The Advanced Research on Porcine Circovirus

A special issue of Pathogens (ISSN 2076-0817). This special issue belongs to the section "Viral Pathogens".

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 16808

Special Issue Editors


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Guest Editor
Viral Disease Division, Animal and Plant Quarantine Agency, Gimcheon, Korea
PRRS research Laboratory, Viral Diseases Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Korea
Interests: viral disease division; viral respiratory syndrome

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Guest Editor
Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, Korea
Interests: infectious disease; viral respiratory syndrome; modified live virus vaccines; reverse genetics

Special Issue Information

Dear Colleagues,

Porcine circovirus (PCV) consists of four genotypes (PCV1-4) with different pathological and epidemiological features. Among the genotypes, porcine circovirus type 2 (PCV2) has been one of the most devastating pathogens in the swine industry over the last few decades, being considered the only PCV genotype to cause clinical symptoms of pigs like PMWS, PDNS, and PRDC. Recent reports show that the novel genotypes (PCV3 and PCV4) emerged from unknown sources and widely spread to swine farms, which the swine industry needs to further investigate for economic loss. Due to the diverse genetic difference (subtypes) among genotypes plus incomplete neutralizing activity to new subtypes, there has been concern regarding the prevention of PCV-associated diseases by current vaccination. Current PCV2 vaccines are effective only for reduction of clinical problem and viral load in host. We may need more detailed information describing the current field status regarding the current vaccine efficiency. Moreover, it will be inevitable to improve vaccines and adopt new technology to induce sterile immunity by vaccine against new PCV subtypes.

For this Special Issue, we will focus on general topics covering the emergence and distribution of novel PCV subtypes or genotypes and their pathogenesis. It will also include cross immunity among the subtypes and current challenges for the new PCV vaccine development. Any kind of scientific reports on this area will be reviewed for publication.

Prof. Sang-ho Cha
Prof. Changhoon Park
Guest Editors

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Keywords

  • porcine circovirus
  • modified live virus vaccines
  • PCV subtypes or genotypes
  • pathogenesis

Published Papers (6 papers)

