Emergence of a New Strain of DENV-2 in South America: Introduction of the Cosmopolitan Genotype through the Brazilian-Peruvian Border

Abstract

Dengue virus 2 (DENV-2) seriously contributes to dengue-related mortality. It includes five nonsylvatic genotypes, with cosmopolitan being the most widespread with a significant contribution to the total number of DENV-2 cases globally. In South America, the cosmopolitan genotype was first recorded in 2019 in Madre de Dios, Peru, and then in Goiás (Midwest Brazil) in November 2021. In this study, we tested 163 human serum samples from Acre (Northern Brazil) collected during a DENV outbreak between 2020 and 2021 for all DENV genotypes by RT-qPCR. Of the 163 samples, 139 were positive for DENV-2, and 5 were positive for DENV-1. Five DENV-2-positive samples from early 2021 were sequenced, and the sequences clustered with the three other DENV-2 cosmopolitan genotype sequences already recorded on the continent. These results create a geographical link, suggesting the possible route of introduction of the DENV-2 cosmopolitan genotype into Brazil through the border with Peru, from which it may have dispersed to Midwest Brazil.

Detection of a Multiple Circulation Event of Dengue Virus 2 Strains in the Northern Region of Brazil

“…Our findings reinforce what we proposed in our partial report regarding the introduction of a new genotype, raise awareness about its dissemination, and provide insights into the cocirculation of multiple lineages in the Americas [ 56 ]. Although a phylogenetic relationship was observed between the only case of the cosmopolitan genotype in the Midwest region of Brazil and the cases described in Madre de Dios, Peru [ 45 , 46 ], no geographical linkage has been established between these regions that do not share borders [ 46 , 47 , 48 ].…”

“…Recent reports have highlighted the widespread dissemination of the cosmopolitan genotype of DENV-2 in the Brazilian territory. These reports indicate that, after several entries into the country, this genotype has already been established in all geographic regions of Brazil [ 55 , 56 ].…”

“…Ten sequences obtained in this study clustered within a well-supported South American clade, supported by high bootstrap values, including two Peruvian sequences and the only sequence previously described in Brazil. Our previous report revealed the first evidence of the cosmopolitan genotype in the northern region of Brazil during a DENV-2 outbreak in the state of Acre, northern region, in early 2021, months before the single detection case in Goiás [ 46 , 56 ]. Samples in this study were collected between January and March 2021, demonstrating the circulation of this genotype prior to the reported case in Goiás.…”

“…Although the persistence and local evolution of some strains are possible, the crucial element for the dynamics of DENV-2 epidemics in the state seems to have been the introduction of Peruvian strains (OM791800; OM791801). The cosmopolitan genotype of DENV-2 is currently in circulation throughout Brazil, as described in previous research [ 46 , 55 , 56 ]. A recent study identified multiple introductions of this genotype in Brazil originating from Peru, resulting in several clusters that have spread throughout the country with different levels of dissemination.…”

DENV-2 Outbreak Associated With Cosmopolitan Genotype Emergence in Western Brazilian Amazon

“… 29 Then, the analysis of a retrospective cohort, collected from February to March 2021, showed 5 cases infected with this genotype in the state of Acre. 30 The wide dispersion of the cosmopolitan genotype has been demonstrated in other Brazilian states, including the Amazonas State, in a recent study showing multiple introductions of the cosmopolitan DENV-2 in Brazil. 11…”