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Surra caused by Trypanosoma evansi is one of the important pathogenic parasitic diseases of camels, equines, other domestic and wild animals. T. evansi type A is endemic to Africa, Latin America, and Asia while T. evansi type B is so far identified only in Ethiopian and Kenyan camels. Little is known about the pathogenicity of T. evansi. This study was conducted to determine the pathogenicity of T. evansi type A and B in Swiss albino mice colony. We genetically characterized two T. evansi type A and two T. evansi type B isolated from camels in Tigray and Afar. Six mice were infected by each of the isolates and compared with 6 uninfected mice (control). Parasitemia was followed on Matching Method. Weight and PCV of each mouse were measured pre-infection and after 6 days post-infection. Each mouse was examined for visible clinical signs. Highly parasitaemic mice were euthanized on diethyl ether to collect vital organs for gross and histopathologic examination. Major clinical signs in infected mice were rough hair coats, pale mucous membranes of the eye, and incoordination. Compared to the control, there were no significant reductions in the body weight of mice (T. evansi type A, p= 0.493, T. evansi type B, p=0.299), but there was significant reduction in the mean PCV values in both T. evansi type A (p= 0.0001) and T. evansi type B (p= 0.0008) stocks. Splenomegaly, hepatomegaly, edema and pneumonia were the prominent lesions observed at necropsy. Microscopic lesions seen in vital organs were congestion, capillaries distended with red blood cells, cellular infiltration, accumulation of hemosiderin, necrosis and degenerative changes. The clinical signs and gross and histopathologic lesions were comparable between mice infected by T. evansi type A and B. In conclusion, T. evansi type A and B showed similar in vivo pathogenicity. As a result, a special model for comparative pathological study on host-trypanosome interaction is essential., East African Journal of Veterinary and Animal Sciences, Vol. 3 No. 1 (2019): East African Journal of Veterinary and Animal Sciences

Background Trypanosoma evansi is mechanically transmitted by biting flies and affects camels, equines, and other domestic and wild animals in which it causes a disease called surra. At least two types of Trypanosoma evansi circulate in Ethiopia: type A, which is present in Africa, Latin America and Asia, and type B, which is prevalent in Eastern Africa. Currently, no information is available about the drug sensitivity of any Ethiopian T. evansi type. Methodology/principal findings This study was conducted with the objective of determining the in vivo drug sensitivity of two T. evansi type A and two type B stocks that were isolated from camels from the Tigray and Afar regions of Northern Ethiopia. We investigated the efficacy of four trypanocidal drugs to cure T. evansi infected mice: melarsamine hydrochloride (Cymelarsan), diminazene diaceturate (Veriben and Sequzene), isometamidium chloride (Veridium) and homidium chloride (Bovidium). Per experimental group, 6 mice were inoculated intraperitoneally with trypanosomes, treated at first peak parasitemia by daily drug injections for 4 consecutive days and followed-up for 60 days. Cymelarsan at 2 mg/kg and Veriben at 20 mg/kg cured all mice infected with any T. evansi stock, while Sequzene at 20 mg/kg caused relapses in all T. evansi stocks. In contrast, Veridium and Bovidium at 1 mg/kg failed to cure any T. evansi infection in mice. Conclusions/significance We conclude that mice infected with Ethiopian T. evansi can be cured with Cymelarsan and Veriben regardless of T. evansi type. In contrast, Veridium and Bovidium are not efficacious to cure any T. evansi type. Although innate resistance to phenanthridines was previously described for T. evansi type A, this report is the first study to show that this phenomenom also occurs in T. evansi type B infections., Author summary Surra is a vector borne disease in camels, horses, water buffaloes, cattle and other domestic animals caused by Trypanosoma (T.) evansi. This protozoan parasite is transmitted by biting flies such as tabanids and stable flies and is endemic in many countries in Northern and Eastern Africa, Latin America and Asia. Surra is responsible for high economic losses due to mortality and morbidity of draught animals and leads to animal trade restrictions in endemic regions. Control of surra is mainly based on the treatment of sick animals presenting clinical symptoms. In Ethiopia two different types of T. evansi (A and B) have been described, yet no data existed about the drug sensitivity of any T. evansi type. In this study, we show for the first time that T. evansi type B is naturally in vivo resistant to the phenanthridine class of trypanocidal drugs, a phenonomen that was previously described for T. evansi type A. All Ethiopian T. evansi types are sensitive to melarsamine hydrochloride and diminazene diaceturate. Unfortunately, the most efficacious drugs are either not registered in Ethiopia or escape quality control of the active substance in commercial drug formulations. Furthermore, the inefficacious drugs remain accessible on the market despite their toxicity for animals.

A cross-sectional study was carried out to determine the prevalence and species of camel mange mite infestation in Raya-Azebo district, Northern part of Ethiopia. Accordingly, Three hundred and eighty-four camels were examined and mange mite infestation was detected on 64 of camels. Only Sarcoptes scabiei var. cameli was identified as the only mite species in all skin scraping samples collected from the suspected mange mite lesions. There was significant difference in the prevalence of mange mite infestation between male and female camels (p < 0.05) but no significance difference was observed among the age groups and body condition score of camels (p > 0.05). The result indicated that camel mange mite infestation was a problem in northern part of Ethiopia, hence, further studies and strategic control measures are recommended to reduce the effect of mange mite infestation on camel husbandry.