African swine fever (ASF): Five years around Europe

Sánchez-Vizcaíno, José Manuel; Mur, Lina; Martínez‐López, Beatriz

doi:10.1016/j.vetmic.2012.11.030

Cited by 151 publications

(127 citation statements)

References 11 publications

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“…Originally endemic in sub-Saharan Africa, African swine fever disease was introduced in the Transcaucasian countries (Georgia, Armenia, and Azerbaijan) and in the Russian Federation (2007), where it is maintained (1). In the course of the last few years, new outbreaks of ASFV infection have occurred in Ukraine (2012, 2014, and 2015); Belarus (2013); and Lithuania, Estonia, Latvia, and Poland (2014 and 2015) (2).…”

mentioning

confidence: 99%

DNA-Binding Properties of African Swine Fever Virus pA104R, a Histone-Like Protein Involved in Viral Replication and Transcription

Frouco

Freitas

Coelho

et al. 2017

J Virol

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African swine fever virus (ASFV) codes for a putative histone-like protein (pA104R) with extensive sequence homology to bacterial proteins that are implicated in genome replication and packaging. Functional characterization of purified recombinant pA104R revealed that it binds to single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) over a wide range of temperatures, pH values, and salt concentrations and in an ATP-independent manner, with an estimated binding site size of about 14 to 16 nucleotides. Using site-directed mutagenesis, the arginine located in pA104R's DNA-binding domain, at position 69, was found to be relevant for efficient DNA-binding activity. Together, pA104R and ASFV topoisomerase II (pP1192R) display DNA-supercoiling activity, although none of the proteins by themselves do, indicating that the two cooperate in this process. In ASFV-infected cells, A104R transcripts were detected from 2 h postinfection (hpi) onward, reaching a maximum concentration around 16 hpi. pA104R was detected from 12 hpi onward, localizing with viral DNA replication sites and being found exclusively in the Tritoninsoluble fraction. Small interfering RNA (siRNA) knockdown experiments revealed that pA104R plays a critical role in viral DNA replication and gene expression, with transfected cells showing lower viral progeny numbers (up to a reduction of 82.0%), lower copy numbers of viral genomes (Ϫ78.3%), and reduced transcription of a late viral gene (Ϫ47.6%). Taken together, our results strongly suggest that pA104R participates in the modulation of viral DNA topology, probably being involved in viral DNA replication, transcription, and packaging, emphasizing that ASFV mutants lacking the A104R gene could be used as a strategy to develop a vaccine against ASFV.IMPORTANCE Recently reintroduced in Europe, African swine fever virus (ASFV) causes a fatal disease in domestic pigs, causing high economic losses in affected countries, as no vaccine or treatment is currently available. Remarkably, ASFV is the only known mammalian virus that putatively codes for a histone-like protein (pA104R) that shares extensive sequence homology with bacterial histone-like proteins. In this study, we characterized the DNA-binding properties of pA104R, analyzed the functional importance of two conserved residues, and showed that pA104R and ASFV topoisomerase II cooperate and display DNA-supercoiling activity. Moreover, pA104R is expressed during the late phase of infection and accumulates in viral DNA replication sites, and its downregulation revealed that pA104R is required for viral DNA replication and transcription. These results suggest that pA104R participates in the modulation of viral DNA topology and genome packaging, indicating that A104R deletion mutants may be a good strategy for vaccine development against ASFV.

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mentioning

confidence: 99%

DNA-Binding Properties of African Swine Fever Virus pA104R, a Histone-Like Protein Involved in Viral Replication and Transcription

Frouco

Freitas

Coelho

et al. 2017

J Virol

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“…The last introduction of ASFV to Europe occurred in 2007, when ASFV genotype II entered Georgia, probably through contaminated waste from boats (21,22). From Georgia, ASF rapidly spread to neighbouring countries, such as Armenia, Azerbaijan and the Russian Federation, where the virus continued its spread, affecting Ukraine, Belarus and even reaching countries within the European Union (Lithuania, Latvia, Estonia and Poland) (23,24).…”

Section: Europementioning

confidence: 99%

“…Studies conducted in Spain and Sardinia suggested that the role of the wild boar in maintaining ASF epidemiology was not as significant as that of domestic pigs, imported products and fomites, at least when there were no other sources of infection (25,26,27,28,29). However, the final cases of ASF, reported from Lithuania, Latvia, Estonia and Poland (23,24), demonstrated that wild boar could nonetheless have an important part in disease spread.…”

Section: Europementioning

confidence: 99%

New insights into the role of ticks in African swine fever epidemiology

Sánchez-Vizcaı́no¹,

Mur²,

Bastos³

et al. 2015

Rev. Sci. Tech. OIE

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SummaryAfrican swine fever (ASF), one of the most important diseases of swine, is present in many African countries, as well as in eastern Europe, Russia and Sardinia. It is caused by a complex virus, ASF virus (ASFV), for which neither vaccine nor treatment is available. ASFV affects swine of all breeds and ages, and also replicates in soft ticks of the genus Ornithodoros, facilitating ASFV persistence and reocurrence of disease. Depending on the involvement of these ticks, and the presence or not of sylvatic asymptomatic animals, several epidemiological cycles have been identified. The disease persists in East and southern African countries in a sylvatic cycle between O. porcinus (of the O. moubata species complex) and common warthogs. In some countries a domestic pig-tick cycle exists, whereas in other regions, notably West Africa, the role of soft ticks has not been demonstrated, and ASFV is transmitted between domestic pigs in the absence of tick vectors. Even in several East and Central African countries which have the sylvatic or domestic cycle, the majority of outbreaks are not associated with ticks or wild suids. In Europe, O. erraticus was detected and identified as a crucial vector for ASF maintenance in outdoor pig production on the Iberian Peninsula. However, in most parts of Europe, there is a lack of information about the distribution and role of Ornithodoros ticks in ASF persistence, particularly in eastern regions. This article reviews ASF epidemiology and its main characteristics, with a special focus on the distribution and role of soft ticks in ASF persistence in different settings. Information about tick detection, control measures and future directions for research is also included.

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“…In domestic pigs and wild boar, some ASF virus (ASFv) strains result in mortality rates of almost 100% (Blome et al, 2012;Sanchez-Vizcaino et al, 2012;Guinat et al, 2014). There is currently no vaccine available.…”

Section: Introductionmentioning

confidence: 99%

“…In just a few months, ASFv spread across the country and entered the Russian Federation (RF) in late 2007, probably as a result of the movement of infected wild boar (FAO, 2013;Sanchez-Vizcaino et al, 2013). Initially restricted to the southern regions of the RF, ASFv expanded its geographical distribution in 2011 when it was introduced into central and northern regions where it started to spread locally (Sanchez-Vizcaino et al, 2013). In 2014, ASFv was identified in both domestic pigs and wild boars in several countries of the eastern European Union, including Estonia, Latvia, Lithuania and Poland.…”

Section: Introductionmentioning

confidence: 99%