African Swine Fever Virus 3.0

A special issue of Viruses (ISSN 1999-4915). This special issue belongs to the section "Animal Viruses".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 24111

Special Issue Editor

Special Issue Information

Dear Colleagues,

In recent years, African swine fever (ASF) has become one of the most feared infectious diseases affecting swine production and the commercialization of swine-derived products across many geographical regions of the world. The etiological agent, ASF virus (ASFV), is a large, structurally complex virus with a double-stranded DNA genome encoding over 150 proteins. Although the disease was originally identified in the 1920s, research on ASF has dramatically intensified in just the last ten years. This Special Issue of Viruses will be devoted to covering different aspects of ASFV research. Special emphasis will be placed on reports focused on the molecular mechanisms mediating virus virulence, virus pathogenesis in domestic and wild swine, host immune responses involved in protection against infection, the development of different types of experimental vaccines, the molecular bases of virus replication, virus structure, and novel/improved diagnostic methodologies. Contributions will be accepted in the format of original research reports, reviews covering specific aspects of ASF research, and opinion articles.

This third Special Issue of Viruses expects to offer scientists working on ASF a forum to share high-quality research in a variety of thematic areas of ASF research.

Dr. Manuel Borca
Guest Editor

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Keywords

  • ASF
  • ASFV
  • virus virulence
  • pathogenesis in natural hosts
  • protective host immune response
  • vaccine development
  • virus replication
  • virus structure/morphogenesis
  • ASF diagnostics

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Published Papers (13 papers)

