HighlightsAdult mosquitoes collected in Kinshasa, the Democratic Republic of the Congo (DRC), were screened for viruses in this study.Approximately 40% of mosquitoes were found to be infected with Alphavirus, Flavivirus, and/or Bunyaviridae.Chikungunya, o’nyong’nyong, and Rift valley fever viruses were found in mosquitoes.Habitats favouring mosquito breeding and viral transmission were found in Kinshasa.Screening for mosquito-borne viruses in humans and livestock in DRC is recommended.

21Background: Hepatitis B represents a major global health problem. Despite the high endemicity of 22 hepatitis B in Sub-Saharan Africa, little is known about the molecular characteristics of chronic 23 hepatitis B virus (HBV) infection in Africa, and there are very few published studies that describe 24 the genetic characteristics of HBV in asymptomatic adults in DRC. The present study aimed at 25 determining the molecular diversity of chronic HBV infection in voluntary blood donors in Kinshasa, 26 DRC. 27Methods: Blood samples from 582 voluntary blood donors at the National Blood Transfusion Centre 28 in Kinshasa, DRC, were screened for hepatitis B surface antigen (HBsAg) using enzyme-linked 29 immunosorbent assay (ELISA). Partial amplification and sequencing of S gene in HBV-positive 30 samples was conducted. 31Results: The presence of HBsAg was detected in 6.9 % (40/582) blood donors. Phylogenetic 32 analysis based on partial S gene nucleotide sequences of HBV showed that the majority (66.7 %, 33 10/15) of HBV strains clustered into genotype A, followed by the genotypes E (26.6 %, 4/15) and D 34 (6.7 %, 1/15). Genotype A strains were classified into subgenotype A1, quasi-subgenotype A3, and 35 subgenotype A4, with quasi-subgenotype A3 being predominant. One new genotype A strain did not 36 cluster with any existing HBV/A subgenotype or quasi-subgenotype. 37Conclusions: The present study highlights the high genetic variability of chronic HBV infection in 38 DRC, and the possibility of a new HBV/A subgenotype, suggesting that HBV has a long 39 evolutionary history in DRC. Further molecular characterization of complete HBV genomes is 40 needed for a more accurate assessment of HBV genetic variability and its clinical significance in 41 DRC, as partial sequences are not appropriate for determining HBV new subgenotypes. 42