The top US public health agency’s remarks come as the Trump administration said it’s ‘closely’ watching the incident.

The United States Centers for Disease Control and Prevention (CDC) has said it’s “aware of and closely monitoring” a suspected pneumonic plague outbreak in Russia.

The top US public health agency released a statement on social media Tuesday, attempting to ease rising global concerns after the unexplained death of Darya Shipilova, a 28-year-old woman who worked at an anti-plague laboratory in Siberia.

“While the circumstances of this reported case remain unconfirmed, plague is a serious bacterial disease that is treatable with antibiotics, particularly when recognized and treated early”, the CDC said.

Russian authorities, who have released few details on the events surrounding Shipilova’s death, have quarantined a hospital in the country’s Irkutsk region and are tracing the laboratory technician’s contacts.

Russian media reports also say authorities have placed nearly 200 people under medical observation.

The CDC emphasised the need for “rapid identification and treatment of infected individuals”, but said the incident posed little risk to the US.

“CDC and our interagency partners are prepared and continue to monitor the situation closely”, the agency said.

The remarks from the US health agency come as the Trump administration said it’s “closely” watching the incident, which Russia has said is under control.

US Secretary of State Marco Rubio on Tuesday pushed Moscow for more information on Shipilova’s death.

“I think it’s incumbent upon Russia to obviously share more information with the world,” Rubio told reporters in Iceland.

Rubio added that the US has “measures” available to help Russia if the situation becomes more serious, but needed to know more before it could step in.

Dr Ashish Jha, who coordinated former US President Joe Biden’s response to the COVID-19 pandemic, said on Tuesday that it is unlikely Shipilova was the only person who contracted a case of pneumonic plague.

“That would be great,” Jha wrote on X. “But given the context and history, to assume it is that would be unwise.”

“We need to understand exactly what has happened. And we have to assume we may not know the full truth,” he added in a separate post as he echoed the Trump administration’s calls for more transparency from Russia.

Pneumonic plague is caused by the bacterium Yersinia pestis, which is usually found in small mammals and their fleas. According to the World Health Organization, the plague is highly infectious and can be transmitted through respiratory particles. It can be fatal if not treated early.