Urban Recreation Areas as Foci of Tick Hazard: Multi-Year Seasonal Patterns of Ixodes ricinus and Dermacentor reticulatus Activity and Host Spectrum of Their Juvenile Stages in Eastern Poland

TL;DR

Urban parks in Poland have predictable seasonal patterns of tick activity, with rodents playing a key role in maintaining tick populations.

Contribution

Long-term seasonal patterns and host associations of two tick species in urban recreational areas are described over five years.

Findings

Dermacentor reticulatus was more abundant and showed autumn activity peaks, while Ixodes ricinus peaked in late spring and early summer.

Seasonal timing was a stronger predictor of tick activity than short-term temperature or humidity changes.

Juvenile ticks of both species were most commonly found on striped field mice (Apodemus agrarius).

Abstract

Urban parks and green spaces are widely used for recreation but may also increase human exposure to ticks. In this study, tick activity was monitored over five years in urban park in eastern Poland. Two common European species, Dermacentor reticulatus and Ixodes ricinus, were examined to describe their seasonal activity and host associations. D. reticulatus was more abundant and showed pronounced autumn activity, whereas I. ricinus was most active in late spring and early summer. Tick activity was primarily related to seasonal timing rather than short-term variation in temperature or humidity. Juvenile stages of both species were most frequently found on striped field mice (Apodemus agrarius), highlighting the role of urban-adapted rodents in maintaining tick populations. These results indicate that urban recreational areas can act as persistent sources of tick exposure with predictable seasonal risk.

Urban green spaces increasingly serve as sites of human–tick contact, yet long-term data on tick activity and host associations in urban recreational areas remain limited. This study investigated the seasonal activity patterns of Ixodes ricinus and Dermacentor reticulatus and the host spectrum of juvenile tick stages in an urban park in eastern Poland over a five-year period (2015–2019). Questing ticks were collected from vegetation using the flagging method, while small mammals were live-trapped to assess tick infestation of juvenile stages. The effects of air temperature, relative humidity, and seasonality on tick activity were analysed using generalized additive models (GAMs). D. reticulatus was the dominant tick species throughout the study, exhibiting pronounced autumn activity peaks, whereas I. ricinus occurred at lower densities with peak activity in late spring and early summer. GAM analyses revealed that apparent temperature effects observed in uncorrected models disappeared after accounting for seasonality, while seasonal timing remained a strong and consistent predictor of tick activity across species, developmental stages, and sexes. Juvenile ticks of both species were most frequently associated with Apodemus agrarius, indicating that urban-adapted rodent hosts play a key role in sustaining tick life cycles in simplified urban ecosystems. These findings demonstrate that urban recreational areas can function as persistent foci of tick hazard, with tick activity driven primarily by intrinsic seasonal dynamics rather than short-term weather variation.

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