Sub-subgenotype 2.1c isolates of classical swine fever virus are dominant in Guangdong province of China, 2018

Xing, Chaonan; Lu, Zexi; Jiang, Jianfeng; Huang, Li; Xu, Jialun; He, Desheng; Wei, Zelin; Huang, Haijie; Zhang, Hongren; Murong, Cangyao; Tu, Changchun; Gong, Wenjie

doi:10.1016/j.meegid.2018.12.029

Cited by 28 publications

(25 citation statements)

References 14 publications

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“…On the one hand, since the molecular mechanisms driving the evolution, antigenic diversity, virulence and pathogenesis of CSFV are still poorly understood (Rios et al, ; Wang et al, ), the implementation of control programs to prevent outbreaks of new emergent strains is far from being achieved. On the other hand, if it is considered that the vaccination programs for the control of CSF are mainly based on live modified vaccines or lapinized vaccines developed during the mid‐1950s, together with the issue that the parameter to consider full protection against CSFV in most countries, is based on the capacity of these vaccines to induce certain titres of neutralizing antibodies (Xing et al, ), then, in‐depth researches are urgently needed to explain the mechanisms by which CSFV evades the cell‐mediated immune response, which compromise the efficacy of these vaccines. Furthermore, the reinspection of the parameters to evaluate the vaccines in use (protective doses, efficacy against different emerged strains induced by the action of positive selection pressure and interaction with immunosuppressant viral agents such as PRRS and PCV2) is also imperative investigations to conduct.…”

Section: Discussionmentioning

confidence: 99%

Positive selection pressure on E2 protein of classical swine fever virus drives variations in virulence, pathogenesis and antigenicity: Implication for epidemiological surveillance in endemic areas

Coronado

Rios

Frı́as

et al. 2019

Transbound Emerg Dis

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Classical swine fever (CSF), caused by CSF virus (CSFV), is considered one of the most important infectious diseases with devasting consequences for the pig industry. Recent reports describe the emergence of new CSFV strains resulting from the action of positive selection pressure, due mainly to the bottleneck effect generated by ineffective vaccination. Even though a decrease in the genetic diversity of the positively selected CSFV strains has been observed by several research groups, there is little information about the effect of this selective force on the virulence degree, antigenicity and pathogenicity of this type of strains. Hence, the aim of the current study was to determine the effect of the positive selection pressure on these three parameters of CSFV strains, emerged as result of the bottleneck effects induced by improper vaccination in a CSF‐endemic area. Moreover, the effect of the positively selected strains on the epidemiological surveillance system was assessed. By the combination of in vitro, in vivo and immunoinformatic approaches, we revealed that the action of the positive selection pressure induces a decrease in virulence and alteration in pathogenicity and antigenicity. However, we also noted that the evolutionary process of CSFV, especially in segregated microenvironments, could contribute to the gain‐fitness event, restoring the highly virulent pattern of the circulating strains. Besides, we denoted that the presence of low virulent strains selected by bottleneck effect after inefficient vaccination can lead to a relevant challenge for the epidemiological surveillance of CSF, contributing to under‐reports of the disease, favouring the perpetuation of the virus in the field. In this study, B‐cell and CTL epitopes on the E2 3D‐structure model were also identified. Thus, the current study provides novel and significant insights into variation in virulence, pathogenesis and antigenicity experienced by CSFV strains after the positive selection pressure effect.

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Section: Discussionmentioning

confidence: 99%

Positive selection pressure on E2 protein of classical swine fever virus drives variations in virulence, pathogenesis and antigenicity: Implication for epidemiological surveillance in endemic areas

Coronado

Rios

Frı́as

et al. 2019

Transbound Emerg Dis

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“…The E2 protein is the main structural protein of CSFV and is highly variable among isolates; it induces the neutralizing antibodies and shows a relationship with virulence [ 4 , 5 ]. On the basis of the E2 gene, CSFV isolates can be divided into three genotypes (1, 2 and 3) and are further subdivided into 11 subgenotypes (1.1–1.4, 2.1–2.3 and 3.1–3.4) [ 6 ]. CSFV outbreaks caused by genotype 2 have been increasing in Europe and Asia [ 2 , 3 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…Given this situation, the genetic evolution of CSFV has been analyzed in detail and subgenotype 2.1 isolates have been further classified into 10 clades (2.1a–2.1j). Phylogenetic analysis indicates that CSFV in pigs in China includes subgenotypes 1.1, 2.1, 2.2 and 2.3b [ 6 , 9 ]. Since 2000, subgenotype 2.1 has become dominant in China.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the Pathogenicity of Classical Swine Fever Virus Subgenotype 2.1c and 2.1d Strains from China

