Methomyl poisoning in dogs: report of 5 cases and literature review

Methomyl is a widely available carbamate pesticide that acts as an acetylcholinesterase inhibitor. Here, we describe 5 cases of methomyl poisoning in dogs. The main gross and microscopic findings included pulmonary edema and multisystemic congestion and hemorrhages, which were most severe in the respiratory tract. The diagnosis of poisoning was confirmed in all cases by detecting methomyl in gastric contents using gas chromatography-mass spectrometry. Differential diagnoses include poisoning by organophosphates, coumarin rodenticides, and sodium fluoroacetate, which share clinical and pathology features but differ in pathogenesis. Additionally, we conducted a review of the literature on methomyl poisoning in animals focused on pathogenesis, clinical signs, lesions, and diagnosis.