Gross and Microscopic Lesions of Epizootic Lymphangitis on Carthorses in Central Oromia, Ethiopia

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Addis Ababauniversity


A cross sectional study was conducted in eight towns in central Oromia, Ethiopia, from March to August of 2015 with an objective of describing the pathological findings of topical and internal organs lesion in carthorses naturally infected with Epizootic lymphangitis and revealing the presence of the fungus within the lesions of internal organs. The study animals were local breed carthorses located in the study areas that are naturally infected with Histoplasma capsulatum variety farciminosum. Among the 70 disease suspected carthorses that were found in the study area 30 were purposively screened out. Field assessment, clinical observation, microscopical examination, isolation of the agent, autopsy examination, and histopathological examination were used for this investigation. Field Survey part of this study revealed presence of a gap on knowhow of the disease. In spite of the fact that 76% (76/100) of the interviewed carthorse owners were trained by SPANA, 44% of them still believe that the disease is caused by an evil-eye or “Buda”.71% of them are accustomed to use both traditional and modern treatment methods. 37% of them believe presence of small and large nodular lesions which is found to be true that out of the 804 nodular lesions counted on this study 396 (49.3%) were small type (Female) and 408 (51.7%) large type (Male). Early and moderate stages of Epizootic lymphangitis are considered curable, however, the fate of carthorses with sever stage of the disease was euthanasia. Severely affected and abandoned carthorses were usually found staggering at the middle of highways. All the 70 disease suspected carthorses showed signs of the cutaneous forms of the disease and there were no clearly separated three forms, rather there were an extension and manifestation of the cutaneous form lesions in and around eye and respiratory organs. Giemsa stained smears of the contents of pyogranulomatous skin nodules and imprint smear of affected internal organs revealed yeast like organisms; showing that the disease. The topical body parts affected with lesion were skin and superficial lymphatics of skin of the body extremities. Nodular lesions were observed mostly in the limbs, lower trunk and head regions. Severely affected regions were the limb extremities, especially the hind limb extremities. Tick infested parts seems to be more vulnerable. The gross lesions detected on internal organs were few in number and even on few organs. Although, diverse types of lesions were detected on different organs, a mass of nodule on x mucosal part of trachea and a large nodular lesion of right lung together with diffused small granulomatous nodules of both lungs were the reportable findings of this study. Hematoxylin and Eosin stained histopathological sections reveled the characteristic pyogranulomatous lesion and many yeast-like organisms distended within macrophages. Those characteristic histopathological lesions were found both from topical and internal organ lesions. The inflammatory cells that infiltrate the tissue were macrophages, polymorphonuclear cells and plasma cells; macrophages being the predominant one. There were neither gross nor microscopic lesions detected within internal organs of some cases in this study; even in one organ. There was neither pyogranulomatous lesion nor yeast-like organisms detected from normal tissue sections of internal organs and from some non-nodular lesions of internal organs. Having such an open skin, their internal organs were found to be normal in pathologically point of view. The pathological lesions were restricted on the skin and most of the vital organs were found normal. Additionally skin has a great regeneration capacity and early and moderate stages of Epizootic lymphangitis are curable. Therefore all stages of EZL seem curable, if handled properly. The treatment may not be cost effective, however, euthanasia of carthorses in sever stage of Epizootic lymphangitis for welfare reason seems against the principle of welfare. Key words: Epizootic lymphangitis, carthorses, pyogranulomatous lesion, necropsy, biopsy, histopathology



Epizootic lymphangitis, carthorses, pyogranulomatous lesion, necropsy, biopsy, histopathology