Clinical Signs of Experimental Trypanosoma Evansi Infection in Donkeys: Ameliorative Effects of Isometamidium Chloride and Buparvaquone Treatments

Abstract

Trypanosoma evansi (T. evansi) infection causes a progressively wasting and ultimately fatal animal trypanosomosis mainly in camels, horses, donkeys, zebra, mules and cattle in Africa, Asia, Middle East and South America resulting in reduced traction power and annual death of thousands of affected animals. The aim of this study was to evaluate the ameliorative effects of Isometamidium chloride (standard trypanocide) and Buparvaquone (anti-theilerial drug) treatments on the clinical signs of T. evansi infection in donkeys as part of study on the efficacies of the drugs against T. evansi infection. Twenty four apparently healthy donkeys were used for the experiment. The animals were housed, fed on hay and concentrate feed, and water was provided adlibitum. Animals were identified with neck-tags and grouped into 4 namely; groups A1, A2, A3 (T. evansiinfected groups) and B (control) of 6 animals each (3 males and 3 females) at random. Two milliliters of buffered, parasitaemic Wister rat blood containing 2.0x10 of T. evansi (Sokoto isolate) was used to infect each of all donkeys in the ‘A’ category through jugular vein. On day28 post-infection, groups A2 and A3 animals were treated with Isometamidium chloride and Buparvaquone respectively. Groups A1 and B remained as Infected-Untreated and Un-infected-Untreated respectively. Animals were monitored and evaluated postinfection and post-treatment for clinical signs including vital parameters and body weight changes. The effects of treatments on the observed-parameters were evaluated. Result showed that T. evansi infection in donkeys is predominantly a chronic disease, with an incubation period of 3-7 days. Isometamidium chloride treated group showed greater reduction in prevalence of signs than buparvaquone treated group which did not differ much from the Un-treated group. It was concluded that Trypanosoma evansi infection in donkeys is a chronic disease and treatment with Isometamidium chloride, ameliorates the clinical signs while buparvaquone does not.