The mother of a scientist who died of pneumonia after researching ‘plague-infected squirrels’ is looking for answers amid fears of a global outbreak.

Co-workers at the Anti-Plague Institute said that Daria Shipilova, 28, had developed cold symptoms after working with Yersinia pestis – the bacterium behind the medieval Black Death.

Daria, nicknamed Dasha, fell ill after research expedition to Buryatia, on Russia’s border with Mongolia, to study plague-infested squirrels.

‘There was no fever, but then her condition worsened, and swelling developed’, they told independent Siberian outlet The Baikal Journal.

‘Dasha was extremely afraid of infecting anyone if something happened. This was clear from how often she washed her hands, even outside of work.’

Her mother Svetlana, who is a doctor, accused doctors of failing to save her daughter who was placed on a ventilator on September 29.

She said: ‘I saved more than one patient like that, but they didn’t save my daughter. They simply let my daughter die.’

Four days later, she is still waiting for an explanation, other than it being a ‘pneumonia case of unknown origin’.

She said: ‘I’m waiting for it to become official. It has to be an official document. It’s very hard for me right now. This whole spectacle drags on.’

She refuted reports that a test tube broke in the lab.

‘Only an amateur would say something like that,’ she said.

‘It’s simply impossible to spill or break it. They are so heavily protected.’

In the days after amid fears of the pneumonic plague escaping the remote region triggering a lockdown of hospitals – forensics descended on Daria’s apartment block to disinfect the premises.

A woman in her 40s living in the building, said: ‘The smell was unbearable and very pungent’ suspecting it was a strong antiseptic.

The residents opened the doors to the building because ‘it was unbearable to breathe.’

The hazmat suit scientists told the residents they were ‘sent by Russia’s health watchdog Rospotrebnadzor’.

‘When we asked what happened they told us: some girl died, a deadly virus’, the neighbour said.

‘I said, “What are you treating here?” And I already knew all about the plague rumours.

‘She said, “It’s for cockroaches.” And we don’t even have any cockroaches in our house.’ And then I saw her packing her [protective] suit into a bag. I was like, “Well, I get it now.”‘

A sign was put up in the block reading: ‘Dear Residents!!! Due to a significant increase in illness in your building, we strongly ask that you call this number.’

Those who had been in contact with Daria at the lab were isolated and placed under medical observation.

A worker at the research lab said: ‘They locked two hundred people up. They held us for three days, taking swabs twice a day. But they fed us. We slept on chairs, and for those who didn’t have enough space, on jackets. I slept on my jacket. They didn’t sign any documents. They released us on Sunday.’

The risk of the plague spreading to the wider UK population is considered to be ‘very low’, according to the UKHSA.

Chris Lewis, director of global health protection at the organisation, said: ‘We are aware of media reports that emergency containment measures have been introduced in Russia’s Irkutsk region following the death of an employee at the Irkutsk anti-plague institute.

‘We are seeking information through the International Health Regulations channels to further understand the circumstances and verify the accuracy of these reports.

‘The public health risk from plague to the wider UK population currently remains very low.’

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