A1 Journal article (refereed)
Predicting habitat suitability for Ixodes ricinus and Ixodes persulcatus ticks in Finland (2022)


Uusitalo, R., Siljander, M., Lindén, A., Sormunen, J. J., Aalto, J., Hendrickx, G., Kallio, E., Vajda, A., Gregow, H., Henttonen, H., Marsboom, C., Korhonen, E. M., Sironen, T., Pellikka, P., & Vapalahti, O. (2022). Predicting habitat suitability for Ixodes ricinus and Ixodes persulcatus ticks in Finland. Parasites and Vectors, 15, Article 310. https://doi.org/10.1186/s13071-022-05410-8


JYU authors or editors


Publication details

All authors or editors: Uusitalo, Ruut; Siljander, Mika; Lindén, Andreas; Sormunen, Jani J.; Aalto, Juha; Hendrickx, Guy; Kallio, Eva; Vajda, Andrea; Gregow, Hilppa; Henttonen, Heikki; et al.

Journal or series: Parasites and Vectors

eISSN: 1756-3305

Publication year: 2022

Publication date: 30/08/2022

Volume: 15

Article number: 310

Publisher: Biomed Central

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1186/s13071-022-05410-8

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/82907


Abstract

Background
Ticks are responsible for transmitting several notable pathogens worldwide. Finland lies in a zone where two human-biting tick species co-occur: Ixodes ricinus and Ixodes persulcatus. Tick densities have increased in boreal regions worldwide during past decades, and tick-borne pathogens have been identified as one of the major threats to public health in the face of climate change.

Methods
We used species distribution modelling techniques to predict the distributions of I. ricinus and I. persulcatus, using aggregated historical data from 2014 to 2020 and new tick occurrence data from 2021. By aiming to fill the gaps in tick occurrence data, we created a new sampling strategy across Finland. We also screened for tick-borne encephalitis virus (TBEV) and Borrelia from the newly collected ticks. Climate, land use and vegetation data, and population densities of the tick hosts were used in various combinations on four data sets to estimate tick species’ distributions across mainland Finland with a 1-km resolution.

Results
In the 2021 survey, 89 new locations were sampled of which 25 new presences and 63 absences were found for I. ricinus and one new presence and 88 absences for I. persulcatus. A total of 502 ticks were collected and analysed; no ticks were positive for TBEV, while 56 (47%) of the 120 pools, including adult, nymph, and larva pools, were positive for Borrelia (minimum infection rate 11.2%, respectively). Our prediction results demonstrate that two combined predictor data sets based on ensemble mean models yielded the highest predictive accuracy for both I. ricinus (AUC = 0.91, 0.94) and I. persulcatus (AUC = 0.93, 0.96). The suitable habitats for I. ricinus were determined by higher relative humidity, air temperature, precipitation sum, and middle-infrared reflectance levels and higher densities of white-tailed deer, European hare, and red fox. For I. persulcatus, locations with greater precipitation and air temperature and higher white-tailed deer, roe deer, and mountain hare densities were associated with higher occurrence probabilities. Suitable habitats for I. ricinus ranged from southern Finland up to Central Ostrobothnia and North Karelia, excluding areas in Ostrobothnia and Pirkanmaa. For I. persulcatus, suitable areas were located along the western coast from Ostrobothnia to southern Lapland, in North Karelia, North Savo, Kainuu, and areas in Pirkanmaa and Päijät-Häme.

Conclusions
This is the first study conducted in Finland that estimates potential tick species distributions using environmental and host data. Our results can be utilized in vector control strategies, as supporting material in recommendations issued by public health authorities, and as predictor data for modelling the risk for tick-borne diseases.


Keywords: mites; Ixodidae; distribution; zoonoses; pathogens; Borrelia; borreliosis; tick-borne encephalitis; spatial analysis; modelling (representation); forecasts

Free keywords: ixodes ricinus; ixodes persulcatus; species distribution modelling; ensemble prediction; tick-borne pathogen; Borrelia burgdorferi sensu lato


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Ministry reporting: Yes

Reporting Year: 2022

JUFO rating: 1


Last updated on 2024-22-04 at 17:12