Browsing by Author "Yilkal Asfaw"

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    African Horse Sickness Study on Seroprevalence and Identifications in Equidae at Selected Sites in Ethiopia
    (Addis Ababa University Faculty Of Veterinary Medicine, 2006-06) Kassa Demissie; Yilkal Asfaw
    ABSTRACT A study was undenaken to determine the seroprevalence o f Afri can horse sick ness viru s antibod ies, isolate and characterize th e vi ru s re sponsible as well as identi fy potenti al risk facto rs in t he equi ne po pulation of sel ected study areas in Ethio pia In total 1265 seru m samples origina t ing from 824 donkeys, 383 horses and 58 mules were coll ected from September 2005 to mid of April 2006. Comp eti tive Enzy me Linked Immu nosorbent Assay (C-ELISA) configu rati o n was employed to dete rmine the presence of AHSV antibodies The apparent prevalence of AHSV was found to be 297% (95% C I ~ 26.8-33 .0) in donkeys, 104% (95% C I ~ 78- 14 .0) in ho rses and 103% (95% C I ~4 . 8 -22 I) in mules The overall apparent sera prevalence of AJ-I SV was found to be 23% (95% C I~20 8-25 4) There is sig nificant variat ion amongst the types of equidae in seropositivity (P
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    African Horse Sickness: Study On Seroprevalence and Dentification of Risk Factors in Equidae at Selected Sites in Ethiopia
    (2006-06) Kassa Demissie ; Yilkal Asfaw
    A study was undertaken to determine the seroprevalence of African horse sickness virus antibodies, isolate and characterize the virus responsible as well as identify potential risk factors in the equine population of selected study areas in Ethiopia. In total 1265 serum samples originating from 824 donkeys, 383 horses and 58 mules were collected from September 2005 to mid of April 2006. Competitive Enzyme Linked Immunosorbent Assay (C-ELISA) configuration was employed to determine the presence of AHSV antibodies. The apparent prevalence of AHSV was found to be 29.7% (95% CI = 26.8-33.0) in donkeys, 10.4% (95% CI = 7.8-14.0) in horses and 10.3% (95% CI =4.8-22.1) in mules. The overall apparent seroprevalence of AHSV was found to be 23% (95% CI=20.8-25.4). There is significant variation amongst the types of equidae in seropositivity (P<0.05). Statistically significant (P<0.05) difference in seroprevalence was observed in the different study areas, confirming the existence of agro-ecology based variation in the occurrence of African horse sickness. The highest seroprevalence of AHSV was documented in the lowlands followed by midland and highland areas. This has direct correlation with the ecological distribution of the Culicoides vectors. As for age dependent variation in seroprevalence no statistical significant difference was found. All age groups as well as male and female populations were equally affected. The risk of acquiring AHS is more than two fold (OR = 2.1) with respect to the types of equidae affected. Moreover, agro-ecology contributes nearly two fold (OR =1.5) for the occurrence of African horse sickness. There is strong association among C-ELISA result of AHSV antibodies, types of equidae and agro-ecology, but age is not part of the interaction. However, sex has weak effect to precipitate the occurrence of African horse sickness. Active disease search was conducted with the aim of virus isolation and identification. After three blind passages were carried out on vero cell lines the sample was subjected to I-ELISA configuration. However, the result was negative. In the presence of the disease in the field with classical pathognomonic signs and postmortem lesions the negative result is probably due to the improper handling of the tissues processed. The indigenous knowledge base of equine owners about African horse sickness in the study areas was assessed through a structured questionnaire format. The survey result indicated that, the indigenous knowledge of owners was found to be unsatisfactory.
