Estimating risks of importation and local transmission of Zika virus infection.
Estimating risks of importation and local transmission of Zika virus infection.
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作者：
Nah K;Mizumoto K;Miyamatsu Y;Yasuda Y;Kinoshita R;Nishiura H
背景。寨卡病毒（ZIKV）感染的国际传播引起了全球的关注。 ZIKV 由蚊子媒介伊蚊传播，该蚊子也是登革热和基孔肯雅病毒的媒介。方法。每个输入国家的 ZIKV 输入到达时间（即诊断出首例输入病例的时间）是从公开数据源收集的。采用生存分析模型，其中危害是航空公司运输网络数据所告知的有效距离的反函数，并使用登革热和基孔肯雅病毒传播数据，估计了输入和本地传播的风险。结果。总共有 78 个国家发现了输入性病例，自 2015 年在巴西发现第一例 ZIKV 以来，到达时间从 1 周到 44 周不等。虽然航空运输网络数据很好地解释了输入风险，但通过额外考虑登革热和基孔肯雅病毒的存在似乎可以最好地捕捉本地传播风险。讨论。鉴于轻度感染旅行者持续进行全球旅行，输入风险可能很高，但考虑到对 ZIKV 感染的公共卫生担忧源于小头畸形，更重要的是关注可能涉及孕妇的局部和广泛传播的风险。在有登革热或基孔肯雅热流行经历的热带和亚热带国家，经常会出现预期的本地传播风险。
Background. An international spread of Zika virus (ZIKV) infection has attracted global attention. ZIKV is conveyed by a mosquito vector, Aedes species, which also acts as the vector species of dengue and chikungunya viruses. Methods. Arrival time of ZIKV importation (i.e., the time at which the first imported case was diagnosed) in each imported country was collected from publicly available data sources. Employing a survival analysis model in which the hazard is an inverse function of the effective distance as informed by the airline transportation network data, and using dengue and chikungunya virus transmission data, risks of importation and local transmission were estimated. Results. A total of 78 countries with imported case(s) have been identified, with the arrival time ranging from 1 to 44 weeks since the first ZIKV was identified in Brazil, 2015. Whereas the risk of importation was well explained by the airline transportation network data, the risk of local transmission appeared to be best captured by additionally accounting for the presence of dengue and chikungunya viruses. Discussion. The risk of importation may be high given continued global travel of mildly infected travelers but, considering that the public health concerns over ZIKV infection stems from microcephaly, it is more important to focus on the risk of local and widespread transmission that could involve pregnant women. The predicted risk of local transmission was frequently seen in tropical and subtropical countries with dengue or chikungunya epidemic experience.