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African swine fever: a global view of the current challenge

View Article: PubMed Central - PubMed

ABSTRACT

African Swine Fever (ASF) is an important contagious haemorrhagic viral disease affecting swine whose notification is mandatory due to its high mortality rates and the great sanitary and socioeconomic impact it has on international trade in animal and swine products.

This disease only affects porcine species, both wild and domestic, and produces a variety of clinical signs such as fever and functional disorders of the digestive and respiratory systems. Lesions are mainly characterized by congestive-haemorrhagic alterations. ASF epidemiology varies significantly between countries, regions and continents, since it depends on the characteristics of the virus in circulation, the presence of wild hosts and reservoirs, environmental conditions and human social behaviour. Furthermore, a specific host will not necessarily always play the same active role in the spread and maintenance of ASF in a particular area.

Currently, ASF is endemic in most sub-Saharan African countries where wild hosts and tick vectors (Ornithodoros) play an important role acting as biological reservoirs for the virus. In Europe, the disease has been endemic since 1978 on the island of Sardinia (Italy) and since 2007, when it was first reported in Georgia, in a number of Eastern European countries. It is also endemic in certain regions of the Russia Federation, where domestic pig and wild boar populations are widely affected. By contrast, in the affected eastern European Union (EU) countries where ASF is currently as epidemic, the on-going spread of the disease affects mainly wild boar populations located in restricted areas and, to a much less extent, domestic pigs. Unlike most livestock diseases, no vaccine or specific treatment is currently available for ASF. Therefore, disease control is mainly based on early detection and the application of strict sanitary and biosecurity measures. Epidemiology of ASF is very complex by the existence of different virus circulating, reservoirs and a number of scenarios, and the on-going spread of the disease through Africa and Europe. Survivor pigs can remain persistently infected for months which may contribute to virus transmission and thus the spread and maintenance of the disease, thereby complicating attempts to control it.

No MeSH data available.


Electron micrograph of ASFV (source, INIA-CISA, Valdeolmos, Spain). By electronic microscopy, viral particles show an average diameter of 200 nm. The virion is formed by several concentric structures with an external hexagonal envelope. The main target cells for ASFV replication are monocytes and macrophage cells
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Fig5: Electron micrograph of ASFV (source, INIA-CISA, Valdeolmos, Spain). By electronic microscopy, viral particles show an average diameter of 200 nm. The virion is formed by several concentric structures with an external hexagonal envelope. The main target cells for ASFV replication are monocytes and macrophage cells

Mentions: The causative agent of the disease, the ASF virus (ASFV), is the only member of the Asfaviridae family, genus Asfivirus [8] (Fig. 5). It is a complex enveloped virus with icosahedral morphology consisting of four concentric layers and a large double-stranded DNA molecule that ranges in length between isolates from about 170 to 193 kbp [9]. It contains a conserved central region of about 125 kb and two variable ends. The differences in genome length are largely due to the gain or loss of members of the multigene families (MGF) located in the left and right variable regions [9]. A full genome sequencing of up to 16 virus isolates has recently been completed [10–14]. The ASF viral DNA contains between 151 and 167 open reading frames (ORFs) encoding 54 structural proteins and around 100 polypeptides in the targeted infected cells, monocytes and macrophages [15, 16]. The major components of the viral capsid, the protein p72, the two structural proteins p30 (p32) and p54 and the polyprotein pp62, have been identified as the most antigenic of the proteins that are responsible for the induction of antibodies after a natural infection [17, 18]. However, despite the usefulness of these proteins as sero-diagnostic targets, they are not sufficient for developing antibody-mediated protection against virus strains [19].Fig. 5


African swine fever: a global view of the current challenge
Electron micrograph of ASFV (source, INIA-CISA, Valdeolmos, Spain). By electronic microscopy, viral particles show an average diameter of 200 nm. The virion is formed by several concentric structures with an external hexagonal envelope. The main target cells for ASFV replication are monocytes and macrophage cells
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5382474&req=5

Fig5: Electron micrograph of ASFV (source, INIA-CISA, Valdeolmos, Spain). By electronic microscopy, viral particles show an average diameter of 200 nm. The virion is formed by several concentric structures with an external hexagonal envelope. The main target cells for ASFV replication are monocytes and macrophage cells
Mentions: The causative agent of the disease, the ASF virus (ASFV), is the only member of the Asfaviridae family, genus Asfivirus [8] (Fig. 5). It is a complex enveloped virus with icosahedral morphology consisting of four concentric layers and a large double-stranded DNA molecule that ranges in length between isolates from about 170 to 193 kbp [9]. It contains a conserved central region of about 125 kb and two variable ends. The differences in genome length are largely due to the gain or loss of members of the multigene families (MGF) located in the left and right variable regions [9]. A full genome sequencing of up to 16 virus isolates has recently been completed [10–14]. The ASF viral DNA contains between 151 and 167 open reading frames (ORFs) encoding 54 structural proteins and around 100 polypeptides in the targeted infected cells, monocytes and macrophages [15, 16]. The major components of the viral capsid, the protein p72, the two structural proteins p30 (p32) and p54 and the polyprotein pp62, have been identified as the most antigenic of the proteins that are responsible for the induction of antibodies after a natural infection [17, 18]. However, despite the usefulness of these proteins as sero-diagnostic targets, they are not sufficient for developing antibody-mediated protection against virus strains [19].Fig. 5

View Article: PubMed Central - PubMed

ABSTRACT

African Swine Fever (ASF) is an important contagious haemorrhagic viral disease affecting swine whose notification is mandatory due to its high mortality rates and the great sanitary and socioeconomic impact it has on international trade in animal and swine products.

This disease only affects porcine species, both wild and domestic, and produces a variety of clinical signs such as fever and functional disorders of the digestive and respiratory systems. Lesions are mainly characterized by congestive-haemorrhagic alterations. ASF epidemiology varies significantly between countries, regions and continents, since it depends on the characteristics of the virus in circulation, the presence of wild hosts and reservoirs, environmental conditions and human social behaviour. Furthermore, a specific host will not necessarily always play the same active role in the spread and maintenance of ASF in a particular area.

Currently, ASF is endemic in most sub-Saharan African countries where wild hosts and tick vectors (Ornithodoros) play an important role acting as biological reservoirs for the virus. In Europe, the disease has been endemic since 1978 on the island of Sardinia (Italy) and since 2007, when it was first reported in Georgia, in a number of Eastern European countries. It is also endemic in certain regions of the Russia Federation, where domestic pig and wild boar populations are widely affected. By contrast, in the affected eastern European Union (EU) countries where ASF is currently as epidemic, the on-going spread of the disease affects mainly wild boar populations located in restricted areas and, to a much less extent, domestic pigs. Unlike most livestock diseases, no vaccine or specific treatment is currently available for ASF. Therefore, disease control is mainly based on early detection and the application of strict sanitary and biosecurity measures. Epidemiology of ASF is very complex by the existence of different virus circulating, reservoirs and a number of scenarios, and the on-going spread of the disease through Africa and Europe. Survivor pigs can remain persistently infected for months which may contribute to virus transmission and thus the spread and maintenance of the disease, thereby complicating attempts to control it.

No MeSH data available.