Lying in wait: the resurgence of dengue virus after the Zika epidemic in Brazil

Abstract

After the Zika virus (ZIKV) epidemic in the Americas in 2016, both Zika and dengue incidence declined to record lows in many countries in 2017–2018, but in 2019 dengue resurged in Brazil, causing ~2.1 million cases. In this study we use epidemiological, climatological and genomic data to investigate dengue dynamics in recent years in Brazil. First, we estimate dengue virus force of infection (FOI) and model mosquito-borne transmission suitability since the early 2000s. Our estimates reveal that DENV transmission was low in 2017–2018, despite conditions being suitable for viral spread. Our study also shows a marked decline in dengue susceptibility between 2002 and 2019, which could explain the synchronous decline of dengue in the country, partially as a result of protective immunity from prior ZIKV and/or DENV infections. Furthermore, we performed phylogeographic analyses using 69 newly sequenced genomes of dengue virus serotype 1 and 2 from Brazil, and found that the outbreaks in 2018–2019 were caused by local DENV lineages that persisted for 5–10 years, circulating cryptically before and after the Zika epidemic. We hypothesize that DENV lineages may circulate at low transmission levels for many years, until local conditions are suitable for higher transmission, when they cause major outbreaks.

Clinical outcomes of dengue virus infection in pregnant and non-pregnant women of reproductive age: a retrospective cohort study from 2016 to 2019 in Paraná, Brazil

“…Although variations in dengue incidence are expected, this drop in cases raises some questions, such as a possible influence of the Zika virus (ZIKV) epidemic that took place in Brazil and Latin America in the year of 2016. This epidemic was followed by a dramatic decrease of dengue and Zika cases in 2017 and 2018 [ 38 , 39 ]. Several hypotheses were considered as possible explanations, such as changes in epidemiological surveillance systems, cross-immunity and impact of climate change and multiple arboviruses in mosquito population [ 38 ].…”

“…This epidemic was followed by a dramatic decrease of dengue and Zika cases in 2017 and 2018 [ 38 , 39 ]. Several hypotheses were considered as possible explanations, such as changes in epidemiological surveillance systems, cross-immunity and impact of climate change and multiple arboviruses in mosquito population [ 38 ]. In a previous debate, the protective cross-immunity generated by the simultaneous circulation of more than one type of arboviruses was considered as the most probable explanation by a panel of experts [ 38 ].…”

“…Several hypotheses were considered as possible explanations, such as changes in epidemiological surveillance systems, cross-immunity and impact of climate change and multiple arboviruses in mosquito population [ 38 ]. In a previous debate, the protective cross-immunity generated by the simultaneous circulation of more than one type of arboviruses was considered as the most probable explanation by a panel of experts [ 38 ]. Additionally, a study conducted in two different Brazilian states found that between 2000 and 2019 population susceptibility to dengue infection had reduced related to previous dengue and Zika infection, resulting in cross-immunity which could partially explain the decrease in dengue cases observed in 2017 and 2018 [ 39 ].…”

Molecular Characterization of Imported and Autochthonous Dengue in Northeastern Spain

“…albopictus strains have shown that local mosquitoes are more susceptible to CHIKV than to DENV [36]. This may contribute to explaining why large outbreaks of CHIKV have occurred in countries like Italy despite the fact that the number of imported CHIKV infections is, by far, much lower than the number of imported DENV cases in Europe [37,38]. However, autochthonous transmission of DENV in the last decade in continental Europe has been reported almost every year since 2013, with several countries experiencing different local transmission events in the same year [5].…”

Development and Characterization of a Multiplex Assay to Quantify Complement-Fixing Antibodies against Dengue Virus

“…However, the immune interaction among Flaviviruses may be more complex than expected. A DENV2 outbreak of unprecedented magnitude was reported in Nicaragua in 2019 and its severity was linked to previous ZIKV exposure [ 51 ], yet a similar pattern was not observed in other countries heavily affected by the outbreak [ 52 ]. The circumstances by which ZIKV immunity might confer protection against DENV or mediate pathogenesis are not entirely clear, although rapid waning of antibody responses may contribute to these different outcomes [ 53 , 54 ].…”