New Delhi, Oct. 7 -- The rumours that emerged sounded like the opening of a thriller. A young woman working in a Siberian research lab supposedly breaks a test tube containing a lethal plague pathogen. She is dead within 48 hours. Authorities race to contain the situation. The questions outnumber the answers, breeding suggestions of conspiracy. The fears may prove unfounded: there may not have been a leak at Russia's Irkutsk Anti-Plague Research Institute. But the world can be forgiven for its panicked interest.

Some facts are not under dispute. Darya Shipilova, a 28-year-old researcher at the institute, died at a regional hospital on October 2nd. Around 200 of Ms Shipilova's contacts have been placed under medical observation, suggestin...