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An Updated Review of Ornithodoros Ticks as Reservoirs of African Swine Fever in Sub-Saharan Africa and Madagascar. Pathogens 2023; 12:pathogens12030469. [PMID: 36986391 PMCID: PMC10059854 DOI: 10.3390/pathogens12030469] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
This updated review provides an overview of the available information on Ornithodoros ticks as reservoirs and biological vectors of the ASF virus in Africa and Indian Ocean islands in order to update the current knowledge in this field, inclusive of an overview of available methods to investigate the presence of ticks in the natural environment and in domestic pig premises. In addition, it highlights the major areas of research that require attention in order to guide future investigations and fill knowledge gaps. The available information suggests that current knowledge is clearly insufficient to develop risk-based control and prevention strategies, which should be based on a sound understanding of genotype distribution and the potential for spillover from the source population. Studies on tick biology in the natural and domestic cycle, including genetics and systematics, represent another important knowledge gap. Considering the rapidly changing dynamics affecting the African continent (demographic growth, agricultural expansion, habitat transformation), anthropogenic factors influencing tick population distribution and ASF virus (ASFV) evolution in Africa are anticipated and have been recorded in southern Africa. This dynamic context, together with the current global trends of ASFV dissemination, highlights the need to prioritize further investigation on the acarological aspects linked with ASF ecology and evolution.
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Mushagalusa CA, Penrith ML, Etter EMC. Spatiotemporal analysis of African swine fever outbreaks on South African smallholder farms, 1993–2018. J S Afr Vet Assoc 2022; 93:82-88. [DOI: 10.36303/jsava.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Affiliation(s)
- CA Mushagalusa
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria,
South Africa
- Department of Animal Production, Faculty of Agriculture, Université Evangélique en Afrique,
Democratic Republic of Congo
- Laboratoire de Biomathématiques et d’Estimations Forestières (LABEF), Faculté des Sciences Agronomiques (FSA), Université d’Abomey-Calavi,
Benin
| | - M-L Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria,
South Africa
| | - EMC Etter
- Department of Production Animal Studies, Faculty of Veterinary Sciences, University of Pretoria,
South Africa
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Petit-Bourg, Guadeloupe,
France
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier,
France
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3
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Craig AF, Schade-Weskott ML, Rametse T, Heath L, Kriel GJP, de Klerk-Lorist LM, van Schalkwyk L, Trujillo JD, Crafford JE, Richt JA, Swanepoel R. Detection of African Swine Fever Virus in Ornithodoros Tick Species Associated with Indigenous and Extralimital Warthog Populations in South Africa. Viruses 2022; 14:1617. [PMID: 35893686 PMCID: PMC9331695 DOI: 10.3390/v14081617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 11/23/2022] Open
Abstract
We investigated the possibility that sylvatic circulation of African swine fever virus (ASFV) in warthogs and Ornithodoros ticks had extended beyond the historically affected northern part of South Africa that was declared a controlled area in 1935 to prevent the spread of infection to the rest of the country. We recently reported finding antibody to the virus in extralimital warthogs in the south of the country, and now describe the detection of infected ticks outside the controlled area. A total of 5078 ticks was collected at 45 locations in 7/9 provinces during 2019-2021 and assayed as 711 pools for virus content by qPCR, while 221 pools were also analysed for tick phylogenetics. Viral nucleic acid was detected in 50 tick pools representing all four members of the Ornithodoros (Ornithodoros) moubata complex known to occur in South Africa: O. (O.) waterbergensis and O. (O.) phacochoerus species yielded ASFV genotypes XX, XXI, XXII at 4 locations and O. (O.) moubata yielded ASFV genotype I at two locations inside the controlled area. Outside the controlled area, O. (O.) moubata and O. (O.) compactus ticks yielded ASFV genotype I at 7 locations, while genotype III ASFV was identified in O. (O.) compactus ticks at a single location. Two of the three species of the O. (O.) savignyi complex ticks known to be present in the country, O. (O.) kalahariensis and O. (O.) noorsveldensis, were collected at single locations and found negative for virus. The only member of the Pavlovskyella subgenus of Ornithodoros ticks known to occur in South Africa, O. (P.) zumpti, was collected from warthog burrows for the first time, in Addo National Park in the Eastern Cape Province where ASFV had never been recorded, and it tested negative for the viral nucleic acid. While it is confirmed that there is sylvatic circulation of ASFV outside the controlled area in South Africa, there is a need for more extensive surveillance and for vector competence studies with various species of Ornithodoros ticks.
