Changing Weather Patterns: El Niño
There are many things that influence our weather patterns. One of those factors is a phenomenon called El Niño. During an El Niño, the trade winds over the Pacific weaken. This enables the warmer waters in the western Pacific to flow further east, warming the usually cooler waters around Peru and the South American Coast. Rainfall follows the warmer waters, leading to heavy rain and flooding in Peru and drought conditions in northern Australia, Indonesia and the Philippines.

In the U.S., El Niño is associated with drier than average conditions in the Pacific Northwest, increased rain in the Southwest, fewer than average tropical storms/hurricanes in the Atlantic, warmer fall and winter temperatures in the Great Plains and a wetter winter/more frequent storms along the Gulf Coast and parts of California.

The intensity of weather during an El Niño can vary widely. The last El Niño, between 2002 and 2003, was relatively mild. However, a 1982-1983 El Niño was one of the strongest on record, causing torrential storms in the southwest US and a severe drought in Australia.

In July, the National Oceanic and Atmospheric Administration officially declared the arrival of El Niño. An El Niño occurs about every two to five years and lasts about 12 months. The current El Niño is expected to last into the winter.

Weather and Health
Researchers have linked weather to risk for many different kinds of health problems. In the summer months, high temperatures are associated with heat illness. In fact, heat waves are the most prominent cause of weather-related deaths in the U.S., killing more people per year than other natural disasters combined (like hurricanes, lightning, tornadoes, floods and earthquakes). Rainy weather during the summer brings more mosquitoes and may be associated with outbreaks of diseases like West Nile Virus. Warmer weather is also associated with increased levels of pollen and pollutants, increasing symptoms of allergy and asthma in susceptible people.

One of the main health concerns during the late fall and winter months is seasonal flu. Vicky Kistler, M.Ed., Health Director of the Allentown Health Bureau, says when the weather turns colder, people tend to spend more time indoors. Poor ventilation and heated, dry air help spread the flu virus from one person to another. Kistler says less sunlight during the winter months increases the risk for depression, which can weaken the immune system and increase susceptibility for the flu.

Recently, researchers made an important discovery in how the flu virus survives and spreads so well during the winter months. Reporting in the journal, Nature Chemical Biology, investigators found the flu virus is surrounded by an outer membrane of lipids, or fats. When the virus hits the cold air, the lipid membrane solidifies into a gel, protecting the germs and allowing them to be safely carried from person to person. Once inside the warm respiratory tract, the gel melts back into a liquid form, enabling the virus to infect the cells of a new host.

El Niño and the Flu
Traditionally, flu outbreaks wane in the spring and reappear in the fall. However, the new H1N1 flu virus continued to spread through the summer months. No one knows the exact reason for the persistence of the virus. However, Katie Fehlinger, AccuWeather.com Broadcaster, says the Northeast US experienced unusually cooler temperatures this summer. The report in the previously mentioned journal found the lipid coating surrounding the flu virus remains in gel form even at temperatures of 70 degrees F. Those cooler temperatures may have helped the virus survive.

What’s in store for the coming winter? Forecasters at AccuWeather.com believe El Niño will weaken, bringing colder and drier air into much of the country. Although no one knows how the H1N1 virus will behave this fall and winter, if more people stay inside to keep out of cold, wet weather, the virus may spread readily, leading to a severe flu season.

The best bet is to be prepared for a flu outbreak. Health experts offer some tips on how you can reduce your risk for H1N1 and seasonal flu:

* Wash your hands frequently with soap and water. When soap and water aren’t available, use alcohol-based hand gel.

* Cover your nose and mouth during a cough or sneeze to prevent spreading germs. Use a disposable tissue or cough/sneeze into the bend of your elbow.

* Avoid close contact with sick people. Vice-versa, if you get sick, stay home. The CDC currently recommends people with the flu stay home for at least 24 hours after fever has gone.

* Get a flu shot. Seasonal flu shots are available now. A vaccine for H1N1 is expected to be available in a few weeks.



Kistler also recommends families make a plan and prepare for a possible flu emergency. Have extra food, pharmacy supplies (like pain/fever medications), hand sanitizers and disposable tissues available in case care givers are unable to leave the house.

AUDIENCE INQUIRY
For information on El Niño or other weather issues:
The National Oceanic and Atmospheric Administration, http://www.elnino.noaa.gov, or http://www.noaa.gov

For information on H1N1 or seasonal flu:
Centers for Disease Control and Prevention, http://www.cdc.gov/flu

BIBLIOGRAPHY
Kovats, R. Sari, et al., “El Niño and Health,” The Lancet, published online, May 20, 2003.

Kovats, R. Sari, “El Niño and Human Health,” Bulletin of the World Health Organization, 2000, Vol. 78, No. 9, pp. 1127-1135.

Luber, George, Ph.D., and Michael McGeehin, Ph.D., “Climate Change and Extreme Heat Events,” American Journal of Preventive Medicine, November 2008, Vol. 35, No. 5, pp. 429-435.

Polozov, Ivan, et al., “Progressive Ordering with Decreasing Temperature of the Phospholipids of Influenza Virus,” Nature Chemical Biology, published online, March 2, 2008, Vol. 4, pp. 248-255.

Soverow, Jonathan, et al., “Infectious Disease in a Warming World: How Weather Influenced West Nile Virus in the United States (2001-2005),” Environmental Health Perspectives, July 2009, Vol. 117, No. 7, pp. 1049-1052.

Zaraket, H., et al., “Association of Early Annual Peak Influenza Activity with El Niño Southern Oscillation in Japan,” Influenza and Other Respiratory Viruses, July 2008, Vol. 2, No. 4, pp. 127-130.