A tick-borne parasite which can cause deadly malaria-like illness is spreading in the UK, a study has warned after scientists found it in the north-east of Scotland.
The organism – named Babesia venatorum – causes babesiosis, an disease usually seen in animals but increasingly being diagnosed in people.
There have been reports of deaths in US and infections in Italy and China, but has never been officially diagnosed in people in the UK.
Researchers who discovered the parasite found it in sheep and culled deer in the Scottish Highlands and said it ‘represents a new risk’ to people visiting the region.
It is the second such risk to be found this year after experts discovered the brain infection encephalitis was being spread by ticks in Norfolk, Hampshire and Dorset.
The European Centre for Disease Prevention and Control said infected people may get symptoms such as flu and jaundice but severe cases can lead to death.
Traces of the B. venatorum parasite was discovered in sheep in the area circled in blue in 2014 – the first time it has been spotted in the UK. The red area is where it was found in culled deer
A study by University of Glasgow scientists reported the B. venatorum organism had been identified in sheep in the north-east of Scotland.
Specific locations were not given but they said it was found on sheep on two farms in the Highlands’ east coast, as well as in roe deer over a wider area.
Because none of the animals were imported from other countries the scientists were puzzled about how the parasite infected them.
They suggested migratory birds flying from Scandinavia could have spread it.
Willie Weir, senior university clinician, said: ‘The presence of B. venatorum in the UK represents a new risk to humans working, living, or hiking in areas with infected ticks and livestock, particularly sheep.
‘Although we believe the threat to humans to be low, nevertheless local health and veterinary professionals will need to be aware of the disease if the health risk from tick-borne disease in the UK is to be fully understood.
The B. venatorum parasite is spread by ticks (stock image) and was found on sheep and deer in the Scottish Highlands
WHAT IS BABESIOSIS?
Babesiosis is a malaria-like parasitic infection of the blood which is caused by a tick bite.
It’s caused by microscopic parasites called Babesia microti which infect red blood cells.
Symptoms include a fever, chills, sweats and headaches and nausea.
It is often misdiagnosed or goes unnoticed completely because it can only be detected by looking at a blood sample under a microscope, and many people don’t have any symptoms at all.
For this reason it’s difficult to estimate how many people get the illness, but it is considered to be rare.
In the US in 2013 there were 1,762 cases in 27 states.
It can be life-threatening for people who have weak immune systems – because of old age, other illnesses, cancer treatments, for example – and can cause the vital organs to malfunction and shut down.
‘Our findings follow the recent report of the detection of tick-borne encephalitis virus in the UK.
‘Taken together, these findings signify a change in the landscape of tick-borne pathogens in the UK and the underlying causes for this need to be investigated.’
Babesiosis is described as being malaria-like because it is a parasitic blood infection and causes similar symptoms.
These include fever, chills, headaches, nausea, loss of appetite and exhaustion.
Many people have no symptoms and recover, but for those who have weak immune systems it can cause the vital organs to malfunction and shut down, even proving fatal in some cases.
Scientists collected blood from sheep, cattle and deer in the north-east of Scotland in areas where tick-borne diseases have previously been detected.
DNA from the parasite was detected in the blood of a large number of sheep, which were not showing any signs of disease, making them carrier animals.
The work took place in 2014 but has now been published for the first time.
Researchers believe B. venatorum may have been carried to the UK by migratory birds from Scandinavia.
Identification of this parasite in the UK raises concerns for European public health and farming policy, according to the study’s authors.
The scientists’ paper is published in the December edition of Emerging Infectious Disease.
It comes after Public Health England (PHE) confirmed in October that there were ticks carrying encephalitis in Thetford Forest in Norfolk and on the Hampshire-Dorset border.
Encephalitis is an uncommon but deadly swelling of the brain which can cause seizures and loss of consciousness.
It can have various causes but versions of the illness spread by insects are most common in tropical countries where mosquitoes carry the parasites.
PHE says the risk of catching the virus in the UK is very low but ‘there is the potential for human contact’. It is currently investigating how common the infected ticks may be.