Did ticks develop in front of humans?

Interview: "Ticks have preferences"

Dr. Dobler *, you have collected around 30,000 ticks in your life. How do we have to imagine your forest excursions?

I take an old sheet, walk along the edges of the forest and pull it behind me. The ticks cling to the sheet because they believe it is animal hair. The yield is greatest in the transition area between forest and meadow. There aren't that many ticks in the forest itself. Over the weekend we collected 250 ticks in 90 minutes.

They test the ticks for the TBE virus, which triggers early summer meningoencephalitis. Why is the disease so dangerous?

Because there are no treatment options. Once TBE has broken out, it takes a fateful course. There are two different degrees of severity of the disease: it can be mild, in which case the patient has the symptoms of a flu-like infection. However, TBE can also affect the brain and be fatal. Unfortunately, the disease cannot yet be treated with medication.

Is drug development that complicated?

Yes, because the viruses have adapted well to human cell functions. If you were to switch off the pathogen, the body's own cell functions also suffer. That is why it is so difficult to find therapies. There is no drug in sight for the next five to ten years.

Does a person automatically get sick when they are bitten by a TBE infected tick?

No, 90 percent of the stitches have no consequences. It is unclear whether insufficient amounts of viruses are being transmitted here or whether these are viruses with low disease-causing activity.

Where did the ticks get the virus from?

The ticks ingest the virus when they suck blood on rodents such as mice. You are the natural host. Man is actually just a chance host. In a negative sense, it is like winning the lottery when a tick carrying the virus stings a person. Rodents and ticks do not get sick from TBE, but humans can be affected by the viruses.

Can other animals also transmit the virus?

This is possible, especially when goats or cows are bitten by infected ticks. You excrete the virus in milk. If you drink this untreated, you will also take the pathogen with you. In Germany, however, this is a very rare transmission route. In eastern countries like the Czech Republic, Slovakia or the Baltic States, this happens more often. Studies in the Czech Republic show that ten percent of TBE cases are caused by milk transmission.

There are said to be people who are particularly susceptible to tick bites. Do the bloodsuckers choose their victims?

We know that ticks are rare for some people and very common for others. The animals certainly have preferences, for example the chemical composition of sweat plays a role.

Men are more likely to be affected?

Yes, women are less likely to get sick after an infection. However, men often work in the forest or on the farm. Age is also an important factor. The older a person is, the more severe the disease can be. Children are often mildly ill. Beyond the age of 50, a very high proportion of TBE is a serious illness with symptoms of paralysis.

Could I still protect myself after a tick bite?

No, protection is no longer possible afterwards. You have to take action beforehand, for example with a TBE vaccination.

Few people notice them, why?

I believe that ignorance is a reason. Some people do not know that there is TBE and a vaccination. Some think that it always hits the other. But it could also be the fear of the vaccination.

Especially before their side effects. Which can occur?

There may be pain at the injection site or small swelling. Headaches are also possible. Children sometimes suffer from anorexia. Such reactions only occur in a maximum of ten percent of those vaccinated. Complications are extremely rare. With more than 20 million people vaccinated, five develop neurological diseases. It is difficult or impossible to prove whether the vaccination is actually to blame.

Dr. Dobler, thank you very much for talking to us.

The interview was conducted by Janine Berdelmann.