Background. An international spread of Zika virus (ZIKV) infection has attracted global attention. ZIKV is conveyed by mosquito vector, Aedes species which also act 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 source. Employing a survival analysis model in which the hazard is an inverse function of the effective

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... istance 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. PeerJ reviewing PDF | Abstract 17 Background. An international spread of Zika virus (ZIKV) infection has attracted global 18 attention. ZIKV is conveyed by mosquito vector, Aedes species which also act as the vector 19 species of dengue and chikungunya viruses. 20 Methods. Arrival time of ZIKV importation (i.e. the time at which the first imported case was 21 diagnosed) in each imported country was collected from publicly available data source. 22 Employing a survival analysis model in which the hazard is an inverse function of the effective 23 distance as informed by the airline transportation network data, and using dengue and 24 Chikungunya virus transmission data, risks of importation and local transmission were estimated. 25 Results. A total of 78 countries with imported case(s) have been identified, with the arrival time 26 ranging from 1 to 44 weeks since the first ZIKV was identified in Brazil, 2015. Whereas the risk 27 of importation was well explained by the airline transportation network data, the risk of local 28 transmission appeared to be best captured by additionally accounting for the presence of dengue 29 and Chikungunya viruses. 30 Discussion. The risk of importation may be high given continued global travel of mildly infected 31 travelers, but, considering that the public health concerns over ZIKV infection stems from 32 microcephaly, it is more important to focus on the risk of local and widespread transmission that 33 could involve pregnant women. The predicted risk of local transmission was frequently seen in 34 tropical and subtropical countries with dengue or Chikungunya epidemic experience. PeerJ reviewing PDF |