scholarly journals First molecular assessment of the African swine fever virus status of Ornithodoros ticks from Swaziland

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Carin I. Boshoff ◽  
Armanda D.S. Bastos ◽  
Mzwandi M. Dube ◽  
Livio Heath
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Virus Genome ◽  
Fever Virus ◽  
Nucleotide Sequencing ◽  
Dna Integrity ◽  
Primary Role ◽  
Sylvatic Cycle ◽  
Polymerase Chain ◽  
Haemorrhagic Disease

African swine fever (ASF) is an economically significant haemorrhagic disease of domestic pigs. It is caused by the African swine fever virus (ASFV), a deoxyribonucleic acid (DNA)arbovirus. Argasid ticks of the genus Ornithodoros, which are widely distributed throughout southern Africa, play a primary role in virus maintenance and spread within the endemic sylvatic cycle. The ASF status of Swaziland is unknown, but this land-locked country is surrounded by ASF-positive countries, has a burgeoning pig industry and sylvatic cycle hosts present within its borders. In this first assessment of ASF status, warthog burrows in seven nature reserves and game management areas in Swaziland were investigated for tick and virus presence. Tick infestation rates of between 33.3% – 88.8% were recovered for the four Ornithodoros-infested reserves. A total of 562 ticks were screened for virus genome presence using a duplex Polymerase Chain Reaction (PCR) that targets the C-terminal end of the p72 gene of the ASFV and confirms DNA integrity through amplification of the 16S rRNA tick host gene. All samples were negative for virus genome presence and positive for the tick genome target. Nucleotide sequencing of the latter confirmed that Ornithodoros ticks from Swaziland are identical to those from the Kruger National Park in South Africa across the gene region characterised. Whilst this first evaluation of ASF presence in Swaziland indicates that the virus does not appear to be present in the key virus vector, the presence of sylvatic cycle hosts, together with the country’s proximity to ASF-affected countries calls for expanded investigations and regular monitoring of the ASF status of Swaziland.

scholarly journals Isolation of a non-haemadsorbing, non-cytopathic strain of African swine fever virus in Madagascar

2001 ◽  
Vol 126 (3) ◽  
pp. 453-459 ◽  
Author(s):  
M. GONZAGUE ◽  
F. ROGER ◽  
A. BASTOS ◽  
C. BURGER ◽  
T. RANDRIAMPARANY ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Cytopathic Effect ◽  
Virus Isolation ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Virus Genome ◽  
Nucleotide Sequencing ◽  
Serological Survey ◽  
Chain Reaction ◽  
Polymerase Chain

African swine fever (ASF) suspected clinically in Madagascar (1998–9) was confirmed by polymerase chain reaction (PCR) and nucleotide sequencing, following virus isolation. No haemadsorption or cytopathic effect could be detected following leukocyte inoculation, but viral growth in cells was confirmed by PCR. Detection of ASF virus genome was carried out by amplification of a highly conserved region coding for the p72 protein. Nucleotide sequencing of the amplicon revealed 99·2% nucleotide identity between the recent Malagasy strains and a virus recovered from the 1994 outbreak in Mozambique (SPEC265). A serological survey performed on 449 sera, revealed that only 5·3% of the sera taken from pigs between 1998 and 1999 were positive.

scholarly journals Molecular monitoring of African swine fever virus using surveys targeted at adult Ornithodoros ticks : a re-evaluation of Mkuze Game Reserve, South Africa

2009 ◽  
Vol 76 (4) ◽  
Author(s):  
L.F. Arnot ◽  
J.T. Du Toit ◽  
A.D.S. Bastos
Keyword(s):  
South Africa ◽  
Internal Control ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Dna Integrity ◽  
Molecular Monitoring ◽  
Sylvatic Cycle ◽  
Pcr Screening ◽  
Game Reserve

