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.

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.

Development of a real‐time PCR assay for detection of African swine fever virus with an endogenous internal control

2020 ◽  
Vol 67 (6) ◽  
pp. 2446-2454 ◽  
Author(s):  
Yin Wang ◽  
Lizhe Xu ◽  
Lance Noll ◽  
Colin Stoy ◽  
Elizabeth Porter ◽  
...  
Keyword(s):  
Real Time ◽  
Internal Control ◽  
Real Time Pcr ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Pcr Assay

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 Extension of Sylvatic Circulation of African Swine Fever Virus in Extralimital Warthogs in South Africa

2021 ◽  
Vol 8 ◽  
Author(s):  
Anthony F. Craig ◽  
Mathilde L. Schade-Weskott ◽  
Henry J. Harris ◽  
Livio Heath ◽  
Gideon J. P. Kriel ◽  
...  
Keyword(s):  
South Africa ◽  
Invasive Species ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Serological Evidence ◽  
The South ◽  
Domestic Pigs ◽  
The Past ◽  
The North

Sylvatic circulation of African swine fever virus (ASFV) in warthogs and Ornithodoros ticks that live in warthog burrows historically occurred in northern South Africa. Outbreaks of the disease in domestic pigs originated in this region. A controlled area was declared in the north in 1935 and regulations were implemented to prevent transfer of potentially infected suids or products to the rest of the country. However, over the past six decades, warthogs have been widely translocated to the south where the extralimital animals have flourished to become an invasive species. Since 2016, there have been outbreaks of ASF in pigs outside the controlled area that cannot be linked to transfer of infected animals or products from the north. An investigation in 2008–2012 revealed that the presence of Ornithodoros ticks and ASFV in warthog burrows extended marginally across the boundary of the controlled area. We found serological evidence of ASFV circulation in extralimital warthogs further south in the central part of the country.

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.

Development of a nested PCR and its internal control for the detection of African swine fever virus (ASFV) in Ornithodoros erraticus

2005 ◽  
Vol 151 (4) ◽  
pp. 819-826 ◽  
Author(s):  
A. P. Basto ◽  
R. S. Portugal ◽  
R. J. Nix ◽  
C. Cartaxeiro ◽  
F. Boinas ◽  
...  
Keyword(s):  
Internal Control ◽  
Nested Pcr ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus

Development of an internal control for the detection of the African swine fever virus by PCR

2002 ◽  
Vol 16 (3) ◽  
pp. 237-242 ◽  
Author(s):  
M Gonzague ◽  
C Plin ◽  
L Bakkali-Kassimi ◽  
A Boutrouille ◽  
C Cruciere
Keyword(s):  
Internal Control ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus

scholarly journals Updated distribution and host records for the argasid tick Ornithodoros (Pavlovskyella) zumpti: A potential vector of African swine fever virus in South Africa

2021 ◽  
Vol 88 (1) ◽  
Author(s):  
Anthony F. Craig ◽  
Livio Heath ◽  
Jan E. Crafford ◽  
Juergen A. Richt ◽  
Robert Swanepoel
Keyword(s):  
South Africa ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Eastern Cape ◽  
The South ◽  
Domestic Pigs ◽  
The North ◽  
Argasid Tick ◽  
First Time

African swine fever virus (ASFV) causes a lethal and contagious disease of domestic pigs. In South Africa, the virus historically circulated in warthogs and ornithodorid ticks that were only found in warthog burrows in the north of the country. Regulations implemented in 1935 to prevent transfer of infected animals or products to the south initially proved effective but from 2016 there have been outbreaks of disease in the south that cannot be traced to transfer of infection from the north. From 1963 there were widespread translocations of warthogs to the south, initially from a source considered to be free of ornithodorid ticks. We undertook to determine whether sylvatic circulation of ASFV occurs in the south, including identification of potential new vectors, through testing extralimital warthogs for antibody and ticks for virus. Results of testing warthogs for antibody and other species of ticks for virus will be presented separately. Here we report finding Ornithodoros (Pavlovskyella) zumpti ticks in warthog burrows for the first time. This occurred in the Eastern Cape Province (ECP) in 2019. Since African swine fever was recognised in the ECP for the first time in 2020 and outbreaks of the disease in domestic pigs continue to occur there, priority should be given to determining the distribution range and vector potential of O. (P.) zumpti for ASFV.

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