Avian diseases最新文献

{"title":"Characterization of <i>Enterococcus faecalis</i> Isolated from Pullet Layers with Growth Depression and Amyloid Arthropathy.","authors":"Aaliyah Gore, Grayson K Walker, Mitsu Suyemoto, Mike Petrik, Rocio Crespo","doi":"10.1637/aviandiseases-D-24-00064","DOIUrl":"10.1637/aviandiseases-D-24-00064","url":null,"abstract":"<p><p><i>Enterococcus faecalis</i> is a commensal bacterium that colonizes the intestines of mammals and birds. It is characterized as an opportunistic pathogen and has been commonly associated with late-stage embryonic mortality, omphalitis, growth depression, sepsis, and amyloid arthropathy in poultry. In this study, <i>E. faecalis</i> isolates recovered from a flock of 6200 layer pullets located in Canada exhibited impaired growth, poor uniformity, and sporadic lameness that started at 1 wk of age and extended throughout the rearing phase. <i>Enterococcus faecalis</i> was isolated from swollen tarsometatarsal joints of lame pullets that contained yellow-orange material and from the house environment. Two sequence types (STs) known to be pathogenic to chickens, ST82 and ST49, were identified among the joint isolates. Seventeen known <i>E. faecalis</i> virulence genes were detected in these strains, including <i>gelE</i> for gelatinase production and the <i>fsrB</i> quorum-sensing signaling peptide gene required for virulence regulation. Phylogenetic analysis revealed that an ST82 strain isolated from an environmental sample was clonally related to the joint isolate. Furthermore, both sequence types, ST82 and ST49, had antimicrobial-resistance genes against tetracyclines, lincosamide, and streptogramin antimicrobials. ST49 had additional resistance genes to common ionophores used in poultry production. An embryo lethality assay was conducted to determine the pathogenicity of isolates. Inoculation with ST82 resulted in significantly lower survivability of embryos compared to ST49. To date, cases of amyloid arthropathy caused by <i>E. faecalis</i> are reported in European countries, but rarely from North American poultry operations. Further characterization of these <i>E. faecalis</i> strains is needed to elucidate transmission routes, uncover environmental reservoirs, and identify specific virulence genes in the development of amyloid arthropathy in poultry.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"435-442"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144061586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Case Control Survey of Farm Characteristics, Biosecurity Measures, and Risk Events in Flocks With and Without Infectious Coryza.","authors":"Meghann Pierdon, Rowan Prown, Sherrill Davison, Donna Kelly, Laurel Redding","doi":"10.1637/aviandiseases-D-24-00009","DOIUrl":"10.1637/aviandiseases-D-24-00009","url":null,"abstract":"<p><p>The Pennsylvania poultry industry experienced an outbreak of infectious coryza (IC) starting at the end of 2018. Since the disease had not previously been found routinely in Pennsylvania, many questions emerged about the source of the infection and routes of transmission. To better understand the factors related to farm characteristics, risk events, and biosecurity that could influence the risk for the occurrence of IC, a case control study was undertaken to survey those flocks affected and a matched set of controls. Several factors were identified that increased the odds of being a case, including multiple vehicle entrances and having multiple categories of visitors. Other factors, such as bench entry, were found to be protective. This study indicates that fomites are a likely route of transmission for IC and that improvements in biosecurity can mitigate the risk of IC introduction.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"398-403"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144047619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ornithobacterium rhinotracheale in Moroccan Poultry: Antimicrobial Susceptibility Profiles, Characterization of Recent Isolates, and Retrospective Study (2019-23) of Its Occurrence in Different Poultry Production Systems.","authors":"Yassmina Bidoudan, Siham Fellahi, Ouafaa Fassi Fihri, Enrico Bollo, Mounir Khayli, Mohamed Mouahid, Noursaid Tligui","doi":"10.1637/aviandiseases-D-24-00078","DOIUrl":"10.1637/aviandiseases-D-24-00078","url":null,"abstract":"<p><p><i>Ornithobacterium rhinotracheale</i> (ORT) is one of the most important respiratory pathogens of poultry, notably in turkeys, while <i>Riemerella anatipestifer</i> (RA) is the etiologic agent of infectious serositis, the most economically