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Affiliation(s)
- Anthony F. Craig
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (A.F.C.); (M.L.S.-W.); (L.v.S.); (J.E.C.); (R.S.)
| | - Mathilde L. Schade-Weskott
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (A.F.C.); (M.L.S.-W.); (L.v.S.); (J.E.C.); (R.S.)
| | - Thapelo Rametse
- Agricultural Research Council-Onderstepoort Veterinary Research Transboundary Animal Diseases Laboratory, Onderstepoort, Pretoria 0110, South Africa; (T.R.); (L.H.)
| | - Livio Heath
- Agricultural Research Council-Onderstepoort Veterinary Research Transboundary Animal Diseases Laboratory, Onderstepoort, Pretoria 0110, South Africa; (T.R.); (L.H.)
| | - Gideon J. P. Kriel
- Provincial Veterinary Services, Department of Agriculture, Land Reform and Rural Development, Kimberley 8300, South Africa;
| | - Lin-Mari de Klerk-Lorist
- Office of the State Veterinarian, Department of Agriculture, Land Reform and Rural Development, Kruger National Park, P.O. Box 12, Skukuza 1350, South Africa;
| | - Louis van Schalkwyk
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (A.F.C.); (M.L.S.-W.); (L.v.S.); (J.E.C.); (R.S.)
- Office of the State Veterinarian, Department of Agriculture, Land Reform and Rural Development, Kruger National Park, P.O. Box 12, Skukuza 1350, South Africa;
- Department of Migration, Max Planck Institute of Animal Behavior, Am Obstberg 1, D-78315 Radolfzell, Germany
| | - Jessie D. Trujillo
- Diagnostic Medicine/Pathobiology, Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA;
| | - Jan E. Crafford
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (A.F.C.); (M.L.S.-W.); (L.v.S.); (J.E.C.); (R.S.)
| | - Juergen A. Richt
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (A.F.C.); (M.L.S.-W.); (L.v.S.); (J.E.C.); (R.S.)
- Diagnostic Medicine/Pathobiology, Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA;
| | - Robert Swanepoel
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria 0110, South Africa; (A.F.C.); (M.L.S.-W.); (L.v.S.); (J.E.C.); (R.S.)
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4
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Costard S, Perez AM, Zagmutt FJ, Pouzou JG, Groenendaal H. Partitioning, a Novel Approach to Mitigate the Risk and Impact of African Swine Fever in Affected Areas. Front Vet Sci 2022; 8:812876. [PMID: 35274016 PMCID: PMC8902292 DOI: 10.3389/fvets.2021.812876] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/31/2021] [Indexed: 11/13/2022] Open
Abstract
As African swine fever (ASF) continues to expand geographically, supplementary control strategies are needed to reduce disease risk and impact in affected areas. Full depopulation is central to current ASF control efforts, and its efficacy depends on surveillance and timely disease reporting, while resulting in large losses regardless of the producers' efforts to promptly detect, report, and contain the disease. This disconnect between prompt detection and reporting, and subsequent farm losses, can deter producers to invest in ASF detection and control. Alternative approaches are needed to incentivize individual producers to invest in early detection and reporting. We postulate that commercial swine farms may be effectively partitioned in separate units, or subpopulations, to which biosecurity, surveillance and control can be applied. The suggested Partitioning framework relies on three main components: 1. external and internal biosecurity to reduce the risk of ASF introduction and maintain separate subpopulations; 2. cost-effective on-farm ASF surveillance to enhance early detection; 3. response plans at the unit level, including culling of affected subpopulations, and demonstration of freedom from disease on the remaining ones. With such Partitioning approach, individual producers may reduce ASF risk on a farm and in the region, while also reducing ASF outbreak losses via targeted depopulation of affected units. It requires relevant legislation to incorporate the notion of within-farm subpopulations and provide a regulatory framework for targeted depopulation and substantiation of disease freedom. Its design should be tailored to fit individual farms. Partitioning can be an effective public-private partnership approach for ASF risk reduction. It should be driven by industry, as its benefits are accrued mainly by individual producers, but regulatory oversight is key to ensure proper implementation and avoid further disease spread. Partitioning's value is greatest for producers in ASF-affected regions, but ASF-free areas could also benefit from it for preparedness and early detection. It could also be adapted to other transboundary animal diseases and can be implemented as a stand-alone program or in conjunction with other efforts such as zoning and compartmentalization. Partitioning would contribute to the improved resilience and sustainability of the global pork industry and will benefit consumers and society through improved food security and animal welfare.
