Browsing by Author "Olana Merera"

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    Assessment of Stray Dog Counting and Knowledge, Attitudes, And Practice to Wards Rabies in Households in Addis Ababa City, Ethiopia
    (Addis Abeba University, 2024) Tewodros Legesse; Olana Merera
    Rabies is a fatal viral disease of animals and people. Dogs are the primary source of infection and the majority of human rabies cases result from dog bites. Information on both domestic and stray dog populations along Knowledge Attitude Practice (KAP) assessment regarding rabies is vitally important for rabies control. However the situation of rabies is poorly known in Ethiopia, mainly in urban areas. Therefore, this study aimed to assess the demography of stray dogs, the incidence of dog bites, and the knowledge, attitude, and practice (KAP) of society concerning rabies. Questionnaire survey was collected from November, 2023 to May, 2024 using Kobo Collect toolbox in selected sub city Gulele, Yeka and Arada in order to assess KAP of the respondents towards rabies in ouseholds. In the survey, out of 384 households (96.35%) of households owned at least one dog with a total number of 463 dogs (range: 1 to 5 dogs per household); the mean number of dogs per household was 1.25 (SE 0.58). From this 96.35% of dog owning households 51.2% of respondents, owned only one dog with dog: human ratio of 1:9. 70% of dog owning households have vaccinated their dogs against rabies. Nearly all (99%) of the respondents recognized the right response regarding the route of rabies transmission and had heard of rabies. However, 64.3% of research participants had a satisfactory level of suitable rabies prevention practices score, whereas 61.8% of individuals had a moderate level of knowledge and 59.8% had an intermediate level of attitude. In this study, even though the study participants have moderate knowledge, attitude and practice towards rabies, the dog bite management and dog vaccination practice is unsatisfactory on the last three years. Age, occupation, and the source of rabies information were all significantly correlated with knowledge score (P<0.05). The counting method was by using photo capturing method and by observation. In this study, male dogs were higher than female dogs. The total dog estimation of Gulele, Arada and Yeka sub cities had estimate 1050,783, 1282 respectively. There is huge population of stray dog in the studied sites which may serve as a risk for maintaining and transmission of rabies. Along the set of study objectives, the RabiCare android app was developed to create awareness on transmission, prevention and control of rabies in three most spoken languages.
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    Development of Rapid, Specific, and Field-Deployable Diagnostic Assays for Sheepox and Goatpox Viruses Using Crispr-Cas Technology
    (Addis Ababa University, 2024) Birtukan Zenebe; Olana Merera
    Ethiopia is home to a large population of sheep and goats, which are raised for their meat, hides, and skins. Even with this huge financial resource, animal diseases are still the main factor that limits their productivity. sheeppox and goatpox is one of the most prevalent diseases caused by a genus of Capripoxvirus that have a negative impact on sheep and goats throughout the world. One of the main obstacles to the quick diagnosis of the sheeppox and goatpox viruses is the lack of rapid, specific, and point-of-care diagnostic tests. Thus, the aim of this study is to develop a rapid, specific and field deployable diagnostic assay to detect sheeppox and goatpox viruses based on recombinase polymerase amplification (RPA) and trans-cleavage activity of clustered regularly interspaced short palindromic repeats (CRISPR/Cas12a) and to validate its diagnostic specificity. Thus, a lab-based experimental study was employed from November 2023 to April 2024 to develop this assay. RPA-CRISPR/Cas12a-lateral flow assay was developed to detect the entry fusion complex component gene of the sheeppox and goatpox viruses’ genomes. The assay was optimized to be completed within one hour, including nucleic acid extraction for 25 minutes, RPA reaction at 39°C for 15-20 minutes, CRISPR/Cas12a reaction at 37°C for 20 minutes, and visual detection through lateral flow (3 minutes). The primers for RPA, CRISPR RNA (crRNA), and ssDNA reporter for lateral flow detection (LFD) were synthesized and optimized. In this study, quick, specific, and versatile diagnostic method for goatpox and sheeppox virus was successfully developed. This innovative approach harnesses recombinase-polymerase amplification in conjunction with the CRISPR/Cas12a system, offering a cost-effective and efficient solution for identifying these viral infections. This diagnostic technique shows no cross-reactivity with Peste des petits ruminants (PPR). In conclusion, RPA-CRISPR/Cas12a is a potentially useful method for quickly and accurately diagnosing goatpox and sheeppox, especially in environments with limited resources. Therefore, Further research is needed to ensure the assay's reliability and robustness across diverse sample populations and varying environmental conditions.
