African Swine Fever Virus Induces STAT1 and STAT2 Degradation to Counteract IFN-I Signaling

African swine fever virus (ASFV) causes a serious disease in domestic pigs and wild boars and is currently expanding worldwide. No safe and efficacious vaccines against ASFV are available, which threats the swine industry worldwide. African swine fever virus (ASFV) is a complex dsDNA virus that displays multiple mechanisms to counteract the host innate immune response, whose efficacy might determine the different degrees of virulence displayed by attenuated and virulent ASFV strains. Here we report that infection with both virulent Arm/07/CBM/c2 and attenuated NH/P68 strains prevents interferon-stimulated gene (ISG) expression in interferon (IFN)-treated cells by counteracting the JAK/STAT pathway. This inhibition results in an impaired nuclear translocation of the interferon-stimulated gene factor 3 (ISGF3) complex, as well as in the proteasome-dependent STAT2 degradation and caspase 3-dependent STAT1 cleavage. The existence of two independent mechanisms of control of the JAK/STAT pathway, suggests the importance of preventing this pathway for successful viral replication. As ASFV virulence is likely associated with the efficacy of the IFN signaling inhibitory mechanisms, a better understanding of these IFN antagonistic properties may lead to new strategies to control this devastating pig disease.

Download Full-text

BA71ΔCD2: a New Recombinant Live Attenuated African Swine Fever Virus with Cross-Protective Capabilities

Journal of Virology ◽

10.1128/jvi.01058-17 ◽

2017 ◽

Vol 91 (21) ◽

Cited By ~ 51

Author(s):

Paula L. Monteagudo ◽

Anna Lacasta ◽

Elisabeth López ◽

Laia Bosch ◽

Javier Collado ◽

...

Keyword(s):

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Sub Saharan Africa ◽

Swine Industry ◽

Lethal Challenge ◽

Major Threat ◽

Attenuated Viruses ◽

Genotype Ii

ABSTRACT African swine fever is a highly contagious viral disease of mandatory declaration to the World Organization for Animal Health (OIE). The lack of available vaccines makes its control difficult; thus, African swine fever virus (ASFV) represents a major threat to the swine industry. Inactivated vaccines do not confer solid protection against ASFV. Conversely, live attenuated viruses (LAV), either naturally isolated or obtained by genetic manipulation, have demonstrated reliable protection against homologous ASFV strains, although little or no protection has been demonstrated against heterologous viruses. Safety concerns are a major issue for the use of ASFV attenuated vaccine candidates and have hampered their implementation in the field so far. While trying to develop safer and efficient ASFV vaccines, we found that the deletion of the viral CD2v (EP402R) gene highly attenuated the virulent BA71 strain in vivo. Inoculation of pigs with the deletion mutant virus BA71ΔCD2 conferred protection not only against lethal challenge with the parental BA71 but also against the heterologous E75 (both genotype I strains). The protection induced was dose dependent, and the cross-protection observed in vivo correlated with the ability of BA71ΔCD2 to induce specific CD8+ T cells capable of recognizing both BA71 and E75 viruses in vitro. Interestingly, 100% of the pigs immunized with BA71ΔCD2 also survived lethal challenge with Georgia 2007/1, the genotype II strain of ASFV currently circulating in continental Europe. These results open new avenues to design ASFV cross-protective vaccines, essential to fight ASFV in areas where the virus is endemic and where multiple viruses are circulating. IMPORTANCE African swine fever virus (ASFV) remains enzootic in most countries of Sub-Saharan Africa, today representing a major threat for the development of their swine industry. The uncontrolled presence of ASFV has favored its periodic exportation to other countries, the last event being in Georgia in 2007. Since then, ASFV has spread toward neighboring countries, reaching the European Union's east border in 2014. The lack of available vaccines against ASFV makes its control difficult; so far, only live attenuated viruses have demonstrated solid protection against homologous experimental challenges, but they have failed at inducing solid cross-protective immunity against heterologous viruses. Here we describe a new LAV candidate with unique cross-protective abilities: BA71ΔCD2. Inoculation of BA71ΔCD2 protected pigs not only against experimental challenge with BA71, the virulent parental strain, but also against heterologous viruses, including Georgia 2007/1, the genotype II strain of ASFV currently circulating in Eastern Europe.

Download Full-text

A Simple Method for Sample Preparation to Facilitate Efficient Whole-Genome Sequencing of African Swine Fever Virus

Viruses ◽

10.3390/v11121129 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1129 ◽

Cited By ~ 9

Author(s):

Ferenc Olasz ◽

István Mészáros ◽

Szilvia Marton ◽

Győző L. Kaján ◽

Vivien Tamás ◽

...

