Phylogenetic characterization
Nine IAV detected in wild dabbling ducks from the Lerma marshes were
isolated in chick embryos. All eight influenza gene segments of each
virus were sequenced, and the sequences were submitted into the GenBank
database (Table 2).
The phylogenetic analysis of the HA gene showed three major clades. The
upper clade had 3 strains
(A/blue-winged_teal/EstadodeMexico/Lerma/UIFMVZ507/2017 (H5N2), A/
green-winged_teal/EstadodeMexico/Lerma/UIFMVZ80/2016 (H5N2), and
A/northern_ shoveler/EstadodeMexico/Lerma/UIFMVZ613/2017 (H5N2))
related to Mexican swine and chicken sequences of H5N2 viral subtype
(Figure 4). Whereas one strain
(A/Mexican_duck/EstadodeMexico/Lerma/UIFMVZ377/2016 (H5N2)) was
phylogenetically related to wild duck sequences of H5N1, H5N2, H5N5, and
H5N9 subtypes reported in United States of America (Figure 4). The HA
gene from A/blue-winged_teal/EstadodeMexico/Lerma/UIFMVZ322/2016 (H1N1)
was found in a different clade, and it was strongly genetically related
to U.S. and Mexican swine H1N1 viruses (Figure 4). Finally, in the lower
clade were found four sequences (A/green-winged_teal/
EstadodeMexico/Lerma/UIFMVZ169/2016 (H3N2),
A/green-winged_teal/EstadodeMexico/ Lerma/UIFMVZ456/2017 (H3N2),
A/green-winged_teal/EstadodeMexico/Lerma/UIFMVZ 465/2017 (H3N2), and
A/blue-winged_teal/EstadodeMexico/Lerma/UIFMVZ478/2017 (H3N2))
genetically similar to U.S. and Mexican swine H3N2 subtypes (Figure 4).