Browsing by Author "Kassa Demissie"

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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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    Epidemiology of Tuberculosis in Bovine and Swine, and its Zoonotic Implication in Central Ethiopia
    (Addis Ababa University, 2021) Kassa Demissie; Gezahegne Mamo
    Tuberculosis is a global priority disease of humans and animals. Bovine tuberculosis has been first reported in Ethiopia in the year 1967. Since then its prevalence has been rising. The nationwide prevalence of bovine tuberculosis has been estimated (5.8%) very recently in Ethiopia and the animal level prevalence ranges from 0.8%-54.6%; the highest prevalence was being reported in intensive dairy farms in and around cities while the lowest prevalence was being recorded in grazing animals in rural areas. However, there are emerging dairy cattle farms in Debre Berhan milkshed where the current epidemiological picture of bovine tuberculosis has not yet been elucidated. Similarly, there is little scientific information on the epidemiology of tuberculosis in swine in the country although swine production has been growing in central Ethiopia since two decades following the privatization policy. Besides affecting animals and reducing their productivity, animal tuberculosis is transmitted to and causes illness in humans. However, there is little information on the magnitude of human tuberculosis of animal origin in Ethiopia that requires additional studies. This study was initiated to investigate the epidemiology of tuberculosis in bovine and swine and its zoonotic implication in central Ethiopia. A cross-sectional study was conducted on 96 herds consisting of 625 heads of dairy cattle in Debre Berhan milkshed and 11 herds comprising of 329 heads of swine raised in selected sites in central Ethiopia. Skin testing was carried out by making use of single intradermal cervical comparative tuberculin test for cattle and single intradermal comparative tuberculin test for swine. Moreover, mycobacterial culturing, gross and microscopic characterization of tuberculosis like lesions and molecular typing of mycobacteria were used. Face-to-face interview using semi-structured and open-ended questionnaire was also presented to 165 respondents (146 farm workers and 19 human health professionals) to assess their knowledge and practices on the zoonotic transmission of tuberculosis from farm animals to humans. The finding showed that the apparent individual animal level prevalence of bovine tuberculosis was 17% (106/625; 95% CI: 14.2-20.2) at ≥4mm and 18.4% (115/625; 95% CI: 15.5-21.7) at >2mm cut-off values in 625 heads of dairy cattle tested. Whereas, the herd prevalence was 16.7% (16/96; 95% CI: 10.1-26) at ≥4mm and 22.9% (22/96; 95% CI: 15-33) at >2mm cut-off values in 96 dairy herds tested. Multivariable logistic regression analysis at ≥4mm cut-off value revealed that dairy cattle with poor body condition score (AOR = 3.7; 95% CI: 1.6-8.4; p = 0.002), in the large herd size (AOR= 29.5; 95% CI: 5.6-154.1; p = 0.000) and of exotic breed (AOR = 3.7; 95% CI: 1.3-10.7; p = 0.018) had 4, 30 and 4 times the odds of tuberculin positivity with statistical significance, respectively compared to their counterparts. The apparent individual animal level prevalence of bovine tuberculosis in swine was 3% (10/329; 95% CI: 2-6) at > 2mm cut-off value. In the total 9 clusters tested, the herd prevalence was 11% (1/9; 95% CI: 1-49) at >2mm cut-off value. In addition, the abattoir lesion prevalence of tuberculosis in swine was 4.1% (26/640; 95% CI: 2.8-6.0) on the basis of gross tuberculosis like lesions. The awareness level of farm owners/attendants towards the transmission of tuberculosis from farm animals to humans was generally low. Culturing of tuberculosis like tissue lesions from swine and human sputa from suspected active TB patients as well as molecular typing indicated M. tuberculosis as the principal finding. In conclusion, the current study demonstrated the endemic occurrence of animal tuberculosis in the study areas and low level of public awareness towards its zoonotic transmission. Poor body condition, large herd size and exotic breed were important predictors of bovine tuberculin positivity in dairy cattle. M. tuberculosis was the predominant species cycling in the study areas. The findings of the current study compliment research works done so far in Ethiopia and contribute its own share to the control options of bovine tuberculosis. The study forwarded recommendations for intervention and future research.