Keyword(s):

Sample Preparation ◽

African Swine Fever Virus ◽

Animal Health ◽

African Swine Fever ◽

Fever Virus ◽

Whole Genome ◽

Swine Industry ◽

Viral Dna ◽

Simple Method ◽

Generation Sequencing

In the recent years, African swine fever has become the biggest animal health threat to the swine industry. To facilitate quick genetic analysis of its causative agent, the African swine fever virus (ASFV), we developed a simple and efficient method for next generation sequencing of the viral DNA. Execution of the protocol does not demand complicated virus purification steps, enrichment of the virus by ultracentrifugation or of the viral DNA by ASFV-specific PCRs, and minimizes the use of Sanger sequencing. Efficient DNA-se treatment, monitoring of sample preparation by qPCR, and whole genome amplification are the key elements of the method. Through detailed description of sequencing of the first Hungarian ASFV isolate (ASFV_HU_2018), we specify the sensitive steps and supply key reference numbers to assist reproducibility and to facilitate the successful use of the method for other ASFV researchers.

Download Full-text

Estimation of the transmission dynamics of African swine fever virus within a swine house

Epidemiology and Infection ◽

10.1017/s0950268817001613 ◽

2017 ◽

Vol 145 (13) ◽

pp. 2787-2796 ◽

Cited By ~ 3

Author(s):

J. P. NIELSEN ◽

T. S. LARSEN ◽

T. HALASA ◽

L. E. CHRISTIANSEN

Keyword(s):

African Swine Fever Virus ◽

African Swine Fever ◽

Simulation Models ◽

Fever Virus ◽

Economic Consequences ◽

Estimation Of Parameters ◽

Swine Industry ◽

Transmission Parameters ◽

The Individual ◽

The Impact

SUMMARYThe spread of African swine fever virus (ASFV) threatens to reach further parts of Europe. In countries with a large swine production, an outbreak of ASF may result in devastating economic consequences for the swine industry. Simulation models can assist decision makers setting up contingency plans. This creates a need for estimation of parameters. This study presents a new analysis of a previously published study. A full likelihood framework is presented including the impact of model assumptions on the estimated transmission parameters. As animals were only tested every other day, an interpretation was introduced to cover the weighted infectiousness on unobserved days for the individual animals (WIU). Based on our model and the set of assumptions, the within- and between-pen transmission parameters were estimated to βw = 1·05 (95% CI 0·62–1·72), βb = 0·46 (95% CI 0·17–1·00), respectively, and the WIU = 1·00 (95% CI 0–1). Furthermore, we simulated the spread of ASFV within a pig house using a modified SEIR-model to establish the time from infection of one animal until ASFV is detected in the herd. Based on a chosen detection limit of 2·55% equivalent to 10 dead pigs out of 360, the disease would be detected 13–19 days after introduction.

Download Full-text

Rapid and sensitive RPA-Cas12a-fluorescence assay for point-of-care detection of African swine fever virus

PLoS ONE ◽

10.1371/journal.pone.0254815 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0254815

Author(s):

Jinyu Fu ◽

Yueping Zhang ◽

Guang Cai ◽

Geng Meng ◽

Shuobo Shi

Keyword(s):

African Swine Fever Virus ◽

Point Of Care ◽

African Swine Fever ◽

High Sensitivity ◽

Fluorescence Assay ◽

Fever Virus ◽

Diagnostic Methods ◽

High Morbidity ◽

Swine Industry ◽

Control And Prevention

African swine fever (ASF) is a serious contagious disease that causes fatal haemorrhagic fever in domestic and wild pigs, with high morbidity. It has caused devastating damage to the swine industry worldwide, necessitating the focus of attention on detection of the ASF pathogen, the African swine fever virus (ASFV). In order to overcome the disadvantages of conventional diagnostic methods (e.g. time-consuming, demanding and unintuitive), quick detection tools with higher sensitivity need to be explored. In this study, based on the conserved p72 gene sequence of ASFV, we combined the Cas12a-based assay with recombinase polymerase amplification (RPA) and a fluorophore-quencher (FQ)-labeled reporter assay for rapid and visible detection. Five crRNAs designed for Cas12a-based assay showed specificity with remarkable fluorescence intensity under visual inspection. Within 20 minutes, with an initial concentration of two copies of DNA, the assay can produce significant differences between experimental and negative groups, indicating the high sensitivity and rapidity of the method. Overall, the developed RPA-Cas12a-fluorescence assay provides a fast and visible tool for point-of-care ASFV detection with high sensitivity and specificity, which can be rapidly performed on-site under isothermal conditions, promising better control and prevention of ASF.

