http://etd.aau.edu.et:80/dspace/handle/123456789/420 Search the Channel search http://etd.aau.edu.et:80/dspace/simple-search http://etd.aau.edu.et:80/dspace/handle/123456789/2860 Title: EPIDEMIOLOGY OF BOVINE TRYPANOSOMOSIS IN THE ABBAY BASIN AREAS OF NORTHWEST ETHIOPIA <br/> <br/>Authors: SHIMELIS, DAGNACHEW NIGATU <br/> <br/>Abstract: Tsetse transmitted animal trypanosomosis is a serious constraint to livestock production and agricultural development in Ethiopia. Part of Abbay basin (Blue Nile) in northwest Ethiopia is tsetse infested where animal trypanosomosis is a serious threat to economic development. The objectives of the study were to generate a base line data on epidemiology of tsetse and trypanosomosis, to assess trypanocidal drug resistance and to know the community awareness regarding the disease and control methods in the area. The study was conducted between September 2003 to April 2004 in Dembecha and Jabitehenan weredas of the Abbay basin areas of northwest Ethiopia. The study methodology was based on questionnaire survey, seasonal cross-sectional studies of tsetse and trypanosomosis and longitudinal study for the assessment of trypanocidal drug resistance in the field. The questionnaire survey indicated that trypanosomosis is the most important problem affecting the animals and impeding agricultural activity in the area. Entomological survey revealed that Glossina. m. submorsitans was the only prevalent tsetse fly along with other biting tabanid and muscid flies. The apparent fly densities were significantly higher (p<0.05) in the late rainy season (1.08fly/trap/day, 8.78fly/trap/day and 91fly/trap/day) for G. m. submorsitans, tabanids and muscids respectively than the dry season (0.68fly/trap/day, 0.35fly/trap/day and 7.33fly/trap/day) respectively. In the lowland areas (<1600 m. a. s. l.) the apparent density for G. m. submorsitans was significantly higher (p<0.05) than the midland areas (1600-2000 m.a.s.l.) in the both seasons. The altitudinal distribution limit of G. m. submorsitans was upto 1780 m.a.s.l.The proportion of tsetse flies caught was higher in the savanna vegetation type followed by riverine, forest, bush and cultivated lands with maize, teff and horticulture plantations. In the parasitological survey a total of 1,648 animals, 814 in the late rainy season and 834 in the dry season were examined with buffy coat technique and the prevalence of trypanosomosis was 17.07% and 12.35% respectively with a significant difference (p<0.05) between seasons. Higher infection rates found in the lowland areas below 1600 m.a.s.l. (19.87% and 17.62%) than the midland areas ≥1600 m.a.s.l.(13.39% and 6.54%) in the late rainy and dry season respectively with significant difference (p<0.05).The mean PCV values (%) of parasitaemic and aparasitaemic animals during the late rainy season were 20.7±3.5SD VII and 26.6±4.3SD (p<0.001, 95% CI=25.3-25.9) while during the dry season 21.4±3.6SD and 26.6±4.3SD (p<0.001, 95% CI=25.4-25.9) respectively. The regression analysis of herd average PCV from herd prevalence indicated that herd average PCV decreased with increasing prevalence of trypanosome infections with a regression coefficient of negative values in both the seasons. A total of 100 animals were selected for the assessment of Isometamidium chloride (ISMM) and Diminazine aceturate resistance, 50 from each of the high risk villages identified in the area with similar agroecological zones. The selected animals in each village were grouped into 25 in control and 25 in treatment groups and were identified with ear-tags. At day minus 14 of the study all the 100 cattle were treated with Diminazine aceturate at a dose rate of 7mg/kg bw. After two weeks (day 0) the treatment groups were given ISMM at a dose rate of 1mg/kg bw. Both groups of cattle were examined for trypanosome parasite using buffy coat technique every 14 days interval until 84 days. The three indices used in assessing ISMM resistance (the proportion of infection during 8 weeks follow-up period, the 25% survival time and the ratio of mean hazard rates in the control and treatment groups of cattle) provided consistent results across the two villages for the occurrence of ISMM resistant trypanosome infections in the area. There was no significant difference between the Kaplan-Meier survival curve estimates of the control and treatment groups in both villages (p>0.05).The results of Diminazine aceturate efficacy showed 16 animals became recurrent infections with T. congolense but there was no significant difference between trypanosome incidence rate and trypanosome recurrence rate. Therefore, trypanosomosis is the most important problem for agricultural activity and animal production in the Abbay basin areas of northwest Ethiopia (Dembecha and Jabitehenan weredas of Amhara Region) and the situation is getting worse as the control and prevention of trypanosomosis is facing a challenge due to limitation of