Molecular epidemiology of Respiratory Syncytial Virus in children in sub-Saharan Africa

This study investigated the molecular epidemiology of respiratory syncytial virus (RSV) among febrile children with acute respiratory tract infection in Ghana, Gabon, Tanzania and Burkina Faso between 2014-2017 as well as the evolution and diversification of RSV strains from other sub-Saharan countries. Pharyngeal swabs were collected at four study sites (Agogo, Ghana: n=490; Lambaréné, Gabon: n=182; Mbeya, Tanzania: n=293; Nouna, Burkina Faso: n=115) and analysed for RSV and other respiratory viruses using rtPCR. For RSV positive samples, sequence analysis of the second hypervariable region of the G-gene was performed. A dataset of RSV strains from sub-Saharan Africa (2011-2017) currently available in GenBank was compiled. Phylogenetic analysis was conducted to identify the diversity of circulating RSV genotypes. In total, 46 samples tested RSV positive (Ghana n=31 (6.3%), Gabon n=4 (2.2%), Tanzania n=9 (3.1%), Burkina Faso n=2 (1.7%)). The most common RSV co-infection was with rhinovirus. All RSV-A strains clustered with genotype ON1 strains with a 72-nucleotide duplication and all RSV-B strains belonged to genotype BAIX. Phylogenetic analysis of amino acid sequences from sub-Saharan Africa revealed the diversification into 11 different ON1 and 22 different BAIX lineages and differentiation of ON1 and BAIX strains into potential new sub-genotypes, provisionally named ON1-NGR, BAIX-KEN1, BAIX-KEN2 and BAIX-KEN3. The study contributes to an improved understanding of the molecular epidemiology of RSV infection in sub-Saharan Africa. It provides the first phylogenetic data for RSV from Tanzania, Gabon and Burkina Faso and combines it with RSV strains from all other sub-Saharan countries currently available in GenBank.