A case of tick-borne encephalitis virus (TBEV) has been confirmed in England by the UK Health Security Agency (UKHSA), prompting enhanced surveillance for the disease where TBEV has been detected, along with recommendations for changes to testing in hospitals.
Experts at UKHSA say that the risk to the general public remains low, but are encouraging people to check themselves for ticks after going outdoors.
“Our surveillance suggests that tick-borne encephalitis virus is very uncommon in the UK and that the risk to the general population is very low,” says Dr Meera Chand, deputy director at UKHSA.
“Ticks also carry various other infections, including Lyme disease, so take steps to reduce your chances of being bitten when outdoors in areas where ticks thrive, such as moorlands and woodlands, and remember to check for ticks and remove them promptly.”
Although common in many parts of the world, this is the first time that a TBEV case has been confirmed in England.
Since 2019, there have been three cases of probably or confirmed TBEV cases where the infection has occurred in England, and another confirmed case where the infection was confirmed in England but is thought to have been acquired in Scotland.
The only confirmed case for England is thought to have occurred from exposure while mountain biking on the North Yorkshire Moors.
“Our tick surveillance tells us TBEV is present in England and we know there have been cases who acquired their infection in this country,” says Clare Gordon, Consultant in Infections at the Rare and Imported Pathogens Lab at UKHSA.
“We are now actively testing patients with encephalitis for TBEV to see if it could be the cause, even if they haven’t travelled outside the UK, and we are also enhancing our surveillance programme by testing blood samples in people in the areas where TBEV has been found in ticks, to see if there is evidence of any previous infection.”
TBEV-infected ticks have been identified in four locations in the UK since 2019: Thetford Forest, the Hampshire and Dorset border, the New Forest and the North Yorkshire Moors.
What are the symptoms of tick-borne encephalitis?
Tick-borne encephalitis can range from being completely asymptomatic through to a severe infection of the central nervous system that causes symptoms similar to those of meningitis: high fever with headache, neck stiffness, confusion or reduced consciousness. UKSHA says that urgent medical attention should be sought if meningitis-like symptoms are exhibited.
The 50-year-old man who was infected in Yorkshire initially presented symptoms of fatigue, muscle pain and fever, five days after being bitten by a tick. These symptoms faded, but a week later his fever returned with a headache and reduced co-ordination, and MRI scans suggested viral encephalitis. TBEV was confirmed by polymerase chain reaction testing.
In a 2017 episode of The Plodcast, England rugby world cup winner Matt Dawson talked to Countryfile editor Fergus Collins about contracting Lyme disease, the severe effect it had on his health, and why he is now a champion for The Big Tick Project.
Matt Dawson talks to Fergus Collins/Credit: Oliver Edwards
What are ticks?
Ticks are a group of arachnids in the order Ixodida, and are part of the larger mite superorder Parasitformes. As arachnids, they are related to spiders, harvestmen, scorpions and pseudoscorpions. The three common species in the UK are Ixodes ricinus (the sheep/deer tick); Ixodes hexagonus (the hedgehog tick) and Ixodes canisuga (the British dog or fox tick).
“All tick species feed on the blood of vertebrates, but humans tend to be regarded as accidental or opportunistic hosts, rather than the preferred ones,” says Dr Anne Baker, an acarologist at the Natural History Museum, London. “Viruses and other pathogens can be ingest by ticks while blood-feeding on an infected host, and transmitted to hosts when the ticks produce salivary secretions to create a pool of blood during feeding.”
The most common disease carried by ticks in the UK is Lyme disease, caused by the bacterium Borrelia burgdorferi, which can cause flu-like symptoms, extreme tiredness and a range of other symptoms.
