A clinico-pathological analysis of Ivermectin-induced toxicity in eight Hermann’s Tortoises treated for tick infestation

Abdulhakeem Binhambali; Musa Halidu; Dauda Dauda Ibrahim; Zainab Oyiza Idris; Raji Bolaji Abdulsallam; Raphael Omerah Attah

doi:10.5455/JRVS.20240328090505

Abstract
This study presents a clinico-pathological examination of ivermectin-induced toxicity in eight Hermann's tortoises, administered to address tick infestation. Subsequently, nervous signs were observed, leading to the demise of five tortoises. Clinical manifestations included inappetence, weakness, diarrhea, tremors, and paralysis preceding death. Postmortem examination revealed hemorrhagic lung tissues, fatty liver, and significant tick infestation. Laboratory analysis detected Borrelia spp. in blood smears, Oxyuris spp. eggs and cysts in fecal samples, and Escherichia coli and Salmonella enterica in microbial cultures. Histopathological analysis indicated hepatic vacuolar degeneration. The correlation between clinical, pathological, and histopathological findings suggests acute infection and drug toxicity, particularly ivermectin toxicity. The tortoises, initially weighing an average of 900 grams, were pets at Niger Resort Minna and were presented to the Nigerian Police Veterinary Hospital, Garki 2 on the 27th of May 2023, after exhibiting symptoms of inappetence and severe diarrhea following the administration of 1% ivermectin (Ivanor from Jubaili Animal Health Ltd) at a dose rate of 0.04 mg/kg. Three tortoises died shortly after administration, with two succumbing within hours.

Key words: Ivermectin toxicity, Hermann's tortoise, Tick infestation, pathology, Hepatic vacuolar degeneration.