Hong Kong researchers claim a major breakthrough in establishing how swine flu spreads from animals to humans.
The research, led by Li Ka Shing Faculty of Medicine at Hong Kong University, was published in the Proceedings of the National Academy of Sciences, a respected US journal.
The team used ferrets as animal models to take advantage of the transmission similarities between ferrets and humans.
"There are two significant points for this new discovery," said Professor Malik Peiris from HKU.
"First is that it allows us to identify a virus with potential ability to transmit from animals to humans. Then we can focus on them instead of tackling all viruses."
Most animal viruses are found incapable of transmitting from animals to humans.
Normally, they were not major threats until H1N1 pandemic in 2009, during which the virus was found to have gained genetic changes and thereafter can be transmitted to humans.
The research team discovered that once a balance is achieved between two specific virus surface proteins, namely haemagglutinin and neuraminidase, a swine influenza virus then gains the "ability to transmit efficiently" through the air.
"Second, this discovery can guide us to our next stop of the research. In the long term, understanding the mechanism of the virus transmission will help to tackle the pandemic transmission," said Peiris.
The result has helped understanding of what caused the H1N1 pandemic, which killed about 12,220 people and spread to 199 regions according to a report from World Heath Organization in December 2009.
"Though this is a new start in the whole area," said Peiris, "the findings are not only significant to Hong Kong people, but the whole world."
The research was carried out mainly by local professors and doctors from HKU, with collaboration of Taiwan and US researchers.