2011年～2012年中国部分地区猪细环病毒在不同猪群中的流行病学调查及其与PCV2、PPV4或PRRSV的共感染分析

Molecular epidemiological investigation of porcine Torque Teno virus and its co-infection analysis with PCV2, PPV4 and PRRSV in different swine herds from 2011 to 2012

为了解猪细环病毒(TTV)在无明显临床症状的猪群和不同发病猪群中的感染情况,本实验于2011年～2012年期间共采集江苏、安徽、天津、湖北、上海、浙江6个省份的无明显临床症状的母猪血清共488份,发病猪群样品352份,包括发生PMWS的猪血清及组织样品203份,发生PRRSV感染的猪群样品105份,发生流产的初产母猪血清23份,以及流产胎儿组织样品21份。对无明显临床症状的猪群进行TTV1和TTV2的病原学检测,对发病猪群样品进行TTV和PCV2、PPV4、PRRSV共感染检测,并对40条TTV1和32条TTV2的UTR部分基因分群区域进行测序和进化分析。结果显示,在488份无明显临床症状的母猪和种公猪中,猪源TTV1和TTV2感染率较高,分别为41%和67%,二者混合感染率为28%。PMWS发病猪样品中PCV2阳性率高达75%,PCV2和TTV2的混合感染高达61%。在PRRSV为阳性的病料中,TTV2的阳性率高达86%。在初产母猪和流产胎儿中,TTV1和TTV2的感染率,以及与不同病毒的混合感染率均高于健康猪群的感染率。对基因序列的进化分析表明,TTV1主要可以分为8个基因群,TTV2可以大致分为4个基因亚群。本研究为研究猪源TTV的潜在致病力以及分子进化提供了进一步的资料。

To investigate the molecular epidemiological features and potential pathogenicity of porcine Torque Teno virus （TTV）, the epidemiology of TTV and the co-infection with different viruses were investigated in pig farms from the tissue and blood samples with different background collected in 6 provinces during 2011 to 2012. In addition, the partial UTR sequences from 40 TTV1 and 32 TTV2 were sequenced and analyzed by phylogenetic alignment. The results showed that the TTV1 （41%） and TTV2 （67%） infection rate of 488 samples from the clinical healthy swine herds and the co-infection （28%） was much higher than that of previous study. Among the samples which were collected from the PMWS herds, the PCV2 infection was 75%. The co-infection rate of PCV2 and TTV2 was 61%, also the co-infection of TTV2 with PRRSV was 86%. The infection andco-infection rote in the aborted fetus of both TTV1 and TTV2 with PCV2 were much higher than that of the healthy herds. The phylogenetic analysis showed that TTV1 were divided into 8 groups and TTV2 were divided into 4 sub-genotypes. This study provided further data about the potential pathogenicity and its molecular evolution diversity of porcine TTV.