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    The Epidemiology of Bovine Brucellosis in Intra and Peri-Urban Dairy Production Sysems in and Around Addis Ababa
    (Addis Ababa Universty, 1998-01) Yilkal Asfaw; Baykyegn Molla
    Bovine brucellosis is an infectious disease of economic importance by causing abortions and infertility. Bovint: brucellos is considered a zoonosis infprmation on the extent of bovine brucellosis. however. is scarce for the expanding intra- and peri- urban dairy enterprise in Ethiopia. The purpose of this study was to investigate the status of bovine brucellosis and its impact on reproduction in some intra- and peri-urban dairy production systems in Ethiopia. A cross-sectional investigation of bovine brucellosis was carried out from Jun to October 1917 on -42 dairy farms located in Debre Zeit, Kalili, Sebela, and Addis Ababa. The farms represent peri-urban systems. Intra-urban systems in secondary towns and intra-urban production systems. Bulk milk samples were collected from each farm (herd ) in June, August, and October Blood samples from 950 non-vaccinated breeding animals above six months of age were collected once in June. The milk Ring Test (WRT), the Rose Bengal Plate Test (ROPT). and the Complement Fixation Test (CFT) were carried out on milk and serum samples. Farm management parameters and zoonotic aspects were cullected by administering a questionnaire . An overall herd infection rate of 33.3% was determined. With respect to the production systems 100%. 30%, and 12.5% of the farms were infected in peri-u rban. intra.-urbun stecondary town. and intra -urban systems, respectively. The within herd prevalence ranged from 0-16.7%. At least one or two reactors were idemilied in 64.3% of the farrms. An overall prevalence rate of 811% was found on individual animals. A prevalence rate of 9.8 % was observed in the age group 2 to 4 years. A prevalence rale af 9.1 % and 3.3% was identified in fams that keep more than 100 animals, and less than 50 animals, respectively. Significant difference in prevalence rate was observed in animals aged below and above 2 yeas and between no arturition and at least one parturition. A significant difference in prevalence rate was also observed between farms that keep below 50 and above 100 animals. Odds ratios (OR) of 2.1 4 (1.04·483) between age and brucellosis infection and 2.99 ( 1.29· 8.06) between herd size and brucellosis infection were determined. Significant differences in prevalence rates were not observed among the production systems and districts in indvidual animals. Agreement (kappa values) between RBPT +/'CFT+ and MRT tests were 0.31 (first MRT result ), 0.43 (first and second MRT results pooled), and 0.58 (first. second and third MRT results pooled). Moderate agreement (k=0.44) was found between RBPT+ and CFT +and good agreement (k=O.74) was found between RBPT+ and RBPT +ICFT + testing procedure Considering positive results in both RBPT and CFT as gold standnrd the sensitivity (SE) and specificity (SP) of the pooled MRT were 57.1% and 89.3%respectively). Sensitivty and specilicity, of RBPT were 100% and 94.6%. respectively. Associations betweer reproductive and production parameters and brucellosis infection could not be established for individual animals. However. on the basis of questionnaire .answers, previous abortions and use of natural service were associated with Brucellar infection: OR of 15.58 (1.72-79.16) and 0.06(0·0.61) were calculated respectively·. Abortions were recorded in 56.1 % of the farms. Lack of knowledge of brucellosis was recorded in 87.8% of the farms. Cleaning and disinfection was done regularly in 29.3,% removal of infected animals was farm practice in 14.6%provision of maternity pens was found in 4,9% of the farms, and 21.9% of the farms obtained repbcement stock from outside source. Prokmged fever was observed in nine persons interviewed . They were attending cows for at least six months. Absence of vaccination . herd size, cuttle density, lack of knowledge of brucellosis, and nonmanagement and husbandry practices are likely factors responsibl to explain the relaively high prevalence rate observed in his study. Due to its impact on production and lfor its 'Zoonotic significance. Awareness of brucellosis in urban farming should be given priority. Conclusions and recommendations in this regard, emphasizing control of brucellosis are given.
