Suspected anticoagulant rodenticide toxicosis in captive nutria (Myocastor coypus) in Thailand.

Nutria (Myocastor coypus) is a large, herbivorous rodent found in Africa, Europe, North America, and Asia. Anticoagulant rodenticide (AR) toxicosis was diagnosed in captive nutrias based on anamnesis, clinical signs and chemical analysis, marking suspected case in this species in Thailand. Six out of the eight nutrias in the same herd died, showing initial clinical signs such as abnormal bleeding and abortion in pregnant individuals. A carcass of the dead nutria was analysed for exposure to rodenticides. Screening tests on liver specimens, using thin-layer chromatography and spectrophotometry, confirmed the presence of AR. In contrast, the two surviving nutrias were clinically observed and remained healthy during an 18-month follow-up period. To date, there have been no reports of nutrias with diagnosed AR poisoning. This case likely resulted from rodenticide contamination of introduced soil, underscoring the importance of proper rodenticide management to protect nontarget species and prevent environment contamination.