First
detection of NADC34-like PRRSV as a main epidemic strain on a large farm
in Heilongjiang Province, China
Chao Li a 1,
Bangjun Gong a 1, Qi Suna 1, Hu Xua, Jing Zhao a, Lirun
Xianga , Yan-dong Tanga, ChaoLiang
Lengb, Wansheng Lia, Zhenyang
Guoa, Jun Fua, Jinmei
Penga, Qian Wanga, Guohui Zhoua, Ying Yuc, Fandan
Menga, Tongqing An a, XueHui
Caia, Zhi-Jun
Tiana, HongLiang
Zhanga*
a State Key Laboratory of Veterinary Biotechnology,
Harbin Veterinary Research Institute, Chinese Academy of Agricultural
Sciences, Harbin 150001, China
b Henan Key Laboratory of Insect Biology in Funiu
Mountain, Henan Provincial Engineering Laboratory of Insects
Bio-reactor, China-UK-NYNU-RRes Joint Laboratory of Insect Biology,
Nanyang Normal University, Nanyang 473061, China
c Department of Preventive Veterinary Medicine,
College of Veterinary Medicine, Qingdao Agricultural University,
Qingdao, 266109, China
1 These authors contributed equally to this work.
* Corresponding author contact: Harbin Veterinary Research Institute,
CAAS, No. 678 Haping Road, Xiangfang District, Harbin 150001, China.
Tel.: +86-13624503578
E-mail address: zhanghongliang01@caas.cn
Abstract: Newly emerged sublineage 1.5 (NADC34-like) porcine
reproductive and respiratory syndrome virus (PRRSV) has posed a direct
threat to the Chinese pig industry since 2018. However, the prevalence
and impact of NADC34-like PRRSV on Chinese pig farms is unclear. In the
present study, we continuously monitored pathogens, including PRRSV,
African swine fever virus (AFSV), classical swine fever (CSFV),
pseudorabies virus (PRV) and porcine circovirus 2 (PCV2), on seven
fattening pig farms with strict biosecurity practices located in five
provinces of China from 2020 to 2021. The results showed that multiple
types of PRRSVs commonly coexisted on a single pig farm. NADC30-like
PRRSV was the predominant strain on most pig farms. Importantly,
NADC34-like PRRSV, detected during the period of peak mortality, was one
of the predominant strains on one pig farm in northern China. Sequence
alignment suggested that these strains shared the same 100-aa deletion
in the Nsp2 protein as IA/2014/NADC34 isolated from the United States
(U.S.) in 2014. Phylogenetic analysis based on open reading frame 5
(ORF5) showed that the genetic diversity of NADC34-like PRRSV on this
farm was relatively singular, but it had a relatively high rate of
evolution. Restriction fragment polymorphism pattern (RFLP) analysis
showed that almost all ORF5 RFLPs were 1-7-4, with one 1-4-4. In
addition, two complete genomes of NADC34-like PRRSVs were sequenced.
Recombination analysis and sequence alignment demonstrated that both
viruses, with 98.9% nucleotide similarity, were nonrecombinant viruses.
This study reports the prevalence and characteristics of NADC34-like
PRRSV on a large-scale breeding farm in northern China for the first
time. These results will help reveal the impact of NADC34-like PRRSV on
Chinese pig farms and provide a reference for detection and further
prevention and control of NADC34-like PRRSV.
Keywords:
NADC34-like PRRSV, main epidemic strains, 100-aa deletion, RFLP