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Research

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13 pages, 18305 KiB  
Article
The Prevalence and Genetic Diversity of PCV3 and PCV2 in Colombia and PCV4 Survey during 2015–2016 and 2018–2019
by Diana S. Vargas-Bermudez, José Darío Mogollón and Jairo Jaime
Pathogens 2022, 11(6), 633; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens11060633 - 31 May 2022
Cited by 12 | Viewed by 1882
Abstract
Four genotypes of circovirus have been recognized in swine, with PCV2 and PCV3 being the most associated with clinical manifestations, while PCV4 does not have a defined disease. In addition, PCV2 is associated with different syndromes grouped as diseases associated with porcine circovirus [...] Read more.
Four genotypes of circovirus have been recognized in swine, with PCV2 and PCV3 being the most associated with clinical manifestations, while PCV4 does not have a defined disease. In addition, PCV2 is associated with different syndromes grouped as diseases associated with porcine circovirus (PCVAD), while PCV3 causes systemic and reproductive diseases. In the present study, we retrospectively detected PCV2, PCV3, and PCV4 in Colombia during two periods: A (2015–2016) and B (2018–2019). During period A, we evaluated stool pools from the 32 Colombian provinces, finding a higher prevalence of PCV3 compared to PCV2 as well as PCV2/PCV3 co-infection. Furthermore, we determined that PCV3 had been circulating since 2015 in Colombia. Regarding period B, we evaluated sera pools and tissues from abortions and stillborn piglets from the five provinces with the highest pig production. The highest prevalence found was for PCV3 in tissues followed by sera pools, while PCV2 was lower and only in sera pools. In addition, PCV2/PCV3 co-infection in sera pools was also found for this period. The complete genome sequences of PCV3 and PCV3-ORF2 placed the Colombian isolates within clade 1 as the majority in the world. For PCV2, the predominant genotype currently in Colombia is PCV2d. Likewise, in some PCV3-ORF2 sequences, a mutation (A24V) was found at the level of the Cap protein, which could be involved in PCV3 immunogenic recognition. Regarding PCV4, retrospective surveillance showed that there is no evidence of the presence of this virus in Colombia. Full article
(This article belongs to the Special Issue The Advanced Research on Porcine Circovirus)
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12 pages, 1884 KiB  
Article
Minimal Dosage of Porcine Circovirus Type 2d Based Virus-like Particles to Induce Stable Protective Immunity against Infection
by Jong-Hyuk Baek, Sang-Ho Cha, Sun-Hee Cho, Myung-Shin Lee and Changhoon Park
Pathogens 2021, 10(12), 1644; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens10121644 - 20 Dec 2021
Cited by 1 | Viewed by 2801
Abstract
In recent years, porcine circovirus type 2d (PCV2d) has achieved a dominant position worldwide. Various PCV2d capsid-based vaccines have been used to alleviate concerns regarding the emergence of the variant. This study aimed to determine the dosage of recombinant PCV2d capsid protein to [...] Read more.
In recent years, porcine circovirus type 2d (PCV2d) has achieved a dominant position worldwide. Various PCV2d capsid-based vaccines have been used to alleviate concerns regarding the emergence of the variant. This study aimed to determine the dosage of recombinant PCV2d capsid protein to induce protective efficacy against experimental challenge with a virulent PCV2d strain. Conventional 3-week-old pigs were intramuscularly inoculated with different doses of the protein (60, 20, 10 and 2 µg). Four weeks after vaccination, all pigs were challenged with pathogenic PCV2d (SNU140003), which was isolated from a farm severely experiencing PCV2-associated disease in Korea. Vaccination with greater than 10 µg of the capsid protein caused a significant (p < 0.05) reduction in PCV2d viremia, lymphoid lesions and lymphoid PCV2 antigen levels in vaccinated challenged pigs compared to unvaccinated challenged pigs. The vaccination also resulted in significantly higher (p < 0.05) titers of neutralizing antibodies against PCV2d. However, the pigs vaccinated with 2 µg had significantly lower neutralizing antibody titers than the other vaccinated groups. They showed a similar level of challenged PCV2d in serum and lymphoid lesion score compared to unvaccinated challenged pigs. The difference in efficacy among the vaccinated groups indicates that there may be a baseline dosage to induce sufficient neutralizing antibodies to prevent viral replication in pigs. In conclusion, at least 10 µg dosage of capsid protein is essential for stable protective efficacy against PCV2d in a pig model. Full article
(This article belongs to the Special Issue The Advanced Research on Porcine Circovirus)
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14 pages, 3425 KiB  
Article
Porcine Circovirus (PCV) Genotype 2d-Based Virus-like Particles (VLPs) Induced Broad Cross-Neutralizing Antibodies against Diverse Genotypes and Provided Protection in Dual-Challenge Infection of a PCV2d Virus and a Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)
by Seok-Jin Kang, Sung-Min Bae, Hye-Jeong Lee, Young-Ju Jeong, Min-A Lee, Su-Hwa You, Hyang-Sim Lee, Bang-Hun Hyun, Nakhyung Lee and Sang-Ho Cha
Pathogens 2021, 10(9), 1145; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens10091145 - 06 Sep 2021
Cited by 14 | Viewed by 3150
Abstract
As PCV2d infection has been continuously reported in swine farms in which pigs were vaccinated with PCV2a- or 2d-based vaccines, we attempted to develop a novel vaccine using a PCV2d-based capsid to enhance its protective efficacy. In this study, recombinant virus-like particles (VLPs) [...] Read more.
