Tick-borne encephalitis (TBE)

Tick-borne encephalitis is a viral infection passed on by the bite of a tick which, in some of those affected, reaches the brain and its coverings. It is an uncommon illness, but it has a feature that makes a page like this genuinely useful: there is no treatment aimed at the virus itself, while there is a vaccine, and the vaccine really does protect. Everything that can be done about this disease, in other words, is done before it starts. That is why most of the space here goes to prevention rather than to treatment.

Where the disease occurs and how people catch it

Tick-borne encephalitis is far more widespread in Europe than is generally assumed. There are foci in Austria, Germany, Switzerland, the Czech Republic, Slovakia, Hungary, Slovenia, Poland, the Baltic states, southern Sweden and Finland, northern Italy, Ukraine, European Russia and further east as far as Japan. In Spain and Portugal the disease is practically absent, but a resident of either can easily bring it home from a holiday in the Alps or a trip to see relatives.

The boundaries of the foci do not follow national borders: within one country infected ticks may be present in a few districts and entirely absent from the rest, and the map shifts from year to year. So the question of whether there is a risk is answered by the particular place you are going to, not by the name of the country.

Ticks live in woodland, along forest edges, in long grass and in scrub, but they also turn up in town parks and in gardens. They are active from roughly early spring to late autumn, with a peak in late spring and a second one in early autumn; mild winters lengthen the season.

There is a second route of infection that is hardly ever mentioned: raw, unpasteurised goat's and sheep's milk and fresh cheese made from it. If the goat grazed where infected ticks are present, the virus passes into the milk. This is how family outbreaks arise, with several people falling ill at once and not one of them having been bitten. Cow's milk can also be a source, though less often. The disease does not spread from person to person.

How it runs: two phases and a deceptive pause between them

Most people who become infected have no symptoms at all — they get through it without ever knowing. In the rest the illness usually comes in two instalments, and that is its defining feature.

The first phase begins on average a week after the bite, though it may be two days or a month. It looks like ordinary flu: fever, headache, aching muscles and joints, weakness, nausea. There is nothing about it to mark it out from any other viral infection. It lasts a few days and passes.

Then comes the pause — about a week during which the person feels recovered and goes back to normal life. That is the trap: the tick bite seems a closed subject, and the second deterioration is no longer connected with it.

The second phase does not happen to everyone, only to a minority, and it means the virus has reached the nervous system. Now there is severe headache, high fever, a stiff neck, vomiting, intolerance of bright light, confusion, drowsiness or on the contrary agitation, tremor, unsteadiness, weakness or loss of movement in an arm, a shoulder or a leg, and sometimes seizures.

Severity rises with age: children generally get through it more lightly, while severe forms are commoner in older people. Some are left for a long time with fatigue, headaches, difficulty concentrating and weakness in an arm or shoulder; recovery takes months.

And an important detail: many of those who fall ill remember no bite at all. A tick can be the size of a poppy seed and the bite is painless. What counts is simply the fact that you were in woodland or parkland in a risk area.

When to call an ambulance

Signs that the infection has reached the brain and its coverings call for emergency help, not for an appointment. Call an ambulance — in Spain, Italy, Portugal, Poland and Ukraine that is the single European number 112 — if you or someone near you develops:

• severe headache together with a high fever;
• a stiff neck, an inability to bring the chin to the chest;
• marked intolerance of light, repeated vomiting;
• confusion, odd behaviour, slurred speech, unusual drowsiness that is hard to rouse someone from;
• a seizure;
• weakness or loss of movement in an arm, shoulder or leg, double vision, difficulty swallowing or breathing.

Do not drive yourself, and do not take a confused or weakened person to hospital under your own steam. And be sure to tell the medical team that you have been in woodland where tick-borne encephalitis occurs, that a tick bit you, or that you drank unpasteurised milk: without that sentence the diagnosis takes far longer to reach.

There is no treatment for the virus itself

This is the unwelcome but important part. No antiviral drug exists that acts on the tick-borne encephalitis virus, and antibiotics are useless because they do nothing against viruses. Giving immunoglobulin after a bite, which used to be done, is no longer part of European practice.

Hospital care is supportive, and it is far from pointless: it holds the body up while it deals with the infection itself. That means fluids, painkillers and medicines to bring down fever, drugs to control seizures, monitoring of breathing and, in severe cases, intensive care and mechanical ventilation. Many people need rehabilitation after discharge. From which the conclusion is simple: the only genuinely effective thing can be done in advance.

The vaccine exists, and it works

The vaccine against tick-borne encephalitis is the main reason to read this page. It has been in use for a long time, is well studied and protects the great majority of those who receive it; where vaccination is widespread the number of cases has fallen several times over.

It is an inactivated vaccine, meaning it contains no live virus and cannot give you the illness. There are versions for children and for adults. The primary course is three doses: the first two a few weeks apart and the third some months later, followed by boosters every few years. The exact intervals and the age at which vaccination starts differ from country to country, so follow the national schedule and your doctor's advice.