significant disease of domestic ducks and, to a lesser extent, geese and turkeys. Currently, little is known about ORT and RA infections in Moroccan poultry. Thus, the main aim of this study was to describe ORT incidence in Moroccan poultry flocks during the period from 2019 to 2023 and gain better insights into genetic characteristics in combination with assessment of antimicrobial susceptibility of Moroccan ORT isolates during 2023 outbreaks. In addition, we report the first detection of RA in Moroccan turkeys and caged layer chickens. For this purpose, poultry flocks exhibiting elevated mortality rates along with respiratory clinical signs were necropsied. Additionally, the birds presenting fibrinous pleuropneumonia were investigated for ORT infection during the period from January to December 2023. Samples of the lungs, air sacs, and tracheas were collected for bacteriology testing, and the antimicrobial susceptibility testing was conducted on the isolates. Furthermore, trachea and lung samples were subjected to real-time quantitative polymerase chain reaction (qPCR), and positive qPCR samples were then selected for further amplification of the <i>rpoB</i> gene, followed by sequencing. Moreover, a retrospective study of the incidence of ORT from 2019 to 2023 was carried out. The results showed a significant increase of ORT cases (<i>p</i> , 0.001); additionally, age was identified as the sole significant risk factor associated with ORT diagnosis in the multivariable logistic regression analysis (odds ratio = 4.87, 95% confidence interval = 2.54-9.37, <i>p</i> , 0.001). Bacteriology confirmed 10 ORT isolates. Additionally, antimicrobial susceptibility testing revealed complete resistance to several antibiotics, with varying levels of resistance and sensitivity across isolates, including 100% sensitivity to florfenicol in broilers and turkeys. Sequencing of the <i>rpoB</i> gene revealed that 10 ORT isolates had nucleotide similarity ranging from 98% to 100% with other known ORT isolates from chickens and turkeys reported in the U.K., Chile, China, Portugal, and the United States. On the other hand, two ORT isolates were found to be genetically very close to known RA strains, despite testing positive for ORT by real-time qPCR. Amino acid sequence comparisons for these isolates reached 83.10% similarity with <i>Riemerella</i> sp. strain WJ4 isolated in China and 98.79% similarity with strain IPDH 98/90 isolated in Germany. In conclusion, the prevalence of ORT in Moroccan poultry flocks increased over the 5-yr period covered by this retrospective study, contributing significantly to recent respiratory disease outbreaks. Additionally, RA may also contribute to polyserositis in poultry; however, further stu","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"469-480"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144061492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Retrospective Analysis to Identify Epidemiologic Patterns of the Infectious Coryza Outbreak in California 2016-22.","authors":"Veronica Nguyen, Simone Stoute, Shayne Ramsubeik, Ian Miller, Carmen Jerry, Charles Corsiglia, Rodrigo A Gallardo","doi":"10.1637/aviandiseases-D-24-00022","DOIUrl":"10.1637/aviandiseases-D-24-00022","url":null,"abstract":"<p><p>Infectious coryza (IC) is a poultry respiratory disease caused by the bacterium <i>Avibacterium paragallinarum</i>. IC has major economic impacts in both the layer and broiler industries because this disease can cause increased mortality in affected flocks, an increase in condemnations at the processing plants, and decreased egg production in laying hens. In 2017, an increased number of IC-positive cases was seen in the Turlock Branch of the California Animal Health and Food Safety (CAHFS) Laboratory System. The objective of this study was to assess the epidemiologic patterns of IC before, during, and after this outbreak, as the number of positive cases remained elevated from 2017 to the end of 2022. Necropsy cases positive for IC in the CAHFS electronic database were analyzed from January 1, 2016, a year prior to the outbreak, to December 31, 2022. Out of 1935 submissions tested for IC during this period, the 674 cases found to be positive were then categorized by age, poultry type, season, and spatial distribution to investigate risk factors for IC. Raw data trends showed that most of the cases were from backyard poultry flocks (50.5%, 341/674), which appeared to be mainly localized to Los Angeles County and San Joaquin County. Commercial layers made up the second greatest number of cases (31.4%, 212/674) and were mostly localized to Merced County and Stanislaus County. Last, most of the commercial broiler cases (18.0%, 121/674) were in Merced County. Statistical analysis of this raw data was also performed and demonstrated that poultry in commercial egg layer operations located in the Central Valley and southern regions of California were at an increased risk for IC (odds ratio = 1.3, 95% confidence interval: 1.01-1.65, <i>p</i> = 0.039). Ultimately, this study provides updated information on IC trends in California and the risk factors associated with the outbreak.