Could global warming give us late, light flu seasons?
In Ventura, the Star's first-rate health and society reporter Tom Kisken documents the lightest flu season in decades. Seriously, for some reason, it's been 29 years since the flu season took until February to get started. Usually it happens by Christmas. That's according to the official Centers for Disease Control.
Why so late?
In California and Ventura County, officials also declared influenza a late bloomer that began to emerge in late January and early February. Activity remains mostly light.
Ask why and they say the same things as the feds: No way to know.
Over at The New York Times, Charles Pierce has an idea.
Scientists are still studying the complex relationship between flu and climate, and other factors, like an absence of new strains or immunity from past vaccinations, may have contributed to this season's low numbers. But there is reason to believe that the weather is an important factor. For one thing, studies have extablished that the flu virus thrives in low humidity, and therefore low temperature — there's a reason, after all, that the flu usually hits us in January, not July. Cold weather also dries out the nasal passages, making it easier to get the coughts and sneezes that transmit the flu. And it keeps us cooped up inside, passing illnesses around.
Ironically, the same La Niña pattern that may have suppressed flu transmission this year in the U.S. among humans could in the Pacific among birds lead to the creation of new and potentially dangerous viruses, according to a study presented in December at the AGU.
"We know that pandemics arise from dramatic changes in the influenza genome. Our hypothesis is that La Niña sets the stage for these changes by reshuffling the mixing patterns of migratory birds, which are a major reservoir for influenza," says Jeffrey Shaman, PhD, Mailman School assistant professor of Environmental Health Sciences and co-author of the study.
The climate giveth, and the climate taketh away.