Despite the widespread use of anticoagulant rodenticides in baits for controlling commensal rodent pests, their application is problematic due to secondary intoxication and increasing resistance. In contrast to studies on Western European house mice (Mus musculus domesticus), few resistance studies have focused on Eastern European house mice (M. musculus musculus), which have a western distribution boundary in the Czech Republic. This study newly analysed the VKORC1 gene in M. m. musculus field populations from Czech farms and grain stores and identified a nonsynonymous mutation Tyr139Phe. This mutation was common throughout the Czech Republic and was present in 80.2% of the 86 individuals sampled. Additionally, all individuals exhibited a genotype with three synonymous mutations specific to the subspecies M. m. musculus. The functional (mortality-survival) response of the Tyr139Phe mutation was validated in a laboratory choice feeding test using bromadiolone-based bait, where all resistant homozygous individuals survived, while all susceptible mice died, with a mean survival of 6.9 days.

Czech Agrifood Research Center Drnovska 507 73 CZ 16100 Prague 6 Czech Republic

Department of Zoology Faculty of Science Charles University Vinicna 7 CZ 12800 Prague 2 Czech Republic

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Buckle, A. & Eason, C. Control Methods: Chemical in Rodent Pests and Their Control. 2 edn, 123–154 (eds Buckle, A. & Smith, R.) (CABI International, 2015).

Fisher, P. Review of house mouse (Mus musculus) susceptibility to anticoagulant poisons. DOC. Sci. Intern. Ser.198, 1–18 (2005).

Fisher, P., Campbell, K. J., Howald, G. R. & Warburton, B. Anticoagulant rodenticides, islands, and animal welfare accountancy. Animals9, 919 (2019). PubMed PMC

Frankova, M., Aulicky, R. & Stejskal, V. Efficacy of eight anticoagulant food baits in house mouse (Mus musculus): comparison of choice and no-choice laboratory testing approaches. Agronomy12, 1828 (2022).

Horak, K. E., Fisher, P. M. & Hopkins, B. Pharmacokinetics of Anticoagulant Rodenticides in Target and non-target Organisms in Anticoagulant Rodenticides and Wildlife. 87–108 (eds Van den Brink, N.) (Springer, 2018).

Boyle, C. M. Case of apparent resistance of Rattus norvegicus Berkenhout to anticoagulant poisons. Nature188, 517 (1960).

Dodsworth, E. Mice are spreading despite such poisons as warfarin. Munic. Engin. London.3746, 1668 (1961).

Greaves, J. H., Rennison, B. D. & Redfern, R. Resistance of the ship rat, Rattus rattus L. to warfarin. J. Stored Prod. Res.12, 65–70 (1976).

McGee, C. F., McGilloway, D. A. & Buckle, A. P. Anticoagulant rodenticides and resistance development in rodent pest species–A comprehensive review. J. Stored Prod. Res.88, 101688 (2020).

RRAC. Rodenticide Resistance Action Committee. guide.rrac.info/resistancemaps/resistance-maps [Accessed 15 April 2024] (2024).

Pelz, H. J. et al. The genetic basis of resistance to anticoagulants in rodents. Genetics170, 1839–1847 (2005). PubMed PMC

Ruiz-López, M. J. et al. Widespread resistance to anticoagulant rodenticides in Mus musculus domesticus in the city of Barcelona. Sci. Total Environ.845, 157192 (2022). PubMed

Rached, A. et al. Investigation of anticoagulant rodenticide resistance induced by Vkorc1 mutations in rodents in Lebanon. Sci. Rep.12, 1–10 (2022). PubMed PMC

Krijger, I. M. et al. Large-scale identification of rodenticide resistance in Rattus norvegicus and Mus musculus in the Netherlands based on Vkorc1 codon 139 mutations. Pest Manag. Sci.79, 989–995 (2023). PubMed PMC

Cuthbert, R. J., Visser, P., Louw, H. & Ryan, P. G. Palatability and efficacy of rodent baits for eradicating house mice (Mus musculus) from Gough Island, Tristan Da Cunha. Wildl. Res.38, 196–203 (2011).

