What is tick-borne encephalitis and how many people have been infected?

Experts have said the risk of catching tick-borne encephalitis is low. Credit: Erik Karits/Unsplash

By Daniel Boal, ITV News Multimedia Producer

A virus that is carried by ticks and can cause meningitis has been detected in several areas of England, prompting health officials to remind the public on how to avoid being bitten by the tiny bugs.

Experts have said the chances of getting tick-borne encephalitis are low, but the tick species that carries the virus could be widespread across the UK.

And, while most people don't develop symptoms, it can possibly lead to severe infections in the central nervous system such as meningitis or encephalitis. Encephalitis is an uncommon but potentially deadly condition in which the brain becomes swollen.

What is tick-borne encephalitis virus?

Tick-borne encephalitis (TBE) is an infection spread by tick bites. Ticks that spread it are found in parts of Europe and Asia, and some parts of the UK.Most infections remain asymptomatic, but some cases will develop a number of symptoms:

  • Initial symptoms can include fatigue, headache and general malaise, usually combined with fever of 38°C.

  • Up to 15% of patients experience a second phase of the disease characterised by fever frequently exceeding 40°C and signs of central nervous system involvement

  • The central nervous system involvement can include meningitis (e.g. fever, headache, and a stiff neck), encephalitis (e.g., drowsiness, confusion, and sensory disturbances), myelitis or radiculitis.

  • Encephalitis developing during this second phase may result in paralysis, permanent sequelae or death.

  • Severity of illness increases with age of the patient, but fatalities have been reported from all age groups.

Where have the infected ticks been found?

Virology Professor Ian Jones said wearing appropriate clothing removes the risk of tick bites. Credit: PA Images

There have been three cases of probable or confirmed tick-borne encephalitis (TBE) in England since 2019, with the first confirmed case in Yorkshire in 2022, and a probable case detected in the Loch Earn area of Scotland in the same year.The virus has also been detected in the Hampshire, Dorset and Norfolk areas of the country, but may also be present elsewhere, according to a risk assessment published by the UKHSA and DEFRA.

The virus is also found in most of Europe, Russia and parts of China and Japan.

Ticks live in forests and grassy areas. You're more at risk of being bitten if you do activities such as hiking and camping.

Not all ticks spread TBE. Even if you're bitten, the risk of getting seriously ill is low.

How to avoid ticks:

Always try to avoid being bitten in places where ticks are found.

According to NHS England the best way to reduce the risk of being bitten is to:

  • Cover your skin while walking outdoors and tuck your trousers into your socks

  • Use insect repellent on your clothes and skin – products containing DEET are best

  • Stick to paths whenever possible

  • Wear light-colored clothing so ticks are easier to spot and brush off

If you are bitten however, health experts advise removing the tick as soon as possible.

A graphic showcasing how to remove them by grasping them close to the skin with fine-tipped tweezers or a tick removal tool. Credit: NHS England

Ticks can be removed using a pair of tweezers - which is best done by grasping the tick as close to the skin as possible, pulling upwards slowly and firmly.

The whole tick needs to be removed as the mouthparts left in the skin can cause infection.

Doctors advise that you wash the area and monitor it for changes, but if you experience flu-like symptoms or a red circular rash they advise contacting your GP.

What do the experts say?

Ian Jones, professor of virology at the University of Reading, said wearing appropriate clothes "essentially removes the risk".

"Tick-borne encephalitis virus was reported in ticks in Thetford Forest in 2019 and today’s update would suggest that it has now become established at other sites and caused sporadic disease in people," he said.

"Genetically the UK viruses have been close to European or Scandinavian strains so they may have originally arrived from the near continent in ticks attached to birds.

"The virus is found naturally in some ticks and gets transferred to a person if they are bitten (only if the tick is infected), usually on bare arms and legs whilst walking through undergrowth. Wearing appropriate clothing essentially removes the risk."

Prof Jones added: "Now here, it’s unlikely that TBEV will disappear, but the general threat level is very low and there is no reason to suppose cases in people will be any more than sporadic in nature.

"Vaccine is used in areas of high incidence in Europe and could be considered here for individuals with outdoor occupations in areas where the virus is found. For the general public however the risk is minimal."

Dr Meera Chand, deputy director at the UK Health Security Agency, said: "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."

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