The Mkuze Game Reserve (MGR), in north-eastern KwaZulu-Natal Province, South Africa is an African swine fever virus (ASF) controlled area. In a survey conducted in 1978, ASF prevalence in warthogs and Ornithodoros ticks in MGR was determined to be 2 % and 0.06 %, respectively. These values, acknowledged as being unusually low compared to other East and southern African ASF-positive sylvatic-cycle host populations, have not been assessed since. The availability of a sensitive PCR-based virus detection method, developed specifically for the sylvatic tampan host, prompted a re-evaluation of ASF virus (ASFV) prevalence in MGR ticks. Of the 98 warthog burrows inspected for Ornithodoros presence, 59 (60.2 %) were found to contain tampans and tick sampling was significantly male-biased. Whilst gender sampling-bias is not unusual, the 27 % increase in infestation rate of warthog burrows since the 1978 survey is noteworthy as it anticipates a concomitant increase in ASFV prevalence, particularly in light of the high proportion (75 %) of adult ticks sampled. However, despite DNA integrity being confirmed by internal control amplification of the host 16S gene, PCR screening failed to detect ASFV. These results suggest that ASFV has either disappeared from MGR or if present, is localized, occurring at exceptionally low levels. Further extensive surveys are required to establish the ASFV status of sylvatic hosts in this controlled area.

Two Novel Multigene Families, 530 and 300, in the Terminal Variable Regions of African Swine Fever Virus Genome

Virology ◽  
1994 ◽  
Vol 202 (2) ◽  
pp. 997-1002 ◽  
Author(s):  
T. Yozawa ◽  
G.F. Kutish ◽  
C.L. Afonso ◽  
Z. Lu ◽  
D.L. Rock
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Virus Genome ◽  
Fever Virus ◽  
Multigene Families ◽  
Variable Regions

Characterization of the African swine fever virus protein p49: a new late structural polypeptide

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Inmaculada Galindo ◽  
Eladio Viñuela ◽  
Angel L. Carrascosa
Keyword(s):  
Cell Attachment ◽  
African Swine Fever Virus ◽  
Rabbit Antiserum ◽  
African Swine Fever ◽  
Virus Genome ◽  
Fever Virus ◽  
Virus Protein ◽  
Significant Similarity ◽  
Reading Frame ◽  
Cell Extracts

The open reading frame B438L, located within the EcoRI B fragment of the African swine fever virus genome, is predicted to encode a protein of 438 amino acids with a molecular mass of 49·3 kDa. It presents a cell attachment RGD (Arg–Gly–Asp) motif but no other significant similarity to protein sequences in databases. Northern blot and primer extension analysis showed that B438L is transcribed only at late times during virus infection. The B438L gene product has been expressed in Escherichia coli, purified and used as an antigen for antibody production. The rabbit antiserum specific for pB438L recognized a protein of about 49 kDa in virus-infected cell extracts. This protein was synthesized late in infection by all the virus strains tested, was located in cytoplasmic virus factories and appeared as a structural component of purified virus particles.

scholarly journals Detection of African swine fever virus genotype XV in a sylvatic cycle in Saadani National Park, Tanzania

2020 ◽  
Author(s):  
Emma Peter ◽  
Eunice Machuka ◽  
Dedan Githae ◽  
Edward Okoth ◽  
Sarah Cleaveland ◽  
...  
Keyword(s):  
National Park ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Virus Genotype ◽  
Sylvatic Cycle

scholarly journals Identification of a functional small non-coding RNA encoded by African swine fever virus

2019 ◽  
Author(s):  
Laura E. M. Dunn ◽  
Alasdair Ivens ◽  
Christopher L. Netherton ◽  
David A. G. Chapman ◽  
Philippa M. Beard
Keyword(s):  
Small Rnas ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Dna Viruses ◽  
Log Reduction ◽  
Complex Interactions ◽  
Non Coding Rna ◽  
Haemorrhagic Disease ◽  
Cellular Components

