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

2017 ◽  
Vol 145 (13) ◽  
pp. 2787-2796 ◽  
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.

scholarly journals Simultaneous Deletion of the 9GL and UK Genes from the African Swine Fever Virus Georgia 2007 Isolate Offers Increased Safety and Protection against Homologous Challenge

2016 ◽  
Vol 91 (1) ◽  
Author(s):  
Vivian O'Donnell ◽  
Guillermo R. Risatti ◽  
Lauren G. Holinka ◽  
Peter W. Krug ◽  
Jolene Carlson ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
Genetically Modified ◽  
African Swine Fever ◽  
Viral Disease ◽  
Fever Virus ◽  
Economic Consequences ◽  
Swine Industry ◽  
Recombinant Viruses ◽  
High Doses ◽  
Highly Virulent

ABSTRACT African swine fever virus (ASFV) is the etiological agent of a contagious and often lethal viral disease of domestic pigs that has significant economic consequences for the swine industry. The control of African swine fever (ASF) has been hampered by the unavailability of vaccines. Successful experimental vaccines have been derived from naturally occurring, cell culture-adapted, or genetically modified live attenuated ASFV. Recombinant viruses harboring engineered deletions of specific virulence-associated genes induce solid protection against challenge with parental viruses. Deletion of the 9GL (B119L) gene in the highly virulent ASFV isolates Malawi Lil-20/1 (Mal) and Pretoriuskop/96/4 (Δ9GL viruses) resulted in complete protection when challenged with parental isolates. When similar deletions were created within the ASFV Georgia 2007 (ASFV-G) genome, attenuation was achieved but the protective and lethal doses were too similar. To enhance attenuation of ASFV-G, we deleted another gene, UK (DP96R), which was previously shown to be involved in attenuation of the ASFV E70 isolate. Here, we report the construction of a double-gene-deletion recombinant virus, ASFV-G-Δ9GL/ΔUK. When administered intramuscularly (i.m.) to swine, there was no induction of disease, even at high doses (106 HAD50). Importantly, animals infected with 104 50% hemadsorbing doses (HAD50) of ASFV-G-Δ9GL/ΔUK were protected as early as 14 days postinoculation when challenged with ASFV-G. The presence of protection correlates with the appearance of serum anti-ASFV antibodies, but not with virus-specific circulating ASFV-specific gamma interferon (IFN-γ)-producing cells. ASFV-G-Δ9GL/ΔUK is the first rationally designed experimental ASFV vaccine that protects against the highly virulent ASFV Georgia 2007 isolate as early as 2 weeks postvaccination. IMPORTANCE Currently, there is no commercially available vaccine against African swine fever. Outbreaks of the disease are devastating to the swine industry and are caused by circulating strains of African swine fever virus. Here, we report a putative vaccine derived from a currently circulating strain but containing two deletions in two separate areas of the virus, allowing increased safety. Using this genetically modified virus, we were able to vaccinate swine and protect them from developing ASF. We were able to achieve protection from disease as early as 2 weeks after vaccination, even when the pigs were exposed to a higher than normal concentration of ASFV.

scholarly journals Rapid CRISPR/Cas9 Editing of Genotype IX African Swine Fever Virus Circulating in Eastern and Central Africa

2021 ◽  
Vol 12 ◽  
Author(s):  
Hussein M. Abkallo ◽  
Nicholas Svitek ◽  
Bernard Oduor ◽  
Elias Awino ◽  
Sonal P. Henson ◽  
...  
Keyword(s):  
Recombinant Virus ◽  
Essential Gene ◽  
African Swine Fever Virus ◽  
Central Africa ◽  
African Swine Fever ◽  
Cost Effective ◽  
Fever Virus ◽  
Economic Consequences ◽  
Swine Industry ◽  
Genotype Ix

African swine fever virus (ASFV) is the etiological agent of a contagious and fatal disease of domestic pigs that has significant economic consequences for the global swine industry. Due to the lack of effective treatment and vaccines against African swine fever, there is an urgent need to leverage cutting-edge technologies and cost-effective approaches for generating and purifying recombinant virus to fast-track the development of live-attenuated ASFV vaccines. Here, we describe the use of the CRISPR/Cas9 gene editing and a cost-effective cloning system to produce recombinant ASFVs. Combining these approaches, we developed a recombinant virus lacking the non-essential gene A238L (5EL) in the highly virulent genotype IX ASFV (ASFV-Kenya-IX-1033) genome in less than 2 months as opposed to the standard homologous recombination with conventional purification techniques which takes up to 6 months on average. Our approach could therefore be a method of choice for less resourced laboratories in developing nations.