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Affiliation(s)
- Solenne Costard
- EpiX Analytics, Fort Collins, CO, United States
- *Correspondence: Solenne Costard
| | - Andres M. Perez
- Center for Animal Health and Food Safety, College of Veterinary Medicine, University of Minnesota, Minneapolis, MN, United States
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Penrith ML, Kivaria FM. One hundred years of African swine fever in Africa: where have we been, where are we now, where are we going? Transbound Emerg Dis 2022; 69:e1179-e1200. [PMID: 35104041 DOI: 10.1111/tbed.14466] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/26/2022]
Abstract
One hundred years have passed since the first paper on African swine fever (ASF) was published by Montgomery in 1921. With no vaccine, ineffectiveness of prevention and control measures, and lack of common interest in eradicating the disease, ASF has proven to be one of the most devastating diseases because of its significant sanitary and socioeconomic consequences. The rapid spread of the disease on the European and Asian continents and its recent appearance in the Caribbean puts all countries at great risk because of global trade. The incidence of ASF has also increased on the African continent over the last few decades, extending its distribution far beyond the area in which the ancient sylvatic cycle is present with its complex epidemiological transmission pathways involving virus reservoirs in ticks and wild African Suidae. Both in that area and elsewhere, efficient transmission by infected domestic pigs and virus resistance in infected animal products and fomites mean that human driven factors along the pig value chain are the dominant impediments for its prevention, control, and eradication. Control efforts in Africa are furthermore hampered by the lack of information about the size and location of the fast-growing pig population, particularly in the dynamic smallholder sector that constitutes up to 90% of pig production in the region. A vaccine that will be both affordable and effective against multiple genotypes of the virus is not a short-term reality. Therefore, a strategy for management of ASF in sub-Saharan Africa is needed to provide a roadmap for the way forward for the continent. This review explores the progression of ASF and our knowledge of it through research over a century in Africa, our current understanding of ASF, and what must be done going forwards to improve the African situation and contribute to global prevention and control. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mary Louise Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Fredrick Mathias Kivaria
- Food and Agriculture Organization of the UN, Block P, Level 3, United Nations Complex, UN Avenue, Gigiri, Nairobi, PO Box: 30470, GPO, Nairobi, 00100, Kenya
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6
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Craig AF, Schade-Weskott ML, Harris HJ, Heath L, Kriel GJP, de Klerk-Lorist LM, van Schalkwyk L, Buss P, Trujillo JD, Crafford JE, Richt JA, Swanepoel R. Extension of Sylvatic Circulation of African Swine Fever Virus in Extralimital Warthogs in South Africa. Front Vet Sci 2021; 8:746129. [PMID: 34901242 PMCID: PMC8651561 DOI: 10.3389/fvets.2021.746129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 10/20/2021] [Indexed: 11/17/2022] Open
Abstract
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.
