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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: 4] [Impact Index Per Article: 1.3] [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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