Veterinary Microbiology

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Partial Soybean Cake Replacement with Black Soldier Fly Larvae: Effects on Performances, Carcass Traits, Breast Meat Attributes and Economic Efficiency in Broilers
(Addis Abeba University, 2025-10) Abdulkaf Kemal; Ashenafi Mengistu; Yitbarek Woldehewariyat; Araya Gebresilassie
By 2050, there will be about 9.7 billion people on the planet, which needs sustainable, efficient and alternative sources of proteins to feed animals that used for human consumption. This study evaluated the effects of replacing soybean cake (SBC) in broiler chicken diets with black soldier fly larvae meal (BSFLM) in terms of growth performance, carcass characteristics, meat quality and economic efficiency. A total of 156 Cobb-500 broiler day old chicks were assigned to four treatments: control (TR0), 15% (TR1), 30% (TR2), and 45% (TR3) BSFLM replacement levels for SBC. Over a 42- day feeding period, TR1 (15% substitution) produced the highest final body weight (2,077.6 g) and average daily gain (49.5 g/day), significantly outperforming TR3 (1,900.9  g; 45.9 g/day) (p < 0.05). Feed conversion ratios remained optimal at 1.65 in TR1, while higher substitution levels (TR2 and TR3) resulted in performance decline. Carcass yield reflected growth trends, with TR1 showing superior live weight at slaughter (2,315  g) and dressed weight (1,767  g), and the highest dressing percentage (76.3%), compared to TR3 (1,964 ; 1,460 g; 74.5%) (p < 0.05) but it has not shown any significant differences from TR0 and TR2. Meat quality analyses revealed no significant differences in crude protein content (~23.7%), but a marked reduction in crude fat was observed in TR1 (6.3%) compared to TR0 (8.0%) (p = 0.044). Drip loss (3.5–4.0%), cook loss (23.4–28.6%), and textural properties (hardness, springiness, cohesiveness) were consistent across treatments, although higher BSFLM levels resulted in minor alterations in meat colors, lightness (L*) increased (up to 46.0 in TR3), redness (a*) decreased (2.5 in TR1/TR2 vs. 3.1 in TR0), and yellowness (b*) increased at higher inclusion levels. Economic analysis demonstrated that TR1 achieved the lowest feed cost per kg of carcass weight (109.4 birr), compared to 111.7 birr in TR0, while TR2 and TR3 incurred higher costs due to reduced growth performance and carcass yield. According to these results, a moderate replacement of SBC with BSFLM (15%) promotes the sustainable integration of insect-based proteins into broiler chicken production systems while optimizing broiler growth, carcass traits, and financial returns without compromising meat quality. Further studies are recommended to refine inclusion levels, cost-effectiveness, and environmental impacts.
‘Isolation and molecular characterization of camelpox virus from outbreak cases in Borena, Ethiopia
(Addis Abeba University, 2025) Abdurezak Abrar; Fufa Dawo (PhD)
An outbreak investigation was conducted from October-2024 to May-2025 in Borena Zone, Ethiopia focussing on isolation and molecular characterization of camelpox virus from recent outbreak cases. The study included clinical evaluation, isolation and molecular characterization using PCR, RT-PCR, sequencing and phylogenetic analysis. During clinical investigation camels manifesting typical pox-like lesions, fever and swollen lymph nodes were observed. The outbreak had 33.8% morbidity rate, i.e 24 out of 71 camels were clinically sick, and the case fatality rate was 4.2%, 1 camel out of 24 clinically sick camels died. The study showed successful isolation of the virus using Vero cell line, with typical cytopathic effects such as rounding of cells, syncytia, giant cell formation, aggregation and detachment of cell sheet. The conventional PCR result showed skin scab and nasal swab samples yielded the amplification products of the expected 881bp size, which corresponds to the partial fragment of A-type inclusion protein (ATIP) gene. Specifically, 26.3% of skin scab and 26.3% of nasal swab samples tested positive for camelpox virus genome. The RT-PCR employing HRM assay detected CMLV DNA in ten out of 19 samples (52.6%), with a specific melting temperature of 73.00±0.20 °C for CMLV, and no amplific -ation was observed Capripoxvirus and Parapoxvirus. The molecular characterization and the phylogenetic analysis of the five sequenced isolates of the ATIP gene showed 100% nucleotide similarity with comparable reference CMLV strains of CMLV M-96, CMLV CMS, strain 0408151v and CMLV genome (NC_003391). Despite the overall high similarity, a single nucleotide variations were noted when compared to the previously reported Ethiopian isolates (KU705085-KU705110) and Israeli isolates (MK910851 and MZ300856) at position 448 (A:G). Furthermore, two nucleotides mismatches were observed at positions 6 and 448 (A:G) when aligned with Sudanese isolates (KT931624 and KT931625). The phylogenetic analysis showed that the current isolates of this study clustered with CMLV strains of CMLV M-96, CMLV CMS, strain 0408151v and other, but distinct from previously reported Ethiopian isolates, indicating genetically related but evolutionarily unique viral isolate. This successful isolation and molecular characterization of camelpox virus in Ethiopia provides significant insights on early diagnosis, vaccine development and control strategies.