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    The Epidemiology of Bovine Brucellosis in Intra-and Peri- urban Daban Dairy Production Systems in and around Addis Ababa
    (Addis Ababa University Faculty Of Veterinary Medicine, 1998-01) Yilkal Asfaw; Bayleyegn Molla
    Bovine brucellosis is an infsease of economic importance by causing abortions and infertility .Bovine brucellosis is considered azoonosis information on the extent of bovine brucellosis . however, is scarce for the expanding intra- and peri- urban dairy enterprise in Ethiopia .the purpose of this study was to investigate the status of bovine brucellosis and its impact on reproduction in some intra and peri – urban dairy production systems in Ethiopia across- sectional investigation of bovine brucellosis was carried out from june to October 1997 on 42 dairy farms located in debre zeit ,kaliti, Sebeta .and Addis Ababa
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    I Ddis Ababa University Faculty of Veterinary Medicine Sero – Epidemiology of Brucellosis in Small Ruminants in Southern Ethiopia
    (2007-06) Mengistu Mekuria; Yilkal Asfaw
    A cross sectional study was conducted in Oromia and Regional state of SNNPRS from August 2006 to April 2007 to determine the prevalence of brucellosis in goats and sheep and areas associated risk factors using mRBT and CFT. A total of 2905 goats and 1059 sheep were included in this study. The modified Rose Bengal Test (mRBT) prevalence rate in goats’ over all is 5.5% (n=2905) while in sheep is 4.0% (n=1059) and total in small ruminants 5.1% (n=3964) in extensive farming system. The mRBT positive rates, in relation to production systems are 7.11% and 0.5% in pastoral and sedentary respectively. In the intensive farming system, in Adami Tullu Agricultural Research Center, no sero-positive animals while in Awassa Agricultural College, the prevalence rate is 20% by mRBT. The serial test positives (mRBT and CFT) prevalence rate in goats is 3.2% (n=2905) while in sheep is 1.6% (n=1059). The small ruminants’ prevalence rates are 3.9% and 0.33% in pastoral and sedentary production systems respectively. In the intensive farming system, in Adami Tullu Agricultural Research Center, no sero-positive animals while in Awassa Agricultural College, the prevalence rate is 18.4 % by serial tests. Risk factors analysis was carried out in relation to production system, species and sex and significant differences were observed to counter categories (p<0.05). Age factor showed no significant difference in this analysis, which may be due to low number of observations at higher ages. xii Flock prevalence was determined only in pastoral production system, but not in mixed crop livestock production system because of small holdings and difficulty to consider as herd (flock). Herd (flock) prevalence was observed only in pastoral production system. Herd prevalence by serial test in Borerna (Oromya) is 38.8 %( n=73), while in South Omo and Konso (SNNPRS) is 22.7 %( n=75). The cut-off value for flock prevalence was greater or equal to one. In general brucellosis in small ruminants is prevalent in the low land pastoral production system at individual and herd level. In the sedentary areas at higher altitude the prevalence is 0%, except in some fringed areas bordering the pastoral production system as in konso district. Based on the result of the study concluding remarks and recommendation are forwarded.
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    Prevalence of bovine mastitis in lactating cows among small holder dairy herds and antimicrobial sensitivity test on major isolated pathogens in and around Gondar
    (2007-06) Nibret Moges; Yilkal Asfaw