Wheeler, R. et al. Evaluating the susceptibility of invasive black rats (Rattus rattus) and house mice (Mus musculus) to brodifacoum as a prelude to rodent eradication on Lord Howe Island. Biol. Invasions21, 833–845 (2019).

Lin, W. L., Chen, K. H., Liao, C. P. & Tseng, H. Y. Short-term exposure of anticoagulant rodenticides leads to the toxin accumulation from prey (Rattus losea) to predator (Elanus caeruleus). Ecotoxicol. Environ. Saf.233, 113361 (2022). PubMed

Sran, S. P., Gartrell, B. G., Fisher, P. & Armstrong, D. P. Apparent resistance to brodifacoum in Rattus rattus in a New Zealand site with no history of anticoagulant-based rodent control. Wildl. Res.50, 28–38 (2022).

Frankova, M., Radostna, T., Aulicky, R. & Stejskal, V. Less brodifacoum in baits results in greater accumulation in the liver of captive Rattus norvegicus in a no–choice trail. J. Pest Sci.97, 2273–2280 (2024).

Pelz, H. J. et al. Distribution and frequency of VKORC1 sequence variants conferring resistance to anticoagulants in Mus musculus. Pest Manag. Sci.68, 254–259 (2012). PubMed

Goulois, J., Lambert, V., Legros, L., Benoit, E. & Lattard, V. Adaptative evolution of the Vkorc1 gene in Mus musculus domesticus is influenced by the selective pressure of anticoagulant rodenticides. Ecol. Evol.7, 2767–2776 (2017). PubMed PMC

Iannucci, A. et al. First record of VKORC1 sequence mutation associated with resistance to anticoagulant rodenticides in Italian individuals of Mus musculus domesticus. Hystrix30, 183–185 (2019).

Carromeu-Santos, A., Mathias, M. L. & Gabriel, S. I. Widespread distribution of rodenticide resistance-conferring mutations in the Vkorc1 gene among house mouse populations in Portuguese macaronesian islands and Iberian Atlantic areas. Sci. Total Environ.900, 166290 (2023). PubMed

Song, Y. et al. Adaptive introgression of anticoagulant rodent poison resistance by hybridization between old world mice. Curr. Biol.21, 1296–1301 (2011). PubMed PMC

Goulois, J. et al. Study of the efficiency of anticoagulant rodenticides to control Mus musculus domesticus introgressed with Mus spretus Vkorc1. Pest Manag. Sci.73, 325–331 (2017). PubMed

Scepovic, T. et al. VKOR variant and sex are the main influencing factors on bromadiolone tolerance of the house mouse (Mus musculus L.). Pest Manag. Sci.72, 574–579 (2016). PubMed

Maltsev, A. N. et al. Low level of resistance to anticoagulant rodenticides in the Vkorс1 gene in house mice (Mus musculus) and Norway rats (Rattus norvegicus) in Russia. Russ. J. Biol. Invasions13, 392–397 (2022).

Aivelo, T., Koivisto, E., Esther, A., Koivisto, S. & Huitu, O. VKORC1-based resistance to anticoagulant rodenticides widespread in Finnish house mice but not in brown rats. Int. J. Pest Manag. 1–8 (2023).

Macholán, M. et al. Genetic conflict outweighs heterogametic incompatibility in the mouse hybrid zone? BMC Evol. Biol.8, 1–14 (2008). PubMed PMC

Chmela, J., Rupeš, V. & Přívora, M. Susceptibility of Rattus norvegicus and Mus musculus to warfarin. Folia Zool.27, 219–228 (1978).

Chmela, J. & Rupeš, V. Development of resistance to warfarin in a population of the domestic mouse (Mus musculus L.) in Czechoslovakia. Československá Hygiena35, 234–237 (1990).

Chmela, J. Detection of rat resistance to warfarin. Zpravodaj Sdružení pracovníků DDD ČR2, 16–18 (1994).

Rost, S. et al. Mutations in VKORC1 cause warfarin resistance and multiple coagulation factor deficiency type 2. Nature427, 537–541 (2004). PubMed

Hall, A. T. BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucl. Acids Symp. Ser.41, 95–98 (1999).

