A laboratory worker at a plague research institute in Irkutsk region in Siberia fell ill and died under circumstances that have not yet been disclosed, after which authorities placed dozens of people in quarantine.

The death has sparked concern on social media about public health, even though Russian authorities said Monday that the situation is under control. A source in Russia's health sector told a publication that Irkutsk doctors are openly talking about plague, even though the disease is not mentioned in official documents.

Varjas said that although Estonia cannot get verified data from Russia and it is difficult to draw conclusions from the case, it is clear that the threat level has not increased.

"Neither here, nor in our neighboring countries, nor according to the European Center for Disease Prevention and Control's risk analysis, is there any reason to think the risk level is higher than usual," Varjas said.

Speaking more broadly, Varjas said the Health Board has extensive information about plague.

"We know plague has not disappeared from the world. There are natural hotspots where the pathogen exists, and from those it occasionally reaches humans. Plague has been diagnosed in people in America, Asia and Africa. In 2025, several countries reported plague cases," Varjas said.

According to Varjas, plague is fairly easy to treat today. "Plague is treated with antibiotics. They are available in Estonia, so people can be cured. The plague pathogen is the bacterium Yersinia pestis, and its natural reservoir is maintained by various species of small rodents, with fleas playing an important role in transmission," Varjas said.

She said Estonia has no such natural areas, where the disease persists.

Varjas explained that plague has three types. "A person can get the plague bacterium from a flea bite, and in that case we talk about bubonic plague. The person develops a fever, feels very ill and the lymph nodes become swollen and painful. This form is not directly contagious from person to person. The second form is septicemic, when the bacterium enters the bloodstream, damages organs and causes bleeding. This also is not directly contagious from person to person. And the third, rarest form is pneumonic plague, where the pathogen is in the respiratory tract. The person develops a high fever, their condition worsens quickly, they develop chest pain and cough. With the droplets they cough out, they can infect others. It is the rarest but the worst variant because it can spread from one person to another," Varjas said.

Without treatment — especially without timely treatment — mortality is very high, she said.

Varjas stressed that the risk of plague infection for Estonia's residents is very low.

"Estonia's borders have epidemic response plans. If they receive a signal about such a disease, they know how to act and whom to notify," Varjas said.

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