We reported probable cases of tick-borne encephalitis virus (TBE) back in 2019, but now it is clear that TBE is definitely in the UK. Encephalitis is inflammation of the brain, but the virus doesn’t always cause this – some cases can be mild and some people don’t even notice symptoms.
Two new cases have now (April 2023) been confirmed as UK acquired. Both are cases diagnosed in England, but one patient probably contracted the virus in Scotland in June 2022 and the other probably from a tick on the North York Moors, also in 2022.
The UK Health Security Agency has a programme of testing ticks for this virus (and other diseases) and TBE has now been found in ticks in several UK sites. Be aware that it may be present in other sites where ticks have not been tested. So far, the virus has been found in ticks in
- Thetford Forest
- Hampshire / Dorset border
- the New Forest
- the North York Moors
Although you need to be tick aware, you do not need to panic!
As with other viruses, not everyone falls ill. If you do, symptoms start with ‘flu-like symptoms of fever, headache, muscle ache and then there tends to be a gap of a few days and some people recover at this point. However, a few then go on to develop a second phase of disease. In children this is usually meningitis, but people older than 40 can develop the more severe encephalitis.
The tick that is responsible for most UK tick bites, Ixodes ricinus, the sheep tick, carries the EUR subtype of this virus. TBEV-EUR is known to cause milder disease with only about 2-3 people out of 10 who experience symptoms having the more severe disease where the virus affects the central nervous system.
All of this can be very like the symptoms of Lyme disease and the UKHSA is raising awareness amongst health professionals so they carry out tests to determine, where possible, the cause of a patient’s symptoms.
Be aware that the TBE virus is carried in tick saliva and can be transmitted to you within minutes of the tick bite, unlike Lyme disease bacteria which usually take some hours to leave the tick’s mid gut. So protect yourself from tick bites as much as possible and carry your tick remover with you when you are out and about. If you have many tick bites, and live or work in one of the areas where TBE has been found in ticks, consider tick repellents or impregnated clothing if you do not already use these.
The virus can also be acquired from unpasteurised dairy products, but this is very much less common.
The NorthTick project has produced a very useful animation on TBE.
For more detail on TBE, and how it differs from Lyme disease, see our article from 2019 when the first UK cases were reported.
The UKHSA has produced a detailed risk assessment – a lot of reading, but essential for those responsible for the health and safety of those who work outdoors.
If you are travelling abroad, see the NHS website for countries affected and how to get a vaccine.