scholarly journals African Swine Fever Virus as a Difficult Opponent in the Fight for a Vaccine—Current Data

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1212
Author(s):  
Hanna Turlewicz-Podbielska ◽  
Anna Kuriga ◽  
Rafał Niemyjski ◽  
Grzegorz Tarasiuk ◽  
Małgorzata Pomorska-Mól
Keyword(s):  
African Swine Fever Virus ◽  
Complex Structure ◽  
African Swine Fever ◽  
Biological Properties ◽  
Current Data ◽  
Fever Virus ◽  
Effective Vaccine ◽  
Targeted Gene Deletion ◽  
The Many ◽  
And Control

Prevention and control of African swine fever virus (ASFV) in Europe, Asia, and Africa seem to be extremely difficult in view of the ease with which it spreads, its high resistance to environmental conditions, and the many obstacles related to the introduction of effective specific immunoprophylaxis. Biological properties of ASFV indicate that the African swine fever (ASF) pandemic will continue to develop and that only the implementation of an effective and safe vaccine will ensure a reduction in the spread of ASFV. At present, vaccines against ASF are not available. The latest approaches to the ASFV vaccine’s design concentrate on the development of either modified live vaccines by targeted gene deletion from different isolates or subunit vaccines. The construction of an effective vaccine is hindered by the complex structure of the virus, the lack of an effective continuous cell line for the isolation and propagation of ASFV, unpredictable and stain-specific phenotypes after the genetic modification of ASFV, a risk of reversion to virulence, and our current inability to differentiate infected animals from vaccinated ones. Moreover, the design of vaccines intended for wild boars and oral administration is desirable. Despite several obstacles, the design of a safe and effective vaccine against ASFV seems to be achievable.

scholarly journals The African Swine Fever Virus (ASFV) Topoisomerase II as a Target for Viral Prevention and Control

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 312 ◽  
Author(s):  
João Coelho ◽  
Alexandre Leitão
Keyword(s):  
Topoisomerase Ii ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Effective Vaccine ◽  
Type Ii ◽  
Cancer Treatments ◽  
Promising Target ◽  
Multicellular Organisms ◽  
And Control

African swine fever (ASF) is, once more, spreading throughout the world. After its recent reintroduction in Georgia, it quickly reached many neighboring countries in Eastern Europe. It was also detected in Asia, infecting China, the world’s biggest pig producer, and spreading to many of the surrounding countries. Without any vaccine or effective treatment currently available, new strategies for the control of the disease are mandatory. Its etiological agent, the African swine fever virus (ASFV), has been shown to code for a type II DNA topoisomerase. These are enzymes capable of modulating the topology of DNA molecules, known to be essential in unicellular and multicellular organisms, and constitute targets in antibacterial and anti-cancer treatments. In this review, we summarize most of what is known about this viral enzyme, pP1192R, and discuss about its possible role(s) during infection. Given the essential role of type II topoisomerases in cells, the data so far suggest that pP1192R is likely to be equally essential for the virus and thus a promising target for the elaboration of a replication-defective virus, which could provide the basis for an effective vaccine. Furthermore, the use of inhibitors could be considered to control the spread of the infection during outbreaks and therefore limit the spreading of the disease.

scholarly journals Generation and Evaluation of an African Swine Fever Virus Mutant with Deletion of the CD2v and UK Genes

Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 763
Author(s):  
Teshale Teklue ◽  
Tao Wang ◽  
Yuzi Luo ◽  
Rongliang Hu ◽  
Yuan Sun ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
Clinical Signs ◽  
African Swine Fever ◽  
Virus Genome ◽  
Fever Virus ◽  
Effective Vaccine ◽  
Post Inoculation ◽  
Virus Mutant ◽  
And Control

African swine fever (ASF) is a highly contagious and often lethal disease caused by African swine fever virus (ASFV). ASF emerged in China in August 2018 and has since rapidly spread into many areas of the country. The disease has caused a significant impact on China’s pig and related industries. A safe and effective vaccine is needed to prevent and control the disease. Several gene-deleted ASFVs have been reported; however, none of them is safe enough and commercially available. In this study, we report the generation of a double gene-deleted ASFV mutant, ASFV-SY18-∆CD2v/UK, from a highly virulent field strain ASFV-SY18 isolated in China. The results showed that ASFV-SY18-∆CD2v/UK lost hemadsorption properties, and the simultaneous deletion of the two genes did not significantly affect the in vitro replication of the virus in primary porcine alveolar macrophages. Furthermore, ASFV-SY18-∆CD2v/UK was attenuated in pigs. All the ASFV-SY18-∆CD2v/UK-inoculated pigs remained healthy, and none of them developed ASF-associated clinical signs. Additionally, the ASFV-SY18-∆CD2v/UK-infected pigs developed ASFV-specific antibodies, and no virus genome was detected in blood and nasal discharges at 21 and 28 days post-inoculation. More importantly, we found that all the pigs inoculated with 104 TCID50 of ASFV-SY18-∆CD2v/UK were protected against the challenge with the parental ASFV-SY18. However, low-level ASFV DNA was detected in blood, nasal swabs, and lymphoid tissue after the challenge. The results demonstrate that ASFV-SY18-∆CD2v/UK is safe and able to elicit protective immune response in pigs and can be a potential vaccine candidate to control ASF.

