Toxocara spp. Egg Shedding in a ۱۶-Year-Old Female Lion in a Tehran Zoo A Case Report

Background:Gastrointestinal parasitism in captive wild felids poses significant veterinary and public health challenges. Although Toxocara spp. egg shedding is typically reported in juveniles, occurrences in aged lions are rarely documented. Methods: Following contact with the Small Animal Hospital, University of Tehran, the research team visited the zoological facility in Tehran Province to examine a ۱۶-year-old female African lion with severe diarrhea and passage of long, white nematodes. Evaluation included physical examination, hematological and biochemical analyses, and fecal sample collection. Fecal flotation was performed using saturated sodium chloride (specific gravity ۱.۲ g/cm³) following Willis’ method. Egg morphology was assessed via light microscopy and measured with ImageJ and Axiovision. Egg counts were performed on ۵۵ μL of floated material. The lion had received anthelmintic treatment (praziquantel, febantel, pyrantel-praziquantel) five months earlier. Results:Microscopic examination revealed Toxocara eggs, identified by their round shape, brown color, thick shell, and irregular outer surface, confirming active shedding despite previous anthelmintic treatment. Morphometric analysis matched classical Toxocara egg characteristics. Conclusion:This case demonstrates that aged captive lions may shed Toxocara spp. eggs, potentially influenced by captivity-related stressors, persistent environmental contamination, and immunosenescence. These findings underscore the necessity of regular parasitological surveillance in all captive felids, irrespective of age, to enhance animal health and mitigate zoonotic risk.

کلیدواژه ها:

Toxocara spp. ، zoonotic parasites ، flotation ، captive wild felids