Widespread resistance to anticoagulant rodenticides in Mus musculus domesticus in the city of Barcelona

• Published in: The Science of the total environment 2022-11, Vol.845, p.157192-157192, Article 157192
• Main Authors: Ruiz-López, María José, Barahona, Laura, Martínez-de la Puente, Josué, Pepió, Marta, Valsecchi, Andrea, Peracho, Victor, Figuerola, Jordi, Montalvo, Tomas
• Format: Article
• Language: English
• Subjects: Adaptive introgression; Brodifacoum; Bromadiolone; Pest control; Resistance; Vkorc1 gene
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.157192

Control of rodent populations is a big challenge because of the rapid evolution of resistance to commonly used rodenticides and the collateral negative impacts that these products may have on biodiversity. Second-generation anticoagulants are very efficient but different single nucleotide polymorphisms (SNPs) in the Vkorc1 gene may confer resistance in rodents. We sequenced exons 1, 2 and 3 of the Vkorc1 gene from 111 mice (Mus musculus domesticus) captured across the city of Barcelona and found SNPs associated with resistance to first- and second-generation anticoagulants in all of them. Although most of the SNPs were associated with resistance to bromadiolone, we also found SNPs associated with resistance to brodifacoum. Out of all the individuals analyzed, 94.59 % carried mutations associated to introgression events with Mus spretus, a sympatric rodent species. Currently most of the chemical products for rodent control commercialized in the area are based on bromadiolone, although recent public control campaigns have already shifted to other products. Thus, the widespread occurrence of resistant mice to bromadiolone represents a challenge for rodent control in Barcelona and may increase the risk of secondary poisoning of animals preying on this species. Public health managers, pest control companies and citizens should be aware that the use of bromadiolone based products is ineffective and represents a risk for the environment, including human and animal health. [Display omitted] •All Mus musculus domesticus carried missense mutations in at least one of the exons of the Vkorc1 gene.•94.60 % of individuals carried mutations in exon1 associated with past introgression events.•Only 13.51 % of analyzed individuals presented at least one mutation in exon 3.•Detected mutations provide resistance to anticoagulant rodenticides.•Resistance to rodenticides in Barcelona is driven by adaptive introgression and selective pressure.