    A cross _ sectional study was conducted on 322 local and crossbred lactating hand milked small holder cows in and around Gondar from September 2006 to March 2007 to determine prevalence, the causal agents of infection, associated risk factors and tests susceptibility to drugs using California Mastitis Test, clinical inspection of udder, and bacterial culture. Of the total cows examined, 32.6% (322) had mastitis, 0.93 % (3) was clinical and 31.67% (102) sub clinical mastitis. Out of 1249 quarters examined 164 (13.13%) were found to be infected, 7(4.27%) clinically and 157 (95.73%) sub clinically from 1288 quarters examined 39 (3.02%) were blind. Clinical prevalence at cow level was 0.93% in crossbreds and none in local zebu breeds. Sub clinical mastitis at cow level based on CMT was 28.57% in crossbreds compared to indigenous zebu 3.10% (P<0.05). Quarter sub clinical prevalence based on CMT was 16.05% and 5.12% for crossbreds and local zebu, respectively. Among potential risk factors considered breed, age, parity and stage of lactation were found to affect the occurrence of mastitis significantly (p< 0.05). The prevalence of mastitis was significantly higher in Holstein _Friesian crossbreds than indigenous zebu, in the early lactation stage than in the mid lactation stage. Of 176 CMT and clinically positive udder quarter samples analyzed microbiologically 164 were culturally positive for known mastitis pathogens and 1085 were negative. Of the 164 positive samples isolation rate of Staphylococcus aureus 16.5%, Coagulase negative Staphylococci 31.1%, Streptococcus agalactiae 15.9%, Streptococcus dysgalactiae 14.0%, Streptococcus uberis 6.7%, Micrococcus spp 7.3%, Corynebacterium bovis 2.4%, Actinomyces pyogens 1.2%, Bacillus cereus 0.6% and Escherichia coli 4.3%. Staphylococcus aureus, Coagulase negative Staphylococcus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Micrococcus species, Corynebacterium bovis, Actinomyces pyogenes, Bacillus cereus and Escherichia coli were isolated from cases of sub clinical mastitis. Generally, it was found that Sulfisoxazole was the most effective antibiotic VII where 91.07% of the total isolates were found susceptible, followed by clindamycin and kanamycin (89.3%), (88.4%) The least effective antibiotics were streptomycin (45.5%) and ampicillin (49.1%). Tetracycline, erythromycin, chloramphenicol, oxacillin, 65.2%, 59.8%, 64.3%, 58.04% respectively, were categorized as drugs of weak efficacy. Inadequate sanitation of dairy environment, poor animal health services and lack of proper attention to health of the mammary glands were important factors contributing to high prevalence of mastitis. Some recommendations were forwarded to reduce the tend of mastitis in the study area.
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    Seropreva Alence Study of Brucellosis in Cattle and Human in Bahirdar Milkshed
    (AAU, 2005-06) Mussie Hailemelekot ; Yilkal Asfaw
    A Cross – Sectional Study Was Conducted In South Gondar, West Gojjam And Awi Zones of Amhara Regional State, Between October 2004 And March 2005, to Determine the Sero – Prevalence of Brucellosis in Cattle and Humans as Well as to Identify the Likely Potential Risk Factors. Two Sage Cluster – Sampling Was Employed, by Which 11 towns as Identified Primary Units and 195 Farms as Secondary Units in Semi – Intensive Production System. Similarly, 29 Peasant Associations as Primary Units and 145 Individual Cattle Owners as Secondary Units Were Selected for the Extensive Production System. in the Government Cattle Breeding Ranch all Eligible Cattle Were Sampled. Human Risk Groups Were Sampled Using Purposive Sampling Method. the Study Methods Involved Collection Serum Sample, Data, Questionnaire Surveys and Serological Tests Conducted in Laboratoris. Accordingly, 1944 Cattle (341 Clusters in the Three Production Systems)Were Sampled. the Sampling Involved all Cattle Above 6 Months of Age With No History of Previous Vaccination Against Brucellosis. the Number of Cattle Sampled in Extensive, Semi – Intensive and Ranch Were 864, 754 and 326, Respectively. the Types of Tests Used to Detect the Presence of Brucella Antibodies Were Rose Bengal Plate Test (RBPT) as Sereening Test, and Complement Fixation Test (CFT) as Confirmatory Test, Results of The Two Tests Were Interpreted Serially. A Cluster Was Said to Be Positive if at Least one Animal Reacts Positively by Both RBPT And CFT.