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Affiliation(s)
- Anthony F Craig
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Mathilde L Schade-Weskott
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Henry J Harris
- Agricultural Research Council-Onderstepoort Veterinary Research Transboundary Animal Diseases Laboratory, Pretoria, South Africa
| | - Livio Heath
- Agricultural Research Council-Onderstepoort Veterinary Research Transboundary Animal Diseases Laboratory, Pretoria, South Africa
| | - Gideon J P Kriel
- Provincial Veterinary Services, Department of Agriculture, Land Reform and Rural Development, Kimberley, South Africa
| | - Lin-Mari de Klerk-Lorist
- Office of the State Veterinarian, Department of Agriculture, Land Reform and Rural Development, Kruger National Park, Skukuza, South Africa
| | - Louis van Schalkwyk
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Office of the State Veterinarian, Department of Agriculture, Land Reform and Rural Development, Kruger National Park, Skukuza, South Africa.,Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
| | - Peter Buss
- Veterinary Wildlife Services, South African National Parks, Kruger National Park, Skukuza, South Africa
| | - Jessie D Trujillo
- Diagnostic Medicine/Pathobiology, Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Jan E Crafford
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Juergen A Richt
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Diagnostic Medicine/Pathobiology, Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Robert Swanepoel
- Vectors and Vector-Borne Diseases Research Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
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Uwishema O, Chalhoub E, Zahabioun A, David SC, Khoury C, Al-Saraireh TH, Bekele BK, Mwazighe RM, Onyeaka H. The rising incidence of African swine fever during the COVID-19 pandemic in Africa: Efforts, challenges and recommendations. Int J Health Plann Manage 2021; 37:561-567. [PMID: 34636084 PMCID: PMC8652873 DOI: 10.1002/hpm.3357] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Olivier Uwishema
- Research and Education, Oli Health Magazine Organization, Kigali, Rwanda.,Clinton Global Initiative University, New York, New York, USA.,Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey
| | - Elie Chalhoub
- Research and Education, Oli Health Magazine Organization, Kigali, Rwanda.,Faculty of Medicine, University of Saint Joseph of Beirut, Beirut, Lebanon
| | - Amirsaman Zahabioun
- Clinton Global Initiative University, New York, New York, USA.,Department of Biology, College of Arts and Sciences, University of North Carolina at Chapel Hill, Chapell Hill, North Carolina, USA
| | - Success Chekwube David
- Research and Education, Oli Health Magazine Organization, Kigali, Rwanda.,Faculty of Pharmaceutical Sciences, University of Nigeria, Nsukka, Nigeria
| | - Carlo Khoury
- Research and Education, Oli Health Magazine Organization, Kigali, Rwanda.,Faculty of Medicine, University of Saint Joseph of Beirut, Beirut, Lebanon
| | - Taif Haitham Al-Saraireh
- Research and Education, Oli Health Magazine Organization, Kigali, Rwanda.,Faculty of Surgery and Medicine, Mutah University, Karak, Jordan
| | - Bezawit Kassahun Bekele
- Research and Education, Oli Health Magazine Organization, Kigali, Rwanda.,School of Medicine, College of Health Science, Addis Ababa University, Addis Ababa, Ethiopia
| | - Rehema Mkamburi Mwazighe
- Research and Education, Oli Health Magazine Organization, Kigali, Rwanda.,Medical Laboratory Technologist, The Mombasa Hospital, Mombasa, Kenya
| | - Helen Onyeaka
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
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Mushagalusa CA, Etter E, Penrith ML. Review of African swine fever outbreaks history in South Africa: From 1926 to 2018. Onderstepoort J Vet Res 2021; 88:e1-e10. [PMID: 34636620 PMCID: PMC8517827 DOI: 10.4102/ojvr.v88i1.1919] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 06/17/2021] [Accepted: 06/25/2021] [Indexed: 11/04/2022] Open
Abstract
The article reviews the outbreaks and distribution of African swine fever (ASF) in South Africa since the first probable outbreak that occurred in the Koedoesrand Ward in 1926. Retrospective data on the ASF outbreaks in South Africa were obtained from the World Organisation for Animal Health (OIE) disease database and the South African veterinary services annual reports in addition to published articles and online sources. South Africa has experienced many outbreaks that can be divided into 2 time periods: the period before the development of the OIE diseases database (1993) and the period after. More than 141 outbreaks of ASF were reported during the first period. Since the development of OIE disease database, 72 outbreaks directly involving 2968 cases, 2187 dead and 2358 killed pigs mainly in smallholder pig farms were reported. The median number of cases for a given ASF outbreak is 17, but in 50% of outbreaks no pigs were killed for prevention. The most important ASF outbreak was reported in April 2014 in the Greater Zeerust district (North West province) involving 326 cases and 1462 killed pigs. However, the outbreak with highest mortality involving 250 pigs was reported in 2016 (Free State province). According to phylogenetic analysis, nine p72 genotypes (I, III, IV, VII, VIII, XIX, XX, XXI and XXII) have been identified in South Africa. Season-wise, more outbreaks were recorded during summer. It was also observed that the OIE disease database could contain errors that would have been introduced through compiled forms at country level. Spatiotemporal studies on ASF outbreaks in South Africa are therefore required in order to assess statistically and quantitatively the clustering of outbreaks over space and time.
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Affiliation(s)
- Ciza A Mushagalusa
- Department of Animal Production, Faculty of Agriculture, Université Evangélique en Afrique, Bukavu, the Democratic Republic of the Congo.
