Detection of Evolutionarily Distinct Avian Influenza A Viruses in Antarctica

Abstract

Distinct lineages of avian influenza viruses (AIVs) are harbored by spatially segregated birds, yet significant surveillance gaps exist around the globe. Virtually nothing is known from the Antarctic. Using virus culture, molecular analysis, full genome sequencing, and serology of samples from Adélie penguins in Antarctica, we confirmed infection by H11N2 subtype AIVs. Their genetic segments were distinct from all known contemporary influenza viruses, including South American AIVs, suggesting spatial separation from other lineages. Only in the matrix and polymerase acidic gene phylogenies did the Antarctic sequences form a sister relationship to South American AIVs, whereas distant phylogenetic relationships were evident in all other gene segments. Interestingly, their neuraminidase genes formed a distant relationship to all avian and human influenza lineages, and the polymerase basic 1 and polymerase acidic formed a sister relationship to the equine H3N8 influenza virus lineage that emerged during 1963 and whose avian origins were previously unknown. We also estimated that each gene segment had diverged for 49 to 80 years from its most closely related sequences, highlighting a significant gap in our AIV knowledge in the region. We also show that the receptor binding properties of the H11N2 viruses are predominantly avian and that they were unable to replicate efficiently in experimentally inoculated ferrets, suggesting their continuous evolution in avian hosts. These findings add substantially to our understanding of both the ecology and the intra- and intercontinental movement of Antarctic AIVs and highlight the potential risk of an incursion of highly pathogenic AIVs into this fragile environment.

Migratory birds in southern Brazil are a source of multiple avian influenza virus subtypes

“…After 21 days, blood was collected to test for seroconversion by HI assay with turkey red blood cells 37, 38. The HI assay was conducted in triplicate, and the titers are reported as the geometric means.…”

Identification of an avian polyomavirus associated with Adélie penguins (Pygoscelis adeliae)

“…Most of the early studies have relied on serological assays for identifying putative paramyxoviruses, orthomyxoviruses, flavirviruses and birnaviruses in wild penguin populations (Alexander et al, 1989;Austin & Webster, 1993;Gardner et al, 1997;Miller et al, 2010;Morgan et al, , 1985Smith et al, 2008;Thomazelli et al, 2010) and herpesviruses and togaviruses in captive individuals (Kincaid et al, 1988;Tuttle et al, 2005). A handful of recent studies have identified some of the viruses (avipoxviruses, Newcastle disease viruses, adenovirus, avian influenza virus and papillomavirus) at a molecular level (Carulei et al, 2009;Hurt et al, 2014;Kane et al, 2012;Lee et al, 2014;Thomazelli et al, 2010;Varsani et al, 2014).…”

“…To the best of our knowledge, this is one of the five genomes of viruses associated with Antarctic animals to be characterized to date; previously identified viral genomes include those of a P. adeliae papillomavirus and an avian influenza virus subtype H11N2 from Adélie penguins (Hurt et al, 2014;Varsani et al, 2014) and adenoviruses from South Polar skuas and chinstrap penguins (Pygoscelis antarctica) (Lee et al, 2014;Park et al, 2012). This highlights the poor knowledge of viruses associated with Antarctic animals.…”

Avian Influenza in Wild Birds from South America: Review, Implications and Perspectives

“…For instance, recent studies have found that penguins (Sphenisciformes) play an important role along with Charadriiformes in the persistence and evolution of AIV in Antarctica, a dynamic that could not have been witnessed in studies conducted in the Northern Hemisphere since penguins do not occur there. 29,30 Inversely, murres and auklets (Alcidae) play an important role in AIV transmission in the Northern Hemisphere but are absent in the Southern Hemisphere. 31,32 Furthermore, even though it is reasonable to consider aquatic birds as prime candidates for AIV surveillance in South America, the role of terrestrial birds as reservoirs of AIV should not be dismissed.…”