Detection, Isolation, Molecular Characterization, And Phylogenetic Analysis Of Peste Des Petits Ruminants Virus (PPRV) Circulating In Afar Region, North Eastern Ethiopia
(Addis Abeba University, 2025) Kebede Debebe; Dr. Hika Waktole; Dr. Olana Merere
Peste des Petits Ruminants (PPR) is a highly contagious viral disease of small ruminants, causing significant economic losses in endemic regions like Ethiopia. This study aimed to detect, isolate, and molecularly characterize PPR virus (PPRV) in suspected outbreaks across six districts of the Afar region. A total of 64 clinical samples were collected from ocular and nasal swabs, and 2 tissue samples were collected from suspected cases in goats and sheep. Immunocapture ELISA (Ic-ELISA) revealed an overall antigen positivity rate of 31.25% (20/64), all from goats (46.5%, 20/43), while sheep samples were uniformly negative. Virus isolation on Vero cell lines confirmed active viral replication in 7/20 swab and 2 tissue samples, as evidenced by characteristic cytopathic effects (CPE). RT-qPCR further validated PPRV in 80% (16/20) of the ELISA-positive samples, with Ct values ranging from 21.06 to 33.51, indicating variable viral loads. Twelve RNA extracts with low Ct values were submitted for partial nucleocapsid (N) gene sequencing; four yielded high-quality amplicons. Phylogenetic analysis of a 278 bp N gene fragment revealed that three isolates (ETH-7, ETH-8, ETH-12) clustered within Lineage IV, closely related to East African strains (e.g., ETH-PPRV2019, Tanzania-PPRV 2018). One isolate (ETH-11), however, was genetically indistinguishable from the Nigeria 75/1 vaccine strain (Lineage II), suggesting potential vaccine virus shedding or exposure. These findings confirm the endemic circulation of PPRV predominantly Lineage IV in goats in Afar, with occasional detection of vaccine-like strains. The study highlights the need for DIVA compatible diagnostics, thermo stable vaccine formulations, and enhanced molecular characterization to support Ethiopia’s PPR control and eradication efforts.
Physicochemical, Heavy Metal and Microbiological Evaluation of Kality Wastewater Treatment Plant: Treatment Efficiency and Implications for Antimicrobial Resistance Within a One Health Nexus
(Addis Abeba University, 2025) Tesfaye Fatalo; Takele Beyene Tufa; Professor Feleke Zewge
Background: Antimicrobial resistance (AMR) poses a growing threat to global health and economic stability. Wastewater treatment plants (WWTPs) serve as critical hotspots for resistant pathogens due to contaminants of emerging concerns (CECs). Understanding the role of CECs in AMR within WWTPs and One Health domains is essential for effective mitigation. However, gaps remain in wastewater-based AMR epidemiology and its driving factors. This study aimed to evaluate CECs of Kality WWTP along antimicrobial resistance and efficiency of treatment within one health nexus. Methods: A cross-sectional study was conducted at Kality WWTP and its surrounding areas. A total of 173 samples were aseptically collected from wastewater, humans, and cattle near and downstream to the WWTP. Physicochemical parameters, bacteria load, and heavy metals-including lead (Pb), chromium (Cr), copper (Cu), zinc (Zn), manganese (Mn), and cadmium (Cd) – were analyzed for using inductively coupled plasma optical emission spectrometry. To ascertain quantitative parameters, triplicate independent replication sets were utilized. E. coli was isolated, identified, and tested for extended spectrum beta lactamase (ESBL) and carbapenemase producing (CP) E. coli using the double disk synergy test and the modified carbapenem inactivation method, respectively. Data analysis employed logistic regression and one-way ANOVA, with statistical significance set at p < 0.05. Results: Overall, 20.23% (35/173) of E. coli isolates were confirmed using iochemical and supplementary tests. The AMR study showed 97.1% of the isolates demonstrated multidrug resistances (MDR), with 20% of them were ESBL and 5.7% were CP E. coli. Isolates from the trickling filter exhibited co-resistance, both ESBL and CP E. coli, emphasizing rise of resistance mechanisms within the WWTP. The findings indicated a notable 1.47 log reduction in bacterial load, with an overall removal efficiency of 96.5%. Although effective removal rates were recorded for most physicochemical parameters and heavy metals, the concentrations of Cd (6.9%) and Mn (21.6%) remained high in the effluent. Conclusions: These findings underscore the critical role of WWTP as hotspots for MDR pathogens and highlight the need for improved wastewater treatment and sanitation practices to safeguard the environment and public health within a one health nexus.
