Glaciers may preserve viruses for millions of years

Evidence shows that viruses, bacteria and fungi may be preserved in glacial ice for up to 140,000 years, and become mixing pools for these pathogens when the lakes thaw during warmer seasons or periods of global warming.

Lakes in the northeastern Siberia frequented by large populations of migratory waterfowls showed proof of trapping high concentrations of influenza A virus H1 genes.

“Ice may act as a reservoir for influenza A viruses, preserving them fro later release and infection of animals, including migratory waterfowls and humans, ” postulated the authors led by Scott Rogers. The study published in the Journal of Virology also found that viruses degenerated much slower at or below freezing, in fact were preserved even better as the temperatures fall.

The periodic thawing and refreezing of glacial ice and lakes may explain why “some influenza virus strains have appeared, disappeared and then reemerged decades later virtually unchanged”. This abiotic mode of preservation may also explain the slow rates of mutation of the influenza viruses; they’ve been well preserved in some way by such reservoirs between epidemics.

Will we expect therefore, an increase in bird flu incidence during periods of global warming events? The authors think this is not impossible.

[Source: Journal of Virology. Evidence of Influenza A Virus RNA in Siberian Lake Ice. 2006:80:12229. Free abstract link]

Tags: bird flu, glacial ice, Siberia, global warming, abiotic preservation