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"391-397"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144048832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Avibacterium paragallinarum</i>, the Causative Agent of Infectious Coryza: A Comprehensive Review.","authors":"Mohamed El-Gazzar, Rodrigo Gallardo, Robert Bragg, Amro Hashish, Hui-Ling Sun, Sherrill Davison, Anneke Feberwee, Yosef Huberman, T Skein, Azil Coertzen, Donna Kelly, Edgardo Soriano-Vargas, Vladimir Morales-Erasto, Ana Da Silva, Meng-Jiao Guo, Brian Ladman, Remco Dijkman, Mostafa Ghanem","doi":"10.1637/aviandiseases-D-24-00105","DOIUrl":"10.1637/aviandiseases-D-24-00105","url":null,"abstract":"<p><p>Infectious coryza (IC) caused by <i>Avibacterium paragallinarum</i> (AP) has risen in importance as a poultry disease over the past several years because of its increased incidence in commercial poultry in both Europe and the United States. Because of this rise in importance, more attention has been focused on diagnosis, isolation, and surveillance of this bacterial pathogen. As a result, new knowledge has been produced and published. This review was compiled with the main purpose of summarizing and presenting the updated knowledge available about AP. However, the new knowledge can only be understood in the context of previously known facts about the disease. Therefore, this review has been organized in two major parts. The first part is a review of the established knowledge about AP, followed by recent updates. In the first part, we summarize the established well-known as well as some of the less-known facts and literature about AP. The second section focuses on specifics of the latest IC outbreaks in commercial poultry in northern latitudes, particularly in Europe and in North America. Additionally, we reviewed the current geographical distribution of the disease in Asia, South America, and Africa. The crises created by emerging or re-emerging disease outbreaks ignite interest in understanding the disease and pathogen in order to combat it properly. This results in new knowledge that improves the understanding of the disease features, leading to improved disease prevention, control, and eradication. Although knowledge about AP has advanced, knowledge gaps about the disease still persist. Therefore, this review concludes with summarizing the current knowledge gaps as well as potential areas for future research.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"362-379"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144016387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review of <i>Enterococcus faecalis</i> Infections of Poultry.","authors":"Donald L Reynolds, Matthew M Hille, Beibei Jia","doi":"10.1637/aviandiseases-D-24-00084","DOIUrl":"10.1637/aviandiseases-D-24-00084","url":null,"abstract":"<p><p><i>Enterococcus faecalis</i> organisms are Gram-positive cocci that are ubiquitous in the environment, occurring in water and soil, and are commensal inhabitants of the intestinal tracts of both vertebrate and invertebrate animals. They are considered opportunists and possess many virulence-encoding traits, including the formation of biofilms and toxins. <i>Enterococcus faecalis</i> produces cytolysin, which is a unique toxin having activity against both eukaryotic and prokaryotic cells. Cytolysin causes hemolysis of red blood cells and has also been termed hemolysin. <i>Enterococcus faecalis</i> organisms are intrinsically resistant to some antibiotics and can transmit antimicrobial resistance to other microorganisms. In poultry, there is ample evidence to indicate that <i>E. faecalis</i> can be egg transmitted, causing decreased hatchability of eggs. <i>Enterococcus faecalis</i> has been found to rapidly spread among hatchlings that are exposed in the hatcher. In older birds, some <i>E. faecalis</i> isolates cause amyloid arthropathy. Various methods have been developed to assess <i>E. faecalis</i> isolates for virulence-encoding traits, including Multilocus sequence typing and embryo lethality assays. However, much variability occurs in interpreting the results of these methods and the correlation between genotypes, phenotypes, and virulence has not been well established. The virulence traits and pathogenesis of <i>E. faecalis</i> in poultry need to be elucidated further.