Eimeria in Rabbits: Diagnostic & Treatment Tips

Eimeria stiedae is a coccidian parasite of rabbits that infects the bile ducts, leading to severe liver disease and death. Infection is effectively treated by toltrazuril for 2 days at 25 to 50 ppm in drinking water. A single report claimed that ivermectin (2 doses of 0.5 mg/kg SC) was effective for treating intestinal coccidiosis in rabbits. This study thoroughly investigates hepatic disease pathology in experimentally infected rabbits and compares treatment with toltrazuril and ivermectin, alone and in combination. Oocyst shedding was greatly reduced in toltrazuril-treated rabbits, but shedding in untreated or ivermectin-treated rabbits increased over time. Clinical signs were not observed in rabbits treated with toltrazuril (alone or with ivermectin) but were seen in all other infected rabbits. Biochemical studies indicate that rabbits with clinical signs had increased plasma malondialdehyde values and decreased erythrocyte catalase, superoxide dismutase, and glutathione peroxidase activity by 8 days after infection. At day 16, leukocyte counts had increased and hematocrit and hemoglobin values had decreased. By 24 days after infection, serum alanine transaminase, aspartate transaminase, and γ-glutamyl transferase were elevated, and albumin levels had declined. All infected rabbits showed some signs of disease by liver ultrasonography, including hyperechogenic bile ducts and intrahepatic vessels. Rabbits with clinical signs also had enlargement and thickening of the liver, bile ducts, and gallbladder. Necropsy and histopathologic examination confirmed the ultrasonography results and revealed nodule and fibrous tissue formation and necrotic areas.COMMENTARY: This is the first report of ultrasonography for hepatic coccidiosis, and the study demonstrated its value as a diagnostic tool. Clinicians observed signs of liver disease using this method as early as 8 days after infection, and their observations correlated well with necropsy and histopathologic findings. Ultrasound was also useful for monitoring recovery, as healing could be observed following treatment. This study also found that, in contrast to the prior report of its use as a treatment for intestinal coccidiosis, ivermectin had no effect on hepatic coccidiosis.

Eimeria stiedae: Experimental infection in rabbits and the effect of treatment with toltrazuril and ivermectin. C,am Y, Atasever A, Eraslan G, et al. Exp Parisitol 119:164-172, 2008.