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ANTIBODY PREVALENCE TO AFRICAN SWINE FEVER VIRUS, MYCOBACTERIUM BOVIS, FOOT-AND-MOUTH DISEASE VIRUS, RIFT VALLEY FEVER VIRUS, INFLUENZA A VIRUS, AND BRUCELLA AND LEPTOSPIRA SPP. IN FREE-RANGING WARTHOG (PHACOCHOERUS AFRICANUS) POPULATIONS IN SOUTH AFRICA. J Wildl Dis 2021; 57:60-70. [PMID: 33635986 DOI: 10.7589/jwd-d-20-00011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/28/2020] [Indexed: 11/20/2022]
Abstract
The warthog (Phacochoerus africanus) can be used as a model for investigating disease transmission at the human, wildlife, and livestock interface. An omnivore and scavenger, a warthog moves freely between natural ecotypes, farmland, and human communities and is susceptible to diseases of zoonotic, agricultural, and conservation concern. A retrospective study using 100 individual serum samples collected from May 1999 to August 2016 was performed to determine antibody prevalence to seven pathogens in warthogs from five locations in northeastern South Africa. Higher prevalence of antibodies to African swine fever virus and Mycobacterium bovis were detected in warthogs from the Greater Kruger National Park ecosystem in comparison to lower prevalence of antibodies to M. bovis and no antibodies to African swine fever virus in warthogs from uMhkuze Game Reserve. Low prevalence of antibodies to foot-and-mouth disease virus, Rift Valley fever virus, and influenza A virus was detected in all locations, and no antibodies against Brucella and Leptospira spp. were detected. No statistically significant difference in antibody prevalence was found between sexes for any disease. At the univariate analysis, M. bovis seropositivity was significantly different among age categories, with 49% (35/71) of adults found positive versus 29% (4/14) of juveniles and 9% (1/11) of sub-adults (Fisher's exact test, P=0.020), and between the sampling locations (Fisher's exact test, P=0.001). The multivariate model results indicated that juvenile warthogs had lower odds of testing positive to M. bovis antibodies than adults (juveniles' odds ratio [OR]=0.17, 95% confidence interval [CI]: 0.02-1.0), although this result was not statistically significant at the 5% level (P=0.052). For warthogs sampled at Satara Buffalo Camp, the odds (OR=0.22, 95% CI: 0.035-0.96) of being M. bovis antibody positive were significantly lower (P=0.043) than for warthogs sampled at Skukuza. Of particular interest in this study was the detection of warthogs seropositive for influenza A virus.
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Amar S, De Boni L, de Voux A, Heath L, Geertsma P. An outbreak of African swine fever in small-scale pigs, Gauteng, South Africa, July 2020. Int J Infect Dis 2021; 110 Suppl 1:S44-S49. [PMID: 33895412 DOI: 10.1016/j.ijid.2021.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/01/2021] [Accepted: 04/03/2021] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVES Since 2012, outbreaks of African swine fever (ASF) in domestic pigs have increased outside of South Africa's ASF control zone. This study describes the epidemiological investigation and findings of an ASF outbreak in a small-scale pig unit in Gauteng Province and makes recommendations to prevent future outbreaks. METHODS PCR testing and molecular analysis were performed on pig tissue samples. Veterinary services conducted epidemiological investigations, forward and backward tracing, and surveillance. Farm management and biosecurity practices were assessed. Quarantine, culling, carcass disposal, and disinfection were implemented. RESULTS ASF virus genotype I was detected. A concurrent ASF outbreak in neighbouring Mpumalanga Province was identified as a possible source. Inadequate biosecurity measures probably facilitated viral transmission. Potential mechanisms for the introduction of the ASF virus include swill feeding practices, free roaming of pigs, scavenging, illegal slaughter, and trade of pig products within the community. CONCLUSIONS Molecular typing of the ASF virus linked the outbreak to an ongoing ASF outbreak in Mpumalanga Province. Pig enterprises with poor biosecurity practices may face greater risk of ASF introduction. Small-scale pig keepers should be targeted for ASF awareness and education campaigns. Innovative and cost-effective biosecurity solutions are needed in this resource-poor setting.
