Browsing by Author "Mengistu, Araya"

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    The Effect of Herbal Preparations on Staphylococcus Aureus and Streptococcus Agalactiae Isolated from Clinical Bovine Masstitis
    (Addis Ababauniversity, 2004-06) Mengistu, Araya; Gebreab, Feseha (Prof)
    A study was conducted in Debre-Zeit town to determine the incidence of bovine clinical mastitis in a purposefully selected two dairy farms and the efficacy of conventional antimicrobial drugs and traditional herbs, from September 2003-March 2004. The objectives of the work were to assess the invitro effect of six herbal preparations; namely, Brucea antidysentrica, Combertum molle, Cyphostemma adenocale Persicaria senegalensis, Plantago lanceolata and Zehneria scabra on major isolates of clinical bovine mastitis, to compare their efficacy, with conventional antimicrobial agents that are commonly used for the treatment of bovine mastitis, and to investigate the effect of the herbs on the growth inhibition of resistant isolates. The herbs were collected from their natural habitats and processed and extracted with 80% methanol. Both absolute methanol and aqueous extracts of Combertum molle were assessed foe antimicrobial property. Milk samples from clinical cases were collected aseptically and causal agents were identified after the severity of the diseases in each cow was categorized into Grade I-Grade III by following standard laboratory procedures and finally sensitivity test was conducted on Staphylococcus aureus (n=17) and Streptococcus agalactiae (n=14), which were the predominant isolates. The incidence rate was 12.4 new clinical mastitis cases/ 100cows-month and 6.7 new clinical mastitis cases/100cows-month at risk in EARO and Fair-field dairy farms respectively with an overall incidence of 9 new clinical mastitis cases/100cows-month at risk. Staphylococcus species (42.3%) and Streptococcus species (34.5%) were the major isolates from Grade I (84%) and Grade II (16%) clinical cases. Single infection of 46.8% and mixed 37.5% and contaminated 9.4% infections were recorded with 6.3% negative cultures. Staphylococcus aureus was resistant to Oxytetracycline (23.5%) and Penicillin G (64.7%) and Streptococcus agalactiae was resistant to Neomycin and Streptomycin (85.7% each) and Oxytetracycline (100%). Burcae antidysentrica, Combertum molle, Cyphostemma adenocaule and Persicaria senigalensis were effective against susceptible and resistant isolates and among those absolute methanol extract of Combertum molle showed a better effect on both test organisms. Plantago lanceolata and Zehneria scabra were not showing visible inhibitory zone against test organisms. None of the herbal extract preparations showed visible inhibitory effect on Escherichia coli. This study indicated that mastitis is a great problem in the two dairy farms and resistant isolates are VIII circulating within farms. For this herbal preparations might be considered as an alternative option for the treatment of resistant isolates of clinical bovine mastitis for the future. Keywords: Clinical mastitis, herbal preparations, aetiological agents, Staphylococcus aureus, Streptococcus agalactiae, sensitivity, effect, conventional antimicrobials and resistant isolates
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    Instructors' Provision of Written Responses to Students' Business Letter Writing
    (Addis Ababa University, 2003-07) Mengistu, Araya; Haile, Messele(PhD)
    This study is conducted to prepare seismic microzonation map to central part of Addis Ababa City. The basic method used is the observation and analysis of microtremors. The first effort was made by Ayele (2001) based on 40 observation sites. Latter detailed study was initiated by dividing the city in to five parts namely the northeastern, northwestern, central, southeastern and southwestern parts of which the central part is the study area for this thesis. In this thesis seismicity and related hazard for Addis Ababa city and its locality, historic records, geologic conditions and effects on earthquake, and the theoretical background used in preparing microzonation maps are presented. The nature of microtremors, basic characteristics and their use in estimating site-effects is also discussed together with the method of measurement, equipments used and available tools to analyze collected data. The suitability of microtremor based site-effect study has been tested by comparison of results with solutions from one dimensional analytical model for selected sites.
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    Seismic Microzonation For Central Addis Ababa
    (Addis Ababa University, 2003-07) Mengistu, Araya; Haile, Messele(PhD)
    This study is conducted to prepare seismic microzonation map to central part of Addis Ababa City. The basic method used is the observation and analysis of microtremors. The first effort was made by Ayele (2001) based on 40 observation sites. Latter detailed study was initiated by dividing the city in to five parts namely the northeastern, northwestern, central, southeastern and southwestern parts of which the central part is the study area for this thesis. In this thesis seismicity and related hazard for Addis Ababa city and its locality, historic records, geologic conditions and effects on earthquake, and the theoretical background used in preparing microzonation maps are presented. The nature of microtremors, basic characteristics and their use in estimating site-effects is also discussed together with the method of measurement, equipments used and available tools to analyze collected data. The suitability of microtremor based site-effect study has been tested by comparison of results with solutions from one dimensional analytical model for selected sites