More than a week after a reported pneumonia death of unknown cause at a Siberian epidemic research facility, Russian authorities have yet to disclose the pathogen responsible for the death.

According to The New York Times (NYT) on the 10th (local time), the official cause of death for Daria Shipilova, 28, a researcher at the Siberia and Far East Plague Control Research Institute who died on October 2, remains listed as "pneumonia of undetermined cause."

Shipilova was responsible for handling dangerous pathogens, including the plague bacterium.

Russian health authorities stated that tests on Shipilova's remains did not detect dangerous pathogens from the institute, and no plague bacteria were identified.

They also explained that two inspections of the facility found no emergency situations, such as a pathogen leak.

Tests conducted on contacts in the Irkutsk region have also revealed no additional cases of infection.

However, as the exact cause of death has not been made public even after thousands of tests, questions surrounding the Russian authorities' transparency persist.

Experts believe that, given current testing technology, Russian authorities likely already completed genomic sequencing to determine the cause.

Raj Panjabi, who served as a White House public health official in the Joe Biden administration, said, "It is likely they have already conducted the tests, but the fact that they are not releasing the results is concerning."

In the United States, the incident is being viewed with heightened sensitivity due to intelligence assessments that Russia maintains a biological weapons program.

However, U.S. intelligence officials stated there are no indications that the Irkutsk institute where Shipilova worked was engaged in biological weapons research.

The World Health Organization (WHO) is also demanding confirmation of the "causative pathogen" that triggered Shipilova's pneumonia.

Maria Van Kerkhove, the WHO's head of epidemic and pandemic preparedness and prevention, asked at a press conference, "If plague has been ruled out, what was the actual cause of death?"

Nevertheless, the WHO maintains that it is difficult to conduct its own risk assessment because it has not received sufficient information from Russia.

Some point out that the incident should not be linked to Russia's biological weapons research solely based on a lack of information.

Alexander Kelle, a senior researcher at the Institute for Peace Research and Security Policy at the University of Hamburg in Germany, said, "The lack of information should not be immediately equated with malicious intent," adding that there are also legitimate public health reasons to study dangerous pathogens.

(Photo: Provided by the Irkutsk Oblast Institute, AP, Yonhap News)