Genome comparison of a novel classical swine fever virus isolated in China in 2004 with other CSFV strains

Li, Xiangmin; Zhao, Xu; He, Yueping; Yao, Qinxia; Zhang, Keshan; Jin, Meilin; Chen, Huanchun; Qian, Ping

doi:10.1007/s11262-005-0048-2

Cited by 28 publications

(26 citation statements)

References 27 publications

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“…Two CSFV isolates (CSFV-PY-2009 and CSFV-NH-2009) collected from Hainan were closely related to the SWH and cF114 Chinese strains, while only one strain (CSFV-JY-2010) A previous study showed that seven Chinese CSFV isolates from six provinces, including Guangxi, Guizhou, Shanxi, Jilin, Qinghai, and Xizang, were grouped together with the Shimen reference strain in subgroup 1.1 [25]. Li et al [26] indicated that the SWH isolate was closely related to the highly virulent isolate, cF114, and deduced that it belonged to the highly virulent isolate group. In our study, the 13 CSFV isolates cluster together with Shimen, SWH, and cF114, only one CSFV isolate was placed closely to Alfort 187, while they were distant from the vaccine strain (hog cholera lapinized virus) HCLV.…”

Section: Resultsmentioning

confidence: 98%

Genetic diversity and positive selection analysis of classical swine fever virus isolates in south China

et al. 2011

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Classical swine fever virus (CSFV) causes a highly contagious disease that leads to significant economic losses in the pig industry worldwide. However, there is a paucity of knowledge on the accurate genotyping of CSFV isolates in south China. This study genotyped the E2 gene of 14 CSFV strains isolated during 2008-2010 from domestic pigs in different districts of south China. Phylogenetic analyses revealed that all of the 14 CSFV isolates were clustered into genetic subgroup 1.1. This contrasts with most parts of China, where group 2 isolates are predominant. Furthermore, the positive selection pressures acting on the E(rns) and E2 envelope protein genes of CSFV were assessed and a site-by-site analysis of the dN/dS ratio was performed to identify specific codons that undergo diversification under positive selection. While no significant evidence for positive selection was observed in E(rns), two positively selected sites at amino acid residues 49 and 72 in the E2 encoding region were identified. Our results revealed that a predominance of subgroup 1.1 CSFV isolates is currently circulating in some districts of south China, which appear to be unrelated to the Chinese C-strain vaccine. Moreover, the envelope protein gene, E2, has undergone positive selection in 14 CSFV strains and two positively selected sites have been identified in this study. Understanding the molecular epidemiology and functional importance of these positively selected amino acid positions could help to predict possible changes in virulence, the development of vaccines and disease control.

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Section: Resultsmentioning

confidence: 98%

Genetic diversity and positive selection analysis of classical swine fever virus isolates in south China

et al. 2011

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“…The disease has been eradicated in several countries or under control in other countries. Sporadical outbreaks were reported in the Americas and Asia as well as some European countries during the past few years [3,4,[10][11][12][13][16][17][18][19]. To control the disease in endemic areas, live attenuated C-strain vaccine has been proven to be efficacious and safe [20,21].…”

Section: Discussionmentioning

confidence: 99%

Genetic characterization of E2 gene of classical swine fever virus by restriction fragment length polymorphism and phylogenetic analysis

Chen

Yuan

et al. 2010

Virus Genes

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An RT-nested PCR (RT-nPCR)-based restriction fragment length polymorphism (RFLP) analyses of the E2 gene were developed for genetic subtyping and differentiation of vaccinated and infected classical swine fever virus (CSFV) strains. RT-nPCR identified 96 CSFV-positive samples from 321 clinical specimens from southeastern China during 2003-2008. The PCR products of positive samples were further differentiated using MspI digestion, 23 were identified as the C-strain, 62 as field strains, and 11 as mixture of the vaccine strain and field ones. RFLP with BglI, DdeI, DraI, and PstI were then used for subtyping of the field CSFV isolates. Thirty-eight field isolates phylogenetically classified as subgroup 2.1 based on E2 were divided into 11 subtypes by this RFLP scheme. Both RFLP profiling and sequence-based phylogenetic analysis revealed genetic diversity of CSFV in the field. Three novel substitutions at amino acid positions 17, 93, and 286 were identified in the predominant subtype VI strains isolated in 2008 as compared to other strains including historical subtype VI strains. These results suggest that CSFV in China experienced gradual variations and evolutionary accumulation progress. Thus, the RFLP methods targeting on the CSFV E2 gene are suitable for epidemiological survey in endemic area where the C-strain is applied for vaccination. Combination of the RFLP schemes with sequence-based phylogenetic analysis could provide more detailed information on transmission of CSFV in the region or even its evolution.