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"412-420"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144039757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic Comparison of <i>Enterococcus</i> Species Isolated from Osteomyelitis Lesions and the Barn Environment of Successive Broiler Chicken Flocks.","authors":"Nicolas Deslauriers, Martine Boulianne","doi":"10.1637/aviandiseases-D-24-00081","DOIUrl":"10.1637/aviandiseases-D-24-00081","url":null,"abstract":"<p><p>Osteomyelitis caused by <i>Enterococcus cecorum</i> is an emerging disease in broiler chickens in Canada. Other <i>Enterococcus</i> species have been reported as causative agents in certain outbreaks. The epidemiology of this disease is unknown, but contaminated barns are affected by recurring episodes. A broiler chicken flock located in Quebec, Canada, exhibited osteomyelitis lesions positive for <i>E. cecorum</i> and <i>Enterococcus faecalis</i>. Surprisingly, the following lot, in the same barn, revealed the presence of <i>E. faecalis</i>- and <i>Enterococcus raffinosus</i>-positive lesions but no <i>E. cecorum.</i> To better understand the epidemiology of these two outbreaks, verify the persistence of pathogenic isolates in the barn, and identify the possible transfer of genetic material between the <i>Enterococcus</i> species isolated from both events, 16 isolates (1 <i>E. cecorum</i>, 13 <i>E. faecalis</i>, and 2 <i>E. raffinosus</i> isolates) were sequenced, and their genomes were compared. Interestingly, more than one <i>Enterococcus</i> species could be isolated from the same lesion, while other lesions also revealed several nonclonal isolates from the same species. This might suggest the opportunistic nature of <i>Enterococcus</i> spp. as there was no predominant isolate in the lesions. The number of virulence genes varied from 1 to 34 across three <i>Enterococcus</i> species with no common virulence gene. The number and nature of antimicrobial resistance genes among those isolates were worrisome because they indicate the presence of multidrug resistance on the farm. Both plasmids and phages were shared by different <i>Enterococcus</i> species, which suggests potential horizontal gene transfer of mobile genetic elements within this enterococci population.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 S1","pages":"421-426"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144060501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cochlosoma anatis in Poultry and its Industry Impact.","authors":"Justin Lowery, Elle Chadwick, Chongxiao Chen, Robert Beckstead, Lin Walker","doi":"10.1637/aviandiseases-D-23-00080","DOIUrl":"10.1637/aviandiseases-D-23-00080","url":null,"abstract":"<p><p><i>Cochlosoma anatis</i> is a flagellated protozoan parasite classified in the Trichomonadidae family and is the causative agent of cochlosomiasis, an enteric disease of turkeys, waterfowl, and other wild birds. Cochlosomiasis symptoms largely consist of watery diarrhea, lethargic birds, depressed weight gain, and widespread flock morbidity causing flock nonuniformity. The known distribution of <i>C. anatis</i> is centered around areas of turkey production farms in the southeast United States, e.g., North Carolina, Missouri and Arkansas, but has been reported in other states and some other countries. Diagnosis is confirmed through examination of enteric mucosal scrapings using light microscopy. Following the withdrawal of approval of effective antiprotozoal medications for use in commercial animal production, cochlosomiasis has become a greater concern for commercial turkey industry professionals. Transmission of <i>C. anatis</i> occurs via the fecal-oral route, but the organism is fragile outside the host, suggesting the implication of a vector in the introduction of disease to susceptible farms. Research regarding <i>C. anatis</i> pathogenicity, transmission, and environmental involvement has been limited, creating a gap in cochlosomiasis knowledge. Future research is needed to further explore ways to prevent and treat cochlosomiasis, with needs centered on disease pathogenesis, transmission patterns, and prophylaxis and treatment methods.