http://ir.bdu.edu.et/handle/123456789/14030 2001-01-13T06:42:15Z http://ir.bdu.edu.et/handle/123456789/16804 Comparative Evaluation of Humoral antibody Responses to various Newcastle disease Vaccines in Chickens at Andassa Livestock Research Center, Northwest Ethiopia Belayneh Lulie on their comparative efficacy across different vaccine types and chicken breeds. Therefore, this experimental study was conducted from October 2024 to January 2025 at the Andassa Livestock Research Center poultry farm to evaluate the humoral antibody response of NCD vaccines in Tillili and Koekoek chicken breeds.The study comapared three vaccines (I2 thermostable, LaSota, and HB1) along with a positive control. The specific objectives of the study were to evaluate the antibody responses to the three vaccines and the positive control in both breeds, to identify risk factors associated with variations in antibody responses,to determine the magnitude of mortality and survival of chickens and to assess differences in maternally-derived antibody levels between the Tillili and Koekoek breeds. A Completely Randomized Design with a 2x4 factorial arrangement was employed. A total of 480 day-old chicks (DOCs), comprising 240 indigenous Tillili and 240 exotic Koekoek, were randomly assigned to 24 pens (20 birds/pen). A total of 1,092 blood samples were collected one day before and 14 days after each vaccination, with 964 samples successfully processed. Antibody titers against NCD were quantified using an indirect ELISA. Independent and paired t-tests were used to compare mean antibody titers between the treatment and control groups before and after vaccination, respectively. Additionally, multiple linear regression, and Cox regression were used to evaluate and quantify the effect of covariates on mean antibody titer and chicken mortality rates, respectively. The overall chick mortality percentage across all treatment groups was 4.6%. During the study period, 76% of chickens developed protective antibody levels against NCD across the four treatments. Koekoek chickens exhibited significantly higher maternal antibody levels (mean titer 4,460.3) compared to Tillili chickens (mean titer 202.3) during the first week of life. A relatively higher antibody response (5475.4 ± 2821.1) was also detected in Koekoek compared to Tillili (4200.9 ± 2092.8. Overall, antibody responses were higher at 42days postvaccination with thermosatble vaccines (6031.2±420.2), Comparison of vaccine types revealed significant differences in antibody levels before and after vaccination among bleeding dates (P = 0.0274) and between treatment groups (P = 0.0002). However, an independent t-test comparing the positive control and treatment groups revealed no significant difference (P=0.1954) in antibody responses. The Multiple linear regression revealed that sex (P = 0.0172), bleeding time (P = 0.001), and age (P = 0.000) were statistically significant with mean antibody titer. In conclusion, all three vaccines elicited protective immunity, with the positive control achieving relatively the highest efficacy, followed by the thermostable vaccine. This suggests that the thermostable vaccine demonstrates comparable practical advantages for field use, especially in areas where cold chains are limited. 2025-07-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16803 Epidemiological investigation of Goat Mastitis,associated risk Factors and antimicrobial resistance Patterns of its Causative Bacteria In Waghimra Zone, Northeastern Ethiopia Abebe Tibebu Mastitis is a multifactorial disease of mammals that has substantial implications on production, welfare, and public health, but it is far less studied in goats than in cows. A cross-sectional study with simple random sampling at the lowest unit was conducted in selected districts of Northeastern Amhara, Ethiopia, from September 2024 to May 2025. The objectives of the study were to assess knowledge, attitudes, and practices (KAP) levels of herders on mastitis in goats, estimate its prevalence, assess associated risk factors, identify bacteria, and evaluate their antimicrobial susceptibility. A semi-structured questionnaire survey was utilized to evaluate KAP levels, while a physical examination and the California mastitis test were employed to examine mastitis in goats. Laboratory tests for bacterial identification and antimicrobial resistance were conducted following standard protocols. Stata17 and WHONET software were used for statistical analyses. Out of the 275 survey participants, 30.68% reported mastitis incidents in goats during the study period. The average scores for knowledge, attitude, and practice related to mastitis were 47.78%, 69.39%, and 46.18%, respectively. The majority of respondents did not attend school, and their knowledge of causes of goat‟s mastitis, zoonotic diseases, and subclinical mastitis was significantly associated with district and age demographics. Out of the 397 lactating goats examined, mastitis prevalence was 24.74% at goat level (CM: 2.52%, SCM: 22.22%) and 16.60% in udder halves (CM: 1.39%, SCM: 15.21%). Multivariable logistic regression analysis revealed that lactation stage (OR=1.92; 95% CI: 1.89-6.30), districts (OR=3.47; 95% CI: 1.01-3.65), parity (OR=2.73; 95% CI: 1.11-6.67), and mastitis history (OR = 13.6; 95% CI: 4.64-40.15) (p<0.05) were statistically associated with the occurrence of goat mastitis. Upon bacterial isolation and identification, the most common bacterial isolate was Staphylococcus (39.83%), followed by E. coli (10.17%), Enterococcus, Micrococcus, and Klebsiella (all < 5%). Staphylococcus was resistant to ampicillin and tetracycline, with a multidrug-resistant (MDR) prevalence of 21.16%, whereas E. coli was resistant to ampicillin, with an MDR prevalence of 8.3%. The overall MDR prevalence was found to be 17.31%. In conclusion, herders lacked good knowledge and practices about mastitis and zoonotic risks, which most likely contributed to the high prevalence of mastitis and antimicrobials -resistant bacteria. As a result, tailored training on the causes of mastitis and zoonotic risks, control and prevention for goat farmers, and further research on bacterial species and resistance factor identification are recommended. Furthermore, kanamycin and gentamycin were found to be effective against staphylococci and thus recommended for use, while tetracycline and streptomycin were found to be effective against E. coli and thus recommended. 