AbstractAfrican swine fever virus (ASFV) causes a lethal haemorrhagic disease of domestic pigs, to which there is no vaccine available. ASFV has a large, double-stranded DNA genome that encodes over 150 proteins. Replication takes place in the cytoplasm of the cell and involves complex interactions with host cellular components including small non-coding RNAs (sncRNAs). A number of DNA viruses are known to manipulate sncRNA either by encoding their own or disrupting host sncRNA. In order to investigate the interplay between ASFV and sncRNAs, study of host and viral small RNAs extracted from ASFV-infected primary porcine macrophages (PAMs) was undertaken. We discovered that ASFV infection had only a modest effect on host miRNAs, with only 6 miRNAs differentially expressed during infection. The data also revealed 3 potential novel small RNAs encoded by ASFV, ASFVsRNA1-3. Further investigation of ASFVsRNA2 detected it in lymphoid tissue from pigs with ASF. Overexpression of ASFVsRNA2 led to up to a 1 log reduction in ASFV growth indicating that ASFV utilises a virally-encoded small RNA to disrupt its own replication. This study describes the modest impact of ASFV on host sncRNAs and the identification of a functional ASFV-encoded sncRNA.ImportanceAfrican swine fever (ASF) poses a major threat to pig populations and food security worldwide. The disease is endemic in Africa and Eastern Europe and rapidly emerging into Asia where it has led to the deaths of millions of pigs in the past 12 months. The development of safe and effective vaccines to protect pigs against ASF has been hindered by lack of understanding of the complex interactions between ASFV and the host cell. We focused our work on characterising the interactions between ASFV and sncRNAs. We found only modest changes to host sncRNA abundance after ASFV infection, and discovered a functional ASFV-encoded sncRNA. The knowledge from this study can be exploited to develop more effective ASFV vaccines that take advantage of the sncRNA system.

scholarly journals Increased resolution of African Swine Fever Virus genome patterns based on profile HMM protein domains

2020 ◽  
Author(s):  
Charles Masembe ◽  
My V.T. Phan ◽  
David L. Robertson ◽  
Matthew Cotten
Keyword(s):  
African Swine Fever Virus ◽  
Antiviral Agents ◽  
Protein Domains ◽  
African Swine Fever ◽  
Virus Genome ◽  
Fever Virus ◽  
Functional Protein ◽  
A Genome ◽  
Genomic Relationships ◽  
Genome Scale

ABSTRACTAfrican Swine Fever Virus (ASFV) was originally described in Africa almost 100 years ago and is now spreading uncontrolled across Europe and Asia and threatening to destroy the domestic pork industry. Neither effective antiviral drugs nor a protective vaccine are currently available. Efforts to understand the basis for viral pathogenicity and the development of attenuated potential vaccine strains are complicated by the large and complex ASFV genome. We report here a novel method of documenting viral diversity based on profile Hidden Markov Model domains on a genome scale. The method can be used to infer genomic relationships independent of genome alignments and also reveal ASFV genome sequence differences that alter the presence of functional protein domains in the virus. We show that the method can quickly identify differences and shared patterns between virulent and attenuated ASFV strains and will be a useful tool for developing much-needed vaccines and antiviral agents to help control this virus. The tool is rapid to run and easy to implement, readily available as a simple Docker image.

Pathogenesis of African swine fever virus inOrnithodorosticks

2001 ◽  
Vol 2 (2) ◽  
pp. 121-128 ◽  
Author(s):  
Steven B. Kleiboeker ◽  
Glen A. Scoles
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Sub Saharan Africa ◽  
Hemorrhagic Disease ◽  
Sylvatic Cycle ◽  
Infectious Dose ◽  
Domestic Pigs ◽  
Ornithodoros Porcinus Porcinus ◽  
Sub Saharan

AbstractAfrican swine fever virus (ASFV) is the only known DNA arbovirus and the sole member of the family Asfarviridae. It causes a lethal, hemorrhagic disease in domestic pigs. ASFV is enzootic in sub-Saharan Africa and is maintained in a sylvatic cycle by infecting both wild members of the Suidae (e.g. warthogs) and the argasid tickOrnithodoros porcinus porcinus. The pathogenesis of ASFV inO. porcinus porcinusticks is characterized by a low infectious dose, lifelong infection, efficient transmission to both pigs and ticks, and low mortality until after the first oviposition. ASFV pathogenesis in warthogs is characterized by an inapparent infection with transient, low viremic titers. ThusO. porcinus porcinusticks probably constitute the most important natural vector of ASFV, although both the mammalian and tick hosts are probably required for the maintenance of ASFV in the sylvatic cycle. The mechanism of ASFV transmission from the sylvatic cycle to domestic pigs is probably through infected ticks feeding on pigs. In addition toO. porcinus porcinus, a number of North American, Central American and Caribbean species ofOrnithodoroshave been shown to be potential vectors of ASFV.

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