Progress to environmentally safer rodenticides

Rodents can cause great damage, and carry diseases, therefore people have at all times tried to limit their population. Control of rodent pests worldwide relies heavily on the use of anticoagulant rodenticides. However, due to their widespread use and environmental persistence, they have demonstrated secondary poisonings in non-target animals such as foxes, cats, dogs, wolfs, wolverines and predatory birds like owls and hawks worldwide. A study of wild eagle owls in 2018 in Norway showed anticoagulant rodenticides in 72 of 100 examined birds, some at potentially toxic levels. There is a need to replace the currently used rodenticides by less persistent, but still potent anticoagulants. Anticoagulent rodenticides cause death by internal bleeding. The compounds used today consist of a mixture of several anticoagulants, each in two diastereoisomeric forms. The biological effects of the diastereoisomers are comparable, showing similar potency for inhibiting blood coagulation, but they have different tissue persistence. Consequently, the diastereoisomer with the greatest tissue persistence is associated with a greater risk of secondary poisoning. Technically, it is possible to produce baits, where the most persistent isomer has been removed. Such refined anticoagulants are expected to have a decreased ecological risk for non-target animals, but still to possess the same ability to kill rodents. The project will focus on improved monitoring and solutions to produce anticoagulants with reduced environmental impacts in the future. Statistical analyses of the whole dataset and estimation of the risk for adverse health and welfare effects in non-target populations will give new insight and provide crucial information for governmental authorities and industrial enterprises. The ultimate goal of GreenBait is to evaluate and rank candidate compounds with documented toxic properties, but without the persistency of today's products as refined environmentally safer rodenticides.

Control of rodent pests worldwide relies heavily on the use of anticoagulant rodenticides. However, due to their widespread use and environmental persistence, they have demonstrated adverse effects to non-target animals, like foxes, cats, dogs, wolfs, wolverines, and predatory birds like owls and hawks, worldwide. A study of wild eagle owls in 2018 showed anticoagulant rodenticides in 72 of 100 examined birds in Norway, some at potentially toxic levels. There is a need to shift the use of rodenticides to less persistent, but still potent, anticoagulants. Anticoagulent rodenticides cause death by internal bleeding. The compounds predominatly in use today are a mixture of several anticoagulants, each with two diastereoisomeric forms. The biological properties of both diastereoisomers have been shown to have similar potency for inhibiting blood coagulation, but to have different tissue persistence. Consequently, the diastereoisomer with greatest tissue persistence should be associated with a greater risk of secondary poisoning. Technically, it is possible to produce baits where the most persistent isomer has been removed. Such refined anticoagulants would have decreased ecological risk for non-target animals, but still possess the same ability to kill rodents. The project will focus on improved monitoring and solutions to produce anticoagulants with reduced environmental impacts in the future. Analyses of the whole dataset statistically, and estimating the risk for adverse health and welfare effects in non-target populations, will give new insight and provide crucial information for governmental authorities and industrial enterprises. The ultimate goal of GreenBait is to evaluate and rank candidate rodenticides with documented toxic properties, but without the persistency of today's products as refined environmentally safer rodenticides.