vector control activities and the development of drug resistance in the area. http://etd.aau.edu.et:80/dspace/handle/123456789/662 Title: CALF MORBIDITY AND MORTALITY IN DAIRY FARMS IN DEBRE ZEIT AND ITS ENVIRONS, ETHIOPIA <br/> <br/>Authors: TEMESGEN, WUDU <br/> <br/>Abstract: A longitudinal prospective observational study on calf morbidity and mortality in dairy farms in Debre Zeit and its environs was conducted from October 11, 2003 to April 8, 2004 with the objective of describing incidence of calf morbidity and mortality, investigating potential risk factors related to calf morbidity and mortality and identification of some pathogens associated with calf diarrhea. A total of 236 calves, 51 from three large dairy farms and a random sample of 185 calves from market oriented smallholder dairy farms in Debre Zeit and its surrounding were included in the study. Each calf was individually identified and regularly monitored for clinical health problems up to an age of six months. Information on different potential risk factors were collected by personal observation during the regular visit to farms and from questionnaire survey conducted during the study. Fecal samples were also collected from diarrheic calves for laboratory examination to detect entropathogens involved. The overall incidences of crude morbidity and crude mortality found in this study were 61.5% and 18.0%, respectively. Disease conditions/syndromes that were diagnosed in calves included diarrhea, pneumonia, navel ill, joint ill, septicemic conditions, congenital problems and other miscellaneous cases. The most frequent disease syndrome was calf diarrhea with the incidence of 42.9% followed by pneumonia (4.9%). The incidence of calf diarrhea and crude morbidity were apparently higher in large dairy farms than in the market oriented smallholder farms. However, the mortality was higher in the latter. A total of 20 potential risk factors were investigated for their association with the risk of crude calf morbidity, crude calf mortality and calf diarrhea using Cox’s proportional hazard model. Age was the only factor that was found significantly associated with risk of crude calf mortality (HR= 0.04, P= 0.001). Older calves above three months age were at lower risk of mortality than younger calves under three months of age. When weaned calves were considered, weaning age and age at first colostrum feeding were additional risk factors. Among the risk factors examined, those found significantly associated with the incidence of crude morbidity were age of the calves, age at first colostrum ingestion and cleanness of the calf house. Older calves were at lower risk of crude morbidity (HR=0.42, P = 0.001) than younger calves. Higher risk of crude morbidity were observed in calves that ingested their first colostrum meal later than 6 hours of age as compared with those that ingested before 6 IX hours (HR = 2.24, P = 0.001). Similarly calves housed at unclean house were at higher risk of crude morbidity than those housed in clean house (HR = 1.75, P = 0.024). Risk factors with significant association to calf diarrhea were age, condition of birth and cleanness of calf house. Older age was again associated with low risk of diarrhea as compared with younger age (HR = 0.24, P = 0.000). Calves from prolonged labor or dystocia (HR = 3.01, P = 0.002) and housed at unclean house (HR = 2.34, P = 0.011) were at greater risk of diarrhea than those calves from normal delivery and in clean house, respectively. Based on laboratory examination, Salmonella and Cryptosporidium were detected from diarrheic calves at rate of 2/55(3.6%) and 4/55(7.2%), respectively. The serotypes of Salmonella identified were Salmonella Typhimurium and Salmonella Heidelberg both of which were susceptible to commonly used antibiotics. In conclusion, the incidence of calf morbidity and mortality found in this study were high and could affect the productivity of the dairy farms through mainly decreasing the availability of replacement stock. Among the management risk factors investigated, time of first colostrum ingestion and cleanness of the calf house were found very important; incidentally, these two aspects of calf management are easy for observation and carrying out appropriate interventions. Implementation of good calf management in these areas could contribute in the reduction of the high calf disease problems seen in this study. Salmonella and Cryptosporidium were found in diarrheic calves and these pathogens in addition to their role in calf diarrhea, are potent zoonotics. Individuals particularly very young, elderly and immunocompromised, in contact with calves are at a potential risk of infection and therefore, efforts should be mounted to avoid such risks. <br/> <br/>Description: A thesis submitted to Faculty of Veterinary Medicine, Addis Ababa University in partial fulfillment of the requirements for the Degree of Master of Science in Tropical