It all started when doctors in Sweden’s southern Scania County diagnosed a case of nephropathia epidemica, caused by Puumala virus carried by bank voles, in 2018.

Nephropathia epidemica is also referred to as ‘vole fever’ and is a rare illness that has the potential to cause haemorrhagic fever in people.

Haemorrhagic fevers are a group of diseases caused by different viruses that can be severe and life threatening – they include yellow fever, the Ebola virus and Crimean-Congo hemorrhagic fever.