23 research outputs found
A Review on Infectious Coryza Disease in Chicken
No full textInfectious Coryza (IC) is a serious respiratory tract disease of chickens caused by Avibacterium paragallinarum, formerly known as Haemophilus paragallinarum. The disease has complicated economic impact in poultry industry due to growth retardation and decreased egg production in layer flocks. Chicken (Gallus gallus) is the natural host for A.paragallinarum which are susceptible at all ages. The most prominent clinical sign of IC is edematous swelling of face and distension of infraorbital sinus due to highly accumulation of cheesy like exudates in conjunctival sac. A. paragallinarum is a slow-growing and fastidious bacterium. Most of its strains require V (NAD) factor for their growth in vitro. Three serotypes of A. paragallinarum (A, B and C) have been identified that are distributed throughout the world. Vaccination is the soundest method of preventive practice against infectious coryza. An indigenous coryza vaccine is the best preventive measure against both homologous and heterologous challenges because of those commercial vaccines are not protective against the local variants of A.paragallinarum. Keywords: A.paragallinarum, chicken, infectious coryza, NAD, serotype, serovar, vaccine DOI: 10.7176/JBAH/12-23-04 Publication date: December 31st 202
African Journal of Microbiology Research
No full textA7 combined expressing iron regulated outer membrane protein as a vaccine against intratracheal challenge exposure in shee
Characteristics of factors associated with antenatal depression in Ethiopia by their odds ratio, confidence interval strength of association, author and year.
No full textCharacteristics of factors associated with antenatal depression in Ethiopia by their odds ratio, confidence interval strength of association, author and year.</p
Molecular characterization of Mannheimia haemolytica isolates associated with pneumonic cases of sheep in selected areas of Central Ethiopia
No full textAbstract Background Mannheimia haemolytica has been recognized as the principal cause of pneumonic pasteurellosis in sheep and goats. It is one of the important diseases of small ruminants in Ethiopia. While annual vaccination using a monovalent vaccine (inactivated Pasteurella multocida biotype A) is common, respiratory diseases are still reported in various parts of Ethiopia. This suggests the need for further investigation into the species and strains responsible for the disease, which is vital information for development of a multivalent vaccine. The objective of the current study was to isolate M. heamolytica associated with pneumonic cases of sheep in selected areas of Central Ethiopia, determine its role and the strains/genotypes of the bacterium circulating in the study area. Results Bacteriological analysis of nasal swab samples collected from a total of 76 pneumonic cases of sheep showed that M. haemolytica was isolated from 26 of them while B.trehalosi from two cases. Further molecular analyses of the isolates using M. haemolytica species-specific and M.haemolytica serotype-1 antigen specific PCR assays revealed, 26 of the isolates were identified as M. haemolytica of which 21 of them were M. haemolytica serotype-1. Both M. haemolytica and B.trehalosi isolates were not detected in a PCR assay targeting capsular biosynthesis gene (capA) of P.multocida despite the non-specific products observed in M. haemolytica isolates. Phylogenetic analysis of M. haemolytica isolates included in this study in comparison with the reference strains with respect to PHSSA and Rpt2 genes revealed that the Ethiopian M. haemolytica isolates constituted three distinct genotypes consistent with site of origin. Conclusion The study indicated that M.haemolytica is commonly associated with cases of pneumonia in sheep in the study areas of central Ethiopia although the remaining other pathogens responsible for majority of the cases are yet to be determined. Molecular characterization revealed the existence of three genotypes of M. haemolytica circulating in the study areas consistent to the site of isolation. The findings suggest further extensive work to determine all pathogens associated with sheep pneumonia and the strain distribution of M. heamolytica to understand its molecular epidemiology at national level and design cost effective prevention and control methods
Isolation, molecular identification, and phylogenetic analysis of infectious bronchitis virus from commercial chicken farms in Mekele and Bishoftu, Ethiopia, 2023–2024
No full textAbstract 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
Molecular Detection and Antibiogram Profiling of Pasteurella multocida Isolated From Breeder Chickens Suspected of Fowl Cholera in Gondar City, Ethiopia
No full textFowl cholera is a highly infectious bacterial disease in poultry production. It is caused by Pasteurella multocida (P. multocida) and leads to significant health risks and financial losses. Therefore, this study is aimed at isolating, molecularly detecting, and analyzing the antibiogram of P. multocida from breeder chickens in Gondar City. A cross-sectional study design with purposive sampling was employed to collect a total of 130 tracheal swab samples from breeder chickens showing clinical signs of fowl cholera between January 2023 and December 2023, based on case availability. Bacterial isolation was performed using bacteriological and biochemical tests. The isolated P. multocida was confirmed through conventional polymerase chain reaction (PCR) using a capsular serotype-specific primer (capA). The antibiogram assessment of P. multocida against 10 antimicrobial agents was conducted using the Kirby–Bauer disk diffusion method. Descriptive statistics were used to analyze the isolation rate of the bacterium. Of the 130 sampled swabs, 10 (7.69%) tested positive for P. multocida in the phenotypic assay, and 3 (30%) of those isolates were positive for the hyaD/hyaC virulence gene. The study found that all three isolates were 100% sensitive to penicillin, ampicillin, norfloxacin, and florfenicol, while showing 100% intermediate sensitivity to streptomycin and 66.7% intermediate sensitivity to gentamycin, amoxicillin, tetracycline, trimethoprim/sulphamethoxazole, and kanamycin. The study confirms that P. multocida, the causative agent of fowl cholera in breeder chickens, is circulating in the area and exhibits varying antimicrobial sensitivity profiles