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 3","pages":"169-174"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142485238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Epidemiology of Fowl Aviadenoviruses in Broiler Chickens from Vaccinated and Nonvaccinated Breeders.","authors":"Tansu Bıçakcıoğlu, Hamit Kaan Müştak, Seyyide Sarıçam İnce, Şimal Yörük, Gültekin Ünal","doi":"10.1637/aviandiseases-D-24-00017","DOIUrl":"10.1637/aviandiseases-D-24-00017","url":null,"abstract":"<p><p>Fowl aviadenoviruses (FAdVs) are widely distributed among poultry populations, leading to various diseases, immunosuppression, and economic losses. Molecular characterization and phylogenetic analysis of circulating FAdV isolates play a critical role in epidemiologic studies, contributing to the control, monitoring, and prevention of related outbreaks. This study aimed to determine the serotypes of FAdV and reveal the molecular epidemiology in broiler chicken flocks. Samples were taken based on epidemiologically important parameters, such as vaccination status, age, and transmission route. A total of 20 vaccinated flocks (VF, flocks originated from vaccinated breeder lines) and 20 nonvaccinated flocks (NVF, flocks originated from nonvaccinated breeder lines) were randomly selected from flocks reporting suspected FAdV clinical symptoms and deaths. Vaccination was administered by intramuscular injection into the pectoral muscle with a commercial inactivated vaccine at 12 and 18 wk. Liver and cloacal swab samples were collected from each flock over two different production cycles and for three different age groups (1-day-old, 14-day-old, and 28-day-old chickens). The liver and cloacal swap samples were analyzed for FAdV using PCR targeting the hexon loop-1 gene. Molecular detection revealed that 30.0% (24/80) of all flocks were FAdV positive, with 50.0% (20/40) positivity in NVF and 10.0% (4/40) in VF. Sequence analysis of the hexon loop-1 gene revealed that all samples were FAdV-8b serotype (OR670689-OR670712), with 100.0% similarity. One randomly selected FAdV-8b sample was analyzed by whole-genome sequence analysis. This is the first study in Turkey to deposit an FAdV whole-genome sequence (44,139 bp) into the GenBank database (PP236873). Given the significantly lower FAdV positivity rates in VF compared to NVF, the findings indicate that vaccination is an effective tool for protecting against FAdV-related infections.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 3","pages":"209-216"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142485250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flagellin Enhances the Immunogenicity of <i>Pasteurella multocida</i> Lipoprotein E Subunit Vaccine.","authors":"Yao-Chi Chung, Li-Ting Cheng, Chun-Yen Chu, Haroon Afzal, Thu-Dung Doan","doi":"10.1637/aviandiseases-D-24-00032","DOIUrl":"10.1637/aviandiseases-D-24-00032","url":null,"abstract":"<p><p>Fowl cholera, caused by <i>Pasteurella multocida</i> infection, poses challenges for prevention because of its many serotypes. Bacterins are currently widely used for vaccination against fowl cholera, but protection is limited to homologous strains. Live attenuated vaccines of <i>P. multocida</i> provide some heterologous protection, but side effects are considerable. More recently, protein-based antigens are promising subunit vaccines when their low immunogenicity has been addressed with effective adjuvants. Bacterial flagellin has been widely considered a promising adjuvant for vaccines. In this study, we tested the adjutancy of flagellin in a subunit vaccine against <i>P. multocida</i> in a mice and chicken models. For vaccine formulation, the antigen fPlpE (<i>P. multocida</i> liporotein E) was combined with fFliC (<i>Salmonella</i> Typhimurium flagellin). The recombinant proteins of fPlpE and fFliC were successfully expressed using the <i>Escherichia coli</i> system as the expected sizes of 55 kDa and 70 kDa, respectively. The fFliC elicited strong expression levels of proinflammatory cytokine (IL-1β, IL-8, and IL-6) when stimulated in native chicken peripheral blood mononuclear cells. Immunization of mice and chickens with the subunit vaccines containing fFliC accelerated the antibody response. In the challenge tests, fFliC increased vaccine protective efficacy against the heterologous strain <i>P. multocida</i> A1 and highly virulent strain Chu01 in mice and chickens, respectively. These data indicated potential possibilities of using fFliC as an immunostimulant adjuvant in developing a subunit vaccine against fowl cholera.</p>","PeriodicalId":516846,"journal":{"name":"Avian diseases","volume":"68 3","pages":"183-191"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142485244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}