Spatial, temporal and evolutionary insight into seasonal epidemic Influenza A virus strains near the equatorial line: The case of Ecuador

To study the spatial and temporal patterns of Influenza A virus (IAV) is essential for an efficient control of the disease caused by IAV and efficient vaccination programs. However, spatiotemporal patterns of spread as well as genetic lineage circulation of IAV on a countrywide scale have not been clearly determined for many tropical regions of the world. In order to gain insight into these matters, the spatial and temporal patterns of IAV in six different geographic regions of Ecuador, from 2011 to 2021, were determined and the timing and magnitude of IAV outbreaks in these localities investigated. The results of these studies revealed that although Ecuador is a South American country situated in the Equator line, its IAV epidemiology resembles that of temperate Northern Hemisphere countries. Phylogenetic analysis of H1N1pdm09 and H3N2 IAV strains isolated in five different localities of Ecuador revealed that provinces in the south of this country have the largest effective population size by comparison with provinces in the north, suggesting that the southern provinces may be acting as a source of IAV. Co-circulation of different H1N1pdm09 and H3N2 genetic lineages was observed in different geographic regions of Ecuador.