2007年12月～2008年5月对北京地区的犬病流行情况进行了调查，共调查犬404只，其中患犬瘟热41只，细小病毒性肠炎115只，犬冠状病毒病86只，主要以细小病毒性肠炎多发。本次调查疾病的样品阳性检出率与病犬的免疫预防有一定的关系，定期免疫的犬发病少，未免疫的犬样品阳性检出率高，说明未免疫的犬易感染犬瘟热等病，定期免疫可提高机体免疫力。本试验分析了犬病流行病学的特点，并提出了今后的防治措施和意见。 根据发表的犬瘟热病毒（CDV）参考毒株Onderstepoort的序列设计了一对引物，以感染犬瘟热病毒的犬的粪便总RNA为模板，RT-PCR扩增出17株CDV的H全基因1877 bp的片段，将这个片段连接到pGEM-T easy 载体上，经酶切鉴定得到阳性克隆，将阳性质粒进行序列测定，并与国内外毒株进行同源性比较和系统发育分析，结果显示17株均为Asia-1型。北京地区2008年流行的毒株主要是Asia-1型。 本试验研究了CPV VP2 297位点(Ser变为Ala)的变异情况。根据VP2位点297的改变引起限制性内切酶AluI酶切位点的变化，建立PCR依赖性限制性片段长度多态性分析(PCR-RFLP)方法，检测VP2 297位点的变异。通过基因进化树的分析表明，国内外的CPV起源于共同的祖先。同时根据GenBank中CPV-d株(M23255) VP2的基因序列和CPV-2、CPV-2a与CPV-2b的氨基酸位点差异，建立区分CPV-2、CPV-2a与CPV-2b的等位基因特异PCR，应用型特异性PCR将CPV-2与CPV-2a及CPV-2b区分开来，应用检测点突变的等位基因特异PCR，将CPV-2a与CPV-2b区分开来。在随机抽取的40个CPV阳性样品中，CPV-2、CPV-2a、CPV-2b分别占抽取样品总数的5%、77.5%和17.5%。目前CPV-2a与CPV-2b共同存在于犬群中。 本试验采用Pratelli等建立的套式PCR方法，对采集自北京地区的犬粪便样品进行CCV检测和基因型分析，以调查CCV的流行情况及病毒的基因型。自2007年12月至2008年5月的6个月内收集的86份犬冠状病毒(CCV)阳性粪便样品中，随机抽取28份采自不同地点不同时期的样品，用可鉴定基因型的套式PCR方法检测，结果显示，28份随机样品中有25份检出II型CCV，3份样品检出I型CCV。说明北京地区犬冠状病毒流行的基因型以CCV II型为主。

A total of 404 dogs have been investigated in order to survey the prevalence of canine infectious diseases in Beijing in the period of December, 2007 ~ May, 2008. Among these dogs, 41 were suffered from canine distemper, 115 suffered from canine parvovirus infection and 86 suffered from canine coronavirus infection, with high incidence of canine parvovirus infection. This survey suggested that there was a certain relationship between incidence of diseases and the incidence of regular immunization, dogs with regular immunization have lower incidence of diseases because of immune enhancement, while dogs without immunization have higher incidence, are therefore susceptible to canine distemper and other diseases. A pair of primers were designed according to the published sequence of canine distemper virus(CDV) reference virus strain onderstepoort, and total RNA of faeces from dogs affected with canine diseases virus as templates, seventeen 1877 bp long H genes of CDV were amplified through RT-PCR, then cloned into pGEM-T easy vector, positive clones were identified by digestion, and positive plasmids were sequenced, meanwhile, all these seventeen virus are belong to the type of Asia-1 when comparing homology and phylogenetic analysis with strains at home and abroad. The mainly type strains in Beijing 2008 was mainly the type of Asia-1. The evolution and variation of canine parvovirus (CPV) isolated in Beijing were examined. Mutation at residue 297 in the VP2 sequence of the CPV was examined by the PCR-based restriction fragment length polymorphism. CPV origined from a common ancestor, when comparing homology and phylogenetic analysis with strains at home and abroad. Pairs of primers were designed according to the published sequence of canine parvovirus CPV-d, which could differentiate CPV-2, CPV-2a and CPV-2b. Type-special PCR was used to differentiate CPV-2 from CPV-2a and CPV-2b, and allele-specific PCR amplification was used to differentiate CPV-2a from CPV-2b. A total of 40 CPV samples from 115 dogs collected form Beijng were typed by type-special PCR or allele-specific PCR. The results of the PCR typing of CPV showed CPV-2a and CPV-2b were both present in Beijng. A nested-PCR typing assay was used to test the presence and genotype analysis of canine coronvairus(CCV) from the dogs in Beijing. 28 random samples from 86 canine coronavirus fecal samples during December 2007 and May 2008 within 6 months were tested for genotyping, and the results showed that 25 out of total 28 tested samples were CCV type II, and 3 were CCV type I. It showed that the mainly type strains in Beijing was CCV type II.