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Research

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12 pages, 1686 KiB  
Article
Comparison of Attenuated and Virulent Strains of African Swine Fever Virus Genotype I and Serogroup 2
by Natalia Kholod, Andrey Koltsov, Sergey Krutko, Edan R. Tulman, Sanzhi Namsrayn, Gerald F. Kutish, Sergey Belov, Alexey Korotin, Mikhail Sukher and Galina Koltsova
Viruses 2023, 15(6), 1373; https://doi.org/10.3390/v15061373 - 14 Jun 2023
Viewed by 1284
Abstract
African swine fever (ASF) is a contagious disease of pigs caused by the ASF virus (ASFV). The main problem in the field of ASF control is the lack of vaccines. Attempts to obtain vaccines by attenuating the ASFV on cultured cell lines led [...] Read more.
African swine fever (ASF) is a contagious disease of pigs caused by the ASF virus (ASFV). The main problem in the field of ASF control is the lack of vaccines. Attempts to obtain vaccines by attenuating the ASFV on cultured cell lines led to the production of attenuated viruses, some of which provided protection against infection with a homologous virus. Here we report on the biological and genomic features of the attenuated Congo-a (KK262) virus compared to its virulent homologue Congo-v (K49). Our results showed differences in in vivo replication and virulence of Congo-a. However, the attenuation of the K49 virus did not affect its ability to replicate in vitro in the primary culture of pig macrophages. Complete genome sequencing of the attenuated KK262 strain revealed an 8,8 kb deletion in the left variable region of the genome compared to the virulent homologue K49. This deletion concerned five genes of MGF360 and three genes of MGF505. In addition, three inserts in the B602L gene, genetic changes in intergenic regions and missense mutations in eight genes were detected. The data obtained contribute to a better understanding of ASFV attenuation and identification of potential virulence genes for further development of effective vaccines. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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18 pages, 3487 KiB  
Article
Mass-Spectrometric Evaluation of the African Swine Fever Virus-Induced Host Shutoff Using Dynamic Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC)
by Elisabeth Wöhnke, Barbara G. Klupp, Sandra Blome, Thomas C. Mettenleiter and Axel Karger
Viruses 2023, 15(6), 1283; https://doi.org/10.3390/v15061283 - 30 May 2023
Cited by 1 | Viewed by 1362
Abstract
African swine fever is a viral disease of swine caused by the African swine fever virus (ASFV). Currently, ASFV is spreading over the Eurasian continent and threatening global pig husbandry. One viral strategy to undermine an efficient host cell response is to establish [...] Read more.
African swine fever is a viral disease of swine caused by the African swine fever virus (ASFV). Currently, ASFV is spreading over the Eurasian continent and threatening global pig husbandry. One viral strategy to undermine an efficient host cell response is to establish a global shutoff of host protein synthesis. This shutoff has been observed in ASFV-infected cultured cells using two-dimensional electrophoresis combined with metabolic radioactive labeling. However, it remained unclear if this shutoff was selective for certain host proteins. Here, we characterized ASFV-induced shutoff in porcine macrophages by measurement of relative protein synthesis rates using a mass spectrometric approach based on stable isotope labeling with amino acids in cell culture (SILAC). The impact of ASFV infection on the synthesis of >2000 individual host proteins showed a high degree of variability, ranging from complete shutoff to a strong induction of proteins that are absent from naïve cells. GO-term enrichment analysis revealed that the most effective shutoff was observed for proteins related to RNA metabolism, while typical representatives of the innate immune system were strongly induced after infection. This experimental setup is suitable to quantify a virion-induced host shutoff (vhs) after infection with different viruses. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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13 pages, 1334 KiB  
Article
Characterization of a Novel African Swine Fever Virus p72 Genotype II from Nigeria
by Aruna Ambagala, Kalhari Goonewardene, Lindsey Lamboo, Melissa Goolia, Cassidy Erdelyan, Mathew Fisher, Katherine Handel, Oliver Lung, Sandra Blome, Jacqueline King, Jan Hendrik Forth, Sten Calvelage, Edward Spinard, Douglas P. Gladue, Charles Masembe, Adeyinka J. Adedeji, Toyin Olubade, Nanven A. Maurice, Hussaini G. Ularamu and Pam D. Luka
Viruses 2023, 15(4), 915; https://doi.org/10.3390/v15040915 - 02 Apr 2023
Cited by 7 | Viewed by 2549
Abstract
African swine fever (ASF) is a high-consequence transboundary hemorrhagic fever of swine. It continues to spread across the globe causing socio-economic issues and threatening food security and biodiversity. In 2020, Nigeria reported a major ASF outbreak, killing close to half a million pigs. [...] Read more.
African swine fever (ASF) is a high-consequence transboundary hemorrhagic fever of swine. It continues to spread across the globe causing socio-economic issues and threatening food security and biodiversity. In 2020, Nigeria reported a major ASF outbreak, killing close to half a million pigs. Based on the partial sequences of the genes B646L (p72) and E183L (p54), the virus responsible for the outbreak was identified as an African swine fever virus (ASFV) p72 genotype II. Here, we report further characterization of ASFV RV502, one of the isolates obtained during the outbreak. The whole genome sequence of this virus revealed a deletion of 6535 bp between the nucleotide positions 11,760–18,295 of the genome, and an apparent reverse complement duplication of the 5′ end of the genome at the 3′ end. Phylogenetically, ASFV RV502 clustered together with ASFV MAL/19/Karonga and ASFV Tanzania/Rukwa/2017/1 suggesting that the virus responsible for the 2020 outbreak in Nigeria has a South-eastern African origin. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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14 pages, 2236 KiB  
Article
Evaluation of African Swine Fever Virus E111R Gene on Viral Replication and Porcine Virulence
by Xintao Zhou, Jiaqi Fan, Yanyan Zhang, Jinjin Yang, Rongnian Zhu, Huixian Yue, Yu Qi, Qixuan Li, Yu Wang, Teng Chen, Shoufeng Zhang and Rongliang Hu
Viruses 2023, 15(4), 890; https://doi.org/10.3390/v15040890 - 30 Mar 2023
Cited by 1 | Viewed by 1303
Abstract
African swine fever (ASF) is an acute infectious disease of domestic pigs and wild boars caused by the African swine fever virus (ASFV), with up to a 100% case fatality rate. The development of a vaccine for ASFV is hampered by the fact [...] Read more.
