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Foot-and-mouth disease (FMD) is a contagious viral disease that affects the livelihoods and productivity of livestock farmers in endemic regions. It can infect various domestic and wild animals with cloven hooves and is caused by a virus belonging to the genus Aphthovirus and family Picornaviridae , which has seven different serotypes: A, O, C, SAT1, SAT2, SAT3, and Asia-1. This paper aims to provide a comprehensive overview of the molecular epidemiology, economic impact, diagnosis, and control measures of FMD in Ethiopia in comparison with the global situation. The genetic and antigenic diversity of FMD viruses requires a thorough understanding for developing and applying effective control strategies in endemic areas. FMD has direct and indirect economic consequences on animal production. In Ethiopia, FMD outbreaks have led to millions of USD losses due to the restriction or rejection of livestock products in the international market. Therefore, in endemic areas, disease control depends on vaccinations to prevent animals from developing clinical disease. However, in Ethiopia, due to the presence of diverse antigenic serotypes of FMD viruses, regular and extensive molecular investigation of new field isolates is necessary to perform vaccine-matching studies to evaluate the protective potential of the vaccine strain in the country.

Sheep pox, goat pox, and lumpy skin diseases are economically significant and contagious viral diseases of sheep, goats and cattle, respectively, caused by the genus Capripoxvirus (CaPV) of the family Poxviridae. Currently, CaPV infection of small ruminants (sheep and goats) has been distributed widely and are prevalent in Central Africa, the Middle East, Europe and Asia. This disease poses challenges to food production and distribution, affecting rural livelihoods in most African countries, including Ethiopia. Transmission occurs mainly by direct or indirect contact with infected animals. They cause high morbidity (75-100% in endemic areas) and mortality (10-85%). Additionally, the mortality rate can approach 100% in susceptible animals. Diagnosis largely relies on clinical symptoms, confirmed by laboratory testing using real-time PCR, electron microscopy, virus isolation, serology and histology. Control and eradication of sheep pox virus (SPPV), goat pox virus (GTPV), and lumpy skin disease (LSDV) depend on timely recognition of disease eruption, vector control, and movement restriction. To date, attenuated vaccines originating from KSGPV O-180 strains are effective and widely used in Ethiopia to control CaPV throughout the country. This vaccine strain is clinically safe to control CaPV in small ruminants but not in cattle which may be associated with insufficient vaccination coverage and the production of low-quality vaccines.

Background Avibacterium paragallinarum is a causative agent of infectious coryza (IC), a disease that affects the upper respiratory tracts and paranasal sinuses of chickens, resulting significant economic losses in the poultry industry. The objective of this study was to isolate and identify Av. paragallinarum using bacteriological and molecular methods between February 2022 and April 2024. A total of 74 swab samples were collected from chickens showing ocular and nasal discharges and swelling of the infraorbital sinuses. Method Clinical samples were collected from chickens showing symptoms of IC from six locations of Ethiopia for the isolation and identification of the causative agent. Swab samples from the nasal cavity and cheesy material from the infraorbital sinus were screened using conventional PCR and inoculated onto chocolate agar enriched with 5% sheep blood. Colonies suspected of being Av. paragallinarum were transferred to brain heart agar supplemented with horse serum. Gram staining was used to examine the morphology of bacteria in pure colonies grown on chocolate and brain heart infusion agar. Results The isolation of Av. paragallinarum on chocolate and brain heart infusion agar resulted in the observation of small, translucent, dewdrop-shaped colonies after 24 h of incubation at 37 °C in a 5% CO 2 incubator. A smear prepared from a single colony of revealed Gram-negative, short rod-shaped or coccobacilli Av. paragallinarum bacteria. Biochemical tests conducted on this isolate yielded negative results for catalase, oxidase, urease, indole, methyl red, and Voges-Proskauer tests. However, the bacterium exhibited positive fermentative activity with glucose, sucrose, and maltose. Biochemical assay revealed the presence of Av. Paragallinarum . The bacterial colonies confirmed a 511 bp PCR product. The partial HPG-2 gene nucleotide sequences of eleven isolates were sequenced and deposited in GenBank with the accession number PQ565862-72. A phylogenetic tree was constructed to determine the genetic relatedness of Ethiopian isolates with isolates from other African countries and elsewhere. Conclusion The current investigation confirmed that the outbreaks were caused by Avibacterium paragallinarum and provided scientific evidence on the presence of different strains of Av. paragallinarum in Ethiopia. This is the first study in Ethiopia to detect and identify Av. paragallinarum from diseased chickens using molecular approaches. Further molecular characterization of locally circulating Av. paragallinarum isolates is recommended to be used as a vaccine strain for the prevention and control of infectious coryza.

