Enzootic Circulation of Chikungunya Virus in East Africa: Serological Evidence in Non-human Kenyan Primates
Enzootic Circulation of Chikungunya Virus in East Africa: Serological Evidence in Non-human Kenyan Primates
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DOI：
10.4269/ajtmh.17-0126
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发表时间：
2017-01-01
影响因子：
3.3
通讯作者：
Weaver, Scott C.
中科院分区：
文献类型：
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作者：
Eastwood, Gillian;Sang, Rosemary C.;Weaver, Scott C.
基孔肯雅病毒(CHIKV)是一种全球新出现的病原体，可引起人类虚弱的关节痛和发烧。这种蚊媒甲型病毒最早于坦桑尼亚(1953年)被发现，直到2004年从不明来源重新出现在肯尼亚之前，它几乎没有得到进一步的关注。这次暴发随后蔓延到印度洋，适应了一种新的城市媒介传播。根据假设，在肯尼亚存在CHIKV的先祖周期(如西非报告的那样，在非人类灵长类动物(NHP)和树栖伊蚊之间。蚊子)，我们寻找地方性传播和人类溢出事件的证据。我们最初使用空斑减少中和试验筛选了来自肯尼亚的252份存档的NHP血清。鉴于CHIKV总体血清阳性率为13.1%(肯尼亚西部略高)，我们在2014年从卡卡梅加县的地点寻找了更新的NHP样本，采样了野生蓝猴、橄榄狒狒和红尾猴(N=33)。我们还在肯尼亚沿海的夸莱附近采集了34只黄狒狒的样本。总体而言，2014年CHIKV血清阳性率为13.4%(9/67)。发生了对密切相关的O‘nyong-Nyong病毒(ONNV)的抗体反应；然而，中和效价太低，不能确定ONNV的暴露。还检测到黄病毒登革热的血清阳性率(28%)，主要发生在夸莱附近，这表明可能是人类传染给了狒狒。一些青少年和亚成人NHP中的CHIKV抗体表明最近发生了循环。我们得出结论，尽管2004年的人类暴发只在沿海地区报告，但奇卡病毒仍在肯尼亚西部传播。需要进一步努力了解东非CHIKV的地方性生态，以确定可能启动城市传播的人类外溢接触地点。
Chikungunya virus (CHIKV) is a globally emerging pathogen causing debilitating arthralgia and fever in humans. First identified in Tanzania (1953), this mosquito-borne alphavirus received little further attention until a 2004 re-emergence in Kenya from an unknown source. This outbreak subsequently spread to the Indian Ocean, with adaptation for transmission by a new urban vector. Under the hypothesis that sylvatic progenitor cycles of CHIKV exist in Kenya (as reported in West Africa, between non-human primates (NHPs) and arboreal Aedes spp. mosquitoes), we pursued evidence of enzootic transmission and human spillover events. We initially screened 252 archived NHP sera from Kenya using plaque reduction neutralization tests. Given an overall CHIKV seroprevalence of 13.1% (marginally higher in western Kenya), we sought more recent NHP samples during 2014 from sites in Kakamega County, sampling wild blue monkeys, olive baboons, and red-tailed monkeys (N = 33). We also sampled 34 yellow baboons near Kwale, coastal Kenya. Overall, CHIKV seropositivity in 2014 was 13.4% (9/67). Antibodies reactive against closely related o'nyong-nyong virus (ONNV) occurred; however, neutralization titers were too low to conclude ONNV exposure. Seroprevalence for the flavivirus dengue was also detected (28%), mostly near Kwale, suggesting possible spillback from humans to baboons. CHIKV antibodies in some juvenile and subadult NHPs suggested recent circulation. We conclude that CHIKV is circulating in western Kenya, despite the 2004 human outbreaks only being reported coastally. Further work to understand the enzootic ecology of CHIKV in east Africa is needed to identify sites of human spillover contact where urban transmission may be initiated.