African swine fever (ASF) is an acute infectious disease of domestic pigs and wild boars caused by the African swine fever virus (ASFV), with up to a 100% case fatality rate. The development of a vaccine for ASFV is hampered by the fact that the function of many genes in the ASFV genome still needs to be discovered. In this study, the previously unreported E111R gene was analyzed and identified as an early-expressed gene that is highly conserved across the different genotypes of ASFV. To further explore the function of the E111R gene, a recombinant strain, SY18ΔE111R, was constructed by deleting the E111R gene of the lethal ASFV SY18 strain. In vitro, the replication kinetics of SY18ΔE111R with deletion of the E111R gene were consistent with those of the parental strain. In vivo, high-dose SY18ΔE111R (105.0 TCID50), administered intramuscularly to pigs, caused the same clinical signs and viremia as the parental strain (102.0 TCID50), with all pigs dying on days 8–11. After being infected with a low dose of SY18ΔE111R (102.0 TCID50) intramuscularly, pigs showed a later onset of disease and 60% mortality, changing from acute to subacute infection. In summary, deletion of the E111R gene has a negligible effect on the lethality of ASFV and does not affect the viruses’ ability to replicate, suggesting that E111R could not be the priority target of ASFV live-attenuated vaccine candidates. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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14 pages, 5923 KiB  
Article
Comparison of Genotype II African Swine Fever Virus Strain SY18 Challenge Models
by Xintao Zhou, Jiaqi Fan, Xiaopan Guo, Teng Chen, Jinjin Yang, Yanyan Zhang, Lijuan Mi, Fei Zhang, Faming Miao, Min Li and Rongliang Hu
Viruses 2023, 15(4), 858; https://doi.org/10.3390/v15040858 - 27 Mar 2023
Cited by 1 | Viewed by 1276
Abstract
African swine fever (ASF) is a viral haemorrhagic disease found in domestic and wild boars caused by the African swine fever virus (ASFV). A highly virulent strain was used to evaluate the efficacy of newly developed vaccine candidates. The ASFV strain SY18 was [...] Read more.
African swine fever (ASF) is a viral haemorrhagic disease found in domestic and wild boars caused by the African swine fever virus (ASFV). A highly virulent strain was used to evaluate the efficacy of newly developed vaccine candidates. The ASFV strain SY18 was isolated from the first ASF case in China and is virulent in pigs of all ages. To evaluate the pathogenesis of ASFV SY18 following intraoral (IO) and intranasal (IN) infections, a challenge trial was conducted in landrace pigs, with intramuscular (IM) injection as a control. The results showed that the incubation period of IN administration with 40–1000 50 % tissue culture infective dose (TCID50) was 5–8 days, which was not significantly different from that of IM inoculation with 200 TCID50. A significantly longer incubation period, 11–15 days, was observed in IO administration with 40–5000 TCID50. Clinical features were similar among all infected animals. Symptoms, including high fever (≥40.5 °C), anorexia, depression, and recumbency, were observed. No significant differences were detected in the duration of viral shedding during fever. There was no significant difference in disease outcome, and all animals succumbed to death. This trial showed that IN and IO infections could be used for the efficacy evaluation of an ASF vaccine. The IO infection model, similar to that of natural infection, is highly recommended, especially for the primary screening of candidate vaccine strains or vaccines with relatively weak immune efficacy, such as live vector vaccines and subunit vaccines. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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19 pages, 5175 KiB  
Article
Pathology of African Swine Fever in Reproductive Organs of Mature Breeding Boars
by Julia Sehl-Ewert, Virginia Friedrichs, Tessa Carrau, Paul Deutschmann and Sandra Blome
Viruses 2023, 15(3), 729; https://doi.org/10.3390/v15030729 - 11 Mar 2023
Cited by 1 | Viewed by 1737
Abstract
African swine fever (ASF) is a severe, globally important disease in domestic and wild pigs. The testing of alternative transmission routes has proven that the ASF virus (ASFV) can be efficiently transmitted to sows via semen from infected boars through artificial insemination. Boars [...] Read more.
African swine fever (ASF) is a severe, globally important disease in domestic and wild pigs. The testing of alternative transmission routes has proven that the ASF virus (ASFV) can be efficiently transmitted to sows via semen from infected boars through artificial insemination. Boars intramuscularly inoculated with the ASFV strain “Estonia 2014” showed grossly and microscopically visible changes in the testis, epididymis, prostate, and vesicular gland. The gross lesions included hemorrhages on the scrotum, testicular membranes, and parenchyma; edema; hydroceles; and proliferations of the tunica vaginalis. Histopathologically, vasculitis and perivasculitis was detected in the testis and epididymis. Subacutely infected animals further revealed a degeneration of the testicular and epididymal tubules, pointing to the destruction of the blood–testis and blood–epididymis barriers upon disease progression. This was confirmed by evidence of semen round cells and sperm abnormalities at later time points after the infection. The histopathology was associated with the presence of viral DNA and the infectious virus, and in a limited amount with viral antigens. In most scenarios, the impact of these changes on the reproductive performance and long-term persistence of the virus is probably negligible due to the culling of the animals. However, under backyard conditions and in wild boar populations, infected males will remain in the population and the long-term fate should be further evaluated. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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11 pages, 1763 KiB  
Article
Evaluation of the Function of ASFV Gene E66L in the Process of Virus Replication and Virulence in Swine
by Elizabeth Ramirez-Medina, Elizabeth A. Vuono, Ayushi Rai, Nallely Espinoza, Alyssa Valladares, Edward Spinard, Lauro Velazquez-Salinas, Douglas P. Gladue and Manuel V. Borca
Viruses 2023, 15(2), 566; https://doi.org/10.3390/v15020566 - 18 Feb 2023
Viewed by 1605
Abstract
African swine fever virus (ASFV) is the etiological agent of an economically important disease of swine currently affecting large areas of Africa, Eurasia and the Caribbean. ASFV has a complex structure harboring a large dsDNA genome which encodes for more than 160 proteins. [...] Read more.
African swine fever virus (ASFV) is the etiological agent of an economically important disease of swine currently affecting large areas of Africa, Eurasia and the Caribbean. ASFV has a complex structure harboring a large dsDNA genome which encodes for more than 160 proteins. One of the proteins, E66L, has recently been involved in arresting gene transcription in the infected host cell. Here, we investigate the role of E66L in the processes of virus replication in swine macrophages and disease production in domestic swine. A recombinant ASFV was developed (ASFV-G-∆E66L), from the virulent parental Georgia 2010 isolate (ASFV-G), harboring the deletion of the E66L gene as a tool to assess the role of the gene. ASFV-G-∆E66L showed that the E66L gene is non-essential for ASFV replication in primary swine macrophages when compared with the parental highly virulent field isolate ASFV-G. Additionally, domestic pigs infected with ASFV-G-∆E66L developed a clinical disease undistinguishable from that produced by ASFV-G. Therefore, E66L is not involved in virus replication or virulence in domestic pigs. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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14 pages, 3162 KiB  