The Preparation And Efficacy Evaluation Of Combined Vaccine Against Peste Des Petits Ruminants And Sheepox And Goatpox
(Addis Abeba University, 2025) Bezawit Tesfaye; Dr. Samson Leta; . Dr. Haileleul Negussie
Peste des petits ruminants (PPR), sheeppox (SP) and goatpox (GP) are economically important diseases in Ethiopia. These diseases are commonly distributed throughout Ethiopia, hindering productivity and leading to substantial economic losses. Given Ethiopia's ambitious goal to eradicate PPR by 2027, this research aimed to develop and evaluate the efficacy of a combined vaccine by starting with the preparation of monovalent PPR and SP/GP live attenuated vaccines separately using Vero cell culture and with the determined titer 4.8 log10 TCID50 per ml and 4.6 log10 TCID50 per ml respectively, before being combined. Quality control tests, including sterility, moisture content, and safety in guinea pigs, were performed. A total of 10 sheep and goats were immunized, and their immune responses were monitored through daily body temperature readings that was maintained in the normal range between 37.38oC-39.32oC, C- ELISA test result for antibody detection of PPR read its peak on 10.59% for group A and 10.58% for group B, while Group C remained with no antibody, heightened that Group A and B animals confers protection up on natural infection. The SNT test results also revealed that vaccinated animals in each group had strong antibody titers against SP/GP, defined as values greater than 1.5 log10. Each of these animals challenged by PPR and GP viruses isolated on Verodog-SLAM for PPRV and on Vero and ESH-L cells for GPV. Finally, the challenge experiment discloses that vaccinated animals stayed in their normal behavior while control animals unequivocally manifested disease-specific clinical signs, which was confirmed by molecular detection of nucleic acids of both viruses. These findings underscore the vaccine's robust efficacy in preventing overt disease and secured immunogenicity of both vaccines. Further researches on the deployment of this live attenuated combined vaccine on a field basis have of utmost importance to completely asses its efficacy and effectiveness.
Gastrointestinal Parasites of Household Dogs and Cats: Epidemiology and Community Knowledge, Attitude and Practices About the Parasites in Selected Central Parts of Ethiopia
(Addis Abeba University, 2025) Kibruyesfa Bayou; Professor Bersissa Kumsa; Professor Getachew Terefe
Both dogs and cats are affected by diverse groups of gastrointestinal (GI) parasites and may also act as infection sources for other animals and humans. Despite fragmented reports, a wide area survey of the status of GI parasite infection in these animals and the community’s knowledge, attitude and practices of the problem has never been conducted. Therefore, a cross-sectional study on GI parasites of dogs and cats was carried out from February, 2022 to April, 2023 in Dukem, Bishoftu, Addis Ababa and Sheno areas of central Ethiopia with the objectives to estimate the prevalence and assess the risk factors of these parasites. In addition, a community-based questionnaire survey was conducted on 272 dog and cat owners to assess their knowledge, attitude and practices (KAP) toward dog and cat GI parasites. A total of 914 (701 dog and 213 cat) faecal samples were collected and processed using centrifugalfloatation technique and McMaster technique to identify GI parasites and to quantify their burden. A post-mortem examination was conducted on 13 dogs to explore the GI tract for any adult parasites. Based on faecal examination, an overall prevalence of 53.1% (372/701) and 34.7% (74/213) GI parasites was recorded in dogs and cats, respectively. Dogs and cats were found to be infected with nematode (28.2% and 14.6%), cestode (8.4% and 12.7%), and protozoan (5.6% for each: dog and cat). Among these, 42.2% and 32.9% were single infections, while 10.8% and 1.9% were mixed infections in dogs and cats, respectively. In dogs, Ancylostoma spp., doxocara canis, Dipylidium caninum, Giardia spp. and Taenia/Echinococcus spp. were more frequent parasites with the prevalence of 16%, 9.8%, 5%, 3.9% and 3.1%, respectively. Whereas Toxocara cati, Dipylidium caninum, Taenia spp., Giardia spp. and Physaloptera spp. were more frequent parasites in cats with the prevalence of 9.4%, 8.9%, 3.8%, 2.8% and 2.8%, respectively. A statistically significant difference (P<0.05) was observed in the prevalence of GI parasites of dogs of different origin, sex, age, feeding conditions, housing conditions and agro-ecology, and of cats of different sex, age, feeding conditions. Thus, higher prevalence of GI parasites was observed in female dogs and cats (73.8%, OR=0.4 and 49.1%, OR=2.3, respectively), adult dogs (55.3%, OR=0.4), young cats (70%, OR=4.7), in dogs and cats that were commonly fed uncooked food (57.9%, OR=2.7 and 40.5%, OR=3.6, respectively) and in dogs and cats which were housed free outdoor (60.9%, OR=2.4 and 35%, respectively). Similarly, a higher prevalence of GI parasites of dogs and cats was observed in dogs from highland areas (62.1%, OR=1.8) and in cats from midland areas (36.1%, OR=1.3). From the thirteen dogs that were examined using the post-mortem technique, one dog was found to have an intestine packed with Toxocara canis. From the 272 respondents in the KAP study, the majority, 159 (58.5%) of the respondents were found to keep their pets free outdoor, and 133 (48.9%) of them fed their pets raw offal/meat/milk. The questionnaire survey disclosed that dog and cat owners had an overall good knowledge (score=54.6% and 63.9%, respectively), positive attitude (score=82.1% and 84.1%, respectively), and poor practices (score=46% and 37.6%, respectively) towards GI parasites of dogs and cats. In conclusion, the current study indicated a high prevalence of GI parasites in dogs and cats within the considered areas. Dog and cat owners had good knowledge, positive attitude, and poor practices regarding GI parasites of dogs and cats. Therefore, to implement effective control and prevention methods, One Health approach is essential and an in-depth epidemiological and molecular investigation is needed to identify GI parasites of dogs and cats considering wide study areas with different agroecologies to understand their economic and zoonotic impacts. Dog and cat owners should perform good practices and stay current with the most recent knowledge and practices to prevent and control dog and cat GI parasites.
