Posted for David Cyranoski

Researchers in the Netherlands, Egypt and the United States are reporting a worrisomely high secondary transmission rate of the H1N1 virus in Japan.

The researchers also point to a high transmission rates among minors and suggest that “the population of minors could play a key role as a ‘reservoir’ for sustained chains of secondary transmission”.

It might however be difficult to generalize from the Japanese case about how this virus moves. The explosive growth in western Japanese province of Hyogo ken, which along with neighbouring Osaka account for 98% of Japan’s cases, followed a volleyball tournament in which some of the players and fans had the disease (Japan Times).

So the Japanese case might tell us less about race or age-specific transmission patterns than it does about how the disease transmits in an enclosed space when sweating, heavily breathing, people are colliding with and high-fiving each other. And the other unique factor to the Japanese case: fans at the volleyball tournament were blowing up balloons and releasing them, the way fans for the local baseball team, Hanshin Tigers, do. “Jet balloons” have since been banned by the Tigers (Japan Times).

Health ministry authorities say the extent to which the volleyball matches were responsible for the spread of the virus is under investigation. The slow release of information could have to do with complaints from the school that the kids were being scapegoated.

Image: Getty