Article
I329L: A Dual Action Viral Antagonist of TLR Activation Encoded by the African Swine Fever Virus (ASFV)
by Sílvia Correia, Pedro Luís Moura, Sónia Ventura, Alexandre Leitão and Robert Michael Evans Parkhouse
Viruses 2023, 15(2), 445; https://doi.org/10.3390/v15020445 - 05 Feb 2023
Cited by 5 | Viewed by 1931
Abstract
The African Swine Fever Virus (ASFV) is an economically important, large DNA virus which causes a highly contagious and frequently fatal disease in domestic pigs. Due to the acute nature of the infection and the complexity of the protective porcine anti-ASFV response, there [...] Read more.
The African Swine Fever Virus (ASFV) is an economically important, large DNA virus which causes a highly contagious and frequently fatal disease in domestic pigs. Due to the acute nature of the infection and the complexity of the protective porcine anti-ASFV response, there is no accepted vaccine in use. As resistance to ASFV is known to correlate with a robust IFN response, the virus is predicted to have evolved strategies to inhibit innate immunity by modulating the IFN response. The deletion of virus host evasion gene(s) inhibiting IFN is a logical solution to develop an attenuated virus vaccine. One such candidate, the ASFV ORF I329L gene, is highly conserved in pathogenic and non-pathogenic virus isolates and in this study we confirm and extend the conclusion that it has evolved for the inhibition of innate immunity initiated through Toll-like receptors (TLRs). Specifically, the ASFV I329L extracellular (ECD) and intracellular (ICD) domains inhibit TLR signalling by two entirely different mechanisms. Bioinformatics modelling suggests that the ECD inhibits several TLR signalling pathways through a short sequence homologous to the conserved TLR dimerization domain, here termed the putative dimerization domain (PDD). Remarkably, both full length and PDD constructs of I329L were demonstrated to inhibit activation, not only of TLR3, but also TLR4, TLR5, TLR8 and TLR9. Additionally, the demonstration of a weak association of I329L with TLR3 is consistent with the formation of a non-signalling I329L-TLR3 heterodimer, perhaps mediated through the PDD of I329L. Finally, the ICD associates with TRIF, thereby impacting on both TLR3 and TLR4 signalling. Thus, I329L offers potential as a general inhibitor of TLR responses and is a rational candidate for construction and testing of an I329L deletion mutant vaccine. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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12 pages, 2269 KiB  
Article
A Spontaneously Occurring African Swine Fever Virus with 11 Gene Deletions Partially Protects Pigs Challenged with the Parental Strain
by Tomoya Kitamura, Kentaro Masujin, Reiko Yamazoe, Ken-ichiro Kameyama, Mizuki Watanabe, Mitsutaka Ikezawa, Manabu Yamada and Takehiro Kokuho
Viruses 2023, 15(2), 311; https://doi.org/10.3390/v15020311 - 22 Jan 2023
Cited by 3 | Viewed by 1750
Abstract
African swine fever (ASF) is an infectious Suidae disease caused by the ASF virus (ASFV). Adaptation to less susceptible, non-target host cells is one of the most common techniques used to attenuate virulent viruses. However, this may induce many mutations and large-scale rearrangements [...] Read more.
African swine fever (ASF) is an infectious Suidae disease caused by the ASF virus (ASFV). Adaptation to less susceptible, non-target host cells is one of the most common techniques used to attenuate virulent viruses. However, this may induce many mutations and large-scale rearrangements in the viral genome, resulting in immunostimulatory potential loss of the virus in vivo. This study continuously maintained the virulent ASFV strain, Armenia2007 (Arm07), to establish an attenuated ASFV strain with minimum genetic alteration in a susceptible host cell line, immortalized porcine kidney macrophage (IPKM). A mutant strain was successfully isolated via repeated plaque purification in combination with next-generation sequencing analysis. The isolated strain, Arm07ΔMGF, which was obtained from a viral fluid at a passage level of 20, lacked 11 genes in total in the MGF300 and MGF360 regions and showed marked reduction in virulence against pigs. Moreover, all the pigs survived the challenge with the parental strain when pigs were immunized twice with 105 TCID50 of Arm07ΔMGF, although viremia and fever were not completely prevented after the challenge infection. These findings suggest that this naturally attenuated, spontaneously occurring ASFV strain may provide a novel platform for ASF vaccine development. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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12 pages, 1191 KiB  
Article
Point-of-Care Testing for Sensitive Detection of the African Swine Fever Virus Genome
by Ahmed Elnagar, Sandra Blome, Martin Beer and Bernd Hoffmann
Viruses 2022, 14(12), 2827; https://doi.org/10.3390/v14122827 - 19 Dec 2022
Cited by 4 | Viewed by 2168
Abstract
African swine fever (ASF) is a contagious viral hemorrhagic disease that affects domestic pigs and wild boar. The disease is notifiable to the World Organization of Animal Health (WOAH), and causes significant deaths and economic losses. There is currently no fully licensed vaccine [...] Read more.
African swine fever (ASF) is a contagious viral hemorrhagic disease that affects domestic pigs and wild boar. The disease is notifiable to the World Organization of Animal Health (WOAH), and causes significant deaths and economic losses. There is currently no fully licensed vaccine available. As a result, early identification of the causative agent, ASF virus (ASFV), is crucial for the implementation of control measures. PCR and real-time PCR are the WOAH-recommended standard methods for the direct detection of ASFV. However, under special field conditions or in simple or remote field laboratories, there may be no sophisticated equipment or even stable electricity available. Under these circumstances, point-of-care systems can be put in place. Along these lines, a previously published, rapid, reliable, and electricity-free extraction method (TripleE) was used to isolate viral nucleic acid from diagnostic specimens. With this tool, nucleic acid extraction from up to eight diagnostic samples can be realized in one run in less than 10 min. In addition, the possibility of completely omitting viral DNA extraction was analyzed with so-called direct real-time PCR protocols using ASFV original samples diluted to 1:40 in RNase-free water. Furthermore, three real-time PCR cyclers, developed for use under field conditions (IndiField, Liberty16 and UF-300 GenecheckerTM), were comparatively applied for the sensitive high-speed detection of ASFV genomes, with overall PCR run times between 20 and 54 min. Depending on the viral DNA extraction/releasing method used and the point-of-care cycler applied, a total time for detection of 30 to 60 min for up to eight samples was feasible. As expected, the limitations in analytical sensitivity were positively correlated to the analysis time. These limitations are acceptable for ASFV diagnostics due to the expected high ASFV genome loads in diseased animals or carcasses. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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Review

