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.

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.’