Abstract: The weaned piglets from a farm in Hangzhou had high fever, expiratory dyspnea and other symptoms, who were suspected infection of porcine reproductive and respiratory syndrome virus (PRRSV). The samples of pathological lung from three infected pigs were sent to laboratory testing. The nucleic acids of pathogen were detected by real-time PCR. The lung homogenate was sterilized and inoculated into MARC-145 cells, and the virus replication was confirmed by cytopathic effect observation (CPE), Western-blot and indirect immunofluorescence (IFA). The full-length sequence of the viral genome was obtained by segmental RT-PCR and biological sequencing. The nucleotide sequences of the strain were analyzed by MEGA and other softwares. The molecular epidemiology of GP5 and NSP2 amino acid sequences of this virus were obtained. The piglets of three days were infected with PRRSV to evaluate the virulence. The results showed that the virus was successfully isolated and named as 17-ZJ-HZ. The whole genome sequences of PRRSV was obtained, and the length of its sequence was 15 325 bp. The results of sequence analysis showed that, the NSP2 of this virus had deletions of typical 29+1 amino acids compared with the classical strain. The results of phylogenetic analysis indicated that 17-ZJ-HZ was attributed to subgroup of HP-PRRSV, and the PRRSV(17-ZJ-HZ) caused typical clinic symptoms and lesions after infected piglets 60 h. In brief, the strain was North American strain of highly pathogenic PRRSV.

Key words: porcine reproductive and respiratory syndrome virus, isolation and identification, sequence analysis, molecular epidemiological analysis