Scientists of the National Institute for Health Development (TAI) who tested popular green areas in Estonian cities for ticks found up to a few dozen of the parasites per one hundred square meters in some places.
Scientists visited 51 green areas in 47 cities in late May and early June. They covered 55,750 square meters of ground and found 2,825 ticks.
On average, 5.65 ticks were lurking in wait of hosts per 100 square meters. Tick numbers are heavily dependent on the region. For example, the researchers did not find a single tick at the Haapsalu Castle or the central park in Kilingi-Nõmme, while 26.63 ticks were found per 100 square meters at the Valga-Priimetsa walking trail.
Julia Geller, senior research fellow at TAI, said that weather conditions might have played a role in the number of ticks found. The lowest temperature during the campaign to count ticks was 10 degrees, while the highest was 25.8 degrees, meaning that testing got to Valga once more ticks were already on the move.
Of the two species of ticks widespread in Estonia, the scientists found a lot of castor bean ticks (Ixodes ricinus) but fewer-than-anticipated taiga ticks (Ixodes persulcatus).
Ticks were mostly collected from parks, walking trails, song festival grounds and disc golf courses. Central parks yielded relatively little ticks as mowed grass patches with little to no shrubbery make for poor habitat for the arachnids.
Geller said that grass where more species of plants are present also tend to yield more ticks. Ticks are dangerous in places where intermediate hosts of ticks in different developmental stages can be found. In other words, where rodents, hedgehogs, dogs and cats are abundant.
City-dwelling ticks were also looked for at disc golf courses, which have grown in popularity in recent years. Geller said that a participating scientist came up with a few dozen ticks with just a single swipe of a special tick collecting flag at one such location.
In summary, parks in Estonian cities are relatively well tended and the risk of encountering ticks there remains relatively low. At the same time, patches of wilder greenery next to parks have more of the parasitic arachnids, with their numbers especially high close to footpaths running through such areas.
The next stage of the urban ticks study will look for pathogens carried by ticks. The results are expected in the fall of 2023. Julia Geller said that cases of tick-borne encephalitis are expected to go up this year. While awareness has improved, ticks are diagnosed carrying the pathogens increasingly often.
Editor: Marcus Turovski