DNA segments of African Swine Fever Virus detected for the first time in hard ticks from sheep and bovines

2019 ◽  
Vol 24 (1) ◽  
pp. 180 ◽  
Author(s):  
Ze Chen ◽  
Xiaofeng Xu ◽  
Yufeng Wang ◽  
Jinlong Bei ◽  
Xiufeng Jin ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Control Measures ◽  
Single Amino Acid ◽  
Small Rna Sequencing ◽  
Hard Ticks ◽  
Prevention And Control Measures ◽  
And Control ◽  
First Time

In this study, we detected African Swine Fever Virus (ASFV) in Dermacentor (Ixodidae) from sheep and bovines using small RNA sequencing. To validate this result, a 235-bp DNA segment was detected in a number of DNA samples from D. silvarum and sheep blood. This 235-bp segment had an identity of 99% to a 235-bp DNA segment of ASFV and contained three single nucleotide mutations (C38T, C76T and A108C). C38T, resulting in a single amino acid mutation G66D, suggests the existence of a new ASFV strain, which is different from all reported ASFV strains in the NCBI GenBank database and the ASFV strain (GenBank: MH713612.1) reported in China in 2018. To further confirm the existence of ASFV in Dermacentor ticks, three DNA segments of ASFV were detected in D. niveus females from bovines and their first generation ticks reared in our lab. These results also proved that transovarian transmission of ASFV occurs in hard ticks. This study revealed for the first time that ASFV has a wider range of hosts (e.g. sheep and bovines) and vectors (e.g. hard ticks), beyond the well-known Suidae family and Argasidae (soft ticks). Our findings pave the way toward further studies on ASFV transmission and the development of prevention and control measures.

scholarly journals Development and clinical application of a novel CRISPR-Cas12a based assay for the detection of African swine fever virus

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Xiaoying Wang ◽  
Sheng He ◽  
Na Zhao ◽  
Xiaohong Liu ◽  
Yongchang Cao ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
Diagnostic Technique ◽  
African Swine Fever ◽  
Cross Reactivity ◽  
Fever Virus ◽  
Effective Vaccine ◽  
Highly Sensitive ◽  
Resource Poor ◽  
Good Consistency ◽  
Virus Genotypes

Abstract Background As no treatment or effective vaccine for African swine fever virus (ASFV) is currently available, a rapid, highly sensitive diagnostic is urgently needed to curb the spread of ASFV. Results Here we designed a novel CRISPR-Cas12a based assay for ASFV detection. To detect different ASFV genotypes, 19 crRNAs were designed to target the conserved p72 gene in ASFV, and several crRNAs with high activity were identified that could be used as alternatives in the event of new ASFV variants. The results showed that the sensitivity of the CRISPR-Cas12a based assay is about ten times higher than either the commercial quantitative PCR (qPCR) kit or the OIE-recommended qPCR. CRISPR-Cas12a based assay could also detect ASFV specifically without cross-reactivity with other important viruses in pigs and various virus genotypes. We also found that longer incubation times increased the detection limits, which could be applied to improve assay outcomes in the detection of weakly positive samples and new ASFV variants. In addition, both the CRISPR-Cas12a based assay and commercial qPCR showed very good consistency. Conclusions In summary, the CRISPR-Cas12a based assay offers a feasible approach and a new diagnostic technique for the diagnosis of ASFV, particularly in resource-poor settings.

scholarly journals Rapid Sequence-Based Characterization of African Swine Fever Virus by Use of the Oxford Nanopore MinION Sequence Sensing Device and a Companion Analysis Software Tool

2019 ◽  
Vol 58 (1) ◽  
Author(s):  
Vivian K. O’Donnell ◽  
Frederic R. Grau ◽  
Gregory A. Mayr ◽  
Tracy L. Sturgill Samayoa ◽  
Kimberly A. Dodd ◽  
...  
Keyword(s):  
Real Time ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Full Genome Sequence ◽  
Effective Vaccine ◽  
Fast Analysis ◽  
Rapid Acquisition ◽  
Oxford Nanopore

