Volume 22, Number 12—December 2016
African Horse Sickness Caused by Genome Reassortment and Reversion to Virulence of Live, Attenuated Vaccine Viruses, South Africa, 2004–2014
|Parameter†||2004 Stellenbosch||2011 Mamre||2014 Porterville||2014 Robertson|
|No. confirmed cases||23 (16)‡||84 (73)§||89||22|
|No. deaths||18 (16)‡||64 (64)§||13||1|
|Case-fatality rate, %
|No. subclinical cases||0||15 (4)†||52||17|
|No. vaccinated cases||2/23||2/84||35/89||3/22|
|No. properties affected||10 (8)‡||47 (45)§||31||8|
*AHS, African horse sickness.
†The parameters were calculated by using the current World Organization for Animal Health (OIE) case definition. Parameters calculated by using the case definitions when the outbreaks occurred are in parenthesis for the 2004 and 2011 outbreaks.
‡An additional 5 clinical cases and 2 deaths that met the criteria of the current OIE AHS case definition were not included based on the case definition in place at the time of this outbreak (13).
§An additional 11 subclinical cases that met the criteria of the current OIE AHS case definition were not included based on the case definition in place at the time of this outbreak (15).
- Zientara S, Weyer CT, Lecollinet S. African horse sickness. Rev Sci Tech. 2015;34:315–27.
- Du Toit RM. Transmission of blue-tongue and horse-sickness by Culicoides. Onderstepoort J Vet Sci Anim Ind. 1944;19:7–16.
- Maclachlan NJ, Guthrie AJ. Re-emergence of bluetongue, African horse sickness, and other orbivirus diseases. Vet Res. 2010;41:35.
- Maclachlan NJ, Mayo CE. Potential strategies for control of bluetongue, a globally emerging, Culicoides-transmitted viral disease of ruminant livestock and wildlife. Antiviral Res. 2013;99:79–90.
- Guichard S, Guis H, Tran A, Garros C, Balenghien T, Kriticos DJ. Worldwide niche and future potential distribution of Culicoides imicola, a major vector of bluetongue and African horse sickness viruses. PLoS One. 2014;9:e112491.
- Maclachlan NJ, Mayo CE, Daniels PW, Savini G, Zientara S, Gibbs EPJ. Bluetongue. Rev Sci Tech. 2015;34:329–40.
- Guthrie AJ, Weyer CT. African horse sickness. In: Sprayberry KA, Robinson NE, editors. Robinson’s current therapy in equine medicine. 7th ed. Philadelphia: Saunders; 2015. p. 150–1.
- Theiler A. Die Sudafrikanische Pferdesterbe. Deuts Tierarztl Wschr. 1901;9:201–3, 221–6, 233–7, 241.
- M’Fadyean J. African horse sickness. J Comp Pathol Ther. 1900;13:1–20 .
- von Teichman BF, Dungu B, Smit TK. In vivo cross-protection to African horse sickness serotypes 5 and 9 after vaccination with serotypes 8 and 6. Vaccine. 2010;28:6505–17.
- World Organization for Animal Health. Infection with African horse sickness virus. Terrestrial Animal Health Code, 2015 [cited 2016 Jul 5]. http://www.oie.int/index.php?id=169&L=0&htmfile=chapitre_ahs.htm
- Republic of South Africa Department of Agriculture, Forestry, and Fisheries. Animal Diseases Act, 1984 [cited 2016 Jul 5]. http://www.daff.gov.za/daffweb3/Branches/Agricultural-Production-Health-Food-Safety/Animal-Health/importexport/legislation/diseaseact
- Sinclair M, Bührmann G, Gummow B. An epidemiological investigation of the African horsesickness outbreak in the Western Cape Province of South Africa in 2004 and its relevance to the current equine export protocol. J S Afr Vet Assoc. 2006;77:191–6.
- Quan M, van Vuuren M, Howell PG, Groenewald D, Guthrie AJ. Molecular epidemiology of the African horse sickness virus S10 gene. J Gen Virol. 2008;89:1159–68.
- Grewar JD, Weyer CT, Guthrie AJ, Koen P, Davey S, Quan M, The 2011 outbreak of African horse sickness in the African horse sickness controlled area in South Africa. J S Afr Vet Assoc. 2013;84:1–7 .
