Detection To The Infection Of Porcine Circovirus Type 2 By PCR And Analysis Its Homology In Gansu

Porcine Circovirus type 2 virus (Porcine circovirus type 2, PCV2) is one of serious infectious diseases in pig farming industry today.The disease, which spread widely popular, has raised serious threat and significant economic impact on the swine industry world wide. PCV2 is often mixed with other disease infection, lead to the incidence rate on the rise in modernization of the scale pig farms. Therefore, in order to effectively control the epidemic and reduce the resulting economic losses, , This study local PCV2 epidemic strain of materials for research materials, and take gene cloning, molecular structure of analysis, molecular diagnostic and epidemiological investigation, the main research results are as follows:1,To construct a specific PCR detecting method, we designed a pair of primers to ampliy a partial fragment of ORF2 gene from PCV2, referring to complete genome published in Genbank. The PCR product was 758bp in size detected by gelose gel electrophoresis. PCV2 in tissues or serum from 114 diseased or dead pigs collected from 9 large-scale pig farms in Gansu different area was detected by PCR. It showed that the positive rate was 73.3%. So it proved that there was PCV2 infection in Gansu.2,The symptom of pigs infected PCV2 were mainly unthrifty, diarrhoea and abortion. The gross lesions in pigs with PCV2 infection showed wasting depression, gastric ulcerations and icterus. The abnormalities in the lungs and enlargement of all of the inguinal, mesenteric, bronchial and mediastinal lymph nodes were consistent findings. The lung was hemorrhagic, and was dropsy with granulomatous interstitial pneumonia. Histologically the lymphocytes in many organs were decreased, the lymphocytes of germinal center were disappeared, and basophilic inclusion bodies were found in macrophage.3,Comparison of complete genome sequence between GS0601strain and GS0602strain of ORF2 of the clone study in DNAstar software was carried out,the result showed that there was 91.5﹪only,a great different sequence. And the GS0601strain shared higher homology with the isolates from the most of the China, which is more than 98 percent, and shared a high different sequence with the European and North American, which is from 90% to 93%;On the contrary, the GS0602strain shared lower homology with the isolates from the most of the China, which is from 90% to 92%.4,In order to have a further study of the genetic feature and relationship of PVC2,we have drawn the systematic evolution tree of 29 viruses following the sequence feature of ORF2.It can be concluded that the PCV2 could be defined as two major group ,One of the group includes the GS0601 and 13 isolates of China,four of Netherlands together with the France .however, the other group contains the GS0602 and the isolates from China and other countries, To recap, there's some difference between the prevailing PVC2 in ZhangYe and Baiyin of GanSu province.