ABSTRACT African swine fever virus (ASFV) is the causative agent of a severe and highly contagious viral disease of pigs that poses serious economic consequences to the swine industry due to the high mortality rate and impact on international trade. There is no effective vaccine to control African swine fever (ASF), and therefore, efficient disease control is dependent on early detection and diagnosis of ASFV. The large size of the ASFV genome (∼180 kb) has historically hindered efforts to rapidly obtain a full-genome sequence. Rapid acquisition of data is critical for characterization of the isolate and to support epidemiological efforts. Here, we investigated the capacity of the Oxford Nanopore MinION sequence sensing device to act as a rapid sequencing tool. When coupled with our novel companion software script, the African swine fever fast analysis sequencing tool (ASF-FAST), the analysis of output data was performed in real time. Complete ASFV genome sequences were generated from cell culture isolates and blood samples obtained from experimentally infected pigs. Removal of the host-methylated DNA from the extracted nucleic acid facilitated rapid ASFV sequence identification, with reads specific to ASFV detected within 6 min after the initiation of sequencing. Regardless of the starting material, sufficient sequence was available for complete genome resolution (up to 100%) within 10 min. Overall, this paper highlights the use of Nanopore sequencing technology in combination with the ASF-FAST software for the purpose of rapid and real-time resolution of the full ASFV genome from a diagnostic sample.

scholarly journals Risk Analysis of the Transmission Route for the African Swine Fever Virus in Mainland China

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiang-Hong Hu ◽  
Xin Pei ◽  
Gui-Quan Sun ◽  
Zhen Jin
Keyword(s):  
African Swine Fever Virus ◽  
Mainland China ◽  
African Swine Fever ◽  
Infection Risk ◽  
Fever Virus ◽  
Transmission Model ◽  
Transmission Route ◽  
Pork Products ◽  
Python Language ◽  
And Control

African swine fever first broke out in mainland China in August 2018 and has caused a substantial loss to China’s pig industry. Numerous investigations have confirmed that trades and movements of infected pigs and pork products, feeding pigs with contaminative swills, employees, and vehicles carrying the virus are the main transmission routes of the African swine fever virus (ASFV) in mainland China. However, which transmission route is more risky and what is the specific transmission map are still not clear enough. In this study, we crawl the data related to pig farms and slaughterhouses from Baidu Map by writing the Python language and then construct the pig transport network. Following this, we establish an ASFV transmission model over the network based on probabilistic discrete-time Markov chains. Furthermore, we propose spatiotemporal backward detection and forward transmission algorithms in semi-directed weighted networks. Through the simulation and calculation, the risk of transmission routes is analyzed, and the results reveal that the infection risk for employees and vehicles with the virus is the highest, followed by contaminative swills, and the transportation of pigs and pork products is the lowest; the most likely transmission map is deduced, and it is found that ASFV spreads from northeast China to southwest China and then to west; in addition, the infection risk in each province at different times is assessed, which can provide effective suggestions for the prevention and control of ASFV.

scholarly journals DNA segment of African Swine Fever Virus first detected in hard ticks from sheep and bovine

2018 ◽  
Author(s):  
Ze Chen ◽  
Xiaofeng Xu ◽  
Xiaojun Yang ◽  
Weihao Dou ◽  
Xiufeng Jin ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Control Measures ◽  
Single Amino Acid ◽  
Small Rna Sequencing ◽  
Hard Ticks ◽  
Wide Range ◽  
Prevention And Control Measures ◽  
And Control

In this study, we aimed to detect viruses in hard ticks using the small RNA sequencing based method. A 235-bp DNA segment was detected in Dermacentor nuttalli (hard ticks) and D. silvarum (hard ticks) from sheep and bovine, respectively. The detected 235-bp segment had an identity of 99% to a 235-bp DNA segment of African Swine Fever Virus (ASFV) and contained three single nucleotide mutations (C38T, C76T and A108C). C38T, resulting in an single amino acid mutation G66D, suggests the existence of a new ASFV strain, which is different from all reported ASFV strains in NCBI GenBank database. These results also suggest that ASFV could have a wide range of hosts or vectors, beyond the well known Suidae family and soft ticks. Our findings pave the way toward further studies of ASFV transmission and development of prevention and control measures.

scholarly journals The structural basis of African swine fever virus pA104R binding to DNA and its inhibition by stilbene derivatives

2020 ◽  
Vol 117 (20) ◽  
pp. 11000-11009 ◽  
Author(s):  
Ruili Liu ◽  
Yeping Sun ◽  
Yan Chai ◽  
Su Li ◽  
Shihua Li ◽  
...  
Keyword(s):  
Dna Binding ◽  
African Swine Fever Virus ◽  
Dna Bending ◽  
Complex Structure ◽  
African Swine Fever ◽  
Fever Virus ◽  
Structural Basis ◽  
Bending Angle ◽  
Stilbene Derivatives ◽  
Dna Complex

