Air Traffic Patterns Predict Swine Flu Spread

June 30 -- MONDAY, June 29 (HealthDay News) -- Countries that received the most airline passengers from Mexico this spring were the most likely to see H1N1 swine flu infection, new research says.

The finding confirms that tracking global flight patterns to determine where an infectious disease may strike next could provide governments and public health officials with a means of preventing and dealing with such threats, according to an analysis by researchers in Canada.

"Infectious diseases don't respect national boundaries, and we live in an incredibly interconnected world," said Dr. Kamran Khan, an infectious disease physician and scientist at St. Michael's Hospital in Toronto. "Yet, infectious diseases do follow airline flight routes. If we can understand how people move around the world, we can understand how infectious diseases are likely to spread around the world."

The findings were published online June 29 in a letter to the editor in the New England Journal of Medicine.

Using an extensive database of global air traffic and passenger itineraries, the research team analyzed information on 2.35 million passengers traveling from Mexico to more than 1,000 cities in 164 nations in March and April 2008. Swine flu emerged this spring, but because passenger data from 2009 was not yet available, the investigators used 2008 flight information, noting that air travel patterns in March and April change little from year to year.

From Mexico, nearly 81 percent of air passengers flew to the United States or Canada, while 8.8 percent went to Central America, South America or the Caribbean Islands, 8.7 percent flew to Western Europe, 1 percent went to East Asia and 0.8 percent flew elsewhere, the researchers found.

The United States received the bulk of passengers from Mexico, with about 1.74 million arrivals, followed by Canada with 149,137 arrivals, France with 47,501, then Spain, Germany, Cuba, Argentina, Italy, Brazil, Guatemala, United Kingdom, Colombia, Japan, Chile, Venezuela, Panama, Costa Rica, Netherlands, Peru and Switzerland.