A Serological Investigation And Indentification And Isolation Of Porcine Reproductive And Respiratory Syndrome Virus In South Henan

Porcine reproductive and respiratory syndrome(PRRS)is a viral disease primarily causing respiratory problems in piglets and growers,but also causing respiratory failure in susceptible sows.Since 1990,PRRS has nearly transmitted to many parts of the world.Currently it is the most economically important infectious disease faced by swine industry of many countries.433 out of 653 sera abstracted from PRRS vaccine farms in South Henan and the positive rate was 66.3%.749 out of 1059 sera abstracted from PRRS not immune farms in South Henan and the positive rate was 70.7%.The survey results showed that not immune farms in the wild exist PRRS infection drug and Yunan throughout the uneven distribution of PRRSV infection and the number of farms over small areas relatively high positive rate and different age groups varying degrees of swine infection.Two PRRSV isolates named by HNXY-1/07 and HNXY-2/07 which were obtained from South Henan differet pig farms.A RT-PCR method was used to amplify the complete ORF5 gene of these virus.Identity and variation analysis of ORF5 gene and the deduced amino acid of these isolates with the other nine published Identity and variation analysis of ORF5 gene and the deduced amino acid of these isolates with the other nine published PRRSV.Isolates from different source showed that percent identity of the ORF5 gene and amino acid of these South Henan isolates share more than 94%identity to each other.Between these South Henan isolates and the other America isolates,the identity ranged from 85%to 98%respectively,but the South Henan isolates and LV have just 57%to 62.9%identity.Further comparision of the deduced amino acid sequence of ORF5 gene of Henan isolates with other America isolates indicated that some sites of GP5 have taken into mutation.So our results showed that the PRRSV isolates from herds experiencing acute PRRS outbreak in South Henan are mutant isolates of America genotype.