Investigations on outbreaks of African horse sickness in the surveillance zone in South Africa.
Abstract: Confirmed outbreaks of African horse sickness (AHS) occurred in the surveillance zone of the Western Cape in 1999 and 2004, both of which led to a two-year suspension on the export of horses. Light trap surveys in the outbreak areas showed that known vector competent Culicoides species, notably C. imicola, were abundant and present in numbers equal to those in the traditional AHS endemic areas. Isolations of AHS virus serotypes 1 and 7, equine encephalosis virus, and bluetongue virus from field-collected C. imicola in the surveillance zone demonstrated that this species was highly competent and could transmit viruses belonging to different serogroups of the Orbivirus genus. Molecular identification of recovered virus isolates indicated that at least two incursions of AHS into the surveillance zone had taken place in 2004. The designation of an AHS-free zone in the Western Cape remains controversial since it can be easily compromised, as evidenced by the two recent outbreaks. In light of the results reported in the present study, the policy of maintaining a large population of unvaccinated horses in the surveillance zone should be reconsidered, as it leaves them vulnerable to infection with AHS virus, which is the most pathogenic of all equine viruses.
Publication Date: 2007-03-17 PubMed ID: 17361773
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- Journal Article
- Review
- African Horse Sickness
- Culicoides
- Diagnosis
- Disease control
- Disease Diagnosis
- Disease Etiology
- Disease Management
- Disease Outbreaks
- Disease Surveillance
- Epidemiology
- Equine Diseases
- Equine Health
- Horses
- Infectious Disease
- Public Health
- Serotypes
- Vector-borne disease
- Veterinary Medicine
- Veterinary Science
- Virology
- Virus
Summary
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The research article discusses the outbreaks of African horse sickness (AHS) in the surveillance zone of Western Cape, South Africa in 1999 and 2004, the vectors involved, virus serotypes isolated, and the implications of these outbreaks on the policy of maintaining a large population of unvaccinated horses.
Outbreaks of AHS and Impact on Horse Exports
- The research investigates the outbreaks of African horse sickness (AHS) in the Western Cape’s surveillance zone in 1999 and 2004. These outbreaks resulted in a two-year suspension on the export of horses due to the highly contagious nature of the disease and its potential threat to global horse populations.
Role of Culicoides Species
- The researchers conducted light trap surveys in the outbreak areas. They found that vector competent Culicoides species, particularly C. imicola — a type of small biting fly or midge — were abundant and present in numbers comparable to those found in traditional AHS endemic areas.
Virus Isolations
- The study further identified that field-collected C. imicola in the surveillance zone were highly competent in transmitting diseases. They isolated AHS virus serotypes 1 and 7, equine encephalosis virus, and bluetongue virus from these species. These diseases belong to different serogroups of the Orbivirus genus.
Multiple Incursions of AHS
- Molecular identification of the recovered virus isolates suggested that at least two separate introductions of the AHS virus into the surveillance zone occurred in 2004.
Controversy Surrounding AHS-Free Zone
- The categorization of an AHS-free zone in the Western Cape remains contested as its status can be easily compromised, as seen by the two recent outbreaks. The research thus questions the policy around maintaining unvaccinated horses in these surveillance zones.
Need for Policy Review
- The susceptibility of the unvaccinated horse population in the surveillance zone is highlighted, given the ability of C. imicola to transmit the AHS virus, which is considered the most pathogenic of all equine viruses. The authors recommend a reconsideration of the policy.
Cite This Article
APA
Venter GJ, Koekemoer JJ, Paweska JT.
(2007).
Investigations on outbreaks of African horse sickness in the surveillance zone in South Africa.
Rev Sci Tech, 25(3), 1097-1109.
Publication
Researcher Affiliations
- Agricultural Research Council-Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort, 0110 South Africa.
MeSH Terms
- African Horse Sickness / epidemiology
- African Horse Sickness Virus / genetics
- African Horse Sickness Virus / isolation & purification
- Animals
- Ceratopogonidae / virology
- Disease Outbreaks / veterinary
- Horses
- Insect Vectors / virology
- Prevalence
- Sentinel Surveillance / veterinary
- South Africa / epidemiology
References
This article includes 48 references
Citations
This article has been cited 14 times.- Li N, Meng J, He Y, Wang W, Wang J. Potential roles of Culicoides spp. (Culicoides imicola, Culicoides oxystoma) as biological vectors of bluetongue virus in Yuanyang of Yunnan, P. R. China. Front Cell Infect Microbiol 2023;13:1283216.
