Poisonings caused by anticoagulant rodenticides between 2010 and 2016

Background: Anticoagulant rodenticides are most commonly used for extermination of rodents in Hungary, so this type of poisoning often occurs. Objectives: The aim of this survey was to describe the experiences of toxicological studies of animal carcasses and other types of test samples received in the laboratory from 2010 to 2016 with suspicion of poisoning with anticoagulant rodenticide. Materials and Methods: During the period under review, 112 animal subjects were examined. In 32 cases, 4 types of 4-hydroxycoumarin derivatives (warfarin, coumatetralyl, bromadiolone, brodifacoum) were detected by HPLC, and in 6 cases, the chlorophacinone of the indandione group was tested with GC-MS. In addition to the examination of animal carcasses, 51 baits were analysed for the presence of 4-hydroxycoumarin derivatives. Results and Discussion: Traces of four different 4-hydroxycoumarin derivatives (bromadiolone, brodifacoum, warfarin, coumatetralyl and one indandione derivative (chlorophacinone) were found in the organs of 38 carcasses (11 dogs, 3 cats, 1 goat, 1 wolf, 1 orangutan, 9 rabbits, 6 deer, 1 otter, 2 foxes, 1 hyena, 1 buzzard, 1 African sacred ibis). Mild to severe coagulation problems were observed in the above cases indicative of anticoagulant rodenticide poisoning. Given the circumstances, these deaths were predominantly malicious poisonings, although some of the cases may have been accidental. Among the poisonings 16 of them were caused by bromadiolone, and 13 of them by brodifacoum, which is 76% of the cases. Six different 4-hydroxycoumarin derivatives were detected (bromadiolone, brodifacoum, difenacoum, flocoumafen, warfarin, coumatetralyl in 41 baits of 51. Since the use of anticoagulant rodenticides is required in the defence against rodents, poisoning of this type should also be expected in the future.