Rospotrebnadzor said tests found no pathogen linked to the deceased lab worker's work at the Irkutsk anti-plague institute, but more than 60 colleagues remained isolated inside the building and several hospitals stayed closed without explanation.
Government spokespeople have not yet responded to every detail in early accounts, and investigators cautioned that initial figures can change as additional witnesses come forward.
Analysts following the international community said the development fits a broader pattern of fast-moving events that require careful verification before policy responses are finalized.