Isolation, Identification, and Antimicrobial Resistance Profile Of E. Coli O157:H7 in Selected Dairy Farms in Wolaita Sodo Town
(Addis Abeba University, 2024-06) Yordanos Kassahun; Biruhtesfa Asrade; Bedaso Mammo
Escherichia coli is one of the microorganisms that are frequently connected to foodborne disease. It is the common cause of bloody diarrhea. A cross-sectional study design with simple random sampling was employed to isolate and identify E. coli O157:H7 in milk, feces, and environmental samples collected from selected dairy farms in Wolaita Sodo Town during the study period. A fecal sample, an environmental swab, and a milk sample were collected from 300 dairy cows. A questionnaire survey was conducted on 100 respondents from the selected farm workers. Bacteriological methods were applied. A polymerase chain reaction was applied for the confirmation of E. coli O157:H7. Antimicrobial susceptibility testing was done using the Kirby-Bauer disc diffusion technique for confirmation of E. coli O157:H7 isolates. Chi-square was used to analyze the data. Based on the analyzed data, 66% (198/300) of dairy cows were positive for E. coli, and 3.3% (10/300) were E. coli O157:H7 isolates. Based on analysis, age, sample type and farm size were significant effect on the occurrence of E. coli. Medium-sized farms (74.19%) were significantly more affected by E. coli than small-scale farms (62.32%). Among the total samples, fecal, environmental swabs, and milk were 4.62% (6/130), 2.5% (1/40), and 2.31% (3/130) positive for E. coli O157:H7, respectively. The occurrence of E. coli was significantly higher in old-aged dairy cows (73.86%) than in adult animals (58.93%) and young dairy cows (51.47%) (p <0.05). The antibiotic susceptibility profiles of the isolates indicated that E. coli were 57.14% more sensitive to ciprofloxacin than other antibiotics. On the other hand, Escherichia coli O157: H7 isolates were 85.71%, 78.57%, and 71.43% resistant to ampicillin, tetracycline, amoxicillin, doxycycline, streptomycin, and ciprofloxacin, respectively. The questionnaire survey analysis showed that hygienic practices during and after milking, as well as the hygienic conditions of the farm and knowledge of the withdrawal period of the drug, were significant potential factors for milk contamination (P<0.05). The drug-resistant E. coli O157:H7 and unhygienic practices were important issues in the current study. It is highly recommended that rational use of antibiotics and proper hygienic practices on the farms should be applied.
Active Outbreak Investigation, Isolation, and Molecular Characterization of Infectious Bronchitis Virus from Poultry Farms in Mekele and Bishoftu, Ethiopia
(Addis Abeba University, 2024) Nigusu Berhanu; Dr. Eyob Hirpa; Dr. Esayas Gelaye
Avian Infectious Bronchitis (AIBV) is a highly contagious respiratory disease that affects the poultry industry globally. In Ethiopia, AIBV has been reported in both commercial and backyard chickens. The currently used vaccine effectiveness is limited due to a lack of cross-strain protection and outbreaks continue to make mitigating the disease in Ethiopia difficult. Therefore, the objectives of this study were to isolate, genomic, and phylogenetic analysis of circulating field AIBV. A cross-sectional study was conducted from November 2023 to May 2024 in Mekele (eighteen samples) and Bishoftu (thirty-one samples) cities. Twelve tissue and thirtyseven pooled swab samples were collected, and six out of forty-nine samples (five swab samples and one tissue sample) tested positive for AIBV using real-time PCR and conventional RT-PCR. The six samples propagated into embryonated eggs and exhibited characteristic AIBV lesions and mortality over five consecutive passages. All the six isolates originating from Bishoftu (n=4) and Mekele (n=2), were amplified targeting 466 bp of the S1 gene and 433 bp of the 3'UTR using one-step RT-PCR. The purified PCR product of the five isolates targeting the 3ˊUTR region was sequenced and analyzed using bioinformatics tools. The sequence alignment of Ethiopia’s five isolates revealed a similar sequence except for one isolate (Bishoftu/03/2024) showed a single nucleotide change (A: C) resulting in amino acid change Glutamine(Q) to Proline (P). The phylogenetic analysis demonstrated the genetic distance was lower among the newly reported isolates (0.001) compared to the broader set of GenBank isolates (0.01), indicating a closer evolutionary relationship between the current local isolates and the Mexican isolates. Therefore, the findings identify genetically related local viral lineages that differ from strains used in imported vaccines. It also indicates that outbreaks were caused by infection with the IB virus which is creating a serious health risk in the poultry industry. Further research on the economic impact of AIB in poultry production, serotyping of circulating AIB viruses, and vaccine development based on the local isolates are recommended.
