| Porcine circovirus (PCV) is the smallest animal virus that people find animal virus so far. PCV was compartmentalized PCV1and PCV2 genotype. Genotype PCV2 have pathogenicity and it can cause Post weaning multi systemic wasting syndrome(PMWS), Sow Abortion and Mortality Syndrome (SAMs), Porcineresp iratory disease syndrome,PRDS), Congential trem or type A2(CT), interstitial pneumonitis(IP) and porcine proliferative and necrotizing pneumonia( PNP) et al. Porcine circovirus disease was prevalent broadly in many countries and areas all over the world which cause tremendous economic losses and affect development of world pig industry badly.More than twenty provinces reported to find PCV2 infecting disease in China and this epidemic disease takes on pervasive trend . At present , people do not know this disease's immune and pathogenetic mechanism and there is not vaccine to defend PCV2 disease and effective prophylactico-therapeutic measures to be established. In shaanxi province, there are less reports about PCV2 infection. Therefore we established special PCR methods and used this PCR method to check suspected pathologic organization. We hope to find out PCV-2 infective cases. On the other hand, we cloned PCV2 ORF1 gene and analysed their sequences. We hope to provide scientific datums in order to contral PCV2 infection. The paper's main content and result as fellow:1. In order to find out PCV2 epidemiology and degree of damage in Shaanxi province, we designed 2 pairs special primers according to PCV2 gene sequence in GenBank and established special PCR methods to check PCV2. This will provide theoretical base and technical base for pig husbandry of shaanxi province.2. We used this special PCR method to check 211 portions pathologic organization which come from different area of Shaanxi province. There are 108 portions positive pathologic tissue and the positive rate is 51.18%. This appeared obvious upwardly mobile compared with 32. 9% reported by scholar Zengqi-Yang in 2006 year. We should have a high regard to this disease.3. Using specific PCR method, we acquired 6 main PCV2 strains ORF1 gene sequences. The 6 main PCV2 strains ORF1 gene sequences were compared with other 10 PCV2 strains, we find these virus share 95.3%~100% nucleotide homology and 93.9%~100% amino acid homology. We find CPV2 ORF1 nucleotide and amino acid share higher homology and conservative trait. From nucleotide sequence cladogram, we can conclude these 6 main PCV2 strains have very near sibship and maybe they come from the same ancestor. |