Background Avian infectious bronchitis (IB) is a highly contagious respiratory disease that affects the poultry industry globally. The disease is caused by avian infectious bronchitis virus (IBV), member of the genus Gammacoronavirus . In Ethiopia, IBV has been reported in both commercial and backyard chickens based on clinical observation. The objectives of this study were to isolate the virus, conduct molecular based identification, and phylogenetic analysis of the circulating IBV isolates. Methods and materials A cross-sectional study was conducted between November 2023 and May 2024 in Mekele and Bishoftu, Ethiopia. A total of 49 clinical samples were collected, comprising 12 tissue samples and 39 pooled swab samples. Of these, 6 samples—specifically, 5 swab samples and 1 tissue sample—tested positive for infectious bronchitis virus (IBV) through virus-specific conventional RT-PCR and real-time PCR. Nested PCR was performed using serotype-specific primers. The purified PCR products, which targeted the spike glycoprotein S1 subunit gene and the 3′ UTR of the IBV, were sequenced, followed by phylogenetic tree analysis. Results The six positive samples propagated into specific pathogen free embryonated eggs and exhibited characteristic IBV lesions and mortality observed over five consecutive passages. IBV isolates from Bishoftu ( n  = 4) and Mekele ( n  = 2) were amplified using one-step RT-PCR to target 466 bp of the S1 subunit gene and 433 bp of the 3ʹUTR. A BLAST search on the S1 partial gene and 3ʹUTR sequences, nested PCR, and phylogenetic analysis revealed that the present IBV isolates are genetically similar to the Massachusetts serotype. The S1 gene sequences of the five IBV isolates were deposited in GenBank with accession numbers PQ389500 to PQ389504. Conclusions This is the first detailed study on IB virus isolation, molecular detection, sequencing, and phylogenetic analysis in Ethiopia. The findings revealed that the outbreaks were caused by the IB virus, which created a serious health risk and economic losses in the chicken industry. To the author’s knowledge, this is the first comprehensive study on the isolation and genetic analysis of IBV in Ethiopia. Further research on the economic impact of IBV in chicken production, farm biosecurity, serotyping of circulating IB virus, and vaccine development based on the local serotypes is recommended.

Infectious bursal disease is a highly contagious disease of young chickens caused by the infectious bursal disease virus. This disease poses an important threat to the commercial poultry industry globally. This study was designed to develop an In-House Indirect Enzyme-Linked Immune Sorbent Assay Kit for the serological detection of antibodies against infectious bursal disease viruses. An infectious bursal disease virus antigen dilution (1:2), sample serum (1:500), and mouse anti-chicken immunoglobulin G (IgG) labeled with horseradish peroxidase (HRP) (1:2,000) were used in this assay. The calculated cutoff value was 0.24. This in-house indirect ELISA method was compared with a commercial ELISA kit for the detection of antibodies against infectious bursal disease virus in chickens. The performance of the newly developed and commercial ELISA kit was evaluated as described by Samad et al. (1994). The sensitivity and specificity of the current ELISA method were 98% (95% CI: 92.96–99.76) and 97% (95% CI: 91.48–99.38), respectively. The average intra-assay % CV of the triplet of 2 samples was 7.6, and interassay comparisons indicated a CV of 5.45%. As indicated by the results, we described a valuable and cost-effective, sensitive and specific in-house indirect ELISA kit for the serological diagnosis of infectious bursal disease in Ethiopia.

