Case report: fipronil contamination of chickens in the Netherlands and surrounding countries

Abstract

Fipronil is mostly used to control parasites in animals and invertebrate pests in crops. Its use in crops has been restricted in Europe due to concerns regarding its potential harmful effects in the environment, including harmful effects in bees. The use of fipronil to treat animal facilities such as laying hen stables is therefore illegal in Europe, and the discovery of fipronil in eggs in Belgium in 2017 triggered an investigation that led to the identification of fipronil in a product that was used by a Dutch service provider to control mites in laying hen facilities. The product had been used in multiple laying hen facilities in The Netherlands, most likely for several months, and eggs and manure from those laying hen facilities were contaminated with fipronil. The Dutch authorities placed restrictions on the movement of eggs, meat and manure from contaminated facilities, and required removal of affected eggs from the market. Numerous eggs were destroyed, and substantial financial losses were incurred by the Dutch egg industry. The incident generated controversy because an earlier report of fipronil contamination in 2016 did not result in actions that could have limited the extent and duration of the problem. Assessments of the toxicological risks associated with consuming affected eggs indicated minimal risk, which also caused the large-scale destruction of eggs to be questioned. Assessments indicating minimal risk were based on the expected consumption patterns of contaminated eggs, which were not expected to result in daily exposure due to the multiple sources of eggs available to consumers, and exposures were not expected to continue indefinitely. The contamination of eggs by illegally-used fipronil demonstrated the importance of prompt and effective action when contaminants are detected in food, and highlighted limitations in the chronic exposure risk assessments used by regulators.