Where do avian influenza viruses meet in the Americas?

Avian influenza virus (AIV) surveillance has been scarce in most countries of Latin America and the Caribbean. Historically, avian influenza surveillance efforts in Central and South America have been localized in places where outbreaks in poultry have occurred. Since the emergence of the H5N1 subtype in Asia, active surveillance in wild birds has increased in a number of Latin American countries, including Barbados, Guatemala, Argentina, Brazil, Mexico, and Peru. A broad diversity of virus subtypes has been detected; however, nucleotide sequence data are still limited in comparison to other regions of the world. Here we review the current knowledge of AIV in Latin America, including phylogenetic relationships among publicly available viral genomes. Overall AIV reports are sparse across the region and the cocirculation of two distinct genetic lineages is puzzling. Phylogenetic analysis reflects bias in time and location where sampling has been conducted. Increased surveillance is needed to address the major determinants for AIV ecology, evolution, and transmission in the region.