title: Zika in Rio de Janeiro: Assessment of basic reproduction number and comparison with dengue outbreaks.
abstract: Zika virus infection was declared a public health emergency of international concern in February 2016 in response to the outbreak in Brazil and its suspected link with congenital anomalies. In this study, we use notification data and disease natural history parameters to estimate the basic reproduction number (R 0) of Zika in Rio de Janeiro, Brazil. We also obtain estimates of R 0 of dengue from time series of dengue cases in the outbreaks registered in 2002 and 2012 in the city, when DENV-3 and DENV-4 serotypes, respectively, had just emerged. Our estimates of the basic reproduction number for Zika in Rio de Janeiro based on surveillance notifications (R 0 = 2·33, 95% CI: 1·97-2·97) were higher than those obtained for dengue in the city (year 2002: R 0 = 1·70 [1·50-2·02]; year 2012: R 0 = 1·25 [1·18-1·36]). Given the role of Aedes aegypti as vector of both the Zika and dengue viruses, we also derive R 0 of Zika as a function of both dengue reproduction number and entomological and epidemiological parameters for dengue and Zika. Using the dengue outbreaks from previous years allowed us to estimate the potential R 0 of Zika. Our estimates were closely in agreement with our first Zika's R 0 estimation from notification data. Hence, these results validate deriving the potential risk of Zika transmission in areas with recurring dengue outbreaks. Whether transmission routes other than vector-based can sustain a Zika epidemic still deserves attention, but our results suggest that the Zika outbreak in Rio de Janeiro emerged due to population susceptibility and ubiquitous presence of Ae. aegypti.
authors.affiliation: Programa de Computação Científica, Fundação Oswaldo Cruz,Rio de Janeiro, RJ,Brazil.
authors.forename: D A M
authors.identifier: 0000-0001-8371-2959
authors.initials: DAM
authors.lastname: Villela
authors.affiliation: Programa de Computação Científica, Fundação Oswaldo Cruz,Rio de Janeiro, RJ,Brazil.
authors.forename: L S
authors.initials: LS
authors.lastname: Bastos
authors.affiliation: Programa de Computação Científica, Fundação Oswaldo Cruz,Rio de Janeiro, RJ,Brazil.
authors.forename: L M
authors.initials: LM
authors.lastname: DE Carvalho
authors.affiliation: Programa de Computação Científica, Fundação Oswaldo Cruz,Rio de Janeiro, RJ,Brazil.
authors.forename: O G
authors.initials: OG
authors.lastname: Cruz
authors.affiliation: Programa de Computação Científica, Fundação Oswaldo Cruz,Rio de Janeiro, RJ,Brazil.
authors.forename: M F C
authors.initials: MFC
authors.lastname: Gomes
authors.affiliation: Secretaria Municipal de Saúde do Rio de Janeiro,Rio de Janeiro, RJ,Brazil.
authors.forename: B
authors.initials: B
authors.lastname: Durovni
authors.affiliation: Secretaria Municipal de Saúde do Rio de Janeiro,Rio de Janeiro, RJ,Brazil.
authors.forename: M C
authors.initials: MC
authors.lastname: Lemos
authors.affiliation: Secretaria Municipal de Saúde do Rio de Janeiro,Rio de Janeiro, RJ,Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Saraceni
authors.affiliation: Escola de Matemática Aplicada, Fundação Getulio Vargas (FGV),Rio de Janeiro, RJ,Brazil.
authors.forename: F C
authors.initials: FC
authors.lastname: Coelho
authors.affiliation: Programa de Computação Científica, Fundação Oswaldo Cruz,Rio de Janeiro, RJ,Brazil.
authors.forename: C T
authors.initials: CT
authors.lastname: Codeço
mesh_terms: D000330:Aedes / Q000821:virology; D000818:Animals; D050936:Basic Reproduction Number; D001938:Brazil / Q000453:epidemiology; D003715:Dengue / Q000453:epidemiology* / Q000821:virology; D003716:Dengue Virus / Q000502:physiology*; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D015994:Incidence; D007303:Insect Vectors / Q000821:virology; D008297:Male; D011634:Public Health; D000071244:Zika Virus / Q000502:physiology*; D000071243:Zika Virus Infection / Q000453:epidemiology* / Q000821:virology
keywords: Basic reproduction number; Zika; dengue