Influenza A(H7N9) 'danger zones' mapped

Now, so-called ‘danger-zones’in Asia which are vulnerable to a new eruption of Influenza A(H7N9) or bird flu have been mapped by scientists. To date this variant of Influenza A has infected 433 people and has killed 62. The study showed that parts of Bangladesh, India and Vietnam could face an explosion of novel cases[1].

Viruses mutate and reassort, they undergo antigenic drift and antigenic shift. They are always a concern because of their unknown potential to spread round the world as a deadly pandemic.

Data from the current Influenza A(H7N9) outbreak was used to build a computer model of other at-risk areas in Asia. It involved mapping 8,000 live-poultry markets and assessing how close together they needed to be to spread the infection.

The map does not show where the virus will end up next, just those areas where conditions are suitable to sustain the virus if it managed to get there. Bangladesh, northern India, the Mekong and Red River deltas in Vietnam and isolated parts of Indonesia and Philippines were identified as at-risk areas. Thailand was not considered a risk zone due to cultural differences, which mean live-poultry markets are not common. Equally noticeable that the whole of China is not equally at risk.

The main use of the maps is to target surveillance, This map can show areas where there is a high chance of the disease flaring up if it arrives.

[1] Gilbert et al: Predicting the risk of avian influenza A H7N9 infection in live-poultry markets across Asia in Nature Communications - 2014