PCV‐2 genotype definition and nomenclature

Segalés, Joaquím; Olvera, Àlex; Grau‐Roma, Llorenç; Charreyre, Catherine; Nauwynck, Hans; Larsen, Lars Erik; Dupont, Kitt; McCullough, Kenneth C.; Ellis, John; Krakowka, Steven; Mankertz, Annette; Fredholm, Merete; Fossum, Caroline; Timmusk, Salme; Stockhofe-Zurwieden, Norbert; Beattie, V.; Armstrong, David M.; Grassland, B.; Bækbo, Poul; Allan, Gordon

doi:10.1136/vr.162.26.867

Cited by 235 publications

(157 citation statements)

References 11 publications

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“…The genotypes of the ORF2 nucleotide sequences of the 37 isolates were designated according the genotype definition and nomenclature proposed by the EU consortium on PCVAD [9,31]. All of the PCV2 isolates were clearly separated into two genotypes with high bootstrap values.…”

Section: Resultsmentioning

confidence: 99%

“…The signature motif (amino acid positions 86-89) of ORF2 can be used to distinguish PCV2a and 2b, which contain the TNKI and SNPR (L) motifs, respectively [6]. The PCV2c genotype has only been found in Denmark to date [31]. In recent years, several reports have suggested that PCV2b is the predominant genotype in many countries worldwide, including Brazil [8,11], Canada [14,15], China [17,21,38], Cuba [29], Denmark [12], Germany [30], Japan [32], Korea [1,2,19,20], Slovakia [37], Spain [10], Sweden [33], Switzerland [39], Thailand [18] and the U.S.A. [6,23].…”

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confidence: 99%

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Genotypic Change and Phylogenetic Analysis of Porcine Circovirus Type 2 in Taiwanese Pig Herds

et al. 2012

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ABSTRACT. Porcine circovirus type 2 (PCV2) is the primary causative agent of postweaning multisystemic wasting syndrome. Two major PCV2 genotypes, PCV2a and PCV2b, have been identified. To explore the prevalence of different subgroups of PCV2 in Taiwan Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated diseases (PCVADs) in pigs and causes significant economic losses in most pig-producing countries [27]. PCVADs can be subclinical or can include 1 or more clinical manifestations such as multisystemic disease with weight loss, respiratory signs, enteric signs, porcine dermatitis and nephropathy syndrome, and reproductive problems individually or in combination in pigs raised on farms or in other groups of pigs [27]. PCVADs are multifactorial syndromes, and factors that are currently thought to influence the outcome of PCV2 infection include the viral strain, the host, coinfections, and immune modulation [27].PCV2 is a small, non-enveloped, circular, single-stranded DNA virus containing a circular genome of 1766-1768 nucleotides [17,34]. PCV2 is a member of the genus Circovirus of the family Circoviridae [27]. Another member of this genus includes PCV1, which does not produce disease in pigs [35]. The PCV2 genome contains three open reading frames (ORFs). ORF1 encodes two replicase proteins, Rep and Rep' [4]. The viral capsid protein is encoded by ORF2 [25], which is involved in the host immune response [24]. The third ORF, ORF3, is in a different reading frame embedded within ORF1 and encodes a protein associated with apoptosis [22].PCV2 viruses are further classified into three genotypes (2a, 2b, and 2c) that differ with respect to the ORF2 sequence [9,26]. The signature motif (amino acid positions 86-89) of ORF2 can be used to distinguish PCV2a and 2b, which contain the TNKI and SNPR (L) motifs, respectively [6]. The PCV2c genotype has only been found in Denmark to date [31]. In recent years, several reports have suggested that PCV2b is the predominant genotype in many countries worldwide, including Brazil [8,11], Canada [14,15] [16,32]. In Taiwan, the first PCV2 outbreak was confirmed in 2001 [3], and a high prevalence of PCV2 infection was noted thereafter. Up to 92% of pig herds and 68.8% of weaned pigs were infected by PCV2 in Taiwan [7]; however, the genotype prevalence of PCV2 in Taiwan is not currently known. The aim of the present study was to investigate the prevalence of the PCV2 genotype in Taiwan in the last decade. MATERIALS AND METHODS Specimen collection and histopathological examination:Clinical samples (lungs, lymph nodes, spleen, brain and serum) were collected from 785 pigs from 186 herds in central and southern Taiwan during 2002-2011. These samples were mainly acquired from weaning and growing pigs with

