Using computer models to simulate an influenza outbreak, two research groups found that it may be possible to contain an outbreak of avian flu in humans with proper strategies.

The scientists said on Wednesday that targeted administration of antivirals, quarantine and pre-vaccination, could potentially contain an outbreak under many circumstances. Their findings are published in Nature and Science, respectively.

The H5N1 strain of the avian flu virus, found in birds throughout Southeast Asia, has infected a number of species including domestic poultry, pigs and people. Scientists fear that a genetic exchange between bird and human flu viruses or the accumulation of H5N1 mutations could soon make efficient person-to-person transmission possible.

In the Nature paper, scientists simulated 85 million people living in Thailand and bordering regions of neighboring countries.

It tested the effectiveness of giving courses of antiviral treatment to everyone, socially or geographically targeting who received them, and combining these drug-sparing approaches with other interventions, such as restricting travel.

The results suggest that an international stockpile of 3 million courses of flu antiviral drugs, combined with other interventions, could contain a pandemic.

Treating infected individuals and everyone in their vicinity, along with closing schools and work places, could have more than a 90 percent chance of stopping the spread of a pandemic virus, according to the model.

"To be effective," said Neil Ferguson, lead author of the Nature paper, "you really must use a combination of strategies. No single one would successfully prevent an epidemic."

He noted that successful containment would depend on the early detection of the first case and the rapid implementation of public health measures.

The model described in Science simulated 500,000 people living in rural Southeast Asia and relied on information about how those individuals move within their communities.

Containment strategies included giving antiviral medication to people in the same social networks, quarantining the houses or neighborhoods of the infected people and combinations of these approaches.

The researchers reported that a combination of targeted antiviral treatment and quarantine introduced two weeks after the first case had the potential to successfully contain the spread of the disease, resulting in less than one case per 1,000 people.

Both models demonstrated that the need for additional public health measures greatly increased as the virus became more contagious.

"Each measure can have a significant effect, but it can't contain spread on its own," said Ferguson, adding that targeted antiviral treatment was a crucial component of all combined strategies.

While the researchers pointed out that implementing such a combination of approaches would be challenging and require a coordinated international response, they offered this good news: The models show that containing an avian flu pandemic at its source is feasible.

"Our findings indicate that we have reason to be somewhat hopeful. If -- or, more likely, when -- an outbreak occurs in humans, there is a chance of containing it and preventing a pandemic." said Elizabeth Halloran of Emory University, a co-author of the Science paper.

"However, it will require a serious effort, with major planning and coordination, and there is no guarantee of success." she noted.

Source: Xinhua