Browsing by Author "Ashebr, Abraha"

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    INVESTIGATION ON THE OCCURRENCE OF PARATUBERCULOSIS IN APPARENTLY HEALTHY SHEEP AND GOATS SLAUGHTERED ON BISHOFTU ELFORA, MOJO MODERN AND ORGANIC EXPORT ABATTOIRS, CENTRAL ETHIOPIA
    (2015-06) Ashebr, Abraha; Dr. Gezahegne Mamo, Prof. Gobena Ameni; Dr. Asegedech Sirak
    A cross sectional study was conducted from October 2014 to June 2015 to investigate the occurrence of paratuberculosis among apparently healthy sheep and goats slaughtered in Bishoftu ELFORA Export Abattoir, Mojo Modern Export Abattoir and Organic Export Abattoir, using gross pathology, histopathology, Ziehl-Neelsen (ZN) staining and bacteriological culture of tissue lesions from paratuberculosis suspected animals. Based on gross pathological examination, the prevalence of paratuberculosis was 5.21% (20/384) (95% CI=2.8-7.4) in sheep and 3.4% (26/768) (95% CI=2.1-4.7) in goats. Association of risk factors including species, age and origin of the animal with the occurrence of gross lesion showed statistically insignificant difference among the groups (P>0.05). However, a relatively higher prevalence was observed in sheep, age group of ≥2 years and in sheep originated from Borana. Out of 13 tissue samples from each species, histopathological examination revealed microscopic lesions consistent with paratuberculosis in 84.62% (11/13) of sheep and 76.9% (10/13) of goats, and the lesions were characterized by diffuse infiltration of many lymphocytes accompanied with few macrophages and epithelioid cells. Necrotic foci surrounded by lymphocytes, macrophages and epithelioid cells were observed in lymph nodes of 15 % (2/13) sheep and 23 % (3/13) goats. Grading of histological lesions based on the type and amount of cellular infiltrate revealed that all positive cases of sheep and goat were categorized in grade 3c lesion type and diffuse lymphocytic lesion type, respectively. On direct ZN staining of 46 tissue samples (20 sheep; 26 goats), acid fast positivity was recorded in 16 (80%) sheep and 14 (53.8%) goats. Out of 46 tissue samples (20 sheep; 26 goats) cultured on Herrold’s egg yolk media (HEYM) and Lowenstein-Jensen (LJ) media with and without 1% ferric ammonium citrate, Mycobacterium avium subspecies paratuberculosis (MAP) was isolated from 2 (10%) sheep and 1 (3.8%) goat on ferric ammonium citrate (1%) supplemented media and all isolates were acid fast positive. Isolated colonies were confirmed as MAP by ferric ammonium citrate dependence, their long incubation period, colony characteristics and their morphology on ZN stained smears. A linearly weighed kappa coefficient of 0.3 was obtained between histopathology xii and ZN staining, indicating fair agreement between the two tests. In conclusion the present study on sheep and goat paratuberculosis using gross pathology, histopathology, ZN staining and culture techniques revealed the occurrence of the disease in apparently healthy sheep and goats in Ethiopia. This result warrants the need for further investigation on the epidemiology, characterization of the causative agent and assessments of the economic impact of paratuberculosis on small ruminants of Ethiopia in order to design feasible control strategies.