On the origin and timing of Zika virus introduction in Brazil

On the origin and timing of Zika virus introduction in Brazil

Author Massad, E. Google Scholar
Nascimento Burattini, M. Autor UNIFESP Google Scholar
Khan, K. Google Scholar
Struchiner, C. J. Google Scholar
Coutinho, F. A. B. Google Scholar
Wilder-Smith, A. Google Scholar
Abstract The timing and origin of Zika virus (ZIKV) introduction in Brazil has been the subject of controversy. Initially, it was assumed that the virus was introduced during the FIFA World Cup in June-July 2014. Then, it was speculated that ZIKV may have been introduced by athletes from French Polynesia (FP) who competed in a canoe race in Rio de Janeiro in August 2014. We attempted to apply mathematical models to determine the most likely time window of ZIKV introduction in Brazil. Given that the timing and origin of ZIKV introduction in Brazil may be a politically sensitive issue, its determination (or the provision of a plausible hypothesis) may help to prevent undeserved blame. We used a simple mathematical model to estimate the force of infection and the corresponding individual probability of being infected with ZIKV in FP. Taking into account the air travel volume from FP to Brazil between October 2013 and March 2014, we estimated the expected number of infected travellers arriving at Brazilian airports during that period. During the period between December 2013 and February 2014, 51 individuals travelled from FP airports to 11 Brazilian cities. Basing on the calculated force of ZIKV infection (the per capita rate of new infections per time unit) and risk of infection (probability of at least one new infection), we estimated that 18 (95% CI 12-22) individuals who arrived in seven of the evaluated cities were infected. When basic ZIKV reproduction numbers greater than one were assumed in the seven evaluated cities, ZIKV could have been introduced in any one of the cities. Based on the force of infection in FP, basic reproduction ZIKV number in selected Brazilian cities, and estimated travel volume, we concluded that ZIKV was most likely introduced and established in Brazil by infected travellers arriving from FP in the period between October 2013 and March 2014, which was prior to the two aforementioned sporting events.
Keywords Force of infection
French Polynesia
mathematical models
risk
Zika virus
Language English
Sponsor CNPq
ZikaPLAN through the European Union's Horizon 2020 Research and Innovation Programme
Canadian Institutes of Health Research (CIHR)
consortium Canada-Latin/America-Caribbean Zika Virus Program
LIM01-HCFMUSP
Grant number ZikaPLAN: 734584
consortium Canada-Latin/America-Caribbean Zika Virus Program: 372512
Date 2017
Published in Epidemiology And Infection. New York, v. 145, n. 11, p. 2303-2312, 2017.
ISSN 0950-2688 (Sherpa/Romeo, impact factor)
Publisher Cambridge Univ Press
Extent 2303-2312
Origin http://dx.doi.org/10.1017/S0950268817001200
Access rights Closed access
Type Article
Web of Science ID WOS:000409124100015
URI http://repositorio.unifesp.br/handle/11600/51438

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