Health authorities in Russia took preventive measures after the death of a laboratory worker sparked fears over a possible plague outbreak, a Russian news agency reported on Oct. 4, citing the country’s consumer watchdog.

Russia’s consumer watchdog, Rospotrebnadzor, said that “a special set of measures” were implemented in response to the case of a worker at the Anti-Plague Research Institute of Siberia and the Far East near Irkutsk, Russian news agency Interfax reported.

Rospotrebnadzor said the worker had been diagnosed with pneumonia of unknown origin, but authorities have not confirmed whether the worker contracted plague, a potentially life-threatening bacterial disease. The timing of her death remains unclear.

Expanded testing of the patient’s samples also found no microorganisms associated with the worker’s professional activities, according to the watchdog.

“Due to the patient’s professional activities, upon receiving information, a comprehensive set of anti-epidemic measures was immediately and fully implemented in accordance with sanitary legislation,” Rospotrebnadzor stated.

“This included identifying the widest possible circle of people who had been in contact with the patient, inpatient medical observation, and daily laboratory testing.”

The watchdog said the public health situation in the Irkutsk region and the cities of Irkutsk and Shelekhov remains under control. It noted that no infectious disease cases have been reported among other employees at the research laboratory in the past 10 days.

“The results revealed two cases of COVID-19 and two cases of rhinovirus infection. No other infectious agents were detected,” it said. “None of the contacts have shown any changes in health related to infectious pathology.”

Plague is a disease caused by the bacterium Yersinia pestis, which can spread through bites from infected rodent fleas or direct contact with an infected animal, according to the Centers for Disease Control and Prevention. The agency said the disease could be cured with antibiotics when treatment is given in a timely manner.

There are three forms of plague: Bubonic plague, which affects the lymph nodes and causes painful swellings; septicemic plague, which occurs when the bacteria infect the blood and cause skin and other tissues to turn black; and pneumonic plague, which occurs when the bacteria infect the lungs. Pneumonic plague is the most severe form of the disease and can spread from person to person through the air, the agency said.

Alexei Tsydenov, head of the nearby Republic of Buryatia, said in a social media post on Oct. 2 that the worker in Irkutsk had “possibly died of plague.”

Tsydenov emphasized that the patient had no travel history to Buryatia and that there are no plague outbreaks in the republic.

Irkutsk Governor Igor Kobzev said on Telegram on Oct. 2 that all contacts placed under medical observation have shown no signs of illness and tested negative for the disease.

The governor added that “an extraordinary meeting of the regional sanitary and anti-epidemic commission” had been convened, with Russia’s chief state doctor in attendance, to address the matter.

A U.S. State Department spokesman told The Epoch Times by email that the United States is aware of reports of “a fatal case of suspected pneumonic plague” in Irkutsk and is monitoring the situation closely with the CDC and other interagency partners.

“Many details have not been confirmed. We encourage Russian authorities to share accurate information quickly and openly,” the spokesman said.