O. Atalay

Eimeria stiedae: Experimental infection in rabbits and the effect of treatment with toltrazuril and ivermectin

The aim of this study was to investigate the clinical, haematological, biochemical, lipid peroxidation, ultrasonographic and pathologic findings in hepatic coccidiosis induced by Eimeria stiedae in rabbits, and also to compare the treatment effects of both toltrazuril and ivermectin separately and in combination. In this study, 56 rabbits were divided into eight groups. The first group was designated as healthy control group. Rabbits were infected with 40.000 sporulated oocysts of E. stiedae. Groups 2, 3, 4, 5, 6, 7 and 8 were allocated as the infected control group, infected+toltrazuril-treated group, infected+ivermectin-treated group, infected+toltrazuril+ivermectin-treated group, non-infected+toltrazuril-treated group, non-infected+ivermectin-treated group, non-infected+toltrazuril+ivermectin-treated group, respectively. Haematocrit, Haemoglobin and MCV values as well as percentage of lymphocyte decreased in Groups 2 and 4 whereas leucocyte counts and percentage of granulocyte leucocyte increased. Serum GGT, ALT and AST activities increased but albumin value decreased. Plasma MDA concentrations increased whereas erythrocyte CAT, GSH-Px, and SOD activities decreased. Mean oocyst numbers in per gram faeces (epg values) increased in both groups during the study. Ultrasonographic examination revealed that the liver was enlarged and had hyperechogenic parenchyma. Bile ducts were dilated and hyperechogenic and the gall bladder was dilated. The livers of these animals were enlarged and typical macroscopic and microscopic findings of coccidiosis were present. Treatment with toltrazuril and toltrazuril+ivermectin combination were highly effective in reducing faecal oocyst output in infected rabbits. Haematological, biochemical and lipid peroxidation parameters and, ultrasonographic findings of the liver were close to control values for Groups 3 and 5. Necropsy of these animals showed no visible lesions related to hepatic coccidiosis although a few oocysts were detected in the bile duct epithelial cells.