Resurgence of Dengue Virus Serotype 3 in Minas Gerais, Brazil: A Case Report

Abstract

This report provides a detailed overview of the resurgence of DENV-3 in the state of Minas Gerais, Brazil, which is a concerning scenario in the context of dengue, a mosquito-borne viral disease. Historically, Brazil has grappled with dengue epidemics caused primarily by the DENV-1 and DENV-2 serotypes. However, in 2023, a significant shift in this pattern was observed as DENV-3 made a notable resurgence. This resurgence was characterized by the increase in DENV-3 cases within the country and the region of the Americas. Given the absence of sustained DENV-3 circulation in Brazil in previous years, this situation poses a significant risk, making the population highly susceptible to a potential novel epidemic. In November 2023, a 31-year-old male patient in Belo Horizonte exhibited symptoms of acute febrile syndrome. Multiplex RT-qPCR using the Kit Molecular ZC D-Tipagem confirmed DENV-3 infection, suggesting a likely autochthonous case, as the patient reported no travel history. To promptly assess this resurgence, we applied the nanopore sequencing technology. This allowed for the rapid characterization of the initial DENV-3 case isolated in Minas Gerais in 2023, representing a 13-year interval since the serotype's previous documented circulation in that state. This case report underscores the critical importance of proactive monitoring and the swift implementation of targeted control strategies to address the evolving dynamics of dengue, with a specific emphasis on the resurgence of DENV-3 in the state.

Keywords: DENV monitoring; molecular epidemiology; next-generation sequencing.

Figure 1

Genomic epidemiology of dengue in Minas Gerais, Brazil. (A) Weekly notified dengue cases normalized per 100,000 individuals per Brazilian macro region (North, Midwest, Southeast, Northeast, and South) during 2014–2023 (up to June 2023). Data from the state of Minas Gerais were plotted separately (outside the Southeast macro region) for better visualization. Epidemic curves are colored according to geographical region. (B) Weekly notified dengue cases from Minas Gerais state (normalized per 100,000 individuals) divided by health mesoregion during 2023 (up to June 2023). (C) Midpoint rooted maximum-likelihood phylogeny of DENV-3 isolates (n = 1702), showing distinct genotypes. The scale bar is in units of substitutions per site (s/s). (D) Time-resolved maximum-likelihood tree showing the clade containing our newly generated DENV-3 III sequence from Minas Gerais State, Brazil. Colors represent different sampling locations.