Weather patterns could have an influence on the spread of epidemics like that of the H1N1 influenza virus, initially known as swine flu, which broke out in Mexico and the United States in 2009.
That is the hypothesis set forth in a scientific article that calls for research into the links between weather variations, bird migration, and influenza pandemics.
“We examined the four most recent human influenza pandemics (1918, 1957, 1968 and 2009) and found that each pandemic occurred in spring or early summer and was preceded by below-normal sea surface temperatures, indicative of the La Niña phase,” Jeffrey Shaman of Columbia University’s Mailman School of Public Health told Tierramérica.
“Wild birds are thought to be the primary reservoir of influenza A viruses and facilitate the emergence of new pandemic lineages through the introduction of virus to domestic animals and humans,” says the article by Shaman and his colleague Marc Lipsitch of the Harvard School of Public Health.
“Migratory birds, with their long travel distances and many stopovers, are thought to be particularly critical for the mixing and reassortment of influenza virus genomes,” the authors add.