Investigation On Epidemiology Of Porcine Reproductive And Respiratory Syndrome In Henan Province

The porcine reproductive and respiratory syndrome(PRRS) is one of the causative diseases which has risen humorous economic losse on swine industry. Its pathogeny is the porcine reproductive and respiratory virus(PRRSV). The disease is characterized by reproductive troubles such as abortions farrowing or weak piglets, preweaning piglets pneumonia mortality and mortality in sows. To investigate the prevalence station, its distribution, occurrence, spread approach in Henan Province, to further research its variation laws. this thesis provide an consult thereunder to effectively establish a prevention program on this disease.This study designed the outer pair of primers P1,P2, a 402bp products was obtained and the inner pair of primers P3, P 4, a 176bp was amplified to establish a nested PCR assay, were used to detect PRRSV MLV,PRV,PCV-Ⅱ,CSFV and negative control. The results showed that except for PRRSV MLV, other detect results are negative; RNA was extracted from 250μL PRRSV MLV cell virus, be diluted 10-1~10-4 , a visible objective strip can be amplified still; The same result can be gained in numeral repeated tests.This indicated that the established nested PCR assay has the virtues of stronger speciation, higher sensitivity and well stability.The epidemiological investigation was carried out by questionnaire in 189 counties in Henan Province. The investigation results showed that immunity hogpen of PRRS is 38%.The PRRS often occur in the Spring and Winter, and in July and Augest of each year. The breed type of disease swine is small scale breed hogpen and individual breed. The proportion of the disease swines of 35~70 days is 41%, 2~28 days swine is 39%, pregnancy sow is 17%. The clinical of PRRS characterized only by sow reproductive troubles is 30%; Piglets respiratory symptom is 50%; sow reproductive problems-Piglets respiratory symptom is 30%; preweaning syndrome is 40%; other clinical symptom is 10%.The samples of 163 hogpen in 20 country of Henan Province were detected, the result showed that the sample in 18 countries had the positive; the positive ratio is 12.5%~100%, the average positive ratio 34.4%. This indicated that the PRRS has been a important disease which damages to swine industry.Genome Sequence of 29 Wild Isolates from Henan, Fujian, Shandong and Zhejiang...