African swine fever virus (ASFV) is a highly contagious nucleocytoplasmic large DNA virus (NCLDV) that causes nearly 100% mortality in swine. The development of effective vaccines and drugs against this virus is urgently needed. pA104R, an ASFV-derived histone-like protein, shares sequence and functional similarity with bacterial HU/IHF family members and is essential for viral replication. Herein, we solved the crystal structures of pA104R in its apo state as well as in complex with DNA. Apo-pA104R forms a homodimer and folds into an architecture conserved in bacterial heat-unstable nucleoid proteins/integration host factors (HUs/IHFs). The pA104R-DNA complex structure, however, uncovers that pA104R has a DNA binding pattern distinct from its bacterial homologs, that is, the β-ribbon arms of pA104R stabilize DNA binding by contacting the major groove instead of the minor groove. Mutations of the basic residues at the base region of the β-strand DNA binding region (BDR), rather than those in the β-ribbon arms, completely abolished DNA binding, highlighting the major role of the BDR base in DNA binding. An overall DNA bending angle of 93.8° is observed in crystal packing of the pA104R-DNA complex structure, which is close to the DNA bending angle in the HU-DNA complex. Stilbene derivatives SD1 and SD4 were shown to disrupt the binding between pA104R and DNA and inhibit the replication of ASFV in primary porcine alveolar macrophages. Collectively, these results reveal the structural basis of pA104R binding to DNA highlighting the importance of the pA104R-DNA interaction in the ASFV replication cycle and provide inhibitor leads for ASFV chemotherapy.

scholarly journals Preliminary Analysis of African Swine Fever Virus Carriage and Transmission by Mosquitoes

2021 ◽  
Author(s):  
Weiyun Qin ◽  
Zhongcheng Gao ◽  
Shenglong Wu ◽  
Wenbin Bao
Keyword(s):  
Large Scale ◽  
Mosquito Control ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Qpcr Analysis ◽  
Pig Farms ◽  
Negative Cycle ◽  
Control Procedures ◽  
And Control

Abstract BackgroundMosquitoes are important insect vectors, but whether they can carry and transmit African swine fever virus (ASFV) in large-scale pig farms in China is unknown. ResultsIn this study, probe qPCR analysis was performed on mosquitoes from five pig farms with ASF virus (ASFV). Analysis of ASFV in 463 mosquitoes yielded negative cycle threshold (CT) value), and detection remained negative after mixing samples from all five pig farms. ConclusionsTherefore, mosquitoes appear unlikely to transmit ASFV, and pose little threat to large-scale pig farms. Thus, farms should continue to follow normal mosquito control procedures when formulating strategies for the prevention and control of ASF.

scholarly journals Efficient inactivation of African swine fever virus by a highly complexed iodine combined with compound organic acids

2022 ◽  
Author(s):  
Mengnan Qi ◽  
Li Pan ◽  
Ying Gao ◽  
Miao Li ◽  
Yanjin Wang ◽  
...  
Keyword(s):  
Organic Acids ◽  
African Swine Fever Virus ◽  
Synergistic Effects ◽  
African Swine Fever ◽  
Fever Virus ◽  
High Morbidity ◽  
Wild Type ◽  
Cleaning And Disinfection ◽  
And Control ◽  
Effective Compound

African swine fever (ASF) is a highly contagious disease with high morbidity and mortality caused by African swine fever virus (ASFV). Cleaning and disinfection remain one of the most effective biosecurity measures to prevent and control the spread of ASFV. In this study, we evaluated the inactivation effects of highly complexed iodine (HPCI) combined with compound organic acids (COAs) against ASFV under different conditions. The results showed that the inactivation rates of the disinfectants on the reporter ASFV increased in dose- and time-dependent manners, the best inactivation effects were obtained when the compatibility ratio of HPCI and COAs was 5:1 at 25°C. Furthermore, there were no significant differences by comparing the efficacy of HPCI combined with COAs (HPCI+COAs) in inactivating wild-type ASFV and the reporter ASFV (P > 0.05). ASFV of 104.0 TCID50/mL was completely inactivated by 0.13% HPCI (0.0065% effective iodine), 0.06% COAs or 0.13% HPCI+COAs (approximately 0.0054% effective iodine), respectively, while 106.0 TCID50/mL ASFV was completely inactivated by 1.00% HPCI (0.05% effective iodine), 0.50% COAs or 1.00% HPCI+COAs (0.042% effective iodine), respectively. Therefore, HPCI+COAs had synergistic effects to inactivate ASFV. This study demonstrated that HPCI+COAs could rapidly and efficiently inactivate ASFV and represent an effective compound disinfectant for the control of ASF.

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