Evidence for the role of migratory ruddy turnstones (Arenaria interpres) in influenza A virus dispersal

Wild birds in the order Charadriiformes (shorebirds and gulls) are considered one of the most important avian groups in influenza A virus (IAV) ecology. Of the shorebirds, Ruddy turnstones (Arenaria interpres) have a... [ view full abstract ]

Wild birds in the order Charadriiformes (shorebirds and gulls) are considered one of the most important avian groups in influenza A virus (IAV) ecology. Of the shorebirds, Ruddy turnstones (Arenaria interpres) have a consistently high annual IAV prevalence at Delaware Bay (DE Bay), USA during their spring migration to northern breeding grounds. Twenty IAV isolates with matching HA and NA subtypes were recovered from interpreting fecal or cloacal/oropharyngeal samples during routine surveillance along the Atlantic coastline in 2012 at Florida (FL) (March and May), and DE Bay (May) field sites. The spatial and temporal separation in the collection of these isolates allowed for the testing of the possibility that A. interpres may play a role in the movement of IAV gene segments along their northern migratory route. Full length genomic sequencing of these viruses [FL: H5N9 (3, March), H6N1 (9, May); DE Bay: H5N9 (1), H6N1 (6), H5N3 (1)] was carried out, and demonstrated that the hemagglutinin (HA) and neuraminidase (NA) genes within each subtype group shared ≥ 99% nucleotide identity. Internal genes also showed a high degree of genetic relatedness when compared between collection locations. The fidelity of these genetic relationships, especially between two highly mutable surface antigens (HA and NA) provides evidence of the role of A. interpres in redistributing IAV gene segments to Delaware Bay, an ecological “hotspot” for influenza viruses, during their spring migration.