Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Equine Health Fund, Wits Health Consortium, Parktown, South Africa.
Transbound Emerg Dis. 2019 Mar;66(2):743-751. doi: 10.1111/tbed.13077. Epub 2018 Dec 3.
An outbreak of African horse sickness (AHS) caused by AHS virus type 1 occurred within the South African AHS surveillance zone during April and May 2016. The index case was detected by a private veterinarian through passive surveillance. There were 21 cases in total, which is relatively low compared to case totals during prior AHS outbreaks in the same region (and of the same AHS virus type) in 2004, 2011 and 2014. The affected proportion of horses on affected properties was 0.07 (95% CI 0.04, 0.11). Weather conditions were conducive to high midge activity immediately prior to the outbreak but midge numbers decreased rapidly with the advent of winter. The outbreak was localized, with 18 of the 21 cases occurring within 8 km of the index property and the three remaining cases on two properties within 21 km of the index property, with direction of spread consistent with wind-borne dispersion of infected midges. Control measures included implementation of a containment zone with movement restrictions on equids. The outbreak was attributed to a reversion to virulence of a live attenuated vaccine used extensively in South Africa. Outbreaks in the AHS control zones have a major detrimental impact on the direct export of horses from South Africa, notably to the European Union.
2016 年 4 月至 5 月期间，南非 AHS 监测区发生了由 AHS 病毒 1 型引起的 AHS 暴发。最初是由一位私人兽医通过被动监测发现了首例病例。总共有 21 例，与该地区（和相同 AHS 病毒类型）2004 年、2011 年和 2014 年的 AHS 暴发相比，这一数字相对较低。受影响的马的比例为 0.07（95%CI 0.04，0.11）。在疫情爆发前，天气条件有利于高角蝇的大量活动，但随着冬季的到来，角蝇的数量迅速减少。疫情是局部性的，21 例中有 18 例发生在距离首例病例 8 公里以内的地点，其余 3 例发生在距离首例病例 21 公里以内的两个地点，传播方向与受感染的角蝇随风传播一致。控制措施包括实施一个包含区，限制受感染的马的移动。疫情归因于南非广泛使用的活减毒疫苗的毒力恢复。AHS 控制区的疫情对南非马的直接出口产生了重大不利影响，特别是对欧盟。