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

2017 ◽  
Vol 91 (21) ◽  
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.

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

Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1129 ◽  
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.

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

PLoS ONE ◽  
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.

scholarly journals Rynek mięsa wieprzowego w Polsce w obliczu afrykańskiego pomoru świń (ASF)

2018 ◽  
Vol 18(33) (3) ◽  
pp. 306-314
Author(s):  
Mirosława Tereszczuk
Keyword(s):  
Negative Impact ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
First Year ◽  
Upward Trend ◽  
Wild Boars ◽  
Central Poland ◽  
The Impact ◽  
Descriptive Method

The aim of the study is to assess the impact of African swine fever virus (ASF) on the development and functioning of the pork market in Poland. This virus appeared in Poland in February 2014 in wild boars, and then in July 2014 in pigs. The study covers the years 2014-2018, the period of ASF virus in Poland. By the end of July 2018, there were 182 cases of ASF in pigs and over 2.6 thousand in wild boars in four provinces of eastern and central Poland, and the largest cluster of this disease is located in the Lublin province. The appearance of ASF virus has had a negative impact on the pork market in Poland, resulting in restrictions on the export of this meat, costs of eradication of outbreaks and biosecurity. Despite these difficulties, the production of pork at this time was characterized by an upward trend, while exports only in the first year of the ASF decreased, but in subsequent years, due to the diversification of markets, there was an increase in exports. The descriptive method and simple statistical analyzes were used for the study.

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

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.

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

2021 ◽  
Vol 12 ◽  
Author(s):  
Elena Riera ◽  
Daniel Pérez-Núñez ◽  
Raquel García-Belmonte ◽  
Lisa Miorin ◽  
Adolfo García-Sastre ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Swine Industry ◽  
Inhibitory Mechanisms ◽  
Host Innate Immune Response ◽  
Serious Disease ◽  
New Strategies ◽  
Stat Pathway

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.

scholarly journals Subunit Vaccine Approaches for African Swine Fever Virus

Vaccines ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 56 ◽  
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.

scholarly journals Experimental pig-to-pig transmission dynamics for African swine fever virus, Georgia 2007/1 strain

2015 ◽  
Vol 144 (1) ◽  
pp. 25-34 ◽  
Author(s):  
C. GUINAT ◽  
S. GUBBINS ◽  
T. VERGNE ◽  
J. L. GONZALES ◽  
L. DIXON ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Quantitative Information ◽  
Fever Virus ◽  
European Countries ◽  
Transmission Dynamics ◽  
Eastern European ◽  
Domestic Pigs ◽  
Transmission Parameters ◽  
Eastern European Countries

SUMMARYAfrican swine fever virus (ASFV) continues to cause outbreaks in domestic pigs and wild boar in Eastern European countries. To gain insights into its transmission dynamics, we estimated the pig-to-pig basic reproduction number (R0) for the Georgia 2007/1 ASFV strain using a stochastic susceptible-exposed-infectious-recovered (SEIR) model with parameters estimated from transmission experiments. Models showed thatR0is 2·8 [95% confidence interval (CI) 1·3–4·8] within a pen and 1·4 (95% CI 0·6–2·4) between pens. The results furthermore suggest that ASFV genome detection in oronasal samples is an effective diagnostic tool for early detection of infection. This study provides quantitative information on transmission parameters for ASFV in domestic pigs, which are required to more effectively assess the potential impact of strategies for the control of between-farm epidemic spread in European countries.

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