World Health Organization Director-General Tedros Adhanom Ghebreyesus said Tuesday that the agency has seen no evidence of plague spreading in Russia following a suspected laboratory incident in Siberia. However, he said the WHO is still seeking additional information from Russian authorities about what caused the illness and whether another employee also became sick.

The case centers on 28-year-old Daria Shipilova, a laboratory worker at the Irkutsk Anti-Plague Institute of Siberia and the Far East. Shipilova died last week after developing severe pneumonia, prompting Russian authorities to place roughly 200 people who had contact with her under medical observation and quarantine.

According to Tedros, Russian health authorities told the WHO that no recent cases of plague had been registered in the Irkutsk region. They also reported that contacts had been identified, tested and monitored and that no high-threat pathogens had been detected among them.

The WHO said it has remained in contact with Russian officials and offered technical assistance, but it has requested more information about the precise cause of Shipilova's illness, the pathogen that prompted the public health response and reports of a second employee suffering from pneumonia of undetermined origin.

Tedros stressed that the WHO's assessment is based in significant part on information supplied by Russian authorities, calling for “timely, complete, and transparent information sharing” under international health regulations.

Russian health agency Rospotrebnadzor said Wednesday that it was winding down precautionary measures in the Irkutsk region after finding no additional plague infections beyond Shipilova's case. The agency said about 90% of the roughly 200 people placed under observation had been released and that nearly 5,000 laboratory tests had found no additional infections.

The circumstances surrounding Shipilova's death have nevertheless raised questions because she reportedly had been vaccinated against the pathogens maintained at the anti-plague institute. Rospotrebnadzor said she had been appropriately vaccinated and should have been protected against the dangerous infections she worked with.

The WHO is also seeking clarification about reports of a second laboratory employee who developed pneumonia of unknown cause. Russian media reports have raised the possibility of another illness, although Kremlin spokesman Dmitry Peskov dismissed those reports Wednesday, saying that much of the media coverage was false and that official statements from Rospotrebnadzor should be relied upon.

The situation has also drawn attention from the Trump administration. President Donald Trump said Wednesday that he expected to speak with Russian President Vladimir Putin about the situation, potentially as soon as Thursday. Peskov said no call had been scheduled at that point, although he said Russia had been engaged in discussions with the United States.

For now, the WHO says there is no evidence of wider plague transmission, but its assessment remains dependent on information provided by Russian authorities as international health officials continue seeking additional details about the unusual illness and events at the Siberian laboratory.