The United States is in the grip of a widespread flu outbreak, with crises in Chicago and Boston. An estimated 36,000 people die of flu in the United States each year and it kills some 500,000 people annually around the world. Doctors say it is an unusually early and busy flu season in the U.S.
Massachusetts is one of 41 U.S. states now reporting widespread cases of influenza. Tom Menino is the mayor of Boston, the state's biggest city.
“I’m declaring a public health emergency in the city of Boston. The latest reports show an increasingly tough flu season," he said.
A hospital in eastern Pennsylvania set up a special tent outside the emergency room to deal with the wave of flu patients.
Several hospitals in Chicago have had to turn patients away and send them to other hospitals in the area.
Dr. Marc Siegel, of George Washington University Hospital in Washington, says seasonal influenza is an international phenomenon. It usually breaks out in the coldest season of the year.
"It generally moves through Eastern Europe, then to Western Europe and then kind of spreads westward to the United States. Now with international travel, we often see it spread everywhere much quicker," he said.
Dr. Siegel describes the typical symptoms of flu. "So influenza generally gives you a muscle ache, headache, high fevers. It can be associated with a sore throat, runny nose, cough, but any number of other viruses can give you similar symptoms that might not be quite as severe," he said.
Influenza Pandemics of the 20th Century
1918 Spanish Flu: Killed more than 500,000 people in the U.S., and 20 million to 50 million people worldwide.
1957 Asian Flu: Killed roughly 70,000 people in the U.S.
1968 Hong Kong Flu: First detected in Hong Kong, this virus caused roughly 34,000 deaths in the U.S.
Doctors say if flu symptoms are severe, such as shortness of breath, patients should see a doctor. And they recommend a flu vaccination as the best protection against the illness.
Doctors warn that small children and the elderly are the most vulnerable to serious complications from the flu.
A six-year-old girl from Dallas died just hours after her grandparents took her to the emergency room with flu-like symptoms and she was seen and released.
Veleta Johnson is her grandmother. “They looked down her throat, checked her ears, vitals were all good, said she had the flu and told me what to do to make sure she felt better," she said.
Doctors say they do not know if this unusually early flu season has peaked yet, or if this year’s outbreak will get worse.