Climate Change And Flu May Be Linked

By John Vlahakis

Shifting global climate patterns could portend a flu pandemic, and an opportunity for nations to a stop a virus before it gains momentum. The link, according to researchers, is weather’s influence on the migratory patterns of wild birds, the primary pool for human flu. “Changes in flight patterns, length of stopovers – can bring together bird species that otherwise wouldn’t intermingle,” said Jeffrey Shaman, an environmental health scientist at the Mailman School of Public Health at Columbia University, lead researcher of the preliminary study. And while mixing with feathered strangers, particularly on water, birds can share viruses orally and fecally. Multiple versions of the flu may then enter a bird’s cells, genetically mingling into a “radically different” viral strain “to which the human population has never been exposed,” and are therefore susceptible, Shaman explained. “That’s what seeds a pandemic,” said Shaman. Other animals and their viruses may also participate in the pool party. The virus behind the 2009 swine flu pandemic, for example, was a mixture of genetic material from human, bird and pig flu. In the study, published Monday in the Proceedings of the National Academy of Sciences, Shaman and his colleague, Marc Lipsitch of the Harvard School of Public Health, found that the last four major flu pandemics -in 1918, 1957, 1968 and 2009 – all followed a climate pattern called La Nina, which brings colder-than-normal sea surface temperatures in the central Pacific Ocean and generally results in cooler global temperatures. One of these episodes, which occur every two to seven years, is currently underway. If the theory holds, it could provide “a little lead time” to prepare for what have generally been unpredictable pandemics, said Shaman. “It could allow us to intensify our vigilance and put more resources in place.”