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    Seroprevalence of Contagious Caprine Pleuropneumonia in Borana and Guji Lowlands, Southern Ethiopia
    (2008-06) Tesfaye Bekele; Yilkal Asfaw
    A multistage cross sectional serological study, questionnaire survey and participatory appraisal were conducted on contagious caprine pleuropneumonia (CCPP) from October, 2007 to April, 2008 in Borana and Guji lowlands, Southern Ethiopia, to determine the prevalence of the disease, to identify the risk factors for the occurrence of the disease and to assess the perception of the community on CCPP in particular and other goat diseases in general. A total of 951 serum samples (900 from goats and 51 from sheep) were collected and tested using Complement Fixation Test (CFT). Questionnaire surveys were conducted with 69 randomly selected households. Participatory disease appraisal was done with 12 informant groups in 12 different villages, the group size varying from 5-12 informants and with a total of 120 informants. Out of the 900 goat sera samples tested, 119 (13.2%) were seropositive for CCPP, giving an overall seroprevalence of 13.2 % (95%CI=11.0%-15.4%) in the study areas. A seroprevalence of 18.3% (95% CI=14.3%-22.7%), 11.7% (95% CI=8%-15.2%) and 9.7% (95% CI=6.3%-12.6%) were recorded in Liban, Teltale and Moyale Districts, respectively. The seroprevalence recorded among the districts was significantly different (p<0.05). The seroprevalence recorded in Liban district was significantly different from that of Moyale District (p<0.05). Moreover, out of 51 sheep samples tested, 3 (5.9%) were seropositive. Statistical analysis on the assumed risk factors showed that the seroprevalence observed in age groups, flock size groups and distance from veterinary service centre were found to be significantly different (p<0.05). Multivariate logistic regression analysis on the assumed risk factors showed that age, flock size and distance from veterinary service centre were the major risk factors for the occurrence of the disease in the area with Odds ratios of 2.18 (95% CI=1.64-2.91), 1.59 (95% CI=1.11-2.29) and 1.43 (95% CI=1.03-1.98), respectively. Contact at watering points, restocking, lack of veterinary service, and large flock size were identified to be the major factors for the spread and occurrence of the disease in the area. Participatory disease appraisal has indicated that the community has good knowledge about contagious caprine pleuropneumonia and other goat diseases, implying that the indigenous knowledge of the pastoral community could be used complementarily with the conventional disease investigation technique in the area. In conclusion, the serological findings, questionnaire survey and participatory appraisal have indicated that contagious caprine pleuropneumonia was XIV the top major goat health problem in the area which warrants appropriate measures to be in place towards the prevention and control of the disease in the study areas.
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    Seroprevalence Of Pest Des Petitis Ruminants and Its Associations with Potential Risk Factors in Domesticated Small Ruminants, Cattle, Camel in Jijiga and Shinille Zone of Somali Region, Ethiopia
    (Addis Ababa University, 2009-06) Teffera Sime; Yilkal Asfaw
    Cross-sectional study was conducted in Jijiga and Shinille Zones of Somali Regional State from October 2008 to April 2009 to determine seroprevalence and associated risk factors. A multistage sampling was used in pastoral and agropastoralsystem. A total of (n=616) goats, (n=202) sheep, (n=110) cattle and (n=94) camel sera were collected for serological study. questionary survey was conducted in pastoral and agro-pastoral system. The seroprevalence of PPR in goats and sheep was 25.6% and 14.4% in the study area respectively. The seroprevalence was lower in camels and cattle, which was 8.5% and 6.63% respectively. Goats were found to be more susceptible than sheep, which was found to be statistically significant (p=O.OOO). However no significant difference was observed between cattle and camel (P=0.558). Seroprevalence of goats between Shinille Zone (pastoral) and Jijiga Zone (agro-pastoral) production system showed 44.09% and 18.9% in goats, 30.01% and 5.42 in sheep respectively. Sero prevalence increased from 21.7%% to 28.9%%% in goats and from 8.1 %to 20.4%in sheep from young to adults age respectively. There was significant difference between age groups in seroprevalence of both goats (p=0.04) and of sheep (0.013). In case of cattle (p=0.062) and camel (p=0.249) statistically no significance difference was observed between age groups in seroprevalence. Regarding sex, 26.4%, and 25.5% was found in goats (p=0.851), 15.6% and 14% in sheep's 8% and 5 %( p=O. 795) in cattle (p=0.488) and8.2% and 9.5% in camel (p=0.095) in male and female respectively. There was statistically no significant difference between sexes in all species. According to the respondent the number of goats affected by CCPP (Sunbub) and PPR (Kollere) was 32.8%, 21.4% and 25.7%, 14.3% in Shinille and Jijiga Zone respectively. However more goats are affected by GIT parasite in Jijiga (40%) than Shinille zone (21.4%). Regarding susceptibility by age 64.28% and 60.7% of the respondent replied that young goats and sheep were more susceptible than adult animals. However, no response (0%) was made indicating susceptibility of goats and sheep less than 6 months of age. Key words: goat, sheep, cattle, camel, , cELISA, Peste des petits ruminants, Seroprevalence, Risk factors, Jijiga Zone, Shinile Zone.