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    Evaluation of Bacterial Contaminations and Mineral Contents of Eggshell Powder Recycled from Hatchery Wastes as an Alternative Animal Feed Source in Bishoftu, Ethiopia
    (Addis Abeba University, 2025) Mohammed Beriso; Olana Merera
    The rising demand for sustainable and cost-effective animal feed ingredients has sparked interest in using hatchery byproducts, specifically eggshells, as a potential mineral source. The research experiment was conducted from November 2024 to May 2025 in Bishoftu town, Ethiopia, to evaluate the levels of bacterial contaminations and mineral content of hatchery waste recycled eggshell for its potential as an alternative animal feed source. A total 36 eggshell samples of different hatch status and breed origins were collected from four hatchery plants. Microbial analyses were conducted to assess total aerobic bacterial count, coliform count, and Escherichia coli count, as well as the presence rate of Escherichia coli and Salmonella spp. before and after preliminary processing of the eggshell. High contamination level was found with total aerobic bacterial count, total coliform count, and Escherichia coli counts averaging 6.80 ± 1.21, 6.23 ± 0.63, and 3.20 ± 2.54 log₁₀ CFU/g, respectively before the processing. Eggshell from unhatched eggs had significantly greater Escherichia coli count (4.24 ± 2.33 log₁₀ CFU/g) than eggshell of hatched eggs (2.11 ± 2.34 log₁₀ CFU/g). The study identified that Escherichia coli and Salmonella ontaminated eggshell powder with 69% and 13.8% frequency, respectively After processing, total aerobic bacterial count and total coliform count levels dropped to 5.32 and 4.53 log₁₀ CFU/g respectively. The frequency of Escherichia coli in eggshell samples dropped to 36.1%, whereas Salmonella was eliminated. The study found that hatchery waste derived eggshell powder is the best natural source of major and minor minerals, particularly when derived from unhatched eggs. The major minerals like magnesium (2429.8mg/kg ± 266.6), calcium (2078.1 mg/kg ± 0.8), phosphorus (1036.9 mg/kg ± 125.0), and sulfur (1389.2mg/kg ± 139.7) were very prominent than other minerals and trace elements. The study confirms that eggshell powder from hatchery waste can be used as a safe and effective mineral supplement in animal feed, but recommends additional thermal treatment or chemical sanitization steps and improved extraction for safe and effective recycling
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    "Molecular Characterization and Antimicrobial Susceptibility of E. coli O157:H7 Strain Across Dairy Animals, Humans and Farm Environmental Interface in Selected Sub-Cities of Addis Ababa
    (Addis Abeba University, 2025) Tigist Nigatu; Olana Merera
    Escherichia coli O157:H7 is a zoonotic pathogen of major public health concern due to its high virulence, ability to survive in the environment, and increasing resistance to antibiotics. This study adopted a One Health approach to investigate the prevalence, molecular characterization, and antimicrobial susceptibility patterns of E. coli O157:H7 isolated from dairy animals, humans, and farm environment in Addis Ababa, Ethiopia. A cross-sectional study was conducted between November 2024 and April 2025 across 60 dairy farms, with 470 samples samples collected from raw milk, human hand swabs, water, and manure (from both bedding and waste areas). A structured questionnaire was administered to 60 farms to identify potential risk factors. Isolation and identification was done using selective culture media and biochemical tests, while confirmation of the E. coli O157:H7 serotype was done via PCR. Antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion method, and data were analyzed using Descriptive statistics and chi-square.Out of 470 total samples, 32.7% (154/470) tested positive for E. coli, and 0.6% (3/470) were confirmed as E. coli O157:H7. Based on analysis, sample types had a significant effect on the occurrence of E. coli and E. coli O157:H7. The prevalence of E. coli O157:H7 was 1.7% in both manure and hand swabs, and 0.4% in milk samples. Overall E. coli detection was significantly highest in waste-area manure (66.7%) compared to bedding manure (56.7%), hand swabs (53.3%), water (23.3%), and milk (14.8%) (p < 0.05). All E. coli O157:H7 isolates exhibited resistance to ampicillin(100%) and tetracycline (90%), while high susceptibility was observed for norfloxacin (90%), cefotaxime (85%), and cefoxitin (85%). Multidrug resistance was observed in isolates showing resistance to at least three antibiotics. The questionnaire survey revealed that lack of handwashing before milking, absence of disinfectant use, and poor farm hygiene were significantly associated with E. coli O157:H7 presence (p < 0.05).The findings highlight the importance of promoting rational antibiotic use and improving hygienic practices at the farm level to reduce the growth of drug-resistant E. coli O157:H7.
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    One Health Surveillance of Zoonotic Diseases at the Wildlife– Human–Livestock Interface in Borena Zone, Ethiopia: Detection and Characterization of Listeria Monocytogenes
    (Addis Abeba University, 2026) Guyo Gelma; Olana Merera
    This study in investigated the prevalence of Listeria monocytogenes in raw camel milk and assessed community knowledge, perceptions, and practices related to zoonotic disease transmission at the livestock-human-wildlife interface in Borena Zone, southern Ethiopia. A cross-sectional study was undertaken from November 2025 to May 2026 in Yabello, Elwaye, and Gomole districts to investigate the zoonotic diseases occurrence and transmission at the livestock- uman-wildlife interface. Additionally, isolation and characterization of Listeria monocytogenes in raw camel milk and milking equipment was done. A total of 411 camel milk related samples were collected from lactating camels and milk handling equipment, while 207 pastoralists participated in a questionnaire survey. Microbiological isolation and identification of Listeria monocytogenes standard bacteriological procedures were employed, and antimicrobial susceptibility testing was performed using the disk diffusion method. The overall prevalence of Listeria in camel milk and related samples was 3.89% (95% CI: 2.0–5.7%), with slightly higher contamination at the animal level (4.47%) than in milk handling equipment (3.77%). None of the investigated animal-level factors, including age, herd size, and body condition, showed a statistically significant association with Listeria occurrence (p > 0.05). Antimicrobial susceptibility testing revealed high sensitivity of isolates to Gentamicin (100%) and high susceptibility to Chloramphenicol, Ciprofloxacin, Amoxicillin, Doxycycline, Azithromycin, and Meropenem (80%). However, Penicillin and Cefoxitin shows higher resistance against tested isolates 80% and 100%, respectively, with evidence of multidrug resistance among some isolates. The questionnaire survey discovered widespread livestock–wildlife interactions, frequent cross-border livestock movement, and high-risk practices including consumption of raw animal products and lack of quarantine measures. Although community awareness of disease risks was relatively high, risky management and unsafe food consumption behaviors remained common. The findings highlight the presence of Listeria monocytogenes in camel milk and emphasize the importance of improved milk hygiene, antimicrobial stewardship, and integrated One Health approaches to mitigate zoonotic disease risks in pastoral production systems.