As the Chinese government openly begins to speculate about the possibility of human-to-human transmission of the H7N9 bird flu strain, an international team of experts, including some from the World Health Organization, have been deployed to investigate the disease in the country.

If true, the development would quickly raise concerns of the disease outbreak leading to a pandemic. Flu experts have long warned once a particularly deadly strain of the flu, as H7N9 appears to be – it has killed 17 of the 87 people it has infected – becomes transmissible between humans, it can quickly spread.

The World Health Organization has said some of those who have contracted the virus have had “no history of contact with poultry,” and the state-run China Daily newspaper says a boy in Shanghai may have caught the disease from his brother.