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Genotypic Change and Phylogenetic Analysis of Porcine Circovirus Type 2 in Taiwanese Pig Herds

et al. 2012

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“…Its high evolutionary rate, the highest recorded for a single‐stranded DNA virus until now, could allow an evolutionary dynamics similar to that of single‐stranded RNA viruses 13. The genotype identification of PCV2 was first proposed by the European project in 2008 based on p ‐distance of neighbor joining (NJ) trees 14. However, it was questioned by Franzo et al and others12, 15, 16 when more sequences became available.…”

Section: Introductionmentioning

confidence: 99%

Origin, Genetic Diversity, and Evolutionary Dynamics of Novel Porcine Circovirus 3

et al. 2018

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Porcine circovirus 3 (PCV3) is a novel virus associated with acute PDNS (porcine dermatitis and nephropathy syndrome)‐like clinical signs identified by metagenomic sequencing from swine. Its high occurrence may pose a potential threat to the swine industry worldwide. The processes resulting in the emergence and spread of PCV3 remain poorly understood. Herein, the possible origin, genotypes, and evolutionary dynamics of PCV3 based on available genomic sequences are determined. The closest ancestor of PCV3 is found to be within the clade 1 bat CVs. Using different phylogenetic methods, two major genotypes are identified, PCV3a and PCV3b. It is found that the effective population size of PCV3 increased rapidly during late 2013 to early 2014 and this is associated with the diversification of PCV3a and PCV3b. A relatively high effective reproductive number (Re) value and higher evolutionary rate were found compared to other single‐stranded DNA viruses, and positive selection on codons 122 and 320 (24 of ORF2) is identified. It is hypothesized that this, together with the prediction of a potential change of an antigenic epitope at position 320, might have allowed PCV3 to escape from the host immune response. Overall, this study has important implications for understanding the ongoing PCV3 cases worldwide and will guide future efforts to develop effective preventive and control measures.

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“…Genotyping of PCV2 is performed employing the nucleotide sequence of ORF2 [20]. PCV2 isolates can be classified into two major types: PCV2a and PCV2b [28]. PCV2 isolates belonging to PCV2a and PCV2b group were originally detected in North America and Europe, respectively.…”

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confidence: 99%

Differential Effects of Porcine Circovirus Type 2 (PCV2) Vaccination on PCV2 Genotypes at Japanese Pig Farms

Takahagi

Toki

Nishiyama

et al. 2010

The Journal of Veterinary Medical Science

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ABSTRACT. Infection of pigs with porcine circovirus type 2 (PCV2) causes a variety of disorders collectively referred to as porcine circovirus associated diseases (PCVADs). PCV2 isolates can be classified into two major types: PCV2a and PCV2b. In the present study, effects of vaccination on antibody titers in sera, PCV2 viremia, and shedding of PCV2 in feces were studied on Japanese commercial pig farms where vaccination of piglets against PCV2 was performed using commercially available vaccines. The effectiveness of vaccination against various PCV2 genotypes was also assessed. Among the 16 farms studied, 10 and 6 had been infected with PCV2a and PCV2b, respectively. PCV2a was further subdivided into PCV2a-1 and PCV2a-2. PCV2a-1 and PCV2a-2 prevailed on 6 and 4 farms, respectively, among the 10 farms infected with PCV2a. The PCV2 vaccines were effective in reducing PCV2 infection on commercial pig farms. Mean mortality rates were significantly decreased over 8 months after the start of the PCV2 vaccination program as compared to those before the start of the PCV2 vaccination program on farms infected with PCV2a-2 (20.8% vs. 12.1%) and PCV2b (26.5% vs. 13.7%). On the farms with PCV2a-1 infected pigs, there was no significant difference in the mean mortality rate before versus after the start of the vaccination program (14.7% vs. 14.1%). Mortality rate reduction with the PCV2 vaccination might depend on the genetic types of PCV2.KEY WORDS: genotype, mortality rate, porcine circovirus associated disease (PCVAD), porcine circovirus type 2 (PCV2), vaccine.

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PCV‐2 genotype definition and nomenclature

Cited by 235 publications

References 11 publications

Genotypic Change and Phylogenetic Analysis of Porcine Circovirus Type 2 in Taiwanese Pig Herds

Genotypic Change and Phylogenetic Analysis of Porcine Circovirus Type 2 in Taiwanese Pig Herds

Origin, Genetic Diversity, and Evolutionary Dynamics of Novel Porcine Circovirus 3

Differential Effects of Porcine Circovirus Type 2 (PCV2) Vaccination on PCV2 Genotypes at Japanese Pig Farms

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