Prevalence and Diversity of Low Pathogenicity Avian Influenza Viruses in Wild Birds in Guatemala, 2010–2013

Abstract

Summary Waterfowl species are known to harbor the greatest diversity of low pathogenicity influenza A virus (LPAIV) subtypes and are recognized as their main natural reservoir. In Guatemala there is evidence of circulation of LPAIV in wild ducks, however the bird species contributing to viral diversity during the winter migration in Central America are unknown. In this study, samples obtained from 1,250 hunter-killed birds from 22 different species were collected on the Pacific coast of Guatemala during three winter migration seasons between 2010 and 2013. Prevalence of LPAIV detected by real-time reverse-transcriptase polymerase chain reaction was 38.2%, 23.5% and 24.7% in the 2010-11, 2011-12, and 2012-13 seasons respectively. The highest virus prevalence was detected in the northern shoveler (Anas clypeata), followed by the blue-winged teal (Anas discors). The majority of positive samples and viral isolates were obtained from the blue-winged teal. Analysis of LPAIV prevalence over time in this species indicated a decreasing trend in monthly prevalence within a migration season. Sixty-eight viruses were isolated and 9 HA and 7 NA subtypes were identified in 19 subtype combinations. In 2012-13, the most prevalent subtype was H14, a subtype identified for the first time in the western hemisphere in 2010. The results from this study represent the most detailed description available to date of LPAIV circulation in Central America.

Evidence of Intercontinental Spread and Uncommon Variants of Low-Pathogenicity Avian Influenza Viruses in Ducks Overwintering in Guatemala

“…Similarly, we find that ducks overwintering in Guatemala harbor relatively high genetic diversity and elevated detection rates (24). This diversity is reflected in the number of genome constellations that were observed (52 different combinations from 68 recovered viruses).…”

“…H14 is a subtype of Eurasian origin and was detected in the Western Hemisphere only within the last decade and only at a low prevalence (32–34). During the 2012-2013 season, we detected the largest number of H14 subtype viruses ever reported in dabbling ducks (the same number of virus sequences available globally for this subtype by 2013, n = 14), specifically in blue-winged teals (24). Time-scaled MCC trees inferred for all H14 sequences available up to 2013 showed clustering of the H14 HA genes from Guatemala by season, interspersed with North American viruses (Fig.…”

“…In all cases, the top matches were contemporary viruses (from 2009 to 2013) from North America, including the subtypes H1 to H5, H7, H11, H12, H14, N2 to N6, and N8 (24). Comparison of the viruses from Guatemala through nucleotide pairwise distance revealed that despite their high identity (>95%) with North American strains, the five viruses with divergent internal gene segments also had highly divergent surface glycoprotein genes of the subtypes H3N8 ( n = 2) and H4N2 ( n = 3).…”

“…In addition to detecting viruses with H3 and H4 segments that are divergent from the main North American lineage, an unexpectedly large number ( n = 14) of H14 subtype viruses were identified in overwintering blue-winged teals in Guatemala (24, 31). H14 is a subtype of Eurasian origin and was detected in the Western Hemisphere only within the last decade and only at a low prevalence (32–34).…”

“…LPAIVs from the North American lineage were first detected in overwintering blue-winged teals in Guatemala during 2009 and 2010 (23). During 2010 and 2013, LPAIVs were detected in samples from 11 hunted bird species of the families Anatidae, Columbidae, Rallidae, Scolopacidae, and Threskiornithidae (24). However, the majority of samples were collected from blue-winged teals, from which LPAIVs were detected at various frequencies throughout and between migration seasons.…”