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Affiliation(s)
- Shira Amar
- South African Field Epidemiology Training Programme, Division of Public Health, Surveillance and Response, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg, South Africa; Division of Epidemiology and Biostatistics, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa.
| | - Liesl De Boni
- Gauteng Veterinary Services, Gauteng Department of Agriculture and Rural Development (GDARD), Johannesburg, South Africa
| | - Alex de Voux
- South African Field Epidemiology Training Programme, Division of Public Health, Surveillance and Response, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg, South Africa; Division of Epidemiology and Biostatistics, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Livio Heath
- Onderstepoort Veterinary Research, Agricultural Research Council, Pretoria, South Africa
| | - Peter Geertsma
- Gauteng Veterinary Services, Gauteng Department of Agriculture and Rural Development (GDARD), Johannesburg, South Africa
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11
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Busch F, Haumont C, Penrith ML, Laddomada A, Dietze K, Globig A, Guberti V, Zani L, Depner K. Evidence-Based African Swine Fever Policies: Do We Address Virus and Host Adequately? Front Vet Sci 2021; 8:637487. [PMID: 33842576 PMCID: PMC8024515 DOI: 10.3389/fvets.2021.637487] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/18/2021] [Indexed: 12/15/2022] Open
Abstract
African swine fever (ASF) is one of the most threatening diseases for the pig farming sector worldwide. Prevention, control and eradication remain a challenge, especially in the absence of an effective vaccine or cure and despite the relatively low contagiousness of this pathogen in contrast to Classical Swine Fever or Foot and Mouth disease, for example. Usually lethal in pigs and wild boar, this viral transboundary animal disease has the potential to significantly disrupt global trade and threaten food security. This paper outlines the importance of a disease-specific legal framework, based on the latest scientific evidence in order to improve ASF control. It compares the legal basis for ASF control in a number of pig-producing regions globally, considering diverse production systems, taking into account current scientific evidence in relation to ASF spread and control. We argue that blanket policies that do not take into account disease-relevant characteristics of a biological agent, nor the specifics under which the host species are kept, can hamper disease control efforts and may prove disproportionate.
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Affiliation(s)
- Frank Busch
- Institute of International Animal Health/One Health, Friedrich-Loeffler-Institute, Greifswald, Germany
| | - Céline Haumont
- National College of Veterinary Medicine, Food Science and Engineering, Oniris, Nantes, France
| | - Mary-Louise Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | | | - Klaas Dietze
- Institute of International Animal Health/One Health, Friedrich-Loeffler-Institute, Greifswald, Germany
| | - Anja Globig
- Institute of International Animal Health/One Health, Friedrich-Loeffler-Institute, Greifswald, Germany
| | - Vittorio Guberti
- Istituto Superiore per la Protezione e la Ricerca Ambientale, Epidemiology and Ecology Unit, Ozzano Emilia, Italy
| | - Laura Zani
- Institute of International Animal Health/One Health, Friedrich-Loeffler-Institute, Greifswald, Germany
| | - Klaus Depner
- Institute of International Animal Health/One Health, Friedrich-Loeffler-Institute, Greifswald, Germany
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Investigation into eradication of African swine fever in domestic pigs from a previous outbreak (2016/17) area of South Africa. Res Vet Sci 2020; 133:42-47. [PMID: 32932197 DOI: 10.1016/j.rvsc.2020.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/20/2020] [Accepted: 08/28/2020] [Indexed: 11/24/2022]
Abstract
A serological survey was conducted to evaluate the eradication of African swine fever (ASF) infection eighteen months after clinical surveillance and selective culling had been completed during domestic cycle outbreaks in parts of South Africa in 2016/17. Three hundred and twenty-two serum samples from 85 pig keepers were collected in the study area and tested for the presence of antibodies against the ASF virus (ASFV). None of the samples contained detectable levels of antibodies against ASFV. These results together with the findings from clinical surveillance following culling activities suggest that the disease had been eradicated from the domestic pig population in this area following the outbreaks. Questionnaire responses from the pig keepers in this area highlighted the need to implement basic biosecurity measures in smallholder pig keepers to prevent outbreaks of ASF in South Africa.