As PCV2d infection has been continuously reported in swine farms in which pigs were vaccinated with PCV2a- or 2d-based vaccines, we attempted to develop a novel vaccine using a PCV2d-based capsid to enhance its protective efficacy. In this study, recombinant virus-like particles (VLPs) of rPCV2a, rPCV2b and rPCV2d were synthesized from the capsid proteins of PCV2a, PCV2b and PCV2d field isolates, respectively. A cross-neutralization assay between the VLPs induced antisera and the field isolates demonstrated the broad cross-neutralizing activities of the rPCV2d-induced antisera. Then, the protective efficacy of rPCV2d as a vaccine candidate was investigated in commercial pigs by rPCV2d vaccination and a single- or dual-challenge infection using a PCV2d strain and a type 1 PRRSV strain. High levels of anti-PCV2d IgG and neutralizing antibodies were induced 3 weeks after vaccination. After the challenge infection, the average ADWG values of the vaccinated group were higher than those of the unvaccinated group. None or a significantly low amount of (p < 0.05) reduced PCV2 genomic DNA was found in the blood, saliva and tissues of the vaccinated pigs, when compared to the unvaccinated group. Moreover, macroscopic and microscopic lesions in the tissues were significantly (p < 0.05) reduced in the vaccinated groups. This study therefore suggests that rPCV2d may be highly useful for the control of diverse field genotypes. Full article
(This article belongs to the Special Issue The Advanced Research on Porcine Circovirus)
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11 pages, 6641 KiB  
Article
A Comparison of Pathogenicity and Virulence of Three Porcine Circovirus Type 2 (PCV2) Genotypes (a, b, and d) in Pigs Singularly Inoculated with PCV2 and Dually Inoculated with Mycoplasma hyopneumoniae and PCV2
by Taehwan Oh, Jeongmin Suh, Kee Hwan Park, Siyeon Yang, Hyejean Cho and Chanhee Chae
Pathogens 2021, 10(8), 979; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens10080979 - 03 Aug 2021
Cited by 7 | Viewed by 2042
Abstract
The objective of this study was to compare the virulence of three different porcine circovirus type 2 (PCV2) genotypes (PCV2a, PCV2b, and PCV2d) in pigs infected with either one of these three PCV2 genotypes versus pigs dually inoculated with Mycoplasma hyopneumoniae and PCV2. [...] Read more.
The objective of this study was to compare the virulence of three different porcine circovirus type 2 (PCV2) genotypes (PCV2a, PCV2b, and PCV2d) in pigs infected with either one of these three PCV2 genotypes versus pigs dually inoculated with Mycoplasma hyopneumoniae and PCV2. Pigs were inoculated intratracheally with M. hyopneumoniae at 4 weeks of age followed by another intranasal inoculation at 6 weeks of age with one of three PCV2 genotypes. Dual infection with two pathogens produced moderate and severe dyspnea, lethargy, and reduced weight gain in pigs regardless of the PCV2 genotype evaluated compared with pigs only inoculated with PCV2. The overall levels of PCV2d viremia and severity of lymphoid lesions, and PCV2-antigen within lymphoid lesions were significantly higher in pigs dually inoculated with M. hyopneumoniae/PCV2d when compared with all other dually inoculated groups. The level of PCV2 viremia and the production of PCV2-associated lymphoid lesions did not differ significantly among PCV2a, PCV2b, and PCV2d single-inoculated pig groups. The results of this study demonstrated that M. hyopneumoniae potentiated the replication of PCV2d more than it did with the other PCV2 genotypes as measured by lymphoid lesion severity. Full article
(This article belongs to the Special Issue The Advanced Research on Porcine Circovirus)
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12 pages, 1940 KiB  
Article
A Comparison of Virulence of Three Porcine Circovirus Type 2 (PCV2) Genotypes (a, b, and d) in Pigs Singularly Inoculated with PCV2 and Dually Inoculated with PCV2 and Porcine Reproductive and Respiratory Syndrome Virus
by Jeongmin Suh, Taehwan Oh, Keehwan Park, Siyeon Yang, Hyejean Cho and Chanhee Chae
Pathogens 2021, 10(7), 891; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens10070891 - 14 Jul 2021
Cited by 6 | Viewed by 2517
Abstract
The aim of this study was to compare the virulence of porcine circovirus type 2 (PCV2) genotypes in dually inoculated pigs with both three genotypes (a, b, and d) of PCV2 and porcine reproductive and respiratory syndrome virus-2 (PRRSV-2) versus pigs singularly inoculated [...] Read more.
The aim of this study was to compare the virulence of porcine circovirus type 2 (PCV2) genotypes in dually inoculated pigs with both three genotypes (a, b, and d) of PCV2 and porcine reproductive and respiratory syndrome virus-2 (PRRSV-2) versus pigs singularly inoculated with the same three PCV2 genotypes (a, b, and d). Differences in this comparison were found in PCV2 viremia levels, lung and lymphoid lesion severity, and the amount of PCV2 antigen within the lymphoid lesions. Regardless of PCV2 genotypes, pigs that were dually inoculated with PCV2/PRRSV had significantly higher clinical scores, less average daily weight gain, higher levels of PCV2 viremia, and more severe lug and lymphoid lesions compared to pigs singularly inoculated with PCV2. Among the dually infected pig groups, pigs infected with PCV2d/PRRSV-2 had significantly higher levels of PCV2 viremia, more severe lung and lymphoid lesions, and more PCV2-positive cells within lymphoid lesions compared to pigs dually inoculated with PCV2a/PRRSV-2 and PCV2b/PRRSV-2. The results of this study demonstrated significant differences in the virulence among dual inoculation of PCV2a/PRRSV-2, PCV2b/PRRSV-2, and PCV2d/PRRSV-2. A significant difference in the virulence among PCV2a, PCV2b, and PCV2d single-inoculated pig groups was not found with respect to the levels of PCV2 viremia and production of PCV2-associated lymphoid lesions. Full article
(This article belongs to the Special Issue The Advanced Research on Porcine Circovirus)
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Review

