Local context and environment as risk factors for acute poisoning in animals in northwest Italy

Animal and bait poisoning data for northwest Italy collected between 2012 and 2017 were described and analyzed to estimate the risk of exposure to hazardous substances by animals. In about 4% of animals necropsied (n = 356/9512), the cause of death was poisoning and domestic pets (9.5%) and synanthropic animals (12.2%) appear to be the most involved. Furthermore, 294 out of 728 baits (40.4%) were positive for toxic substances and/or inert hazardous material. Application of a mixed-effects Poisson regression model and local cluster analysis evidenced increased risk of exposure to poisoning with altimetry (>600 m.a.s.l.) and municipality (PR = 1.6, 95%CI 1.2-2.1 for poisoning, PR = 2.2, 95%CI 1.2-4.2 for poisoning by insecticides and PR = 2.9, 95%CI 1.4-6.2 for poisoning by metaldehyde). Since the mountainous areas in the region are mostly devoted to pasture and extensive farming, the high frequency of animal and bait poisoning events may be related to farmers' need to protect their livestock and crops against foxes, wolves, rodents or wild boars. Summarizing, the type of land use and context may influence the frequency and type of toxin chosen to kill animals considered a nuisance for hunting, farming, agriculture and apiculture. Despite bans and limitations, the use of harmful substances is not perceived as an environmental threat but rather as routine pest control. Animal and bait poisoning constitute a public health concern because it is potentially harmful to humans and the environment. Our findings may inform risk communication strategies, as well as prevention and control measures for the reduction of illegal and non-targeted species poisoning.