Evaluation of Workers' Knowledge, attitudes, and Hygiene practices regarding food safety and the microbial load on meat and its contact surfaces in abattoirs and butcher shops in selected towns of the East Shoa Zone, Oromia, Ethiopia
(Addis Abeba University, 2024) Teferi Atlaw; Dr. Biruhtesfa Asrade; Professor Bekele Megersa; Dr. Nebyou Moje
A primary global goal shared by both the public and private sectors is to ensure the food safety of the meat supply chain to protect public health. Processing meat products in an unsanitary way and selling contaminated meat may harm public health. This study is aimed at the evaluation of workers’ knowledge, attitudes, and hygiene practices regarding food safety and the microbial load on meat and its contact surfaces in abattoirs and butcher shops in selected towns of the East Shoa Zone, Oromia, Ethiopia. A cross-sectional survey and sampling were conducted from November 2023 to March 2024. A total of 110 meat handlers from which 52 from slaughterhouses and 58 from butcher shops by using systematic simple random sampling methods were selected. Data was gathered via structured interviews, and 48 swab samples were randomly selected for bacterial detection. These samples aimed to demonstrate the hygienic conditions at both a slaughterhouse and a butcher shop. The statistical analysis of the data was done by STATA software version 14 for statistical analysis, with descriptive statistics and Pearson's chi-square test for evaluating sociodemographic factors' association with food safety knowledge, attitude, and practices of food handlers in slaughterhouses and butcher shops. Of the 52 slaughterhouse worker meat handlers, 75.0% had good score-level knowledge. The score level of knowledge of slaughterhouse workers was also significantly associated with socio-demographic factors of age group (ꭓ2 , 13.982; P value = 0.003), level of education (ꭓ2 , 12.515; P value = 0.002), and experiences (ꭓ2 , 7.704; P value = 0.021). The good attitude score levels of the slaughterhouse respondents were also assessed and found to be 61.5%. The study found the highest aerobic plate count (APC) in butcher shops hand and meat swabs from laughterhouses in Modjo town, with E. coli and S. aureus colonies on cutting boards. The findings emphasize the importance of knowledge and attitude in influencing food safety practices, emphasizing the need for strict protocols and training
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; Dr. 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.
Study of Peste des Petits Ruminants (RRP) Outbreaks: Isolation, Molecular detection, and Serological identification in Small ruminants of Borana pastoral area, Ethiopia
(Addis Abeba University, 2024) Tolera Fufa; Hika Waktole; Dr. Samson Lata
PPR is a severe, highly transmissible transboundary virus disease that primarily affects pastoral areas by seriously compromising the health of both domestic animals and wild herbivores. An outbreak investigation was carried out from October 2023 to January 2024 in Borana and East Borana zones to figure out the PPR status in sheep and goats by isolation, molecular detection and assessing the antibodies level amongst small ruminants by purposively collecting serum(n=102) and swabs (n=48) samples from the flocks exhibiting active clinical symptoms resembling PPR.. From 48 swabs and 102 serum, 26(54.2%) and 70(68.6%) was positive for RT-PCR and b-ELISA respectively. All positive samples identified by RT-PCR underwent further processing for virus isolation by infecting Vero Dog SLAM (VDS) cells. Among the 26 samples cultured, 17 (65.4%) displayed typical cytopathic effects. To measure the agreement of the two diagnostic techniques that performed on the common animals was analyzed by Kappa statistics (κ) which revealed an agreement between the two tests was 40.7% with kappa value -0.16, it indicating that no agreement between the two tests (RT-PCR and b-ELISA). Goats were the only species suffering with clinical symptoms but no pathological evidence of PPR reported in sheep. Serologically, female animals (72.7%) were highly tested positive than male (61.1%) and the highest percentage was found in old animals followed by adults, young was the least. The sex-wise percentage of RT-PCR value for PPRV was higher in male than females. Unauthorized animal movement, flock size, rearing practices and management system, communal grazing, mixing of unknown origin, lack of quarantine practices are the main factors identified for the continuous emerging of PPRV in study area. The persistent clinical manifestations, high anti-PRV antibody levels, successful virus isolation, and precise nucleic acid detection by RT-qPCR all suggest PPRV as the primary cause of the continuous outbreak in the study area. We recommended controlling animal movement, quarantine newly purchased animals, isolating the symptomatic animals from a flock and effective mass vaccination against the disease among small ruminants.
