scholarly journals Update of Genetic Diversity of Porcine Circovirus Type 2 in Chile Evidences the Emergence of PCV2d Genotype

2021 ◽  
Vol 8 ◽  
Author(s):  
Naomi Ariyama ◽  
Belén Agüero ◽  
Valentina Valdés ◽  
Felipe Berrios ◽  
Sergio Bucarey ◽  
...  

Porcine Circovirus 2 (PCV2) can cause multiple clinical conditions known as porcine circovirus-associated diseases (PCVAD). Before the wide availability of PCV2 vaccines, PCVAD resulted in significant losses to the global swine industry. PCV2's rapid evolutionary dynamics are comparable to single-stranded RNA viruses. Thus, shifts in the dominance and distribution of different genotypes may frequently occur, resulting in the emergence and spread of varying PCV2 genotypes and recombinant strains in swine. This study aims at identifying the PCV2 genotypes currently circulating in Chile. Seven hundred thirty-eight samples were obtained from 21 swine farms between 2020 and 2021. The samples were tested using PCR for species detection and genotyping. Sequencing and phylogenetic analyses were conducted in selected samples. PCV2 was detected in 26.9% of the PCR reactions and 67% of the sampled farms. The genotypes were determined in nine farms, PCV2a in one farm, PCV2b in four, and PCV2d in five, with PCV2b and PCV2d co-circulating in one farm. The phylogenetic analysis of twelve ORF2 sequences obtained (PCV2a = 5; PCV2b = 4; PCV2d = 3) showed a PCV2a Chilean strains monophyletic cluster; closely related to Chilean viruses collected in 2012 and 2013. Of the three different PCV2b sequenced viruses, two viruses were close to the root of the PCV2b group, whereas the remaining one grouped with a South Korean virus. PCV2d sequences were closely related to Asian viruses. A previously reported PCV2a/PCV2d recombinant strain was not detected in this study. Our results suggest the emergence and potential shift to PCV2d genotype in Chilean farms.

2021 ◽  
Vol 8 ◽  
Author(s):  
Ning Li ◽  
Jing Liu ◽  
Jiali Qi ◽  
Feng Hao ◽  
Lei Xu ◽  
...  

As the major pathogen for porcine circovirus-associated disease (PCVAD), porcine circovirus type 2 (PCV2) is no longer treated as an emerging virus anymore. The wide distribution of PCV2 infection in China causes huge economic losses in the swine industry. Currently, it is generally believed that PCV2 has eight genotypes (PCV2a to PCV2h), with PCV2a, PCV2b, and PCV2d being widely distributed. To comprehensively explore the genetic diversity and prevalence of PCV2 in China, PCV-2 sequences submitted from China in the GenBank database were retrieved. With a total of 714 PCV2 strains were retrieved, we found that early-submitted PCV2 sequences were mainly collected from coastal provinces in the southeast part of China, which may indicate PCV2 was initially circulating in those regions. From 2002 to 2008, PCV2b was the dominant prevalent genotype in those retrieved sequences. From 2009, PCV2d became the dominant genotype in those sequences, dropping a hint that a potential shift of PCV2b to PCV2d might occur in 2009, which is similar to the patterns at the global level. In addition to the PCV2a, PCV2b, and PCV2d genotypes, novel strains were also characterized. We further revealed that the amino acid sequences consistency of PCV2a Cap is higher than those in other genotypes. Together, this study provided clues for the possible prevalent genotypes and dynamics of genetic diversity in China from 2000 to 2019.


2018 ◽  
Vol 62 (2) ◽  
pp. 30-34 ◽  
Author(s):  
C. O. Aiki-Raji ◽  
A. I. Adebiyi ◽  
D. O. Oluwayelu

Abstract Porcine circovirus type 2 (PCV2) is recognized as one of the most important agents of reproductive disorders in gilts and sows worldwide. It is associated with considerable economic losses in the swine industry due to the unthriftiness, and variable morbidity and mortality it causes in pigs. In spite of the devastation caused by this virus to the global pig industry, there is little or no report of its occurrence in Nigeria. Hence, a slaughterhouse based survey was conducted to determine the prevalence of PCV2 infections in pigs in Ibadan, southwest Nigeria. Using a commercial ELISA kit, 364 pig sera collected from a major abattoir were screened for IgG antibodies against PCV2. The overall prevalence of anti-PCV2 antibodies in the pigs was 1.4 % (5/364), with more female pigs (4/237, 1.7 %) being seropositive than males (1/127, 0.8 %). Since there is no routine vaccination against this swine disease in Nigeria, thus the antibodies detected in the pig sera indicated a natural exposure to the virus. The absence of clinical disease in the pigs also suggests the possibility of a carrier status for these animals and shows that they could serve as hosts for the perpetuation of the disease. These findings underscore the need for continuous surveillance for PCV2 among pigs in Nigeria in order to determine its contribution to production losses incurred in the Nigerian swine industry and aid the development of prevention and control strategies against the disease.


2007 ◽  
Vol 88 (6) ◽  
pp. 1733-1737 ◽  
Author(s):  
Ching-Man Ma ◽  
Chung-Chau Hon ◽  
Tsan-Yuk Lam ◽  
Vince Yik-Yeung Li ◽  
Creany Ka-Wai Wong ◽  
...  