Who needs it:

• People living in an area where the disease occurs — in several countries this vaccine is part of the routine schedule.
• People travelling to such an area who intend to spend time outdoors: hiking, camping, cycling, fishing, picking mushrooms and berries, gardening.
• People whose work takes them into forest and field: forestry workers, surveyors, soldiers, farmers, biologists.

If you are planning a trip, start the course in good time — at least a month ahead, so that two doses have taken effect by the time you leave. Accelerated schedules exist for those who decide to travel at short notice; a doctor will choose one. And an important caveat: this vaccine protects only against tick-borne encephalitis. It does nothing against the other diseases ticks carry.

How to keep ticks off you in the first place

Vaccination does not do away with the ordinary precautions, all the more so since ticks carry more than this one virus.

• Keep to paths and do not push through long grass and undergrowth — ticks sit on the vegetation and catch onto whoever brushes past.
• Wear long sleeves and long trousers, and tuck the trousers into your socks. Light-coloured clothing has the advantage that a tick shows up on it.
• Put a repellent containing DEET or icaridin on exposed skin, and clothing and kit can be treated with a permethrin product.
• Check yourself every evening and always after you come in. Look where the skin is thin and creased: behind the knees, the groin, the armpits, the waistband, behind the ears, along the hairline. On children check the scalp and neck with particular care.
• Shower after a walk and shake out your clothes; a hot tumble dryer kills ticks, a cold wash does not.
• Check the dog after a walk: dogs bring ticks into the house.
• In an affected area do not drink unpasteurised goat's or sheep's milk and do not eat fresh cheese made from it, however rustic and wholesome it looks.

How to remove a tick properly

If a tick has attached itself, take it off as soon and as plainly as you can.

• Use fine-tipped tweezers or a purpose-made tick remover; pharmacies sell them.
• Grip the tick right against the skin, by the head, not by the swollen body.
• Pull straight up, slowly and steadily, without jerking and without twisting.
• Wash the bite with soap and water or an antiseptic, and wash your hands.

What must not be done: smearing the tick with oil, cream, petroleum jelly, nail varnish, alcohol or petrol, or burning it with a match or a cigarette. All these tricks are meant to make the tick let go by itself. It does not let go; it is put under stress, and while under stress it empties the contents of its gut into the wound — precisely what you were trying to avoid. Time is lost as well, and here time works against you.

If mouthparts stay behind in the skin, do not dig them out with a needle: they work their way out on their own like a splinter. The bite may redden a little and itch over the first few days, which is a reaction to the tick's saliva and not an infection.

After that all you have to do is keep an eye on yourself — not for a couple of days but for about a month. Mark the date of the bite on a calendar. See a doctor if within that time you develop a fever, headache, aching, unusual weakness, or a red patch that starts spreading on the skin. And tell the doctor about the bite even if it was a while ago and you had all but forgotten it.

This is not Lyme disease, even though the tick is the same

The two are constantly confused, and telling them apart matters because what you do about them differs. Lyme disease is caused not by a virus but by a bacterium, and it is far more widely distributed than tick-borne encephalitis, including in countries where encephalitis does not occur. Its hallmark is a spreading red patch at the site of the bite: it appears days or weeks later, widens slowly, often clears in the middle, and it barely hurts and barely itches. Left untreated, joint pains, nerve damage including a drooping face, and heart rhythm disturbances follow later.

The key differences:

• Lyme disease is treated with antibiotics and, caught early, is cured almost every time. For tick-borne encephalitis there is no medicine.
• There is no vaccine against Lyme disease, whereas there is one against tick-borne encephalitis. Being vaccinated against encephalitis gives no protection against Lyme.
• With Lyme the speed of removal genuinely counts: the bacteria do not cross straight away, and a tick taken off within the first day markedly lowers the risk. The encephalitis virus sits in the tick's saliva and passes quickly, so speed matters less for it — but remove the tick at once anyway, for the sake of Lyme.
• One and the same tick can carry both infections.

So a spreading patch after a bite is a reason to see a doctor within days rather than to watch and wait: on its own it is enough for the diagnosis and for a course of antibiotics.

Online consultation

Most tick questions arise not in a hospital but at home in the evening, with the tick already off and in your hand — and they need no examination.

In a consultation a doctor will work out whether there is a tick-borne encephalitis risk where you are going or have just come back from, help you plan the vaccine course around your travel date, and explain what to do after a bite, what to watch for and for how long. They can look at a photograph of the bite and say whether the patch looks like Lyme and whether you need to be seen in person. They will go through what to do about a child, and what to do if you have only remembered the unpasteurised milk once you were home.

What an online consultation does not replace: examination and treatment where Lyme disease is suspected, the vaccination itself and, with the signs of brain involvement set out in the emergency section, calling an ambulance.

This material is for information only and does not replace medical advice.