Isolation And Identification Of Porcine Reproductive And Respiratory Virus And Studies On The Immuno-technique Of PRRS In Shandong

Porcine reproductive and respiratory syndrome (PRRS), caused by porcine reproductive and respiratory syndrome virus (PRRSV), is a serious infectious disease of swine. It is characterized by severe reproductive failure in sows, and respiratory distress in piglets and growing pigs. Since it was first reported in the United States in 1987, PRRS has already been one of the most economically important diseases of the global swine industry.In recent years, many scholars in China conducted an extensive epidemiological investigation and viruses isolation. One strain of virus isolated from pig farm in Tai-an,and the experiment made use of PRRSV by different doses of inactivated vaccine, different immune routes and immune processes to immune pigs and detected of large-scale pig farms of antibody response after immunization, in order to provide theoretical basis for clinical vaccine application, disease prevention and treatment. This study included three parts.Part I: Isolation and identification of PRRSV strain One strain of virus isolated from serum of piglets which died of high fever on a farm in Taian can increase and conduce CPE on Marc-145 cell. It was identified as a strain of an PRRSV by RT-PCR and IFA. The negative piglings inoculated this strain showed obvious clinical symptom and death.Part II: Studies on the Immuno-technique of Porcine Reproductive and Respiratory Syndrome in Shandong province. Vaccines from different manufacturers immuned piglet, and then immune side effects were relatively small, no allergic symptoms. After vaccination with B, the highest of PRRS seropositive rate was 75%, which immunization was best.Vaccine B was immnued same-day-old piglets, One portion, two portions, four were treated, antibody positive rate was not significantly different, which of two copies is highest and the immunization results were best.Different immune-day-old pigs, different antibody positive rate was detected. Production of sows PRRSV antibody positive rate is higher than piglets, back-up sows was higher than that of production sows. Also 3 ~ 4-week-old pigs, PRRSV antibody positive rate was in the lowest (67.2%), but which increased gradually with age.Using different immunization channels, pigs were detected after 21 days and the antibody positive rate was not significantly different, and the houhai acupoint injection is the best .Using different immunization procedures, antibody were detect dafter 21 days. Ahead of immunization, antibody positive rate was 40%, less effective immune; pigs a year 2-3 times immunization, the first immunization to 20-day-old piglets, two in 60-day-old, the immune effect of better antibody positive rate was 75%; kinds of sows with the child immunization (immunization after 20-30 days delivery), the first immunization to 20-day-old piglets, two in 60-day-old antibody-positive rate is highest, up to 80%, which was the best .Partâ…¢: Investigation on serology of Porcine Reproductive and Respiratory Syndrome in Shandong province.PRRSV specific antibodies were detected by the immune pig serum samples from Shandong Province, the results indicated that a higher level of PRRSV antibodies (56.4% ~ 87.9%)were detected after immuned inactivated vaccine in pig farms and inactivated vaccine against PRRSV infection have stronger immune protection.