the double pressure of vaccine and antiviral reagents.
Key words: Porcine circovirus type 2；Capsid protein ；Molecular epidemiology；Genetic variation
目 录
摘要1
关键词1
Abstract1
Key words1
引言（或绪论）2
1材料与方法2
1.1材料 2
1.1.1病料来源2
1.1.2 主要试剂3
1.1.3主要仪器3
1.2方法 3
1.2.1样品采集和处理 3
1.2.2病料DNA的提取 3
1.2.3引物设计与合成 4
1.2.4样品中PCV2的检测4
1.2.5 阳性样品PCV2全序列的扩增与PCR产物回收4
1.2.6目的基因连接4
1.2.7感受态制备5
1.2.8 PCV2全长序列的克隆与鉴定5
1.2.9序列测定与分析 5
1.1.10 PCV2的ORF2基因编码氨基酸序列分析7
2结果与分析 7
2.1样品检测7
2.1.1多个省份PCV2组织样品阳性率7
2.1.2不同年份PCV2组织样品检测结果8
2.2.PCV2基因组序列进化分析8
2.3 ORF2基因编码的氨基酸序列分析13
3讨论17
致谢19
参考文献20
近期我国华东地区猪圆环病毒2型分子流行病学调查引言
猪圆环病毒(porcine circovirus，PCV)属圆环病毒科(circoviridae)圆环病毒属成员，是哺乳细胞中迄今已知最小的无囊膜的单股环状负链DNA病毒。病毒粒子直径约17~20nm[1]。PCV2具有很强的环境耐受性，70℃高温条件下仍能存活15min，对酸和氯仿耐受，可被强碱和季铵化合物灭活[2]。
据PCV的抗原性以及基因组成的不同可将其可分为两种基因型，即PCV1和PCV2[2-4]。PCV1无致病性, 但广泛存在于正常猪体组织和器官中[5]。PCV2已被证明与许多综合征和疾病有关，例如断奶仔猪多系统衰竭综合征（PMWS）、生殖功能衰竭、猪呼吸道疾病综合征（PRDC）、猪皮炎和肾病综合征（PDNS）、渗出性表皮炎[6-7]和肠炎[8]。PCV2还与猪繁殖与呼吸综合征病毒和副猪嗜血杆菌共同感染，并通过免疫抑制加重这些其他病原体的疾病表型[9]。自1991年加拿大首次报道本病以来，世界上许多国家也相继报道该病的流行，我国也于2000年首次报道[10]，目前该病在我国猪群中流行广泛，给养猪业带来了巨大的经济损失。