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    Seroprevalence Study of Brucellosis in Cattle and Human in Bahirdar Milkshed
    (2005-06) Mussie Hailemelekot; Yilkal Asfaw
    A cross-sectional study was conducted in South Gondar, West Gojjam and Awi zones of Amhara Regional State, between October 2004 and March 2005, to determine the sero-prevalence of brucellosis in cattle and humans as well as to identify the likely potential risk factors. Two stage cluster-sampling was employed, by which 11 towns are identified as primary units and 195 farms as secondary units in semi-intensive production system. Similarly, 29 Peasant Associations as primary units and 145 individual cattle owners as secondary units were selected for the extensive production system. In the government cattle breeding ranch all eligible cattle were sampled. Human risk groups were sampled using purposive sampling method. The study methods involved collection serum sample, data, questionnaire surveys and serological tests conducted in laboratories. Accordingly, 1944 cattle (341 clusters in the three production systems) were sampled. The sampling involved all cattle above 6 months of age with no history of previous vaccination against brucellosis. The number of cattle sampled in extensive, semi-intensive and ranch were 864, 754 and 326, respectively. The types of tests used to detect the presence of Brucella antibodies were Rose Bengal Plate Test (RBPT) as screening test, and Complement Fixation Test (CFT) as confirmatory test. Results of the two tests were interpreted serially. A cluster was said to be positive if at least one animal reacts positively by both RBPT and CFT. The overall individual and cluster level sero-prevalence of cattle in the extensive, semi-intensive and ranch were 4.63 % (n=90) and 14.96 % (n=51), respectively. The within cluster sero- prevalence varied between 0% and 100%, with an overall mean (±SD) of 24.27% (±17.68). For semi-intensive production system, the sero-prevalence varied between 0% and 100% the mean (+SD) sero- prevalence was 26.82 % (±22.52), and in the extensive production system the within cluster sero-prevalence varied between 0% and 50% and an average (+SD) sero- prevalence of 25.44% (±10.45). There was a highly significant difference in sero-prevalence to Brucella antibody among Awi, West Gojjam, South Gondar at both individual level (p=0.000) and cluster level (p=0.000). However, Awi and West Gojjam zones did not vary significantly at both individual and cluster X II levels. In the midland and highland Brucella sero-reactor varied significantly at both individual level (p=0.000) and cluster level (p=0.000), respectively. Apparently there was no significant difference among the ranch, extensive and semi-intensive production systems, at both individual and cluster levels (p=0.082) and (p=0.255), respectively. Sero-reactor female and male were found to vary significantly in the semi-intensive production (p=0.042) as opposed to extensive (p=0.115) and ranch (p=0.50). Generally, females were found more affected. Significant difference in sero- prevalence to Brucella antibody among age groups (0.5-1,>1- 3, >3 years) was observed in the semi-intensive production (p=0.001), yet in extensive production and ranch the variation was not significant. Virtually, the sero-porevalences of the three herd categories having < 5 cattle, 5- 10 cattle and those with > 10 cattle were found significantly different in semi-intensive production (p=0.000); however, herd size had not been crucially important in extensive production. Our current finding revealed no significant variation between the two breeds of cattle, Fogera (indigenous zebu) and cross bred (Fogera X Friesian). Abortion and retained fetal membrane were found to be significantly related to brucellosis in the semi-intensive production (p=0.021) and (p=0.001), respectively; however, the two clinical signs were not found significantly associated in the extensive production. None of the management and husbandry related factors from the questionnaires were found significantly associated with sero-positivity, though a few of them had some association. Of the total 238 human serum samples tested, 3.78% (n=9) sera were found positive; both sexes were almost equally affected. Although not statistical significant, middle and old age groups were more affected than younger ones. In conclusion, the present study revealed a wider distribution of sero-reactor cattle in the study area; similarly the zoonotic importance of the disease was established, hence warranting future detailed study in the area.