After a technician at an anti-plague laboratory in Siberia died, Russian officials are attempting to calm global concerns.

Daria Shipilova, a 28-year-old employee at the Anti-Plague Research Institute in Siberia, died on October 2 after being hospitalized days earlier for pneumonia in Shelekhov, a nearby town.

The World Health Organization told the Associated Press on October 6 that the plague presents a "very low" risk to the broader European region.

That doesn't mean we know everything — or really, much of anything — as of now. While there's no confirmation of a plague outbreak so far, conflicting reports about how the alleged "patient zero" got infected, whether she was infected at work, and Russia's current safety protocols have given some medical experts pause.

"It's an odd situation that needs more transparency and requires more information for clarity," Dr. Nahid Bhadelia, the founding director of the Boston University Center on Emerging Infectious Diseases, told Business Insider.

Here's everything we know so far.

What happened to Darya Shipilova?

As of now, not much is known about Shipilova's cause of death. Still, independent regional news outlet Lyudi Baikala said she was hospitalized on September 29. A friend told CNN that Shipilova died on October 2.

Rospotrebnadzor, Russia's public health watchdog, said that testing Shipilova found "no microorganisms associated with the patient's professional activities" and that she died from "pneumonia of unknown etiology."

People of Baikal, an independent regional news outlet, reported that Shipilova was "deeply anxious about ever infecting anyone if something happened," according to one of her colleagues at the institute.

Other colleagues called her "responsible" and described the anti-plague institute as "a serious facility" in terms of safety measures.

Did she die of pneumonic plague?

Reports from Russian exiled publications — ones forced to operate outside Russia or use decentralized reporting methods — speculate whether Shipilova died from the pneumonic plague.

The Moscow Times, an independent publication located in Amsterdam, reported unconfirmed claims that Shipilova may have broken a test tube containing plague bacteria at the institute before she fell ill.

It also reported, citing Russian Telegram channel Mash, that she was hospitalized with pneumonia symptoms and placed on a ventilator before her death.

Russian authorities had not publicly confirmed either account.

Why has this case raised an alarm?

Reports from Russian state media and independent publications have often clashed, leading to more questions than answers. "The scenario, to me, doesn't fit together," Bhadelia said.

If the reports of a broken test tube were true, an anti-plague institute should have several safety measures in place, such as protective equipment, ventilation, and clear treatment protocols.

"She needs to have broken a test tube, have a breach in her personal protective equipment, not reported the incident, not gotten the antibiotic prophylaxis, just gone home under no one's observation, shown up at a local district hospital, and exposed 200 people," Bhadelia added.

That explanation, however, is at odds with another report from the People of Baikal.

There were also confusing reports about Russia's safety protocols.

Rospotrebnadzor said authorities identified and monitored 197 people who had contact with Shipilova. It said that two people tested positive for COVID-19 and two others for rhinovirus. Everyone else who was tested showed no signs of other infectious agents.

"It could be that we just don't have the perfect information, that there might be some media sensationalism in the regional media, or there may be something else going on that we don't know," Bhadelia said.

Still, the current risk is nowhere near a COVID-19-level threat.

What is pneumonic plague — and how does it spread?

Yersinia pestis, or plague, is a bacterial infection that progresses very quickly, Bhadelia said. Patients with pneumonic plague can sometimes develop symptoms in under 24 hours. It can be fatal if left untreated.

Luckily, when caught early, treatment is also pretty straightforward: A course of antibiotics.

In July 2025, an Arizona man contracted pneumonic plague from two ill cats. He was medically evaluated after two days of abdominal pain, chest pain, and dry cough. He died eight hours after admission. However, all 46 people exposed to him recovered after taking antibiotics.

Bhadelia said it points to one of the biggest mysteries of the Russia case so far: If Shipilova was reportedly experienced, knew she was exposed, and reported it, why wouldn't she be under quarantine and quickly treated with medication?

"Early identification and post-exposure prophylaxis is one of the ways that this could be avoided," she said.

Is there any risk to people in the US?

The WHO says the risk outside Russia is "very low," and there is no evidence of cases in the US or beyond the Irkutsk area.

What we're missing from Russia

Bhadelia, who is also the founding director of the Biothreats Emergence, Analysis, and Communications Network, said the organization is trying to provide the most up-to-date information on the pneumonic plague in Russia.

It's not easy.

For one, Russia is notorious for clamping down on the free press, particularly after the start of the Ukraine war. Additionally, some early reports of the plague, including from pro-Kremlin sources such as REN TV, appeared inaccessible when Business Insider checked on October 6.

Some of the official reports from Rospotrebnadzor have also been vague. For example, the agency said it tested Shipilova and found no connection to plagues attached to her work. However, Bhadelia said it's unclear exactly what she was tested for.

"We should find out what the results were of what she was negative for, even if they don't know what she's positive for," she said.

For onlookers, the situation carries some parallels to the COVID-19 pandemic. Over six years later, WHO still hasn't confirmed the origin of COVID-19, which Bhadelia said could be contributing to the panic.

"Transparency is important," she said. "We've learned from the COVID lesson that this can spin out to be much bigger."