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Janse van Rensburg L, Van Heerden J, Penrith ML, Heath LE, Rametse T, Etter EMC. Investigation of African swine fever outbreaks in pigs outside the controlled areas of South Africa, 2012-2017. J S Afr Vet Assoc 2020; 91:e1-e9. [PMID: 32787419 PMCID: PMC7433221 DOI: 10.4102/jsava.v91i0.1997] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 03/30/2020] [Accepted: 03/30/2020] [Indexed: 11/18/2022] Open
Abstract
South Africa historically experienced sporadic African swine fever (ASF) outbreaks in domestic pigs in the northern parts of the country. This was subsequently indicated to be because of spillover from the sylvatic cycle of ASF between warthog and tampans (soft ticks) in the area. South Africa declared this area an ASF-controlled area in 1935, and the area is still controlled in terms of the Animal Diseases Act, 1984 (Act 35 of 1984). Two main epidemics of ASF in domestic pigs were identified outside of the South African ASF-controlled area. The first occurred in 2012 with outbreaks in Gauteng and Mpumalanga provinces, and the second occurred in 2016-2017 with outbreaks in the North West, Free State and Northern Cape provinces. These were the first ASF epidemics in South Africa associated with transmission of the disease via a domestic cycle. This study found that the spread of ASF in these epidemics was mainly via auctions, swill feeding and scavenging. These three aspects need to be addressed in terms of awareness and education on the disease including implementation of biosecurity measures in order to prevent future ASF outbreaks in South Africa. Specific biosecurity measures should be implemented in the semi-commercial sector to prevent ASF-infected pigs and pig products from being moved to naïve pigs and therefore spreading the disease.
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Affiliation(s)
- Leana Janse van Rensburg
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa; and Directorate Animal Health, Department of Agriculture, Forestry and Fisheries of the Republic of South Africa, Pretoria.
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14
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Janse van Rensburg L, Etter E, Heath L, Penrith ML, van Heerden J. Understanding African swine fever outbreaks in domestic pigs in a sylvatic endemic area: The case of the South African controlled area between 1977-2017. Transbound Emerg Dis 2020; 67:2753-2769. [PMID: 32438525 DOI: 10.1111/tbed.13632] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 11/28/2022]
Abstract
South Africa declared a controlled area for African swine fever (ASF) in 1935, consisting of the northern parts of Limpopo, Mpumalanga, North West and Kwa-Zulu Natal Provinces. The area was delineated based on the endemic presence of the sylvatic cycle of ASF, involving warthogs and argasid ticks. Occasionally, spillover occurs from the sylvatic cycle to domestic pigs, causing ASF outbreaks. In the period 1977 to 2017, 59 outbreaks of ASF were reported in domestic pigs within the ASF controlled area of South Africa. During these outbreaks, at least 4,031 domestic pigs either died or were culled. Season did not affect the number of reported ASF outbreaks, but the number of reported outbreaks in this area per year was thought to be slowly increasing, although not statistically significant. Outbreaks occurred predominantly in Limpopo province (93%) and were mostly due to contact (or suspected contact) with warthog or warthog carcasses. Clustering analysis of outbreaks found that the local municipalities of Ramotshere Moiloa, Lephalale and Thabazimbi had the highest relative risk for outbreaks. In 32 of the 59 outbreaks, the genotype of the ASF virus (ASFV) involved could be determined. Phylogenetic analysis of ASFVs detected in domestic pigs during the study period revealed that p72 genotypes I, III, IV, VII, VIII, XIX, XX, XXI and XXII had been involved in causing outbreaks within the ASF controlled area. No outbreaks were reported in the Kwa-Zulu Natal part of the controlled area during this period. South Africa is unlikely to eradicate all sources of ASFV as spillover from the sylvatic cycle in the controlled area continued to occur, but with the implementation of appropriate biosecurity measures pigs can be successfully farmed despite the presence of ASFV in African wild suids and soft ticks.
