Re-visiting the evolution, dispersal and epidemiology of Zika virus in Asia

Abstract

Based on serological evidence and viral isolation, Zika virus (ZIKV) has circulated for many years relatively benignly in a sylvatic cycle in Africa and an urban cycle in South East Asia (SEA). With the recent availability of limited but novel Indian ZIKV sequences to add to the plethora of SEA sequences, we traced the phylogenetic history and spatio-temporal dispersal pattern of ZIKV in Asia prior to its explosive emergence in the Pacific region and the Americas. These analyses demonstrated that the introduction and dispersal of ZIKV on the Pacific islands were preceded by an extended period of relatively silent transmission in SEA, enabling the virus to expand geographically and evolve adaptively before its unanticipated introduction to immunologically naive populations on the Pacific islands and in the Americas. Our findings reveal new features of the evolution and dispersal of this intriguing virus and may benefit future disease control strategies.

Worldwide survey reveals lower susceptibility of African Aedes aegypti mosquitoes to diverse strains of Zika virus

“…Reciprocally, the lack of major epidemics in regions such as Africa and Asia, where conditions are seemingly favorable, is still largely unexplained. It has been hypothesized that this may reflect higher levels of background immunity conferred by cross-protective antibodies against ZIKV-related viruses [15].…”

“…Besides ZIKV evolution or contrasted human background immunity, the potential contribution of vector population genetic diversity to ZIKV epidemiological patterns may have been overlooked [15]. Earlier studies using field-derived Ae.…”

Inferring who-infected-whom-where in the 2016 Zika outbreak in Singapore—a spatio-temporal model

“…Incorporating spatial data in the model allows us to study the geographical-related exposures for these vector-borne diseases. Singapore's outbreak appears qualitatively different from those in less urbanized environments [40][41][42], in that infected Aedes mosquitoes played a less significant role in the long-distance transmission of Zika than did ambulant cases, which may have implications for control of subsequent arbovirus outbreaks in urban settings like Singapore.…”

Expansão da circulação do vírus Zika da África à América, 1947-2018: revisão da literatura*

“…4,6 It is likely that its magnitude was the result of a population with low levels of immunity, high vector density 59 and genetic mutations in which important amino acids were modified, increasing the capacity of Zika virus transmission by the Aedes aegypti vector. 60 ZIKV continued to expand to other Pacific Ocean Islands 4,5,59,61-64 and through Southeast Asia, [65][66][67][68][69][70][71][72] until it was identified in the Americas in May 2015. [73][74][75] Between 2015 and 2016, seroprevalence in Brazil was 63% ( Table 1).…”

“…Another study corroborates the hypothesis that the introduction of ZIKV in South America occurred prior to its introduction in Central America, possibly in the first half of 2013. 60 In Outober 2014, some municipalities of the Brazilian states of Rio Grande do Norte, Paraíba and Maranhão reported suspected cases of a viral disease with presence of exanthema, mild feber, itching and painful joints, these being symptoms not in keeping with suspected cases of other exanthematous viral infections, such as measles and dengue. Before long a further six states reported exanthematous syndrome cases between October 2014 and March 2015.…”