A Survery On The Epidemiology Of Porcine Reproductive And Respiratory Syndrome(PRRS) In Weifang

Porcine reproductive and respiratory syndrome(PRRS), caused by the Porcine reproductive and respiratory syndrome virus(PRRSV)which is characterized by severe reproductive failure in sows, and respiratory distress in piglets and growing pigs, is really a new viral diseases of swine. Since it was first reported in 1987 in the united states and in Europe in 1990,PRRS has been one of the most economically important diseases of global pig industry.The sample of 20 hogpen in 7 counties of Weifang city were detected, the results showed that all sample had positive in the counties; the positive ratio is 35%-82%, the average positive ratio 67.9%. This indicated that the PRRS has an important disease which damages to swine industry. The results of epidemiological investigation demonstrated that PRRS was prevalent in Weifang. Howerer, its positive rate is different in various regions. The positive in the regions with many and small-scale pig farms was relatively high. Additionally, the morbidity and mortality of PRRSV infection vary greatly in herds of variant stage, with the highest mortality in the 30 days-60 days. No significant difference was noted in the susceptibility to virus and positive rate in different varieties.