Danger lurks in those clear skies, weather institute warns

The high season brings blue skies but also possible overexposure to the sun and a wave of respiratory illnesses.

Meanwhile, U.S. scientists are reporting that La Niña, that periodic cooling trend in the central Pacific, might promote influenza.

The Instituto Meteorológico said Monday that the masses of dry air over the country and the moderate winds discourage the formation of clouds. That means the tropical sun can do bad things to the skin if residents here do not take precautions.

The weather institute also noted that the lack of a cloud cover can cause a wide variation in the temperature. In the Central Valley the daytime temperature can reach 30 degrees C. (about 86 F), but in early morning the mercury may bottom out to 12 C or about 54 F. Although cold weather does not cause respiratory diseases, the lower temperatures can be uncomfortable particularly in homes that are not closed to the wind.

Even though school is out there appears to be an increase in respiratory problems in the Central Valley. School begins next month, and children generally pick up germs and bacteria from social interaction there. There is no immediate explanation for a spike in colds, flu, headaches, chills and similar symptoms now. It may be that during vacations children forget the basics of hand washing and other anti-germ measure that are promoted in school.

Jeffrey Shaman, of the Columbia University School of Public Health, speculates that La Niña may indirectly cause flu. La Niña is a periodic cooling of Pacific ocean waters that triggers changes in global weather patterns. Among other things, that altered weather disrupts bird migrations, he notes.

Birds can carry flu virus, and when their migratory patterns change, they can come into contact with other avian species they don’t normally meet, birds which might carry a different strain of flu virus.

In the process, the viruses’ genetic material can get intermingled to create new influenza strains in a process known as reassortment.

“And it’s this reassortment, this creation of new sub-types that takes place, and we think it’s in the bird population that generates, potentially, these pandemic strains that can infect humans and to which most of the world’s population will be susceptible,” Shaman says.

Shaman showed that the four documented flu pandemics in the past century began directly after a La Niña event in the Pacific. He presented his views in a research paper published in the Proceedings of the National Academy of Sciences.

Reports from NASA satellites say that La Niña is strengthening in the Pacific.

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