Porcine circovirus type 2 (PCV2) belongs to the family Circoviridae, and is the causative agent of post-weaning multisystemic wasting syndrome (PMWS) in pigs. In this study, phylogenetic analyses of three complete PCV2 genomic sequences from Hong Kong suggest that natural recombination happened among different lineages of PCV2. A preliminary investigation of the parental strains of these potential recombinants was carried out using bootscanning. Statistical significance of this recombination event was tested and positions of the potential recombination breakpoints were estimated in a maximum-likelihood framework. The recombinant breakpoints were estimated to be located within the origin of replication (ori) and replicase (rep) gene of PCV2. Interestingly, several GenBank sequences of PCV2 in mainland China were found to have a recombination pattern similar to that of the potential PCV2 recombinants from Hong Kong, implying that this recombinant genotype might already be widespread within mainland China.


2010 ◽  
Vol 11 (2) ◽  
pp. 217-234 ◽  
Author(s):  
A. R. Patterson ◽  
T. Opriessnig

AbstractPorcine circovirus type 2 (PCV2) is a small, non-enveloped, circular, single-stranded DNA virus of economic importance in the swine industry worldwide. Based on the sequence analyses of PCV2 strains, isolates can be divided into five subtypes (PCV2a–e). PCV2 is an ubiquitous virus based on serological and viremia data from countries worldwide. In addition, PCV2 DNA was discovered in archived samples prior to the first recognition of clinical disease. Recently, a worldwide shift in PCV2 subtype from PCV2a to PCV2b occurred. PCV2 DNA can be detected in fecal, nasal, oral and tonsillar swabs as well as in urine and feces from both naturally and experimentally infected pigs. PCV2 DNA can be detected early in the infectious process and persists for extended periods of time. The effectiveness of disinfectants for reducing PCV2in vitrois variable and PCV2 is very stable in the pig environment. Limited data exist on the horizontal transmission of PCV2. Direct transmission of PCV2 between experimentally or naturally infected animals and naïve animals has been documented and the incorporation of clinical or subclinically infected animals into a population represents a risk to the herd. Indirect transmission through the oral, aerosol or vaccine routes is likely a lesser risk for the transmission of PCV2 in most swine populations but may be worth evaluating in high heath herds. The objective of this review was to discuss data on the epidemiology and horizontal transmission of PCV2.


2006 ◽  
Vol 87 (4) ◽  
pp. 833-837 ◽  
Author(s):  
Tuija Kekarainen ◽  
Marina Sibila ◽  
Joaquim Segalés

The present study was designed to investigate the prevalence of swine Torque teno virus (TTV) in post-weaning multisystemic wasting syndrome (PMWS)-affected and non-affected Spanish swine. Nested PCR (nPCR) assays to detect two distinct TTV genogroups were applied. A significantly higher prevalence of TTV infection was found in sera from PMWS-affected animals (97 %) than in sera from non-PMWS-affected animals (78 %). Whilst PMWS-affected pigs (91 %) were more likely to be infected with TTV from genogroup 2 than non-PMWS-affected swine (72 %), no such difference was observed with genogroup 1. Nucleotide sequences of nPCR products were 91–99 % identical between strains within a genogroup. In contrast, inter-genogroup sequence identities were 49–58 %. Phylogenetic analyses demonstrated that genogroups form different clusters without association with PMWS or porcine circovirus type 2 infection status of the animals. These results indicate a high prevalence of both swine TTV genogroups in Spain, being present more frequently in PMWS-affected animals than in non-PMWS-affected animals.


2019 ◽  
Vol 26 (10) ◽  
pp. 776-784
Author(s):  
Rui Yang ◽  
Yu Tao ◽  
Gaojian Li ◽  
Jian Chen ◽  
Jianhong Shu ◽  
...  

Background:Porcine circovirus and Mycoplasma hyopneumoniae can cause respiratory diseases in pigs, which cause serious economic loss in the worldwide pig industry. Currently, these infections are mainly prevented and controlled by vaccination. The new vaccines on the market are mainly composed of subunits and inactivated vaccines but usually have lower antigenicity than traditional live vaccines. Thus, there is an increasing need to develop new adjuvants that can cause rapid and long-lasting immunity to enhance the antigenic efficacy for vaccines. Studies have shown that meningococcal porin PorB can act as a ligand to combine with Toll-like receptors to activate the production of immunological projections and act as a vaccine immunological adjuvant.Objective:In this article, we expressed and purified the recombinant PorB protein and verified its immunogenicity against porcine circovirus type 2 and Mycoplasma hyopneumoniae genetically engineered vaccine.Methods:In this article, we used prokaryotic expression to express and purify recombinant PorB protein, four different concentrations of PorB protein, Freund's adjuvant with two genetically engineered vaccines were combined with subcutaneous immunization of mice.Results:Our study shows that the appropriate dose of the recombinant protein PorB can enhance the levels of humoral and cellular responses induced by two genetically engineered vaccines in a short period of time in mice. The PorB adjuvant group may cause statistically higher antibody titers for both genetically engineered vaccines compared to Freund's commercial adjuvant (P<0.001).Conclusion:The recombinant protein PorB may be a good candidate adjuvant for improving the protective effect of vaccines against porcine circovirus type 2 and Mycoplasma hyopneumoniae, and the protein can be used for future practical applications.


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