Molecular identification and phylogenetic characterization of influenza
A virus at a wildlife-livestock interface in Mexico
Abstract
Influenza A virus (IAV) outbreaks constitute a constant threat to public
health and pose a remarkable impact on socio-economic systems worldwide.
Interactions between wild and domestic birds, humans, and swine can lead
to spillover events. Backyard livestock systems in proximity to wetlands
represent a high-risk area for viral spread. However, some gaps remain
in our knowledge of IAV transmission at the wildlife – livestock
interface in Mexico. Hence, the study aimed at molecular identification
and phylogenetic characterization of IAV in the wild duck – backyard
livestock interface at a wetland of Mexico. A total of 875 animals were
tested by real-time RT-PCR (qRT-PCR). We detected IAV in 3.68% of the
wild ducks sampled during the winter season 2016 – 2017. Nonetheless,
the samples obtained from backyard poultry and swine tested negative.
The highest IAV frequency (11.10%) was found in the Mexican duck (Anas
diazi). Subtypes H1N1, H3N2, and H5N2 were detected. Phylogenetic
analysis of influenza viruses isolated from wild ducks of the Lerma
marshes revealed that hemagglutinin (HA) gene sequences were related to
waterfowl, swine, and poultry IAV strains previously isolated in the
United States and Mexico. In conclusion, the co-circulation of three IAV
subtypes in wild ducks close to backyard farms in Mexico, as well as,
the local identification of HA gene sequences genetically related to
Mexican livestock IAV strains and also to North American waterfowl IAV
strains, highlight the importance of the Lerma marshes for influenza
surveillance given the close interaction among wild birds, poultry,
pigs, and humans.