!NEW PUBLICATION! – Citizen science tick observations serve as an early warning system for tick-borne diseases

A new open-access study in Zoonoses and Public Health reports that crowdsourced tick observations can help predict peaks in Lyme borreliosis cases in Finland. The study used nationwide weekly tick observation data from Punkkilive, a Finnish citizen science tick surveillance platform, together with Lyme borreliosis case data from the Finnish Institute for Health and Welfare for the years 2021–2023. Punkkilive is a University of Turku and Pfizer collaboration that allows citizens to report tick sightings and helps researchers map tick prevalence in real time across Finland.

The main finding is that reported tick encounters preceded Lyme borreliosis cases by approximately three to four weeks. This means citizen-reported tick observations may provide a practical early warning signal for when disease cases are likely to rise, enabling better-timed public awareness campaigns.

Lyme borreliosis is one of the most important tick-borne diseases in Finland and elsewhere in the Northern Hemisphere, and the study notes that climate change is increasing the burden of vector-borne diseases globally. Finland has already seen substantial regional differences in Lyme borreliosis incidence, with previous national surveillance research showing especially high levels in the south, southwest coastal areas, eastern areas and Åland.

The research team fitted statistical models to test whether weekly tick observations explained Lyme borreliosis cases beyond simple seasonal patterns. The analysis compared tick reports from different sources, including humans, pets such as dogs and cats, and all observation sources combined. Models based only on tick observations from humans performed best for predicting Lyme borreliosis cases. The study also found that Finland’s two human-biting tick species influenced local timing patterns of tick observations and Lyme borreliosis cases.

The study suggests that health authorities and other actors with access to citizen tick observation data could use similar models to identify likely periods of increased Lyme borreliosis risk. Earlier, better-targeted awareness campaigns may help people recognise symptoms sooner, seek treatment faster and reduce the risk of later complications.

The publication strengthens the case for citizen science as a public health tool. Punkkilive has already demonstrated strong public participation, with earlier research reporting tens of thousands of tick observations and showing that crowdsourcing can support real-time monitoring of tick risk areas in Finland.