- Grewar JD. Suspected African horse sickness outbreak—Melkbosstrand. Western Cape Government Epidemiology Report, 2013;5(5) [cited 2016 Jul 5]. http://www.elsenburg.com/vetepi/epireport_pdf/May2013.pdf
- Grewar JD. African horse sickness outbreak resolved. Western Cape Government Epidemiology Report, 2014;6(6) [cited 2016 Jul 5]. http://www.elsenburg.com/vetepi/epireport_pdf/June2014.pdf
- World Organization for Animal Health. African horse sickness, South Africa [cited 2016 Jul 5]. http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapFullEventReport&reportid=5493
- World Organization for Animal Health. African horse sickness, South Africa [cited 2016 Jul 5]. http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapEventSummary&reportid=6650
- Guthrie AJ, Coetzee P, Martin DP, Lourens CW, Venter EH, Weyer CT, Complete genome sequences of the three African horse sickness virus strains from a commercial trivalent live attenuated vaccine. Genome Announc. 2015;3:e00814–5. http://dx.doi.org10.1128/genomeA.00814-15
- Guthrie AJ, Coetzee P, Martin DP, Lourens CW, Venter EH, Weyer CT, Complete genome sequences of the four African horse sickness virus strains from a commercial tetravalent live attenuated vaccine. Genome Announc. 2015;3:e01375–15. http://dx.doi.org10.1128/genomeA.01375-15
- Guthrie AJ, Maclachlan NJ, Joone C, Lourens CW, Weyer CT, Quan M, Diagnostic accuracy of a duplex real-time reverse transcription quantitative PCR assay for detection of African horse sickness virus. J Virol Methods. 2013;189:30–5.
- Weyer CT, Joone C, Lourens CW, Monyai MS, Koekemoer O, Grewar JD, Development of three triplex real-time reverse transcription PCR assays for the qualitative molecular typing of the nine serotypes of African horse sickness virus. J Virol Methods. 2015;223:69–74.
- Potgieter AC, Page NA, Liebenberg J, Wright IM, Landt O, van Dijk AA. Improved strategies for sequence-independent amplification and sequencing of viral double-stranded RNA genomes. J Gen Virol. 2009;90:1423–32.
- Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Geneious Basic: an integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics. 2012;28:1647–9.
- Katoh K, Standley DM. MAFFT multiple sequence alignment software version 7: improvements in performance and usability. Mol Biol Evol. 2013;30:772–80.
- Guindon S, Dufayard JF, Lefort V, Anisimova M, Hordijk W, Gascuel O. New algorithms and methods to estimate maximum-likelihood phylogenies: assessing the performance of PhyML 3.0. Syst Biol. 2010;59:307–21.
- Pommier T, Canbäck B, Lundberg P, Hagström A, Tunlid A. RAMI: a tool for identification and characterization of phylogenetic clusters in microbial communities. Bioinformatics. 2009;25:736–42.
- Martin DP, Murrel B, Golden M, Khoosal A, Muhire B. RDP4: detection and analysis of recombination patterns in virus genomes. Virus Evol. 2015;1:1–5.
- Sugiyama K, Bishop DHL, Roy P. Analysis of the genomes of bluetongue viruses recovered from different states of the United States and at different times. Am J Epidemiol. 1982;115:332–47.
- Nomikou K, Hughes J, Wash R, Kellam P, Breard E, Zientara S, Widespread reassortment shapes the evolution and epidemiology of bluetongue virus following European invasion. PLoS Pathog. 2015;11:e1005056.
- Weyer CT, Quan M, Joone C, Lourens CW, MacLachlan NJ, Guthrie AJ. African horse sickness in naturally infected, immunised horses. Equine Vet J. 2013;45:117–9.
- Martin LA, Meyer AJ, O’Hara RS, Fu H, Mellor PS, Knowles NJ, Phylogenetic analysis of African horse sickness virus segment 10: sequence variation, virulence characteristics and cell exit. Arch Virol Suppl. 1998;14:281–93.
- Huismans H, van Staden V, Fick WC, van Niekerk M, Meiring TL. A comparison of different orbivirus proteins that could affect virulence and pathogenesis. Vet Ital. 2004;40:417–25.
- Potgieter AC, Wright IM, van Dijk AA. Consensus sequence of 27 African horse sickness virus genomes from viruses collected over a 76-year period (1933 to 2009). Genome Announc. 2015;3:e00921–15.
- Nevill EM, Venter GJ, Edwardes M, Pajor ITP, Meiswinkel R, van Gas JH. Culicoides species associated with livestock in the Stellenbosch area of the Western Cape Province, Republic of South Africa (Diptera: Ceratopogonidae). Onderstepoort J Vet Res. 1988;55:101–6.
- Guthrie AJ, Quan M, Lourens CW, Audonnet JC, Minke JM, Yao J, Protective immunization of horses with a recombinant canarypox virus vectored vaccine co-expressing genes encoding the outer capsid proteins of African horse sickness virus. Vaccine. 2009;27:4434–8.
- Alberca B, Bachanek-Bankowska K, Cabana M, Calvo-Pinilla E, Viaplana E, Frost L, Vaccination of horses with a recombinant modified vaccinia Ankara virus (MVA) expressing African horse sickness (AHS) virus major capsid protein VP2 provides complete clinical protection against challenge. Vaccine. 2014;32:3670–4.