Download Full-text

Development of an Indirect ELISA to Detect African Swine Fever Virus pp62 Protein-Specific Antibodies

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.798559 ◽

2022 ◽

Vol 8 ◽

Author(s):

Kexin Zhong ◽

Mengmeng Zhu ◽

Qichao Yuan ◽

Zhibang Deng ◽

Simeng Feng ◽

...

Keyword(s):

Indirect Elisa ◽

African Swine Fever Virus ◽

African Swine Fever ◽

Viral Disease ◽

Fever Virus ◽

Serum Samples ◽

Swine Industry ◽

Detection Techniques ◽

Positive Serum ◽

Great Reactivity

African swine fever (ASF) is a highly detrimental viral disease caused by African swine fever virus (ASFV). The occurrence and prevalence of this disease have become a serious threat to the global swine industry and national economies. At present, the detection volume of African swine fever is huge, more sensitive and accurate detection techniques are needed for the market. pp62 protein, as a protein in the late stage of infection, has strong antigenicity and a high corresponding antibody titer in infected pigs. In this study, the CP530R gene was cloned into expression vector pET-28a to construct a prokaryotic expression plasmid, which was induced by IPTG to express soluble pp62 protein. Western blot analysis showed that it had great reactivity. Using the purified recombinant protein as an antigen, an indirect ELISA method for detecting ASFV antibody was established. The method was specific only to ASFV-positive serum, 1:1600 diluted positive serum could still be detected, and the coefficients of variation (CV) of the intra assay and inter assay were both <10%. It turns out that the assays had excellent specificity, sensitivity, and repeatability. This provides an accurate, rapid, and economical method for the detection of ASFV antibody in clinical pig serum samples.

Download Full-text

Subunit Vaccine Approaches for African Swine Fever Virus

Vaccines ◽

10.3390/vaccines7020056 ◽

2019 ◽

Vol 7 (2) ◽

pp. 56 ◽

Cited By ~ 13

Author(s):

Natasha N. Gaudreault ◽

Juergen A. Richt

Keyword(s):

Western Europe ◽

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Swine Industry ◽

Fatal Disease ◽

The Caucasus ◽

Caucasus Region ◽

Highly Virulent ◽

Genotype Ii

African swine fever virus (ASFV) is the cause of a highly fatal disease in swine, for which there is no available vaccine. The disease is highly contagious and poses a serious threat to the swine industry worldwide. Since its introduction to the Caucasus region in 2007, a highly virulent, genotype II strain of ASFV has continued to circulate and spread into Eastern Europe and Russia, and most recently into Western Europe, China, and various countries of Southeast Asia. This review summarizes various ASFV vaccine strategies that have been investigated, with focus on antigen-, DNA-, and virus vector-based vaccines. Known ASFV antigens and the determinants of protection against ASFV versus immunopathological enhancement of infection and disease are also discussed.

Download Full-text

The Addition of Nature Identical Flavorings Accelerated the Virucidal Effect of Pure Benzoic Acid against African Swine Fever Viral Contamination of Complete Feed

Animals ◽

10.3390/ani11041124 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1124

Author(s):

Hengxiao Zhai ◽

Chihai Ji ◽

Maria Carol Walsh ◽

Jon Bergstrom ◽

Sebastien Potot ◽

...

Keyword(s):

Benzoic Acid ◽

African Swine Fever Virus ◽

African Swine Fever ◽

Preventive Measure ◽

Viral Disease ◽

Fever Virus ◽

Swine Industry ◽

Effective Measure ◽

Viral Survival ◽

Polymerase Chain

African swine fever virus is one of the most highly contagious and lethal viruses for the global swine industry. Strengthening biosecurity is the only effective measure for preventing the spread of this viral disease. The virus can be transmitted through contaminated feedstuffs and, therefore, research has been conducted to explore corresponding mitigating measures. The purpose of the current study was to test a combination of pure benzoic acid and a blend of nature identical flavorings for their ability to reduce African swine fever viral survival in feed. This virus was inoculated to feed with or without the supplementation of the test compounds, and the viral presence and load were measured by a hemadsorption test and quantitative real time polymerase chain reaction. The main finding was that the combination of pure benzoic acid and nature identical flavorings could expedite the reduction in both viral load and survival in a swine feed. Therefore, this solution could be adopted as a preventive measure for mitigating the risk of contaminated feed by African swine fever virus.

Download Full-text

Rapid and accurate detection of African swine fever virus by DNA endonuclease-targeted CRISPR trans reporter assay

Acta Biochimica et Biophysica Sinica ◽

10.1093/abbs/gmaa135 ◽

2020 ◽

Vol 52 (12) ◽

pp. 1413-1419

Author(s):

Zongjie Li ◽

Jianchao Wei ◽

Di Di ◽

Xin Wang ◽

Chenxi Li ◽

...

