Overview
- The Rutgers study published Wednesday found about 70 percent of house-mouse populations sampled in New York, New Jersey, Pennsylvania and Washington, D.C. carried genetic mutations linked to resistance to common anticoagulant rodenticides.
- Researchers also detected resistance-linked variants in Norway rats but said most of those mutations have not yet been tested to confirm whether they reduce susceptibility to poisons.
- Field observations and industry reports cited in the study show rats are increasingly trap- and bait-avoidant and that some treatments now take longer to reduce populations than they once did.
- The research identified new genetic variants and highlighted Vkorc1, a gene known to confer anticoagulant resistance, prompting calls to reduce reliance on blood-thinning poisons and expand sanitation, exclusion, and trapping programs.
- Follow-up lab and field tests are needed to measure the new variants' effects, and officials warn cities must act to preserve control options, limit harm to non-target wildlife, and guard public health from rodent-borne diseases.