- Tirosh-Levy S, Steinman A. Equine Encephalosis Virus. Animals (Basel) 2022 Jan 29;12(3).
- Goffredo M, Quaglia M, De Ascentis M, d'Alessio SG, Federici V, Conte A, Venter GJ. The Absence of Abdominal Pigmentation in Livestock Associated Culicoides following Artificial Blood Feeding and the Epidemiological Implication for Arbovirus Surveillance. Pathogens 2021 Dec 2;10(12).
- Rutkowska DA, Mokoena NB, Tsekoa TL, Dibakwane VS, O'Kennedy MM. Plant-produced chimeric virus-like particles - a new generation vaccine against African horse sickness. BMC Vet Res 2019 Dec 3;15(1):432.
- Porphyre T, Grewar JD. Assessing the potential of plains zebra to maintain African horse sickness in the Western Cape Province, South Africa. PLoS One 2019;14(10):e0222366.
- Bakhoum MT, Sarr M, Fall AG, Huber K, Fall M, Sembène M, Seck MT, Labuschagne K, Gardès L, Ciss M, Gimonneau G, Bouyer J, Baldet T, Garros C. DNA barcoding and molecular identification of field-collected Culicoides larvae in the Niayes area of Senegal. Parasit Vectors 2018 Dec 3;11(1):615.
- Steyn J, Venter GJ, Labuschagne K, Majatladi D, Boikanyo SN, Lourens C, Ebersohn K, Venter EH. Possible over-wintering of bluetongue virus in Culicoides populations in the Onderstepoort area, Gauteng, South Africa. J S Afr Vet Assoc 2016 Oct 31;87(1):e1-e5.
- Grewar JD, Thompson PN, Lourens CW, Guthrie AJ. Equine encephalosis in Thoroughbred foals on a South African stud farm. Onderstepoort J Vet Res 2015 Sep 30;82(1):966.
- Sambou M, Aubadie-Ladrix M, Fenollar F, Fall B, Bassene H, Almeras L, Sambe-Ba B, Perrot N, Chatellier S, Faye N, Parola P, Wade B, Raoult D, Mediannikov O. Comparison of matrix-assisted laser desorption ionization-time of flight mass spectrometry and molecular biology techniques for identification of Culicoides (Diptera: ceratopogonidae) biting midges in senegal. J Clin Microbiol 2015 Feb;53(2):410-8.
- Diarra M, Fall M, Fall AG, Diop A, Seck MT, Garros C, Balenghien T, Allène X, Rakotoarivony I, Lancelot R, Mall I, Bakhoum MT, Dosum AM, Ndao M, Bouyer J, Guis H. Seasonal dynamics of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in the Niayes area of Senegal. Parasit Vectors 2014 Mar 31;7:147.
- Kim HC, Bellis GA, Kim MS, Klein TA, Chong ST, Park JY. Seasonal abundance of Culicoides (Diptera: Ceratopogonidae) collected by mosquito Magnet® in Northern Gyeonggi-do (Province), Korea. Korean J Parasitol 2014 Feb;52(1):57-62.
- Kim HC, Bellis GA, Kim MS, Chong ST, Lee DK, Park JY, Yeh JY, Klein TA. Seasonal abundance of biting midges, Culicoides spp. (Diptera: Ceratopogonidae), collected at cowsheds in the southern part of the Republic of Korea. Korean J Parasitol 2012 Jun;50(2):127-31.
- van Eeden C, Williams JH, Gerdes TG, van Wilpe E, Viljoen A, Swanepoel R, Venter M. Shuni virus as cause of neurologic disease in horses. Emerg Infect Dis 2012 Feb;18(2):318-21.
- Bitew M, Andargie A, Bekele M, Jenberie S, Ayelet G, Gelaye E. Serological survey of African horse sickness in selected districts of Jimma zone, Southwestern Ethiopia. Trop Anim Health Prod 2011 Dec;43(8):1543-7.
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