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“…Phylogenetic analyses performed in different parts of the world confirmed that CSF virus isolates that differ by genetic typing seem to be characteristic for certain geographic regions (Bartak and Greiser-Wilke, 2000;Blacksell et al, 2005;Chen et al, 2008;Arce et al, 2005;Kamakawa et al, 2006;Li et al, 2006;Pereda et al, 2005;Sabogal et al, 2006;Stadejek et al, 1997;Vilcek et al, 1997).…”

Section: -140mentioning

confidence: 95%

Control and eradication of Classic Swine Fever in wild boar

2009

EFSA Journal

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SummaryClassical swine fever (CSF) is a disease that has been causing major socio-economic damages in the EU during the last decades. Although considerable progress has been made in the eradication and prevention of the disease, the threat for an epidemic still exists.The virus is endemic in the wild boar population of several member states (MS). Wild boar cannot be managed as domestic pigs. Hunting and vaccination have been tentatively used in order to stop transmission by reducing the number of susceptibles. Oral vaccination of wild boar with modified live vaccine based on the C-strain (the only suitable) is used; this vaccine does not allow serological differentiation between vaccinated and infected animals.The aim of the control measures for CSF in wild boar is to reduce the risk of transmission to domestic pigs, to prevent an "endemic phase evolution" or to reduce the endemic phase duration.In order to support and to improve the control and eradication measures as regards CSF in wild boar, EFSA was requested by the Commission to provide scientific advice on the efficacy of the available surveillance, hunting and vaccination measures to control and eradicate CSF in feral pig populations (wild boar), considering the possible use of new diagnostic tests and vaccines.In order to reply to the mandate data were collected from MS through two questionnaires (CSF vaccines, hunting practices and CSF vaccination in wild boar). Data were also extracted from the EU CSF wild boar data base, after requesting permission from the participating MS.Considering that the data received were rather limited and not comparable, the WG decided to use a model in order to fill the gaps in the available knowledge. For the evaluation of the efficacy of CSF control in wild boar a continuous metapopulation compartmental model developed in an EU research project (FP6-5015599-CSFVACCINE&WILDBOAR) was applied.Although the disease manifests in the same manner in both domestic pig and wild boar it is more difficult to identify in wild boar because clinical monitoring of these is hardly possible. Wild boar found dead constitutes the main alert sign of CSF. Hunters and gamekeepers should be instructed to report the finding of each dead wild boar to the competent authority at all times. In case of high-risk situations, a passive surveillance should be complemented by an active serological surveillance. The active sampling of wild boar is not as efficient as in domestic pigs considering that hunting is the sole practical system to obtain samples and that the aim of hunting is quite different.Consequently, the sample size is not controlled by authorities and fits rarely the aim of the survey in terms of detecting the presence of disease at a certain level. In addition, the interpretation of serological results is confounded by maternal derived antibodies (until the 6th month of age), vaccination and the sampling quality.There is no definition at EU level of spatial and temporal units for surveillance, neither for criteria defining a disease free wi...

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Genome comparison of a novel classical swine fever virus isolated in China in 2004 with other CSFV strains

Cited by 28 publications

References 27 publications

Genetic diversity and positive selection analysis of classical swine fever virus isolates in south China

Genetic diversity and positive selection analysis of classical swine fever virus isolates in south China

Genetic characterization of E2 gene of classical swine fever virus by restriction fragment length polymorphism and phylogenetic analysis

Control and eradication of Classic Swine Fever in wild boar

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