What is heamorrhagic fever and why scientist are worried about 'vole fever' emerging in new areas
Eliza Loukou, Health Reporter
Published: 11:25, 29 May 2024Updated: 11:58, 29 May 2024
A POTENTIALLY lethal virus that has the ability to jump from rodents to humans and can trigger Ebola-like bleeding is spreading across northern Europe.
Researchers have discovered that rodents in Sweden are carrying a pathogen that can jump to humans and turn into haemorrhagic fever.
Cases of the illness are being spotted hundreds of miles from where health officials typically see this virus, causing concern among scientists.
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.
Doctors were baffled to spot a case of vole fever so far south in the country, more than 500 km south from where the disease had previously been spotted.
Another case was spotted in 2020, also in the Scania County of Sweden.
In both cases, the patients hadn't travelled and and were infected in their home area.
Their symptoms were typical of hemorrhagic fever with renal syndrome (HFRS) symptoms, including fever, general malaise, nosebleeds, and poor kidney function.
Both patients recovered from their infections, but it prompted scientists from Uppsala University to look into why vole fever infections where popping up so far from where they usually do.
They conducted genetic testing of bank voles in Scania county, catching them in the vicinity of the patients’ homes and analysing them for any occurrence of hantavirus.
Hantaviruses are a family of viruses mainly found in rodents such as mice, rats and voles.
Certain hantaviruses are able to infect people and cause two kinds of diseases: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS).
According to Uppsala University scientists, both of these types of disease are notifiable under the Communicable Diseases Act, as they can cause serious problems and even death.
In northern and central Europe, a variant of the virus - called the Puumala hantavirus - causes a relatively mild form of HFRS.
However, studies have shown that this hantavirus can also cause very severe HRFS, which in the worst case can be fatal.
In Sweden, about 100–450 cases of vole fever require hospital care each year, just in the northern part of the country.
Scientists' analysis found that nine of the 74 bank voles caught in the southern Scania region carried hantavirus genes.
They also discovered that that the virus infecting rodents in this area wasn't the same strain found in northern Sweden.
Instead, it was a distinct variant closely related to Puumala viruses from Finland or Russian Karelia, hundreds of miles away.
Somehow, this strain of the hemorrhagic fever-causing virus had emerged in southern Sweden’s bank vole population, most likely within the last decade or so.
While only two human cases have been identified so far in southern Sweden, scientists worried this emerging viral strain could represent a threat to public health.
"Novel Puumala virus strains in a new geographic area might have a substantial effect on human health," researchers wrote in a study published to the journal Emerging Infectious Diseases.
Elin Economou Lundeberg, study author and infectious diseases doctor at Kristianstad Central Hospital, said: “We were surprised that such high proportion of the relatively few voles that we caught were actually carrying a hantavirus that makes people ill.
"And this was in an area more than 500 km south of the previously known range of the virus."
Researchers now intend to find out where the virus comes from and map its distribution in the southern parts of Sweden.
Professor Åke Lundkvist of Uppsala University, co-author of the study, wondered:“If the virus has existed in the area for a long time and has simply not been discovered, why haven’t more people become ill?
"Or, has it become established in Scania county recently and only just begun to spread? And how did it get there?
"Unfortunately the COVID-19 pandemic intervened, which considerably delayed the completion of this study.
"These findings are very interesting and show how important it is to investigate the causes as quickly as possible when we see an infectious disease in a new geographical area.”
OTHER HAEMORRHAGIC FEVER SIGHTINGS
It's not the first time alarm bells have sounded over haemorrhagic fever cases in Europe.Crimean-Congo haemorrhagic fever is a viral disease that's typically spotted in regions like Africa, the Middle East and western and south-central Asia.
But the virus has caused major outbreaks in the Balkans and Turkey, and well as Russia, the European Centre for Disease Prevention and Control (ECDC) says.
It's also been spotted in popular holiday spots like Spain.
In April 2024, a person in the Salamanca province died after getting infected with Crimean-Congo haemorrhagic fever during a hike.
A forestry worker in the León province also passed away from the fever in 2022, while another person was infected from a tick bite but recovered.
Crimean-Congo haemorrhagic fever is typically spread by bites from ticks, which are "widely distributed across southern and eastern Europe", according to the ECDC.
ETA: I just cut out all the shite the site chose to add, in it's retardation.
MOD EDIT: OP can't even do a simple copy/paste. Wow.
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