For the people by the people: citizen science web interface for real-time monitoring of tick risk areas in Finland

Ticks and tick-borne diseases (TBDs) form a significant and growing threat
to human health and well-being in Europe, with increasing numbers of
tick-borne encephalitis (TBE) and Lyme borreliosis cases being reported
during the past few decades. Increasing knowledge of tick risk areas and
seasonal activity remains the primary method for preventing TBDs.
Crowdsourcing provides the best alternative for rapidly obtaining data on
tick occurrence on a national level. In order to produce and share
up-to-date data about tick risk areas in Finland, an online platform,
Punkkilive (www.punkkilive.fi/en), was launched in April 2021. On the
website, users can submit and browse tick observations, report tick
numbers and hosts, and upload pictures of ticks. Here, we looked at trends
in the crowdsourced data from 2021, assessed the effect of local tick
species on seasonality of observations, and examined sampling bias in the
data. The high number of tick observations (n=78 837) highlights that
there was demand for such a service. Approximately 97% of 5573 uploaded
pictures represented ticks. Seasonal patterns of tick observations varied
across Finland, highlighting variability in the risk associated with the
two human-biting tick species Ixodes ricinus and I. persulcatus, the
latter having a shorter, unimodal activity peak in late spring–early
summer. Tick numbers were low and the proportion of new sightings was high
in northern Finland, as may be expected near the latitudinal distribution
limits of both species. While the number of inhabitants generally
explained the number of tick observations well, geographically weighted
regression models also identified areas that deviated from this general
pattern. This study offers a prime example of how crowdsourcing can be
applied to track vectors of zoonotic diseases, to the benefit of both
researchers and the public. Areas with more or fewer observations than
predicted based on number of inhabitants were revealed, wherein more
specific analyses may reveal factors contributing to lower or higher risk
levels that may be used in increasing awareness. We hope that the success
of Punkkilive serves to highlight the usefulness of citizen science in the
prevention of vector-borne diseases.