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Unique, divergent avian influenza virus found in Antarctic penguins
The characterization of avian influenza viruses found in Adélie penguins in two distinct sites in Antarctica suggests a unique genome that digressed from other avian viruses between 49 and 80 years ago, according to recent study results.
In the study, researchers evaluated 301 Adélie penguins found at two sites on the Antarctic Peninsula from January to February 2013. The researchers took cloacal and tracheal swabs from all of the birds, as well as blood samples from 270 penguins. Real-time reverse-transcription PCR analyses revealed that eight samples (2.7%) contained avian influenza virus (AIV) RNA. Four of the viruses were successfully cultured, and full genome analysis of these four viruses revealed that they were H11N2 influenza A viruses.
The researchers compared full genome sequences with all known animal and human influenza virus sequences in public databases to establish the phylogenetic relationships and histories of each gene segment. They discovered that each AIV gene segment from the Adelie penguin viruses was distinctly different than any of the known AIVs currently in existence in the Northern or Southern hemispheres. The genomic analysis suggested that four of the gene segments were closely linked to the North American avian lineage viruses from the 1960s to the 1980s. The N2 neuraminidase gene appeared to have diverged early, between 49 and 80 years ago, from the known AIV gene pool. Notably, the researchers found that the polymerase basic 1 and polymerase acidic appeared to be most closely related to the equine H3N8 influenza virus ancestry that emerged in 1963. Moreover, the receptor binding properties of the H11N2 viruses appear to be mainly avian, and could not be transmitted to inoculated ferrets.
According to study researcher Aeron Hurt, PhD, of the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne, Australia, these findings underscore the need for further knowledge regarding these newly discovered AIVs.
“This is the first insight into AIV ecology in Antarctica and provides further evidence, in addition to some South American studies, of an avian ancestry to H3N8 equine influenza viruses that emerged and spread globally among horses since 1963,” Hurt and colleagues wrote. “As such, this study and the recent detection of novel influenza A viruses in fruit bats from Central and South America fill important gaps in our understanding of the global movement of AIVs, the reservoir species that may maintain them, and their potential impact on animal and human health.”
Disclosure: The researchers report no relevant financial disclosures.