June 30, 2009
Swine Flu Spread Followed Airline Route Map
A new report published on Monday shows the new strain of H1N1 flu followed the airline route map as it spread around the globe, Reuters reported.
Researchers at St. Michael's Hospital in Toronto found that the swine flu virus spread first and quickest in March and April in the United States and Canada "” where 80 percent of airline passengers traveled in March and April of 2008.
Travel patterns were also similar in 2007 and therefore likely to be similar in 2009, according to Dr. Kamram Khan of St. Michael's and colleagues, who used International Air Transport Association data for their study.
Dr. Michael Gardam of the Ontario Agency for Health Protection and Promotion said the study provides the world with a potent early warning system for emerging infectious diseases.
Khan and colleagues wrote in the New England Journal of Medicine that in March and April 2008, a total of 2.35 million passengers flew from Mexico to 1,018 cities in 164 countries.
The most travelers ended up in Los Angeles, with 221,494 passengers arriving from Mexico in March and April of 2008. New York followed with 126,345. The first non-U.S. city was Toronto, No. 12, with 44,854 passengers arriving from Mexico.
There have been 70,893 confirmed cases of the new H1N1 swine flu pandemic and 311 deaths, according to World Health Organization statistics.
But last week U.S. health officials said there were likely at least 1 million cases there alone. And on Monday Iraq, Lithuania, Monaco and Nepal all confirmed their first cases of the virus.
Tests showed the first known infections were in Mexico, but the first cases were detected in two California children in April. U.S. officials said the virus had spread too far and too fast to try and stop it by the time it had been identified.
Earlier this month, the WHO declared the spread a pandemic.
Khan said newer technology now allows officials to quickly integrate information about worldwide air traffic patterns with information about global infectious disease threats.
He said cities and countries around the world could now respond to news of a threat earlier and more intelligently than ever before.
The United States receives more than 76 million international visitors from around the world every year and the United States and Canada together generate and receive about one-sixth of the global volume of international air traffic, the researchers said.
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