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.
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C. Li, J. Zhuang, J. Wang, L. Han, Z. Sun, Y. Xiao, G. Ji, Y. Li, F. Tan, X. Li and K. Tian. Outbreak Investigation of NADC30-Like PRRSV in South-East China. Transboundary and Emerging Diseases. October 2016. Volume 63, Issue 5. Pages 465–578, e301–e452. DOI: 10.1111/tbed.12530