et al. 2020

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Classical swine fever (CSF) caused by classical swine fever virus (CSFV) is a highly contagious and devastating disease. The traditional live attenuated C-strain vaccine is widely used to control disease outbreaks in China. Since 2000, subgenotype 2.1 has become dominant in China. Here, we isolated subgenotype 2.1c and 2.1d strains from CSF-suspected pigs. The genetic variations and pathogenesis of subgenotype 2.1c and 2.1d strains were investigated experimentally. We aimed to evaluate and compare the replication characteristics and clinical signs of subgenotype 2.1c and 2.1d strains with those of the typical highly virulent CSFV SM strain. In PK-15 cells, the three CSFV isolates exhibited similar replication levels but significantly lower replication levels compared with the CSFV SM strain. The experimental animal infection model showed that the pathogenicity of subgenotype 2.1c and 2.1d strains was less than that of the CSFV SM strain. According to the clinical scoring system, subgenotype 2.1c (GDGZ-2019) and 2.1d (HBXY-2019 and GXGG-2019) strains were moderately virulent. This study showed that the pathogenicity of CSFV field strains will aid in the understanding of CSFV biological characteristics and the related epidemiology.

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“…In this study, two pig kidney tissue samples suspected of classical swine fever (CSF) viral infection, which were collected on 14 June and 16 November 2018 from swine herds located in neighbouring villages of Leping town, Sanshui district, Foshan city, Guangdong province, China, were sent to our laboratory in Changchun for further testing. In herd A, 80 fattening pigs had been introduced from Guangzhou city and most had developed CSF clinical signs and pathogenic lesions, with 65 subsequent deaths (Xing et al., 2019). Herd B infected weaned pigs had also displayed CSF clinical signs and pathogenic alterations, but morbidity and mortality figures are unavailable.…”

Section: Figurementioning

confidence: 99%

Isolation and characterization of Getah virus from pigs in Guangdong province of China

Xing

Jiang

et al. 2020

Transbound Emerg Dis

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Getah virus (GETV) is a mosquito‐borne virus that is widely distributed in Asian countries including China, in which the first case of equine GETV infection was reported in Guangdong province in August 2018. In this study, GETVs were detected in two classical swine fever virus‐positive samples collected from swine herds in Foshan city, Guangdong province, 2018. Infection of porcine PK‐15 cells produced rapid cytopathic effects (CPEs), including shrinking, rounding and detaching, and peak titre of 109.3 TCID50/ml occurred at 24 hr post‐infection. Electron microscopy and ultra‐thin sectioning revealed spherical GETV particles of 70 nm diameter with an isometric interior and are found to be lining the outer membrane of infected cells. Whole‐genome analysis showed that the two GETV isolates are identical to each other and cluster with Group III strains of GETV, sharing 96.1%–99.7% nucleotide sequence identity with all available reference strains. The most closely relative of the obtained GETV isolates was porcine strain HNJZ‐S2 from Henan province (99.7%), with 98.6% sequence identity shared with equine GETV strain GZ201808 first identified in Guangdong province, indicating different sources for porcine and equine GETV infections in this region. No evidence of GETV infection was found in 497 archived porcine samples collected between 1990 and 2018 in Guangdong province.

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Sub-subgenotype 2.1c isolates of classical swine fever virus are dominant in Guangdong province of China, 2018

Cited by 28 publications

References 14 publications

Positive selection pressure on E2 protein of classical swine fever virus drives variations in virulence, pathogenesis and antigenicity: Implication for epidemiological surveillance in endemic areas

Positive selection pressure on E2 protein of classical swine fever virus drives variations in virulence, pathogenesis and antigenicity: Implication for epidemiological surveillance in endemic areas

Comparison of the Pathogenicity of Classical Swine Fever Virus Subgenotype 2.1c and 2.1d Strains from China

Isolation and characterization of Getah virus from pigs in Guangdong province of China

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