A1 Journal article (refereed)
Effects of rodent abundance on ticks and Borrelia : results from an experimental and observational study in an island system (2024)


Kiran, N., Brila, I., Mappes, T., Sipari, S., Wang, Y., Welsh, E., & Kallio, E. R. (2024). Effects of rodent abundance on ticks and Borrelia : results from an experimental and observational study in an island system. Parasites and Vectors, 17, Article 157. https://doi.org/10.1186/s13071-024-06130-x


JYU authors or editors


Publication details

All authors or editors: Kiran, Nosheen; Brila, Ilze; Mappes, Tapio; Sipari, Saana; Wang, Yingying; Welsh, Erin; Kallio, Eva R.

Journal or series: Parasites and Vectors

eISSN: 1756-3305

Publication year: 2024

Publication date: 27/03/2024

Volume: 17

Article number: 157

Publisher: BioMed Central

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1186/s13071-024-06130-x

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/94248


Abstract

Background
Lyme borreliosis is the most common tick-borne disease in Europe and is often caused by Borrelia afzelii, which is transmitted by Ixodes ricinus ticks. The prevalence and abundance of infected ticks fluctuate in time and space, influencing human infection risk. Rodents are reservoir hosts for B. afzelii and important feeding hosts for larval ticks. In the study reported here, we examined how variation in rodent abundance is associated with B. afzelii infection prevalence in ticks, the density of nymphs (DON) and the density of infected nymphs (DIN) in the following year. We further analysed the relationships between the abundance of infected rodents and nymphal infection prevalence (NIP) and DIN.

Methods
We conducted a study that combined experimental and observational approaches on 15 islands (10 small islands and 5 large islands) in Finland. On all of the islands, ticks and rodents were monitored and sampled during the summer of 2019, with the monitoring of tick abundance and sampling continuing into the spring of 2020. On five of the 10 small islands, captured rodents were removed from the island (“removal” islands), and on the other five small islands, captured rodents were released back to the trapping site after marking and sampling (“control” islands). On the five large islands, captured rodents were released back to the trapping site after marking and sampling. The presence of B. afzelii from nymph and rodent samples was examined.

Results
The results of the experimental study showed that neither treatment (removal), rodent abundance index nor abundance index of infected rodents in 2019 was associated with DON, NIP or DIN in 2020. Based on data from the observational study, the NIP in 2020 decreased with increasing rodent abundance index and abundance index of infected rodents in 2019. However, the DIN in 2020 was not associated with the rodent abundance index or the abundance index of infected rodents in 2019. In addition, in the observational study, DON in 2020 increased with increasing rodent abundance index.

Conclusions
Our results suggest that low rodent abundance during the tick activity period is not sufficient for reducing the disease hazard and, hence, rodent removal may not be a feasible control measure in natural ecosystems.


Keywords: Borrelia; borreliosis; mites; rodents; communicable diseases; infections

Free keywords: Ixodes ricinus; Borrelia burgdorferi; Borrelia afzelii; nymphs; infection prevalence; host abundance


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Ministry reporting: Yes

VIRTA submission year: 2024

Preliminary JUFO rating: 1


Last updated on 2024-03-07 at 01:25