Risk Factors For endometritis and its Impact on fertility of postpartum dairy cows in Wolaita Sodo, Southern Ethiopia
(Addis Abeba University, 2024) Tsigereda Teshome; Professor Fikadu Regassa; Tilaye Demise
Despite its significant impact on the dairy industry, there is limited research or documentation on the extent of endometritis, its specific risk factors and its impact on the reproductive performance in postpartum dairy cow in the study area. The present study was aimed to investigate incidence of postpartum endometritis, risk factors contributing to its development and reproductive consequences of endometritis in dairy farms in Wolaita Sodo, Southern Ethiopia, from October 2023 to May 2024. Longitudinal prospective study determined incidence, risk factors and reproductive outcomes prospectively. A study was carried out on 74 dairy cows with 69 clinically healthy and 5 cows diagnosed with clinical endometritis. Subclinical endometritis was diagnosed using endometrial cytology and subclinical mastitis was diagnosed using California Mastitis Test. The clinical, management and reproductive data were obtained from a weekly follow up visit of each cow and from record book of the farm. Incidence of endometritis was 44.59% (33/74) and subclinical endometritis was 40.57% (28/69). Retained fetal membranes (OR=9.23, P=0.007), assisted calving (OR= 5.06, P=0.026), dystocia (OR=7.79, P=0.014), hypocalcaemia (OR=6.49, P=0.027), mastitis (OR=5.06, P=0.026), male calf births (OR=3.06, P=0.04) and poor body condition scores (OR=2.78, P=0.003) were significantly related with subclinical endometritis. Clinical endometritis in this study were reported to be related to retain fetal membrane, vaginal prolapse, and abortion. Cows with endometritis had shown longer (P < 0.001) calving-to-conception interval, extended (P < 0.001) calving-tofirst service interval and higher (P <0.001) number of services per conception. Thus, it could be concluded that endometritis occur at higher incidence and causes a tremendous impact on the reproductive performance of dairy cows in the study area. Therefore, preventive measures should be done to reduce occurrence of endometritis through enhanced reproductive health and management practices and dairy farmers should take awareness creating trainings
Detection and Antimicrobial Resistance Profile of Salmonella Isolated from Cow Milk and its Products in Bishoftu Town, Central Ethiopia: Its Implication for Public Health
(Addis Abeba University, 2024) Lema Temesgen; Dr. Fufa Abunna; Takele Beyene
Salmonella is a significant foodborne pathogen, with milk and milk products commonly implicated in its transmission. However, limited information is available regarding the direct link between antimicrobial use (AMU), dairy hygiene practices, and antimicrobial resistance (AMR) in Salmonella strains isolated from dairy products in Bishoftu town. Cross-sectional research was done from October 2023 to April 2024 to assess dairy farmers' antimicrobial usage (AMU) and hygiene practices and the occurrence of antimicrobial resistance (AMR) profiles of Salmonella isolated from raw cow milk and its products. Two hundred samples were collected from dairy farms, milk vendors, and restaurants and analyzed using standard microbiological methods. Using the OmniLog system, Salmonella enterica was successfully identified. Then, the antimicrobial susceptibility was evaluated using the Kirby-Bauer disc diffusion technique. A structured questionnaire was also used to assess the milk value chain's knowledge, attitude, and practices (KAP) regarding AMU, AMR, and hygiene practices. Data were analyzed using STATA version 14.2. Overall, 2% (n = 4) of the samples tested positive for S. enterica. of the 4 isolates 3 were identified in dairy farm samples, whereas 1 were isolated from milk vendors. However, no Salmonella was identified in cheese or yogurt samples obtained from the restaurants. Regarding the AMR profile, S. enterica isolates were resistant to amoxicillin (75%), streptomycin (75%), and tetracycline (50%). Resistant to two or more antimicrobials were identified in 75% of the isolates. Among 41 dairy farmers interviewed it was found that most of the respondents had sufficient knowledge (78%), desired attitudes (90%), and good practices (76%) regarding AMU and AMR. However, 36% of dairy farms had poor hygienic practices. In conclusion, the current investigation indicated contamination of cow milk and its products with S. enterica. Therefore, appropriate control measures, including awareness creation among personnel and improving hygienic practices at the milk value chains is recommended to mitigate cross-contamination
Production of monoclonal antibody for lumpy skin disease, sheep pox, and goat pox viruses to develop Enzyme-linked immunosorbent assay
(Addis Abeba University, 2024) Kalkidan Asnake; Fufa Dawo
Lumpy skin disease (LSD), sheeppox (SPP), and goatpox (GTP) are economically significant pox disease of ruminants, caused by lumpy skin disease virus (LSDV), sheeppox virus (SPPV), goatpox virus (GTPV), respectively. The new emergence of disease caused by capripoxviruses and spreading outside of their endemic regions, stressing the urgent need to develop high-throughput serological surveillance tools. This experimental study was conducted to produce Monoclonal antibodies (mAbs) against LSDV, SPPV, and GTPV to development ELISA assay. The study was conducted in African Union Pan African Veterinary Vaccine Centre (AU-PANVAC), from October 2023 to May 2024. The mAbs were produced through immunization of BALB/C mice with purified antigen of LSD, SPP, and GTP, with consecutive booster injection. A hybridoma technology was used to produce the hybridoma clones (LC 5.14 and LC 5.4) which were subsequently mass-produced and tested. These LC 5.14 and LC 5.4 mAbs were precipitated and then quantified through the Bicinchoninic Acid protein assay kit. The isotype for the two mAbs were determined through Pierce™ Rapid Antibody Isotyping Kit, and both mAbs were IgG1. The cross-reaction of the two mAbs with GTPV and SPPV Ag were studied and those two mAbs were cross-reacted with the GTPV Ag but not with the SPPV Ag LC 5.14 and LC 5.4 mAbs were then conjugated with horseradish peroxidase enzyme; hence enzyme linked mAbs were used for ELISA development. The dot blot test was conducted by using of the LSDV, SPPV, and GTPV Ags with the two conjugated mAbs on the nitrocellulose membrane. Finally, the conjugated mAbs (LC 5.14 and LC 5.4) were titrated to determine the concentration which is required for ELISA test, and the titer of 1/10 for LC 5.14 and titer of 1/5 for LC 5.4 were determined to use for ELISA assay. Further repeated tests with the positive serum from immunized cattle, sheep, and goat and the negative serum from the same species of animals are required to produce the validate kit which can be used as a diagnostic purpose for the capripoxviruses.