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17 pages, 1475 KiB  
Review
African Swine Fever Virus Interaction with Host Innate Immune Factors
by Ayoola Ebenezer Afe, Zhao-Ji Shen, Xiaorong Guo, Rong Zhou and Kui Li
Viruses 2023, 15(6), 1220; https://doi.org/10.3390/v15061220 - 23 May 2023
Cited by 5 | Viewed by 2849
Abstract
African swine fever virus (ASFV) adversely affects pig farming owing to its 100% mortality rate. The condition is marked by elevated body temperature, bleeding, and ataxia in domestic pigs, whereas warthogs and ticks remain asymptomatic despite being natural reservoirs for the virus. Breeding [...] Read more.
African swine fever virus (ASFV) adversely affects pig farming owing to its 100% mortality rate. The condition is marked by elevated body temperature, bleeding, and ataxia in domestic pigs, whereas warthogs and ticks remain asymptomatic despite being natural reservoirs for the virus. Breeding ASFV-resistant pigs is a promising solution for eradicating this disease. ASFV employs several mechanisms to deplete the host antiviral response. This review explores the interaction of ASFV proteins with innate host immunity and the various types of machinery encompassed by viral proteins that inhibit and induce different signaling pathways, such as cGAS-STING, NF-κB, Tumor growth factor-beta (TGF-β), ubiquitination, viral inhibition of apoptosis, and resistance to ASFV infection. Prospects for developing a domestic pig that is resistant to ASFV are also discussed. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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Other

