Outbreak Investigation of NADC30-Like PRRSV in South-East China

Abstract

Epidemiological outbreak investigations were conducted on NADC30-like porcine reproductive and respiratory syndrome virus (PRRSV) to investigate the prevalence of the disease in south-east China in 2015. Two more provinces were found to have NADC30-like PRRSV circulating besides previously reported six provinces. Phylogenetic analysis showed that these virus isolates were clustered in an independent branch and shared high nucleotide similarity to NADC30, a type 2 PRRSV that has been isolated in Unite States in 2008. One NADC30-like PRRSV strain from Henan province was successfully isolated on porcine alveolar macrophages and was tested on 6-week-old specific pathogen-free pigs for pathogenic study. The virus-inoculated pigs showed typical PRRSV clinical symptoms, but all pigs survived throughout the study with a period of 14 days. At necropsy, the lungs of infected pigs developed PRRSV-specific interstitial pneumonia, and virus antigen was detected in lung samples. Therefore, our results indicated NADC30-like PRRSV has widely spread in China and could cause clinical disease on pigs.

Emergence of mosaic recombinant strains potentially associated with vaccine JXA1-R and predominant circulating strains of porcine reproductive and respiratory syndrome virus in different provinces of China

“…The genetic diversity of this HP-PRRSV has greatly increased by rapid evolution and recombination events [14, 17–19]. The current commercial PRRSV vaccines cannot provide complete protection against this disease [21]. In this study, 117 (39.93%) of 293 clinical samples were positive for PRRSV by RT-PCR, similar to that reported in 2010 (45.2%) [17].…”

“…NADC30 was isolated in the US in 2008 and in China in 2013 [19]. Associated with the importation of NADC30-like strains or recombination events between NADC30-like and domestic strains in China, a third outbreak occurred from 2013 to 2015 [19–21]. …”

“…However, evidence of the risk and inefficacy of MLVs to prevent the spread of the latest PRRSV strain has begun to accumulate [21–24]. In order to investigate the epidemiological and evolutionary characteristics of PRRSV in 2015, a total of 293 clinical samples were collected from pigs in 16 provinces in China and the full-length sequence of 28 PRRSV isolates were sequenced and analyzed.…”

Estimation of Time-Dependent Reproduction Numbers for Porcine Reproductive and Respiratory Syndrome across Different Regions and Production Systems of the US

“…Even though PRRS is endemic in North America, recurrent emergence of new PRRS virus (PRRSV) strains results in an epidemiological dynamic that resembles an epidemic condition for the disease (2, 3). PRRSV epidemics impact the swine industry and commonly require prompt mobilization of resources for diagnostics (i.e., sequencing of the virus), thorough investigations to understand the origin of the emerging PRRSVs, and implementation of effective control measures.…”

Complete Genome Sequence of a Mosaic NADC30-Like Porcine Reproductive and Respiratory Syndrome Virus in China

“…According to the genetic and antigenic characteristics, PRRSVs can be divided into two major genotypes: European type (type 1) and North American type (type 2). Recently, several provinces in northeastern and central China had reported the outbreaks of NADC30-like PRRSVs, which shared high nucleotide similarity with NADC30 isolated in the United States in 2008 (3–5). Here, we report the complete genome sequence of the NADC30-like variant PRRSV HNhx.…”