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16 pages, 940 KiB  
Review
Current Understanding of the Pathogenesis of Porcine Circovirus 3
by Chaitawat Sirisereewan, Roongroje Thanawongnuwech and Roongtham Kedkovid
Pathogens 2022, 11(1), 64; https://0-doi-org.brum.beds.ac.uk/10.3390/pathogens11010064 - 04 Jan 2022
Cited by 21 | Viewed by 3603
Abstract
Circoviruses are closed, circular, single-stranded DNA viruses belonging to the family Circoviridae and the genus Circovirus. To date, at least four porcine circoviruses (PCVs) have been recognized, including PCV1 to PCV4, respectively. Similar to PCV2 pathogenesis, PCV3 has been reported worldwide with [...] Read more.
Circoviruses are closed, circular, single-stranded DNA viruses belonging to the family Circoviridae and the genus Circovirus. To date, at least four porcine circoviruses (PCVs) have been recognized, including PCV1 to PCV4, respectively. Similar to PCV2 pathogenesis, PCV3 has been reported worldwide with myriad clinical and pathological presentations such as reproductive disorders, respiratory diseases, diarrhea etc. Current understanding of PCV3 pathogenesis is very limited since the majority of studies were mostly field observations. Interpretation of the results from such studies is not always simple. Various confounding factors affect the clinical appearance and pathological changes of the infected pigs. Recently, several experimental PCV3 infection studies have been reported, providing a better understanding of its pathogenesis. In this review, we focused on novel findings regarding PCV3 pathogenesis from both field observation and experimental infection studies. Possible factors involved in the conflicting results among the experimental infection studies are also discussed. This review article provides important insight into the current knowledge on PCV3 pathogenesis which would aid in prioritizing research in order to fill the knowledge gaps. Full article
(This article belongs to the Special Issue The Advanced Research on Porcine Circovirus)
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