A pestilence spread by travellers, pets and curious teenagers may show that experts have not taken everything into account when planning for an outbreak of disease, according to us researchers, writing in the medical journal, The Lancet. But luckily they are talking of a computer game gone awry. And more significantly it could prove clues to human behaviour during epidemics.

The virulent, contagious disease, Corrupted Blood, was introduced by maker Blizzard Entertainment Inc. of Irvine, California, as an extra challenge to high-level players of the online game World of Warcraft. "It really looked quite a bit like a real disease,' says Nina Fefferman of Princeton University, who worked on the report with her then-student Eric Lofgren.

Currently, epidemiologists face big constraints because they are limited to observational and retrospective studies.The game allows for experimentation on virtual populations, that too, without such limitations.