Swine flu followed flight paths

BY MICHAEL FOX - STUFF.CO.NZ

Researchers have plotted the spread of swine flu around the world by tracking air travel from Mexico, the origin of the outbreak.

Swine flu swept across Mexico in April before spreading to other parts of the world and triggering the first global flu pandemic since 1968.
 
Dr Kamran Khan from St Michael's Hospital in Toronto said scientists suspected a correlation between air travel and the spread of the disease and the study showed that tracking global flight patterns to predict where an infectious disease might strike next would allow health officials to prepare.

"Our findings suggest that quantitative analysis of worldwide air-traffic patterns can help cities and countries around the world better anticipate their risks of importing global infectious diseases," the report said.
 
Mr Kamran told Forbes.com that the world was so interconnected that the spread of viruses across national borders was inevitable.
 
"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."
 
Mr Khan and physicians at St Michael's Hospital  analysed 2008 air travel data from the International Air Transport Association for March and April. Year-on-year travel patterns are not expected to have changed significantly.

During that time, more than two million passengers from Mexico visited over 1000 cities in 164 countries across the globe.

The study found that of the 20 countries with the highest number of passengers arriving from Mexico, 16 had confirmed cases of swine flu imported from Mexico.

Of the other four countries, Japan, Chile and Peru had confirmed cases, but no link was drawn with travel from Mexico.

The researchers found that countries receiving more than 1400 passengers from Mexico had a "significantly elevated risk of importation".

SPREAD OF VIRUS

Martin Cetron of the US Centre for Disease Control and Prevention told the Associated Press that the research could help forecast how the spread of a new virus could pan out.

"We share a common interest in this issue: If we map the global airline distribution network, we can anticipate, once a virus emerges, where it is likely to show up next."

Only 230 passengers flew from Mexico to New Zealand in that time.

The first reported outbreaks here were 10 Rangitoto College students returning from a trip to Mexico in April.

The cumulative total number of cases in New Zealand, which is believed to be an underestimate, is now 589.

Two women, a 30-year-old in Wellington and a woman in her twenties in Hawke's Bay, are in serious conditions.

As of yesterday 59,814 confirmed cases of swine flu have been reported, with 263 deaths, according to World Health Organisation statistics.

New Zealand health officials had a strong preliminary focus on containing the spread of swine flu. The approach was effective for around two months before the focus was switched to managing the virus earlier this month.

Priority was placed at national borders and passengers were screened as they arrived, in a bid to stop people carrying the infection entering the country and spreading the virus. People confirmed as being infected with the virus were also quarantined.

The study, which was reported in the New England Journal of Medicine, found that authorities should work with other countries where they received the majority of their air traffic to deal with infectious disease risk.