2025-07-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16802 Spatiotemporal analysis and associated risk factors of Dogmediated Human Rabies in the Amhara Region, Northwest Ethiopia Yeshambel Muluye Although dog-mediated rabies poses a significant public health and economic burden in Ethiopia, the spatiotemporal epidemiology of the disease remains poorly defined and understood. The objective of this study was to explore the spatiotemporal dynamics and identify possible risk factors for dog-mediated human rabies in the Amhara region of Northwest Ethiopia. A retrospective time-series ecological study was employed on dogmediated human rabies in Northwest Ethiopia. The study utilized time-series rabies surveillance data collected in the Amhara region between January 2016 and December 2023. Descriptive epidemiological analysis, spatial statistics (including choropleth mapping, GetisOrd Gi* hot spot detection, Moran’s I spatial autocorrelation, and Kulldorff’s space-time scan statistics), and negative binomial regression models were employed to examine incidence trends, identify cluster formations, and assess associated environmental and demographic risk factors. Among 14159 reported dog-mediated human rabies cases, the annual incidence rate ranged from 2.75 to 14.12 per 100,000 population, with a mean of 7.34 and a median of 6.78 over the study period. The overall trend indicated an increasing trend in rabies cases from 2016 up to around mid-2022, peaking between late 2022 and early 2023. The temporal trend showed relative stability in incidence rates between 2016 and 2017 (IR=4.99 to 5.17), with a significant decline in 2018 and a sharp rise from 2020 to 2022 (IR=9.27 to 14.12), and a drop in 2023 (IR=8.39). Seasonal decomposition indicated peaks of cases in summer and autumn. The spatial analysis revealed that the Bahir Dar Special Zone was the most significant hotspot from 2020–2023 with an incidence risk (IR) of 168.65 and a space-time cluster relative risk (RR) of 65.12. Persistent hot spots were detected in the North Gondar zone in 2016, 2020, and 2022 (p < 0.05) and East Gojam zone in 2021, 2022 (p < 0.05) and in 2023 (p < 0.01). Significant spatial autocorrelation of the incidence of cases was also identified in the region in the year 2020 (Moran’s I=0.36, P < 0.05) and 2023 (Moran’s I=0.52, P < 0.01). Negative binomial regression revealed a positive association of rabies incidence in the zones with higher population density, incidence rate ratio (IRR=1.004), temperature (IRR=1.217), and precipitation (IRR=1.001), while dog vaccination coverage was negatively associated (IRR=0.905, p<0.001). Significant risk variation was observed across zones, with the Bahir Dar Special Zone (IRR=2.13) showing the highest risk. In conclusion, this study revealed that dog-mediated human rabies remains a public health threat in Northwest Ethiopia, characterized by pronounced spatiotemporal, seasonal, and geographic heterogeneity. Therefore, multidisciplinary and targeted interventions using a One Health approach are essential to reduce and ultimately eliminate dog-mediated rabies in the study area. 2025-07-01T00:00:00Z http://ir.bdu.edu.et/handle/123456789/16780 Prevalence, Associated Risk Factors and Anti-Microbial Susceptibility profile of Staphylococcus aureus in Different dairy Production System, Chagni District, Northwest Ethiopia Ahmed Wodaje A cross-sectional study was carried out from October 2022 to June 2023 at Chagni cattle breeding and improvement Ranch, and small holder-dairy farms to estimate the prevalence and the anti-microbial susceptibility profile of Staphylococcus aureus isolated from infected cows. The study was conducted on 318 lactating cows selected by simple random sampling techniques in the study areas. The data was analysed using statistical tools. Based on the CMT result and clinical examination, of the 318 cows examined, 44.1%(140/318) were positive for mastitis. Out of this, 35.9% and 8.2% had sub-clinical and clinical mastitis at cow level, respectively. From 1272 quarters examined 55(4.3%) were blind, and 20% (243/1272) were positive for mastitis. In the multivariable logistic regression model, factors significantly associated (p < 0.05) with the occurrence of mastitis were age, breed, management system, lactation stage, parity, floor type, and tick on the teat at Chagni cattle breeding and improvement Ranch. In addition, age, lactation stage, and tick on teat were independently associated with mastitis occurrenc in small-holder dairy farms (p<0.05). Staphylococcus aureus isolates were detected in 45.7% (64/140) of the samples, of which 9 (34.6%) and 55 (48.2%) isolates from clinical and subclinical mastitis cases, respectively. All (n = 64) isolates of S. aureus were tested for their susceptibility to eight selected antimicrobials. The isolates were highly susceptible to sulfamethoxazole (87.5%) and Gentamycin (79.7 %) followed by Tetracycline (75%), Erythromycin (72%), and Azithromycin (71.8%). However, they were highly resistant to Cefoxitin (65.6%), followed by Tetracycline and ciprofloxacin (25%). The high prevalence of masitis in the study area, more importantly the sub-clinical one. And isolates of S. aureus were resistant to a number of drugs. Hence, implementing hygienic conditions, creating awareness on the control and prevention of subclinical mastitis in dairy farms, and rational use of drugs are recommended. 2023-06-01T00:00:00Z