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Affiliation(s)
- Leana Janse van Rensburg
- Department of Production Animal Studies, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, South Africa.,Directorate Animal Health, Department of Agriculture, Forestry and Fisheries of the Republic of South Africa, Pretoria, South Africa
| | - Eric Etter
- Department of Production Animal Studies, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, South Africa.,CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
| | - Livio Heath
- Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa
| | - Mary-Louise Penrith
- TAD Scientific, Pretoria, South Africa.,Department of Veterinary Tropical Diseases, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, South Africa
| | - Juanita van Heerden
- Onderstepoort Veterinary Research, Agricultural Research Council, Onderstepoort, South Africa
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Mulumba-Mfumu LK, Saegerman C, Dixon LK, Madimba KC, Kazadi E, Mukalakata NT, Oura CAL, Chenais E, Masembe C, Ståhl K, Thiry E, Penrith ML. African swine fever: Update on Eastern, Central and Southern Africa. Transbound Emerg Dis 2019; 66:1462-1480. [PMID: 30920725 DOI: 10.1111/tbed.13187] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/21/2019] [Accepted: 03/24/2019] [Indexed: 11/28/2022]
Abstract
Control of African swine fever (ASF) in countries in Eastern, Central and Southern Africa (ECSA) is particularly complex owing to the presence of all three known epidemiological cycles of maintenance of the virus, namely an ancient sylvatic cycle involving the natural hosts and vectors of the disease as well as domestic cycles with and without involvement of natural vectors. While the situation is well documented in some of the countries, for others very little information is available. In spite of the unfavourable ASF situation, the pig population in the sub-region has grown exponentially in recent decades and is likely to continue to grow in response to rapid urban growth resulting in increasing demand for animal protein by populations that are no longer engaged in livestock production. Better management of ASF will be essential to permit the pig sector to reach its full potential as a supplier of high quality protein and a source of income to improve livelihoods and create wealth. No vaccine is currently available and it is likely that, in the near future, the sub-region will continue to rely on the implementation of preventive measures, based on the epidemiology of the disease, to avoid both the devastating losses that outbreaks can cause and the risk the sub-region poses to other parts of Africa and the world. The current situation in the ECSA sub-region is reviewed and gaps in knowledge are identified in order to support ongoing strategy development for managing ASF in endemic areas.
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Affiliation(s)
- Léopold K Mulumba-Mfumu
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo.,Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR- ULiège), Fundamental and Applied Research for Animals & Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Claude Saegerman
- Research Unit of Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR- ULiège), Fundamental and Applied Research for Animals & Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | | | - Kapanga C Madimba
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Eric Kazadi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Ndeji T Mukalakata
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Chris A L Oura
- School of Veterinary Medicine, Faculty of Medical Sciences, University of the West Indies, Champ Fleurs, Trinidad and Tobago
| | - Erika Chenais
- Department of Disease Control and Epidemiology, SVA, Uppsala, Sweden
| | - Charles Masembe
- College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Karl Ståhl
- Department of Disease Control and Epidemiology, SVA, Uppsala, Sweden
| | - Etienne Thiry
- Veterinary Virology and Animal Viral Diseases, Fundamental and Applied Research for Animals & Health (FARAH) Center, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Mary Louise Penrith
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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16
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Costard S, Wieland B, de Glanville W, Jori F, Rowlands R, Vosloo W, Roger F, Pfeiffer DU, Dixon LK. African swine fever: how can global spread be prevented? Philos Trans R Soc Lond B Biol Sci 2009; 364:2683-96. [PMID: 19687038 PMCID: PMC2865084 DOI: 10.1098/rstb.2009.0098] [Citation(s) in RCA: 345] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
African swine fever (ASF) is a devastating haemorrhagic fever of pigs with mortality rates approaching 100 per cent. It causes major economic losses, threatens food security and limits pig production in affected countries. ASF is caused by a large DNA virus, African swine fever virus (ASFV). There is no vaccine against ASFV and this limits the options for disease control. ASF has been confined mainly to sub-Saharan Africa, where it is maintained in a sylvatic cycle and/or among domestic pigs. Wildlife hosts include wild suids and arthropod vectors. The relatively small numbers of incursions to other continents have proven to be very difficult to eradicate. Thus, ASF remained endemic in the Iberian peninsula until the mid-1990s following its introductions in 1957 and 1960 and the disease has remained endemic in Sardinia since its introduction in 1982. ASF has continued to spread within Africa to previously uninfected countries, including recently the Indian Ocean islands of Madagascar and Mauritius. Given the continued occurrence of ASF in sub-Saharan Africa and increasing global movements of people and products, it is not surprising that further transcontinental transmission has occurred. The introduction of ASF to Georgia in the Caucasus in 2007 and dissemination to neighbouring countries emphasizes the global threat posed by ASF and further increases the risks to other countries. We review the mechanisms by which ASFV is maintained within wildlife and domestic pig populations and how it can be transmitted. We then consider the risks for global spread of ASFV and discuss possibilities of how disease can be prevented.
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Affiliation(s)
- Solenne Costard
- The Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, UK
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