Acute fipronil intoxication in Squirrel Monkey (Saimiri sciureus)

A biocidal product in gel form containing 0.05% fipronil active substance was used for pest control in the habitat of thirteen Squirrel Monkey (Saimiri sciureus) in a zoo. Following the application, sudden death was observed in three primates. Routine bacteriological, histopathological and toxicological analyses on one cadaver and tissue samples from the cadaver did not produce any pathogenic agent, pesticide and any pathognomonic findings. In an attempt to investigate the presence of known fipronil intoxication biomarkers, fipronil and fipronil sulfone, we applied modified QuEChERS extraction processes on tissue samples and determined the fipronil and fipronil sulfone levels as 27.1-3.5 μg/kg in cutaneous tissue and 13.8-47.2 μg/kg in brain tissue, respectively, by using UHPLC Q-Orbitrap Mass Spectrometer. In the light of the anamnesis, necropsy, microbiology and histopathology results, and after evaluating the presence of fipronil-fipronil sulfone in tissues, we considered that the deaths could have resulted from acute fipronil toxicity due to species-specific active substance susceptibility.