Abstract
Background: Despite being a vaccine preventable disease, influenza
remains a burden in African countries. In Mauritius, influenza virus
activity is year-round but evidence-based data to guide vaccination and
pandemic preparedness strategies are lacking. This study aimed to
describe the genetic diversity of influenza A viruses detected in
Mauritius between 2017-2019. Methods: Influenza A/H1N1pdm09 and A/H3N2
virus isolates were sequenced using Oxford Nanopore technology. Sequence
reads assembled by CZ ID and Genome Detective web-based tools were
uploaded to the EpiFlu database of the Global Initiative on Sharing All
Influenza Data (GISAID). Sequence alignments and phylogenetic analysis
were performed using Nextclade and MEGA X software. BioEdit software was
used to view amino acid alignments and substitutions compared to annual
vaccine strains. Prediction of potential N-linked glycosylation (PNG)
sites was determined by NetNGlyc 1.0. Results: Influenza A was
predominant (92.6%), with A/H1N1pdm09 prevailing overall (62.5%) but
A/H3N2 dominating in 2017 (55.9%). Phylogenetic analysis identified
clade 6B dominance for A/H1N1pdm09, with notable substitutions E119K,
Q136K and D151E linked to antigenic changes. A/H3N2 exhibited
significant genetic diversity, with co-circulation of 3C.2a4 and 3C.2a1
in 2017 while 2018 predominant subclade 3C.2a1b.1 highlights continued
antigenic drift. Loss of PNG sites at position 158 (11/21; 52.4%) in HA
and position 329 (81.0%, 17/21) in NA of A/H3N2 viruses were observed.
Conclusions: Continued evolution of A/H1N1pdm09 and A/H3N2 viruses in
Mauritius highlights the need for sustained genomic surveillance to
inform vaccine and antiviral strategies. Data from Mauritius will
contribute to understanding of influenza viruses’ ecology in the African
region and globally.