Higgins, D., Thompson, J. D., Gibson, T. J. & Clustal, W. Improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Res.22, 4673–4680 (1994). PubMed PMC

ECHA. Guidance on the Biocidal Products Regulation - Volume II Efficacy - Assessment and Evaluation (Parts B + C), Version 4.1. (2022).

Damin-Pernik, M. et al. Distribution of non-synonymous Vkorc1 mutations in roof rats (Rattus rattus) in France and in Spain-consequences for management. Pestic Biochem. Physiol.183, 105052 (2022). PubMed

Tanaka, K. D. et al. The genetic mechanisms of warfarin resistance in Rattus rattus found in the wild in Japan. Pestic Biochem. Physiol.103, 144–151 (2012).

Marquez, A. et al. Resistance to anticoagulant rodenticides in Martinique could lead to inefficient rodent control in a context of endemic leptospirosis. Sci. Rep.9, 13491 (2019). PubMed PMC

Buckle, A., Cawthraw, S., Neumann, J. & Prescott, C. Anticoagulant resistance in rats and mice in the UK - new data for August 2022 to July 2023. https://www.thinkwildlife.org/downloads/ (2023).

Mooney, J. et al. VKORC1 sequence variants associated with resistance to anticoagulant rodenticides in Irish populations of Rattus norvegicus and Mus musculus domesticus. Sci. Rep.8, 4535 (2018). PubMed PMC

Berny, P., Esther, A., Jacob, J. & Prescott, C. Development of Resistance to Anticoagulant Rodenticides in Rodents in Anticoagulant Rodenticides and Wildlife. (eds. Van den Brink, N. et al.) 259–286 (2018).

Buckle, A. P., Endepols, S. & Prescott, C. V. Relationship between resistance factors and treatment efficacy when bromadiolone was used against anticoagulant-resistant Norway rats (Rattus norvegicus Berk.) in Wales. Int. J. Pest Manag.53, 291–297 (2007).

Endepols, S., Klemann, N., Song, Y. & Kohn, M. H. Vkorc1 variation in house mice during warfarin and difenacoum field trials. Pest Manag. Sci.69, 409–413 (2013). PubMed

Rattner, B. A. & Mastrota, F. N. Anticoagulant Rodenticide Toxicity to Non-Target Wildlife under Controlled Exposure Conditions in Anticoagulant Rodenticides and Wildlife. (eds van den Brink, N. et al.) 45–86 (Springer, 2018).

López-Perea, J. J. & Mateo, R. Secondary Exposure to Anticoagulant Rodenticides and Effects on Predators in Anticoagulant Rodenticides and Wildlife. (eds van den Brink, N. et al.) 159–194 (Springer, 2018).

Cooke, R. et al. Silent killers? The widespread exposure of predatory nocturnal birds to anticoagulant rodenticides. Sci. Total Environ.904, 166293 (2023). PubMed

Musto, C. et al. First evidence of widespread positivity to anticoagulant rodenticides in grey wolves (Canis lupus). Sci. Total Environ.915, 169990 (2024). PubMed

Atterby, H., Kerins, G. M. & MacNicoll, A. D. Whole-carcass residues of the rodenticide difenacoum in anticoagulant‐resistant and‐susceptible rat strains (Rattus norvegicus). Environ. Toxicol. Chem.24, 318–323 (2005). PubMed

Vein, J., Vey, D., Fourel, I. & Berny, P. Bioaccumulation of chlorophacinone in strains of rats resistant to anticoagulants. Pest Manag. Sci.69, 397–402 (2013). PubMed

Berny, P., Caillis, P. & Vey, D. Accumulation of chlorophacinone in susceptible and resistant Norway rat strains. Proceedings of the 8th European vertebrate pest management conference. 56–57 (2011).

ECHA. Information on biocides. echa.europa.eu/cs/information-on-chemicals/biocidal-active-substances [Accessed 16 May 2024] (2024).

Frankova, M., Stejskal, V. & Aulicky, R. Efficacy of rodenticide baits with decreased concentrations of brodifacoum: validation of the impact of the new EU anticoagulant regulation. Sci. Rep.9, 16779 (2019). PubMed PMC