Veterinary Epidemiology http://etd.aau.edu.et:80/dspace/handle/123456789/658 Title: INVESTIGATION ON ECTOPARASITES OF SMALL RUMINANTS IN SELECTED SITES OF AMHARA REGIONAL STATE AND THEIR IMPACT ON THE TANNING INDUSTRY <br/> <br/>Authors: SERTSE, TEFERA <br/> <br/>Abstract: The objectives of this study were to determine the prevalence of ectoparasites on sheep and goats, assess the effect of major ectoparasites on the quality of skin processed in the tanneries and identify the type and magnitude of defects that cause down grading and rejection in pickled sheep and wet blue goat pelts. The study was carried out through questionnaire survey, clinical examination and analysis of pickled and wet blue skin defects in Kombolcha and Dessei tanneries. Out of 752 sheep and 752 goats examined 50.5% of sheep and 56.4% of goats were found infested with one or more ectoparasites. The major ectoparasites identified on sheep were D. ovis (38.5%), M. ovinus (12.5%), tick infestations (3.4%) and Linognathus spp. (2.4%). The major ectoparasites recorded on goats were Linognathus spp. (28.3%), ticks (22.2%), sarcoptic mange (6.1%) and Ctenocephalides spp (8.1%). In sheep, there was significant difference (p<0.001) in prevalence of M. ovinus and D. ovis, between lowland and highland and midland and highland. There was also significant difference in prevalence of Linognathus spp. between midland and lowland (p<0.01) and tick infestations between lowland and midland (p<0.01), and between lowland and highland (p<0.001) but no significant difference (P>0.05) was detected in prevalence of sarcoptic mange and Ctenocephalides spp. In goats, the risk of sarcoptic mange infestation in lowland (Odds ratio (OR) =4.6, p<0.001) and midland (OR=5.0, p<0.05) was 4.6 times and 5.0 times, respectively higher than the highlands. There was also significant difference in prevalence of Linognathus spp between lowland and highland (p<0.01) and Ctenocephalides spp. infestations between midland and highland (p<0.001) and between midland and lowland (p<0.001) agro climate, the risk being higher in midland. Both in sheep and goats no significant difference (p>0.05) was recorded in prevalence of all ectoparasites except D. ovis infestation by age. D. ovis was found to affect more significantly (p<0.05) the adults (42.2%) than the young (29.9%) sheep. Analysis of body condition showed no significant variation (p>0.05) to ectoparasite infestation in sheep. However, poor body condition goats were 4.3 times at risk from sarcoptic mange (OR=4.3, p<0.001), Linognathus spp. (OR=2.1, p<0.001) and tick (OR=1.6, p<0.05) infestation than good body condition goats. The prevalence of M. ovinus was significantly higher in wooly sheep (41.2%) than wooly sheared (0.8%) and hairy (0%) indicating the importance of wool size for the parasite abundance. The prevalence of ‘ekek’ at pickled stage on each group of 20 pickled sheep pelts infested with D. ovis and M. ovinus and each group of 20 pickled goat pelts x infested with sarcoptic mange and Linognathus spp. were 100% and 95% and 100% and nil respectively. However, the prevalence on apparently free control groups 20 sheep and 20 goat pelts were 15% and nil respectively. There was a strong association (p<0.001) between ‘ekek’ and infestation of sheep with M. ovinus and D. ovis and infestation of goats with sarcoptic mange. Besides this, the severity of infestation of sheep with D. ovis and M. ovinus and goats with sarcoptic mange were found to correlate significantly (p<0.05) with severity of ‘ekek’ defect. Study on 1000 pickled sheep pelts and 1000 wet blue goat pelts indicated ‘ekek’ was the predominant defect both in pickled sheep (70.8%) and wet blue goat pelts (42.3%) followed by scratch, scars and technical defects. There was significant difference (OR=3.3, p<0.0001) in proportion of ‘ekek’ between pickled sheep and wet blue goat pelts. Moreover, a strong association (p<0.001) was observed between ‘ekek’ and scratch, and ‘ekek’ and scars both on pickled sheep and wet blue goat pelts. The economic loses due to drop in quality of exported skin in Kombolcha and Dessie tanneries because of ‘ekek’ was estimated to be 1.6 million for pickled sheep and 0.6 million for wet blue goat pelts per year. Favorable climates, poor level of management, poor awareness of farmers and poor animal health extension services are believed to have contributed for widespread occurrences of ectoparasites. The increasing threat of ectoparasites to small ruminant production and the tanning industry necessitate urgent control intervention. <br/> <br/>Description: A thesis submitted to Faculty of Veterinary Medicine, Addis Ababa University in partial fulfillment of the requirement for the Degree of Master of Science in Tropical Veterinary Epidemiology http://etd.aau.edu.et:80/dspace/handle/123456789/656 Title: EPIDEMIOLOGY OF BOVINE TRYPANOSOMOSIS IN THE ABBAY BASIN AREAS OF NORTHWEST ETHIOPIA <br/> <br/>Authors: DAGNACHEW, SHIMELIS <br/> <br/>Abstract: Tsetse transmitted animal trypanosomosis is a serious constraint to livestock production and agricultural development in Ethiopia. Part of Abbay basin (Blue Nile) in northwest Ethiopia is tsetse infested where animal trypanosomosis is a serious threat to economic development. The objectives of the study were to generate a base line data on epidemiology of tsetse and trypanosomosis, to assess trypanocidal drug resistance and to know the community awareness regarding the disease and control methods in the area. The study was conducted between September 2003 to April 2004 in Dembecha and Jabitehenan weredas of the Abbay basin areas of northwest Ethiopia. The study methodology was based on questionnaire survey, seasonal cross-sectional studies of tsetse and trypanosomosis and longitudinal study for the assessment of trypanocidal drug resistance in the field. The questionnaire survey indicated that trypanosomosis is the most important problem affecting the animals and impeding agricultural activity in the area. Entomological survey revealed that Glossina. m. submorsitans was the only prevalent tsetse fly along with other biting tabanid and muscid flies. The apparent fly densities were significantly higher (p<0.05) in the late rainy season (1.08fly/trap/day, 8.78fly/trap/day and 91fly/trap/day) for G. m. submorsitans, tabanids and muscids respectively than the dry season (0.68fly/trap/day, 0.35fly/trap/day and 7.33fly/trap/day) respectively. In the lowland areas (<1600 m. a. s. l.) the apparent density for G. m. submorsitans was significantly higher (p<0.05) than the midland areas (1600-2000 m.a.s.l.) in the both seasons. The altitudinal distribution limit of G. m. submorsitans was upto 1780 m.a.s.l.The proportion of tsetse flies caught was higher in the savanna vegetation type followed by riverine, forest, bush and cultivated lands with maize, teff and horticulture plantations. In the parasitological survey a total of 1,648 animals, 814 in the late rainy season and 834 in the dry season were examined with buffy coat technique and the prevalence of trypanosomosis was 17.07% and 12.35% respectively with a significant difference (p<0.05) between seasons. Higher infection rates found in the lowland areas below 1600 m.a.s.l. (19.87% and 17.62%) than the midland areas ³1600 m.a.s.l.(13.39% and 6.54%) in the late rainy and dry season respectively with significant difference (p<0.05).The mean PCV values (%) of parasitaemic and aparasitaemic animals during the late rainy season were 20.7±3.5SD VIII and 26.6±4.3SD (p<0.001, 95% CI=25.3-25.9) while during the dry season 21.4±3.6SD and 26.6±4.3SD (p<0.001, 95% CI=25.4-25.9) respectively. The regression analysis of herd average PCV from herd prevalence indicated that herd average PCV decreased with increasing prevalence of trypanosome infections with a regression coefficient of negative values in both the seasons. A total of 100 animals were selected for the assessment of Isometamidium chloride (ISMM) and Diminazine aceturate resistance, 50 from each of the high risk villages identified in the area with similar agroecological zones. The selected animals in each village were grouped into 25 in control and 25 in treatment groups and were identified with ear-tags. At day minus 14 of the study all the 100 cattle were treated with Diminazine aceturate at a dose rate of 7mg/kg bw. After two weeks (day 0) the treatment groups were given ISMM at a dose rate of 1mg/kg bw. Both groups of cattle were examined for trypanosome parasite using buffy coat technique every 14 days interval until 84 days. The three indices used in assessing ISMM resistance (the proportion of infection during 8 weeks follow-up period, the 25% survival time and the ratio of mean hazard rates in the control and treatment groups of cattle) provided consistent results across the two villages for the occurrence of ISMM resistant trypanosome infections in the area. There was no significant difference between the Kaplan-Meier survival curve estimates of the control and treatment groups in both villages (p>0.05).The results of Diminazine aceturate efficacy showed 16 animals became recurrent infections with T. congolense but there was no significant difference between trypanosome incidence rate and trypanosome recurrence rate. Therefore, trypanosomosis is the most important problem for agricultural activity and animal production in the Abbay basin areas of northwest Ethiopia (Dembecha and Jabitehenan weredas of Amhara Region) and the situation is getting worse as the control and prevention of trypanosomosis is facing a challenge due to limitation of vector control activities and the development of drug resistance in the area. <br/> <br/>Description: A thesis submitted to the Faculty of Veterinary Medicine, Addis Ababa University in partial fulfillment of the requirements for Degree of Master of Science in Tropical Veterinary Epidemiology