Chickens on sale in a Vietnamese market

N. Rubery/FAO

According to official estimates, 70 people have been infected with bird flu since the beginning of the current epidemic, but researchers say the true number of infections could be much greater.

So far there has been no coordinated effort to determine the spread of the virus and the lack of information is hindering attempts to understand and tackle the disease. In this article in Science, Martin Enserink and Dennis Normile explain why there are gaps in the information being gathered.