“We've found viral RNA in the ice in Siberia, and it's along the major flight paths of migrating waterfowl,” whose pathways take them to North America, Asia and Australia, and interconnect with other migratory paths to Europe and Africa, explains Dr. Scott Rogers, a Bowling Green State University (BGSU) biologist.
Viruses, he says, can be preserved in ice over long periods of time, then released decades later when humans may no longer be immune to them. For instance, survivors of the worldwide flu pandemic of 1918 had immunity to the responsible strain—called H1N1—but that immunity has died with them, meaning a recurrence “could take hold as an epidemic.”
H1, the first of 16 versions of the protein heamagglutinin, is what Rogers and his Russian and Israeli colleagues sought in their research. The information could be used to help develop inoculation strategies for the future. He points out that the World Health Organization annually considers what flu strains are emerging in hopes of tailoring vaccines accordingly. “Sometimes they're wrong,” he says. “We thought that by looking at what's melting and what birds are picking up,” better guesses for the next year might be possible.
The H1 that he and his collaborators have found is closest to a strain that circulated from 1933-38 and again in the ‘60s. “These certain strains come back from time to time,” he says. “People have studied the biotic (transmission) cycle over the years, but it's been clear that some of the virus should be mutating faster. But some of the strains come back, and they haven't mutated.
“We're at a really basic level right now,” Rogers adds, pointing out that it remains to be demonstrated that the frozen viruses are still alive. But “we think they can survive a long time” in ice, he reiterates, saying that tomato mosaic virus has been found in 140,000-year-old ice in Greenland.
MEDICA.de; Source: Bowling Green State University