Dados do Trabalho

Título

Evolution of lineage BR4 of Dengue virus serotype 2 genotype III during an outbreak in Mato Grosso, Midwestern Brazil, 2019

Introdução

DENV-2 was the main responsible for a 70% increase in dengue incidence in Brazil during 2019. Since 1980, several epidemics have been registered in the country, resultant from the introduction of different genotypes and lineages of the four DENV serotypes.

Objetivo (s)

Provide insights on virus detection and evolution through metagenomics in the serum of patients suspected of arbovirus disease, obtained during an outbreak of acute febrile disease in 2019 in the State of Mato Grosso.

Material e Métodos

Subjects were selected under passive surveillance between January and December 2019 (n=92). Their serum samples were allocated in pools according to age or region of origin. Pools were subjected to viral RNA extraction, ds-cDNA synthesis, purification, quantification for preparation of genomic library and sequenced by NextSeq 500. A phylogenetic three was inferred by Coalescent Bayesian Skyline.

Resultados e Conclusão

Eight complete genomes and two nearly complete DENV-2 genotype III (lineage BR4) sequences were detected in serum samples of acute febrile patients suspected of arbovirus infection. All sequences share the aminoacidic identities of lineage BR4 on domains I, II and III of Envelope (E) protein, and were included in a clade with sequences of the same lineage circulating in Southeast Brazil in the same year. Twenty-six non-synonymous mutations unique to the genomes of this study were detected, distributed in the Capsid, E, NS1, NS2B, NS4A and NS5 proteins. Another four aa changes on NS5 and NS2A were previously reported only on DENV-2 genotypes IV and V. All sequences have mutations in the NS5 indicating an evolutionary trend. Two genomes present an amino acid change on the hinge of E protein at domain II, in a critical region for receptor anchoring on the cell membrane. Altogether, presence of these mutations and several others in E protein domain II and domain III in our sequences point for an important evolution of DENV-2 genotype III lineage BR4 during this outbreak in 2019. Genomic surveillance is critical to detect virus evolution in the population, possibly leading to immune evasion and changes on viral fitness leading to future novel outbreaks.

Palavras-chave

dengue virus 2; metagenomic; viral phylogenetics

Agradecimentos

To LACEN-MT employees, CAPES (Doctoral scholarship) and CNPq (PQ2 grant 309750/2020-2) and DECIT/SCTIE/MS, CNPq, FAPEMAT, SES-MT PPSUS grant FAPEMAT.0290384/2018