Molecular characterization and phylogenetic analysis of Chikungunya virus during the 2016 outbreak in Sergipe, northeastern Brazil

Background Chikungunya (CHIKV) is an arbovirus transmitted mainly by Aedes aegypti females. CHIKV has been highlighted as the pathogen with the greatest impact due to the high morbidity caused by the infection. In 2016, Brazil experienced an outbreak that affected almost 272 000 people. Here, we performed a molecular characterization and phylogenetic analysis of the CHIKV circulating in 2016 in the state of Sergipe, Brazil. Methods A partial region of the E1 gene of 16 CHIKV-positive samples from Sergipe State was amplified and sequenced. Results All sequences belonged to the East-Central-South-African genotype and three point mutations were verified. Two of them were silent mutations and one was a non-synonymous mutation, which changed lysine to threonine at position 211 in the E1 protein. This mutation was present in 81.2% of the sequences, as well as in other five Brazilian sequences from previous studies. This study found that CHIKV strains circulating in Sergipe during the 2016 outbreak belonged to two different haplotypes. Conclusions The strains circulating in Sergipe are phylogenetically close to other Brazilian samples circulating in the northeast and southeast of the country, as well as viruses circulating during the same period in Haiti, indicating the rapid spread of these haplotypes.