Keyword(s):

African Swine Fever Virus ◽

African Swine Fever ◽

Cross Reactivity ◽

Fever Virus ◽

Swine Industry ◽

Dna Endonuclease ◽

Effective Strategies ◽

Accurate Detection ◽

First Case ◽

Pig Farm

Abstract The first case of African swine fever (ASF) outbreak in China was reported in a suburban pig farm in Shenyang in 2018. Since then, the rapid spread and extension of ASF has become the most serious threat for the swine industry. Therefore, rapid and accurate detection of African swine fever virus (ASFV) is essential to provide effective strategies to control the disease. In this study, we developed a rapid and accurate ASFV-detection method based on the DNA endonuclease-targeted CRISPR trans reporter (DETECTR) assay. By combining recombinase polymerase amplification with CRISPR-Cas12a proteins, the DETECTR assay demonstrated a minimum detection limit of eight copies with no cross reactivity with other swine viruses. Clinical blood samples were detected by DETECTR assay and showed 100% (30/30) agreement with real-time polymerase chain reaction assay. The rapid and accurate detection of ASFV may facilitate timely eradication measures and strict sanitary procedures to control and prevent the spread of ASF.

Download Full-text

Development of a Blocking Enzyme-Linked Immunosorbent Assay for Detection of Antibodies against African Swine Fever Virus

Pathogens ◽

10.3390/pathogens10060760 ◽

2021 ◽

Vol 10 (6) ◽

pp. 760

Author(s):

Fangfeng Yuan ◽

Vlad Petrovan ◽

Luis Gabriel Gimenez-Lirola ◽

Jeffrey J. Zimmerman ◽

Raymond R. R. Rowland ◽

...

Keyword(s):

Time Course ◽

Serological Test ◽

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Internal Quality ◽

Enzyme Linked Immunosorbent Assay ◽

Post Inoculation ◽

Swine Industry ◽

Control Serum

The incursion of African swine fever virus (ASFV) into Eurasia presents a threat to the world’s swine industry. Highly sensitive and specific diagnostic assays are urgently needed for rapid detection during an outbreak, post-outbreak investigation, and disease surveillance. In this study, a highly specific and repeatable blocking ELISA (bELISA) was developed using a recombinant p30 protein as the antigen combined with biotinylated mAb against p30 as the detection antibody. Initial test validation included sera from 810 uninfected animals and 106 animals experimentally inoculated with ASFV or recombinant alphavirus/adenovirus expressing p30. Receiver operating characteristic (ROC) analysis of the data calculated an optimal percentage of inhibition (PI) cutoff value of 45.92%, giving a diagnostic sensitivity of 98.11% and diagnostic specificity of 99.42%. The coefficient of variation of an internal quality control serum was 6.81% for between runs, 6.71% for within run, and 6.14% for within plate. A time course study of infected pigs showed that bELISA was able to detect seroconversion as early as 7 days post-inoculation. Taken together, these results demonstrate that bELISA can be used as an alternative serological test for detecting ASFV infection.

Download Full-text

Short and Long-read Sequencing Survey of the Dynamic Transcriptomes of African Swine Fever Virus and its Host

10.1101/2020.02.27.967695 ◽

2020 ◽

Author(s):

Ferenc Olasz ◽

Dóra Tombácz ◽

Gábor Torma ◽

Zsolt Csabai ◽

Norbert Moldován ◽

...

Keyword(s):

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Economic Losses ◽

Swine Industry ◽

Rna Molecules ◽

Oxford Nanopore ◽

Combined Use ◽

Long Read ◽

Low Coverage

AbstractAfrican swine fever virus (ASFV) is an important animal pathogen causing substantial economic losses in the swine industry globally. At present, little is known about the molecular biology of ASFV, including its transcriptome organization. In this study, we applied cutting-edge sequencing approaches, namely the Illumina short-read sequencing (SRS) and the Oxford Nanopore Technologies long-read sequencing (LRS) techniques, together with several library preparation chemistries to analyze the ASFV dynamic transcriptome. SRS can generate a large amount of high-precision sequencing reads, but it is inefficient for identifying long RNA molecules, transcript isoforms and overlapping transcripts. LRS can overcome these limitations, but this approach also has shortcomings, such as its high error rate and the low coverage. Amplification-based LRS techniques produce relatively high read counts but also high levels of spurious transcripts, whereas the non-amplified cDNA and direct RNA sequencing techniques are more precise but achieve lower throughput. The drawbacks of the various technologies can be circumvented by the combined use of these approaches.

Download Full-text