Abstract:
Background: Influenza B viruses are receiving attention lately perhaps due to the degree of haemagglutinin (HA) antigen mismatching between vaccine composition strains and circulating strains. Neuraminidase inhibitor (NI) antiviral has also been implicated in prophylaxis and treatment of severe cases of influenza diseases. However, mutations in the two major surface glycoproteins, HA and nueraminidase (NA) could cause the virus to escape host defence mechanisms leading to failure of the host immune system to recognize the viruses as well as failure to antiviral therapy, data seems scanty hence the focus of this research.
Main Objective: To molecularly characterize the lineages of influenza B virus strains that circulated in Ghana between 2016 and 2017.
Methods: This was a retrospective cross-sectional study that used selected Ghanaian archived influenza B clinical specimens: representatives of both lineages. Viral RNAs were extracted and amplified using real time reverse transcriptase assays (rtRT-PCR) and subsequently sequenced and analyzed.
Results: A total of eleven and six amino acids substitutions were detected in the recent Ghanaian influenza B strains-influenza B Victoria and Yamagata lineages, respectively. Both Influenza B Victoria and Yamagata lineages were also closely related to Influenza B/Brisbane/60/2008 and Influenza B/Phuket/3073/2013 respectively.
Conclusions: Three main amino acid substitutions (P31S, I117V and R151K) were found in influenza B Victoria lineages circulating between 2016 and 2017, with one strain possessing a unique glycosylation site at amino acid position 51 in the HA2 subunit. Two main substitutions (L172Q and M251V) were also detected in the HA gene of influenza B Yamagata. The recent deletion sub-group in influenza B virus reported by the US CDC was not identified among analysed specimens. Monitoring of the patterns of influenza B evolution would aid in efficient selection of representative viruses for use in the both the design and formulation of influenza vaccines.
