The tick crawls higher

Researchers have found ticks more than 1,000 meters above sea level, including larvae. So the species is considered established, but there is still very little left.

Previously, no established ticks had been found in Norway higher than 580 meters above sea level and further north than the Helgeland coast. It was hoped that, among other things, climate change and changes in flora and fauna could lead to forest ticks and mouse ticks spreading north and higher.

In January, researchers from the University of Agder and the University of Southeast Norway published a study after mapping the larval appearance of the two tick species in the mountains of southern Norway over time. This is necessary to know if the ticks have really established themselves in a place and not just ended up there through a host animal.

– We found the tick in the larval stage, which clearly shows that it has established itself, at a height of 1,000 meters above sea level. When we find larvae, it means that it is certainly adult ticks that have laid eggs there and hatched, co-author and associate professor of biology Lars Korslund tells NTB.

He emphasizes that even if they follow developments closely, it is not the case that people need to change their behavior because of this.

– This information is important, but for public health the picture does not change based on what we have found. The risk of being bitten by a tick at this height is minimal. I wouldn’t mind if I were to travel there, so to speak, says Korslund.

More important in the future

Changes in geographic distribution have not been investigated in this study, but such a study is in progress.

– We still can’t say anything for sure. The tick may have become established further north than the Helgeland coast, where it has been documented so far, but it will take a lot of work to establish it. And there will be very little in that case, he says.

The mountain research was conducted at Lærdal in Vestland County and at Lifjell in Vestfold and Telemark, and constituted the Ph.D. of lead author Nicolas De Pelsmaeker at the University of Southeast Norway, who defended his dissertation in March. In an interview on forskning.no, he says that climate change and grazing cattle in the open field and at altitude will be affected and affect the spread of ticks in the future.

– A higher incidence combined with a longer period of ticks can lead to more damage to the livestock industry, says De Pelsmaeker.

Livestock, like host ticks, can also contribute to more ticks in the mountains as they can spread to more areas.

Koronapåvirkning

Preliminary figures from last year from the Infectious Disease Notification System (MSIS) show that the number of recorded cases of tick-borne disease Lyme disease was one of the few diseases that not only increased in Norway, but also established a new record year, with 512 cases.

– There was also an apparent increase in the number of detected cases of TBE, tick-borne encephalitis, mainly in Telemark, Agder and Sørlandet. It’s an increase that appears to have lasted for more than three years, but given that there are quite a few cases in total in Norway, it is a bit uncertain if the increase is real, says Randi Eikeland, head of the National Competition Service for tick-transmitted diseases (Flåttsenteret ) at Sørlandet Hospital.

It is also not sure if the increase is due to a real increase in the spread of infectious ticks and ticks, an increase in the number of recorded cases, or that people move more outdoors and are therefore more exposed.

Eikeland points out that the increase in tick-borne diseases in 2020 is not so surprising, seen in light of the number of Norwegians who vacationed in Norway and who also hiked more through forests and fields.

Before Easter, Eikeland participated in an international seminar where participating countries compared the development of tick-borne infections during the pandemic.

– Then there was no doubt that the number of TBE cases has increased in countries where there have been strict travel restrictions, such as Norway and the other Scandinavian countries, Austria and Germany, because we have not traveled abroad and actually we are more in the nature. , she says.