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Helminth parasites of sheep and goats in Eastern Ethiopia

epidemiology, and anthelmintic resistance and its management

Sissay, Menkir Mekonnen (2007). Helminth parasites of sheep and goats in Eastern Ethiopia. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2007:52
ISBN 978-91-576-7351-0
[Doctoral thesis]

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Abstract

A two-year epidemiology study of helminths of small ruminants involved the collection of viscera from 655 sheep and 632 goats from 4 abattoirs in eastern Ethiopia. A further more detailed epidemiology study of gastro-intestinal nematode infections used the Haramaya University (HU) flock of 60 Black Head Ogaden sheep. The parasitological data included numbers of nematode eggs per gram of faeces (EPG), faecal culture L3 larvae, packed red cell volume (PCV), adult worm and early L4 counts, and FAMACHA eye-colour score estimates, along with animal performance (body weight change). There were 13 species of nematodes and 4 species of flukes present in the sheep and goats, with Haemonchus contortus being the most prevalent (65–80%), followed by Trichostrongylus spp. The nematode infection levels of both sheep and goats followed the bi-modal annual rainfall pattern, with the highest worm burdens occurring during the two rain seasons (peaks in May and September). There were significant differences in worm burdens between the 4 geographic locations for both sheep and goats. Similar seasonal but not geographical variations occurred in the prevalence of flukes. There were significant correlations between EPG and PCV, EPG and FAMACHA scores, and PCV and FAMACHA scores. Moreover, H. contortus showed an increased propensity for arrested development during the dry seasons. Faecal egg count reduction tests (FECRT) conducted on the HU flocks, and flocks in surrounding small-holder communities, evaluated the efficacy of commonly used anthelmintics, including albendazole (ABZ), tetramisole (TET), a combination (ABZ + TET) and ivermectin (IVM). Initially, high levels of resistance to all of the anthelmintics were found in the HU goat flock but not in the sheep. In an attempt to restore the anthelmintic efficacy a new management system was applied to the HU goat flock, including: eliminating the existing parasite infections in the goats, exclusion from the traditional goat pastures, and initiation of communal grazing of the goats with the HU sheep and animals of the local small-holder farmers. Subsequent FECRTs revealed high levels of efficacy of all three drugs in the goat and sheep flocks, demonstrating that anthelmintic efficacy can be restored by exploiting refugia. Individual FECRTs were also conducted on 8 sheep and goat flocks owned by neighbouring small-holder farmers, who received breeding stock from the HU. In each FECRT, 50 local breed sheep and goats, 6–9 months old, were divided into 5 treatment groups: ABZ, TET, ABZ + TET, IVM and untreated control. There was no evidence of anthelmintic resistance in the nematodes, indicating that dilution of resistant parasites, which are likely to be imported with introduced breeding goats, and the low selection pressure imposed by the small-holder farmers, had prevented anthelmintic resistance from emerging.

Authors/Creators:Sissay, Menkir Mekonnen
Title:Helminth parasites of sheep and goats in Eastern Ethiopia
Subtitle:epidemiology, and anthelmintic resistance and its management
Year of publishing :May 2007
Volume:2007:52
Number of Pages:50
Papers/manuscripts:
NumberReferences
ALLI. Sissay, M. M., Uggla, A. & Waller, P. J., 2006. Epidemiology and seasonal dynamics of gastro-intestinal nematode infections of sheep in a semi-arid region of eastern Ethiopia. Veterinary Parasitology, 143, 311-321. II. Sissay, M. M., Uggla, A. & Waller, P. J., 2007. Prevalence and seasonal incidence of helminth parasite infections of sheep and goats in eastern Ethiopia: I. Nematodes and trematodes. Tropical Animal Health and Production (accepted for publication). III. Sissay, M. M., Asefa, A., Uggla, A. & Waller, P. J. 2006. Anthelmintic resistance of nematode parasites of small ruminants in eastern Ethiopia: Exploitation of refugia to restore anthelmintic efficacy. Veterinary Parasitology, 135, 337-346. IV. Sissay, M. M., Asefa, A., Uggla, A. & Waller, P. J., 2006. Assessment of anthelmintic resistance in nematode parasites of sheep and goats owned by smallholder farmers in eastern Ethiopia. Tropical Animal Health and Production, 38, 215-222.
Place of Publication:Uppsala
ISBN for printed version:978-91-576-7351-0
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:sheep, goats, nematode infections, helminths, drugs, anthelmintics, nematoda, trematoda, parasites, epidemiology, fasciola, haemonchus contortus, paramphistomum, trichostrongylus, small farms, semiarid zones, seasonal variation, ethiopia
Keywords:Keywords: Africa, Ethiopia, tropical, semi-arid, goat, sheep, small ruminant, small-holder, parasite, helminth, nematode, trematode, fluke, epidemiology, prevalence, anthelmintic resistance, refugia, FAMACHA, Fasciola, Haemonchus, Paramphistomum, Trichostrongylus.
URN:NBN:urn:nbn:se:slu:epsilon-1573
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-1573
ID Code:1435
Department:(VH) > Dept. of Biomedical Sciences and Veterinary Public Health
Deposited By: Sissay Menkir Mekonnen
Deposited On:02 May 2007 00:00
Metadata Last Modified:02 Dec 2014 10:12

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