Developing a PmSLP3-based vaccine formulation that provides robust long-lasting protection against hemorrhagic septicemia–causing serogroup B and E strains of Pasteurella multocida in cattle
No full textBackgroundPasteurella multocida is a bacterial pathogen that causes a variety of infections across diverse animal species, with one of the most devastating associated diseases being hemorrhagic septicemia. Outbreaks of hemorrhagic septicemia in cattle and buffaloes are marked by rapid progression and high mortality. These infections have particularly harmful socio-economic impacts on small holder farmers in Africa and Asia who are heavily reliant on a small number of animals kept as a means of subsistence for milk and draft power purposes. A novel vaccine target, PmSLP-3, has been identified on the surface of hemorrhagic septicemia–associated strains of P. multocida and was previously shown to elicit robust protection in cattle against lethal challenge with a serogroup B strain.MethodsHere, we further investigate the protective efficacy of this surface lipoprotein, including evaluating the immunogenicity and protection upon formulation with a variety of adjuvants in both mice and cattle.ResultsPmSLP-3 formulated with Montanide ISA 61 elicited the highest level of serum and mucosal IgG, elicited long-lasting serum antibodies, and was fully protective against serogroup B challenge. Studies were then performed to identify the minimum number of doses required and the needed protein quantity to maintain protection. Duration studies were performed in cattle, demonstrating sustained serum IgG titres for 3 years after two doses of vaccine and full protection against lethal serogroup B challenge at 7 months after a single vaccine dose. Finally, a serogroup E challenge study was performed, demonstrating that PmSLP-3 vaccine can provide protection against challenge by the two serogroups responsible for hemorrhagic septicemia.ConclusionTogether, these data indicate that PmSLP-3 formulated with Montanide ISA 61 is an immunogenic and protective vaccine against hemorrhagic septicemia-causing P. multocida strains in cattle
Reverse vaccinology-based identification of a novel surface lipoprotein that is an effective vaccine antigen against bovine infections caused by Pasteurella multocida.
No full textPasteurella multocida can infect a multitude of wild and domesticated animals, with infections in cattle resulting in hemorrhagic septicemia (HS) or contributing to bovine respiratory disease (BRD) complex. Current cattle vaccines against P. multocida consist of inactivated bacteria, which only offer limited and serogroup specific protection. Here, we describe a newly identified surface lipoprotein, PmSLP, that is present in nearly all annotated P. multocida strains isolated from cattle. Bovine associated variants span three of the four identified phylogenetic clusters, with PmSLP-1 and PmSLP-2 being restricted to BRD associated isolates and PmSLP-3 being restricted to isolates associated with HS. Recombinantly expressed, soluble PmSLP-1 (BRD-PmSLP) and PmSLP-3 (HS-PmSLP) vaccines were both able to provide full protection in a mouse sepsis model against the matched P. multocida strain, however no cross-protection and minimal serum IgG cross-reactivity was identified. Full protection against both challenge strains was achieved with a bivalent vaccine containing both BRD-PmSLP and HS-PmSLP, with serum IgG from immunized mice being highly reactive to both variants. Year-long stability studies with lyophilized antigen stored under various temperatures show no appreciable difference in biophysical properties or loss of efficacy in the mouse challenge model. PmSLP-1 and PmSLP-3 vaccines were each evaluated for immunogenicity in two independent cattle trials involving animals of different age ranges and breeds. In all four trials, vaccination with PmSLP resulted in an increase in antigen specific serum IgG over baseline. In a blinded cattle challenge study with a recently isolated HS strain, the matched HS-PmSLP vaccine showed strong efficacy (75-87.5% survival compared to 0% in the control group). Together, these data suggest that cattle vaccines composed of PmSLP antigens can be a practical and effective solution for preventing HS and BRD related P. multocida infections
Phylogenetic diversity of PmSLP mature protein sequences from published isolates of <i>P</i>. <i>multocida</i> including the associate capsule type, geographic location, associated disease, and animal host.
No full textPmSLP sequences separate into four distinct clusters, two of which are further separated into two sub-clusters each.</p
Excel sheet containing numerical data used to generate Figs 2–8 and S1.
No full textExcel sheet containing numerical data used to generate Figs 2–8 and S1.</p