Background Bovine Respiratory Disease (BRD) is a multifactorial and economically important illness of cattle. The current study was designed to characterize the major bacterial pathogens associated with BRD and determine the antibiotic susceptibility patterns of isolates. Samples were collected from 400 pneumonic cases of cattle. Results Laboratory assay revealed isolation of 376 (94.0%) bacterial pathogens. The most prevalent bacterial pathogens recovered were Mannheimia haemolytica ( M. haemolytica ) followed by Pasteurella multocida ( P. multocida ), Histophilus somni ( H. somni ), and Bibersteinia trehalosi ( B. trehalosi ) from 191 (50.80%), 81 (21.54%), 56 (14.89%), and 48 (12.77%) samples, respectively. M. haemolytica strains were confirmed using multiplex PCR assay through the amplification of PHSSA (~ 325 bp) and Rpt2 (~ 1022 bp) genes. Capsular typing of P. multocida revealed amplification of serogroup A ( hyaD-hyaC ) gene (~ 1044 bp) and serogroup D ( dcbF ) gene (~ 657 bp). B. trehalosi isolates displayed amplification of the sodA gene (~ 144 bp). Besides, serotyping of M. haemolytica showed the distribution of serotype A:1 (82.20%), A:2 (10.47%), and A:6 (7.33%). Whereas, biotyping of P. multocida revealed a higher prevalence of biotype A:3 (83.95%), then A:1 (8.64%), A:2 (4.94%), and A:12 (2.47%). The majority of the retrieved isolates showed remarkable susceptibility to enrofloxacin, ciprofloxacin, sulfamethoxazole-trimethoprim, florfenicol, and ceftiofur (100%). Besides, varying degree of antimicrobial resistance was observed against streptomycin, gentamicin, penicillin-G, and ampicillin. Conclusions The current findings confirmed that M. haemolytica (A:1) strain is the most common bacterial pathogen identified from BRD cases in the study areas of Ethiopia. Hence, continuous outbreak monitoring and evaluation of antibiotics susceptibility patterns of bacterial pathogens associated with BRD are indispensable to reduce the impact of BRD in the study areas. Further investigation of bacterial pathogens and genotypic analysis of pathogens from a wider area of the country is essential to design a cost-efficient control strategy.

Bovine respiratory disease (BRD) is a potential threat and an economically detrimental disease of calf-rearing in Ethiopia. This study was designed to isolate the major bacterial pathogens associated with respiratory disease of calves and the lung lesions involved. A cross-sectional study with a purposive sampling method was employed in 170 calves during the study period from April 2018 to October 2018. The Bacteriological and molecular assay revealed overall isolation of 156 (91.76%) bacterial pathogens. Gross inspection of pneumonic lungs revealed one or more lesions of hydatidosis (46.67%), emphysema (44.44%), congestion (35.56%), hemorrhage (20.0%) and atelectasis (15.56%). Bacterial pathogen identification showed 86 (50.59%) Mannheimia haemolytica, 31 (18.24%) Pasteurella multocida, 22 (12.94%) Bibersteina trehalosi and 17 (10.0%) Histophilous somni. The distribution of bacterial pathogens in the study areas indicates a higher incidence of M. haemolytica from the nasopharyngeal swab and pneumonic lung tissue at a rate of 68 (61.26%) and 18 (40.0%), respectively. Multiplex PCR of M. haemolytica revealed amplification of the PHSSA gene (~325 bp) and Rpt2 gene (~1022 bp). Conventional PCR assay of P. multocida showed amplification of the species-specific KMT1 gene (~460 bp) and B. trehalosi targeting sodA gene (~144 bp). The findings in the present study indicate that M. haemolytica is the major bacterial pathogen of BRD in calves in the study areas. Thus, it calls for the development of a vaccine from M. haemolytica strains and assessment of pathogen-specific risk factors associated with BRD in calves to design cost-effective control strategies.