Jump to: Research, Review

11 pages, 2416 KiB  
Brief Report
Genetic Profile of African Swine Fever Viruses Circulating at Pig Farms in South Korea during the Outbreaks between 2022 and April 2023
by Ki-Hyun Cho, Dae-Sung Yoo, Seong-Keun Hong, Da-Young Kim, Min-Kyung Jang, Hae-Eun Kang and Yeon-Hee Kim
Viruses 2023, 15(7), 1552; https://doi.org/10.3390/v15071552 - 14 Jul 2023
Cited by 2 | Viewed by 1594
Abstract
Fifteen pig farms were affected by African swine fever (ASF) in South Korea during the outbreaks between 2022 and April 2023. The ASF virus (ASFV) genome was directly extracted from the blood and tissue samples of 15 ASFV-positive pig farms to analyze the [...] Read more.
Fifteen pig farms were affected by African swine fever (ASF) in South Korea during the outbreaks between 2022 and April 2023. The ASF virus (ASFV) genome was directly extracted from the blood and tissue samples of 15 ASFV-positive pig farms to analyze the genetic characteristics. Phylogenetic analysis revealed that the 15 strains belonged to p72 genotype II and CD2v serogroup 8, which were the central variable region (CVR) I variants of the B602L gene. Fourteen strains were intergenic region (IGR) II variants, containing an additional tandem repeat sequence (TRS), between I73L and I329R, with the exception of one strain from an ASFV-infected pig farm reported on 22 January 2023, which was an IGR I variant. In addition, a single-nucleotide polymorphism (SNP) was detected at position 107 from the start of the IGR between A179L and A137R in six isolates. The findings of this study suggest that the sources of the virus at the pig farms from which these variants originated differed from those of other pig farms. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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10 pages, 1447 KiB  
Brief Report
Mammalian Cell-Line-Expressed CD2v Protein of African Swine Fever Virus Provides Partial Protection against the HLJ/18 Strain in the Early Infection Stage
by Rong-Hong Hua, Jing Liu, Shu-Jian Zhang, Ren-Qiang Liu, Xian-Feng Zhang, Xi-Jun He, Dong-Ming Zhao and Zhi-Gao Bu
Viruses 2023, 15(7), 1467; https://doi.org/10.3390/v15071467 - 28 Jun 2023
Cited by 3 | Viewed by 1141
Abstract
A cell line expressing the CD2v protein of ASFV was generated. The efficient expression of CD2v protein was determined by immunofluorescence and Western blotting. The CD2v protein was Ni-affinity purified from the supernatant of cell cultures. The CD2v-expressing cells showed properties of hemadsorption, [...] Read more.
A cell line expressing the CD2v protein of ASFV was generated. The efficient expression of CD2v protein was determined by immunofluorescence and Western blotting. The CD2v protein was Ni-affinity purified from the supernatant of cell cultures. The CD2v-expressing cells showed properties of hemadsorption, and the secreted CD2v protein exhibited hemagglutinating activity. The antigenicity and immunoprotection ability of CD2v were evaluated by immunizing pigs alone, combined with a cell-line-expressed p30 protein or triple combined with p30 and K205R protein. Immunized pigs were challenged with the highly virulent ASFV strain HLJ/18. Virus challenge results showed that CD2v immunization alone could provide partial protection at the early infection stage. Protein p30 did not show synergistic protection effects in immunization combined with CD2v. Interestingly, immunization with the triple combination of CD2V, p30 and K205R reversed the protection effect. The viremia onset time was delayed, and one pig out of three recovered after the challenge. The pig recovered from ASFV clinical symptoms, the rectal temperature returned to normal levels and the viremia was cleared. The mechanism of this protection effect warrants further investigation. Full article
(This article belongs to the Special Issue African Swine Fever Virus 3.0)
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