Genotypic Change of Porcine Circovirus Type 2 on Japanese Pig Farms as Revealed by Restriction Fragment Length Polymorphism Analysis

Takahagi, Yoichi; Nishiyama, Yoshiko; Toki, Shinji; Yonekita, Taro; Morimatsu, Fumiki; Murakami, Hiroshi

doi:10.1292/jvms.70.603

Cited by 17 publications

(14 citation statements)

References 15 publications

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“…We previously reported a genotypic change from PCV2a to PCV2b on Japanese commercial pig farms [29]. Those farms were included in this study as farms infected with PCV2b.…”

Section: Discussionmentioning

confidence: 99%

“…Sampling of sera was performed in same month (i. * The RFLP types were determined by the previously described method [29].…”

Section: Discussionmentioning

confidence: 99%

“…Virological studies: All samples were subjected to polymerase chain reaction (PCR) analysis for detection of PCV2 DNA, and the genotypes of PCV2 isolates were determined by nucleotide sequencing and PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of amplified PCV2 ORF2 as described previously [29]. Briefly, viral DNA was extracted from the serum and fecal swab supernatant immersed in 1 ml of phosphate buffered saline (PBS) using a commercial kit (QIAamp DNA Blood Mini Kit, Qiagen, Hilden, Germany).…”

Section: Methodsmentioning

confidence: 99%

“…GrauRoma et al also suggested that PCV2b exerted greater virulence than PCV2a [14]. In Japan, the presence of PCV2b has recently been reported, raising concerns about increased economic losses from a PCV2b infection pandemic [29].…”

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confidence: 99%

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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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“…We previously reported a genotypic change from PCV2a to PCV2b on Japanese commercial pig farms [29]. Those farms were included in this study as farms infected with PCV2b.…”

Section: Discussionmentioning

confidence: 99%

“…Sampling of sera was performed in same month (i. * The RFLP types were determined by the previously described method [29].…”

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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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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“…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.…”

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confidence: 99%

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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The prevalence and genetic diversity of porcine circovirus types 2 and 3 in Northeast China from 2015 to 2018

et al. 2019

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Genotypic Change of Porcine Circovirus Type 2 on Japanese Pig Farms as Revealed by Restriction Fragment Length Polymorphism Analysis

Cited by 17 publications

References 15 publications

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

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

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

The prevalence and genetic diversity of porcine circovirus types 2 and 3 in Northeast China from 2015 to 2018

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