Isolation and Molecular Characterization of African Horse Sickness Virus AHS Outbreak Cases In Horses in selected areas of Ethiopia
(Addis Abeba University, 2021) Degu Fhetanegest; Hika Waktole; Dr. Esayas Gelaye; Dr. Hana Zewdu
Equines play an important role in the country‟s economy and are a lifeline for millions of people in rural and peri-urban areas of Ethiopia. However, the productivity and welfare of equids are constrained by numerous infectious diseases especially in developing nations like African Horse Sickness disease (AHS). A H S is one of the major infectious diseases that cause severe socioeconomic losses to the equine population and the national economy in general. A cross-sectional study design was undertaken in equines to isolate and detect African horse sickness virus (AHSV) from November 2019 to May 2021 in selected and epidemic areas of Ethiopia. A Total of 30 whole bloods and 2 tissue specimens were collected aseptically from recently dead and clinically sick equids that manifested prominent signs of the disease and transported under cold chain to the National Veterinary Institute, Bishoftu, Ethiopia. A total of 32 samples were subjected to conventional Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) technique targeting Viral protein 7 (VP7) genes to amplify fragments of segment 7 of all serotypes using sero-group specific primers. Only 7 (21.88%) samples were detected with a band size of 102 bp fragments on a 2% agarose gel elctrophoresis. For serotyping, seven universal PCR positive samples were detected again targeting to a gene encoding viral protein 2 (VP2) using serotype-specific primers. Serotype 9 with a band size of 228 bp was identified from tissue samples. Only tissue samples were grown on Vero cells and showed cytopathic effects characterized by aggregation, rounding and detaching of cells on cell line. In conclusion, African Horse Sickness caused by serotype 9 severely affects equines results in death of horses. Strong strategic control of disease through vaccination should be done and further assessment to determine the potential of outbreaks and genotypic characterization of virus from the outbreaks and insects needs further study
Development of Rapid, Specific, and Field-Deployable Diagnostic Assays For Sheepox and Goatpox Viruses Using Crispr-Cas Technology
(Addis Ababa University, 2024) Birtukan Zenebe; Dr. Olana Merera; Dr. Samson Leta
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.
Isolation and Molecular Characterization of Lumpy Skin Disease Virus in Central Ethiopia
(Addis Ababa University, 2021) Mariamawit Zekarias; Dr. Shimels Tesfaye; Dr. Esayas Gelaye
Lumpy skin disease (LSD) is high impact viral disease affecting cattle in various parts of Ethiopia and considerable number of countries worldwide. Taxonomically, LSD virus is classified in the family Poxviridae of the genus Capripoxvirus. The disease is caused by LSD virus and is characterized by nodules on the skin that cause permanent damage to hides and skins. LSD a serious disease that has been impossible to control in Ethiopia which is made clear by the outbreak that occurs year in and year out. Even though a continuous work has been done to understand the disease, tackling it prove to be unrealizable, urging more work to be done as much as possible that can assist as a building block to bring this devastating disease to its annihilation. The current work hopes to do that by isolating and characterizing of the virus that cause this disease from the most recent outbreak incident. A purposive sampling technique was mplemented in the town of Mojo, Ejere, Ejersa and koka. Cell line originated from sheep skin (Embryonic skin of sheep/ESH-L), highly sensitive to Capripoxvirus, was used for the isolation of the infectious virus. The isolates were further processed for classical and real time PCR in order to genotype. The virus that was detected as LSDV, have been further characterized through the RPO30 gene amplification for sequencing and phylogenetic tree construction in relation to different viral isolates from a previous work done though out the country and beyond. Out of 15 samples collected 10 of them were found to be positive for LSD. Further sequencing shows there was a two nucleotide position variation when comparing the present study isolates and the vaccine (KS-1) resulting in a single nonsense amino acid mutation. Constant outbreak investigation and full gene sequencing are the major suggestion of the study.
