The distribution of Ixodes ricinus ticks and their infection with Borrelia spp., Anaplasma phagocytophilum and Neorlichia mikurensis in urban green spaces in Lithuania

Abstract

The transformation of natural ecosystems into urban areas becomes a major problem because it could affect the circulation of tick-borne pathogens in cities. Urban green areas such as urban forests, parks, and open grasslands used for recreational activities have recently been identified as high-risk environments for exposure of the human population to infected ticks. Although the distribution of ticks and their infection with pathogens have been studied in Lithuania in natural habitats, the situation in the urban and suburban areas remains largely unknown. This study aimed to investigate the distribution of Ixodid ticks and their infection with Borrelia spp., Anaplasma phagocytophilum and Neorlichia mikurensis in urban green spaces in Lithuania. A total of 3485 Ixodes ricinus ticks were collected from 28 urban parks in Lithuania during 2021-2023. Ticks were screened for the presence of pathogens using triplex real-time PCR assay. Positive samples were further analyzed by PCR and sequencing using different targets of the bacteria genomes. Borrelia DNA was detected in 25,6% of collected ticks. Five Borrelia species B. garinii, B. burgdorferi s.s., B. afzelii, B. lusitaniae and Borrelia miyamotoi were identified. A. phagocytophilum and N. mikurensis were present in 4.9% and 7.7 % of the samples, respectively. Double and triple co-infections with different pathogens were detected. The prevalence of infection differed among years, urban and peri-urban parks, and it was higher in adults than in nymphs. The present study highlights the risk of tick-borne diseases in urban green spaces in Lithuania. N. mikurensis, a newly emerging pathogen of significant public health importance, was detected in Lithuania for the first time