THE ASAHI SHIMBUN - Researchers pinpoint origin of flu to East, Southeast Asia

[Snowy Owl]

Researchers pinpoint origin of flu to East, Southeast Asia
THE ASAHI SHIMBUN
04/17/2008​

An international team of researchers, including Japanese scientists, identified an area stretching from East Asia to Southeast Asia as the place of origin for annual outbreaks of influenza.

The finding will be published in the U.S. journal Science scheduled for release on Friday.

The team of researchers from Japan, the United States, Europe and Australia concluded the viruses originated in the wide region and then spread to Oceania, Europe and North America via travel, trade and other trans-border human activities.

The viruses completed their mutations, or "evolutions," upon reaching South America, according to the researchers.

The finding is expected to strengthen the widely held view that the source of flu viruses lies in Southeast Asia and its surrounding areas.

Some experts have cited a broader area, such as the Northern Hemisphere and tropical regions, as the possible place of origin.

The latest report highlights the importance of close monitoring of the region for early signs of new flu strains. But the researchers stopped short of singling out any country as the origin of influenza.

The team examined minute differences, including those on the molecular and DNA level, among 13,000 specimens of the influenza A virus (H3N2) collected from around the world between 2002 and 2007.

The researchers tracked down the process of the viruses' mutations and the courses by which they spread.

The virus strain monitored is of the same type as the strain commonly known as Hong Kong flu, whose outbreak in 1968-1969 is said to have killed about 1 million people globally.

A slightly different type of the influenza A virus breaks out each year after mutating, killing an estimated 250,000 to 500,000 people worldwide.

(IHT/Asahi: April 17,2008)