Efficacy of Sulphachloropyrazine, Amprolium Hydrochloride, Trimethoprim-Sulphamethoxazole, and Diclazuril against Experimental and Natural Rabbit Coccidiosis.

There are no anticoccidial drugs labelled for rabbits in Kenya and those available are used as extra labels from poultry. The drugs are used in rabbits with limited knowledge of their efficacy and safety. The aim of this study was to determine the efficacy of sulphachloropyrazine, amprolium hydrochloride, and trimethoprim-sulphamethoxazole relative to diclazuril when used curatively against experimental and natural rabbit coccidiosis. In a controlled laboratory trial, sixty (60) rabbits were randomly allocated to six treatment groups, namely, 1A, 2B, 3C, 4D, 5E, and 6F, each with 10 rabbits. Groups 2B, 3C, 4D, 5E, and 6F were experimentally infected with mixed Eimeria species while group 1A served as uninfected-untreated (negative) control group. Four of the infected groups were treated with sulphachloropyrazine (5E), amprolium hydrochloride (2B), trimethoprim-sulphamethoxazole (6F), and diclazuril (4D) using dosages recommended by manufacturers. Group 3C served as infected-untreated (positive) control. A field efficacy trial in naturally infected rabbits was then undertaken. The results revealed that sulphachloropyrazine and diclazuril were effective against rabbit clinical coccidiosis by significantly reducing oocyst counts from 149.00±110.39 x 10⁴ to 3.31±0.86 x 10⁴ Eimeria spp. oocysts per gram of feces (opg) and 59.70±12.35 x 10⁴ to 0.0±0.0 x 10⁴ opg, respectively, in the laboratory trial. Similarly, sulphachloropyrazine and diclazuril recorded reduced oocyst counts in the field trial from 280.33±44.67 x 10³ to 0.44±0.14 x 10³ opg and 473.44±176.01 x 10³ to 0.0±0.0 x 10³ opg, respectively. Still, sulphachloropyrazine and diclazuril showed superior efficacy by registering lesion scores and fecal scores close to those of uninfected untreated control group. Trimethoprim-sulphamethoxazole recorded a satisfactory efficacy in the field trial by recording reduced oocyst counts from 266.78±37.03 x 10³ to 0.75±0.11 x 10³ opg but was not efficacious in the laboratory trial. Amprolium hydrochloride was not efficacious against clinical coccidiosis in both the experimental and field trials.