Evaluation of different adjuvant formulations of inactivated trivalent foot and mouth disease vaccine in cattle
(Addis Ababa University, 2021) Getu Ayele; Dr. Bedaso Mammo; Dr. Belayneh Getachew
Foot-and-mouth disease is globally one of the most economically important viral diseases of cloven-hoofed animals that can primarily controlled by vaccination. Selection of the effective adjuvants formulated simultaneously with the antigen in the vaccine is crucial in ensuring the quality of vaccine and the protective effect of the vaccine against FMD. Aluminum hydroxide gel and saponin (AS) is the most used adjuvant, with its shortcoming in short duration and poor immune response in FMD vaccine. Therefore, the present experimental study was undertaken to evaluate different formulation of adjuvants for inactivated trivalent FMD vaccine containing A, O and SAT 2 serotypes in cattle. Additionally, this study was also performed to demonstrate the effect of booster dose administration on immune response. The vaccines were prepared by mixing 10 % of aluminum hydroxide gel, 0.3 % of saponin with the virus suspension. Oil based was prepared with equal volume of virus suspension (50:50). Twenty-nine cattle were classified into five groups, with four experimental groups consisting of six cattle in each group (n=6) and the fifth group is a control group with five cattle (n=5). The experimental cattle were grouped as: AS, AS boosted, oil based and AS + oil. The sera sample were collected on day 0, 7, 14, 21, 28 and 42, their immune response was measured using Solid Phase Competitive Enzyme Linked Immune Sorbent Assay (SPCE). There was a significant difference in the immune response between the adjuvant groups (P<0.05, ANOVA). The results showed that, the antibody level in cattle vaccinated with AS were significantly lower than AS boosted group for serotype A, O and SAT 2, indicating that the need for booster dose. Whereas the antibody response in the AS + oil group was higher followed by oil alone, AS boosted and AS. It can be concluded that oil based and AS with oil induce better antibody response relative to others and they could replace the aluminum hydroxide gel and saponin for FMD vaccine production to control the disease. On different note, challenge test was not successful in this study indicating the need for further research on the virus infectivity.
Preparation of Freeze-Dried Clostridium Chauvoei Master Seed Bank from Local Isolate for Production of Safe, Effective and Acceptable Quality of Black Leg Vaccine
(Addis Ababa University, 2021) Jaleta Shuka; Hika Waktole
The research was accompanied from December 2020 to May 2021 amid to develop new preservation method spore form of Cl. Chauvoei from local isolate with the objective of mainly improving vaccine immunogenicity. Currently, in National Veterinary Institute (NVI) of Ethiopia viande-foie (V.F) medium is the sole medium used for preservation of the strain as a vaccine master seed bank. However, this method of preservation has its own drawbacks like low antigenicity maintenance, prone to contamination and difficulty in transportation. Intended for this purpose, samples were composed from Adea district from cattle following outbreak information of black leg disease. The samples were taken to NVI using cold chain system for isolation purpose. The blood and tissue samples were isolated as Cl. Chauvoei. The isolates were identified by cultural, morphological and biochemical features. With the aim of additional confirmation by means of pathogenicity study and acuity estimation, the isolates were inoculated on gunia pigs and up on postmortem examination it was confirmed as Cl. Chauvoei. The study of PCR also revealed the existence of Cl. Chauvoei. New method of preservation was then developed through lyophilization or freeze-drying of the isolated strain. Quality control tests like vacuum, moister content, viability, sterility, safety, lethal dose determination for potency test, and identity tests of freeze-dried spore form of Cl. Chauvoei seed bank were performed. Accordingly, the quality control tests of the freeze-dried product revealed; vacuum (1.5%), moister content (97.5%), LD50/ML (1 x 10 7.2), known to be viable, safe and free of contaminant. Regarding potency test 10 gunia pigs were challenged with LD50 dose of virulent challenge strain, and only one of them was dead, thus it is 90 % protective. It is believed that freeze-dried spore stored at -20 0 C retain viability for years, however in this specific study stability test at different storage temperatures for long period of time is essential to conclude this idea. Moreover, study reinforced by DNA sequencing is also indispensable to finalize these inferences.
Comparative Evaluation of Direct Rapid Immuno-Histochemical Test (DRIT) with Direct Fluorescent-Antibody Test (DFAT) for laboratory diagnosis of animal Rabies in Ethiopia
(Addis Ababa University, 2021) Sintayehu Abedla; Hika Waktole; Dr. Gezahegne Mamo; Dr. Abraham Ali
Direct fluorescent antibody test (DFAT) is used as a gold standard method for rabies virus detection. The present study aimed was to compare and evaluate DRIT with Direct Fluorescent Antibody Test (DFAT) to use equivalently as one of rabies virus diagnosing methods in areas where DFAT is not accessible. The method is based on the capture of rabies nucleoprotein (N) antigen in brain smears using a cocktail of biotinylated monoclonal antibodies specific for the N protein and color development by streptavidin peroxidase-amino ethyl carbazole and counterstaining with hematoxylin. The test was performed in parallel with the standard DFAT and mice inoculation test (MIT) using 100 brain specimens from various species of animals. The majority of them were dogs (n=88), ollowed by cats (n =8), cattle (n =3), and donkey (n =1), and also from those samples that were tested by DRIT and DFAT, we randomly selected and tested 12 brain samples by MIT. The results indicated that 63% of the tests were positive by DFAT and 64% were positive by DRIT. A slight difference was observed in such a way that one sample was negative by DFAT but positive by DRIT and MIT. The DRIT provides powerful, economical tool for rabies diagnosis to improve existing rabies surveillance, prevention and control programs in Ethiopia. Although further laboratory and field examinations are essential, our findings were providing and remark the potential value of the DRIT for countries with limited diagnostic resources.

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