Avian Mycoplasma Research Articles

Genome sequence of Mycoplasma gallisepticum strain A5969.

Mycoplasma gallisepticum strain A5969 is one of the earliest identified and studied avian mycoplasma strains, valued for its ease of growth and production of uniformly sized colonies. Here, we report the genomic sequence of the A5969 strain.

First molecular investigation to detect avian Mycoplasma species in clinical samples from laying-hen farms in Tunisia

BackgroundAvian mycoplasmas are known pathogens, which cause severe economic losses in poultry flocks. PCR is a rapid, sensitive, and less expensive diagnostic tool than culture for the identification of mycoplasmas in poultry farms. The objective of this study was to determine by PCR the presence of Mycoplasma spp., Mycoplasma gallisepticum (MG), Mycoplasma synoviae (MS), and Mycoplasma pullorum (MP) in laying hens located in the Sfax region, in the South of Tunisia.ResultsA total of 781 tracheal swabs were collected from 13 laying-hen farms without clinical signs at the date of sampling. MP was detected by a newly described specific PCR assay. The prevalence calculated from PCR results at the flock level was 100% for Mycoplasma spp., 0% for MG, 84.6% for MS and 61.5% for MP. The overall prevalence at the animal level was 38.7% for Mycoplasma spp., 0% for MG, 25% for MS and 6.4% for MP. The overall prevalence of 100% of avian mycoplasmas in laying-hen farms (38.7% prevalence at the animal level) shows an alarming situation.ConclusionsThese results underline the importance of monitoring the emergence and spread of Mycoplasma strains in farms in order to decrease economic losses due to mycoplasmoses.

Sero-prevalence and Associated Factors of Major Respiratory Diseases (Avian Influenza, Newcastle Disease, Infectious Bronchitis, and Mycoplasma Gallisepticum) in Layers Farms in Dakar and Thiès, Senegal

Purpose: This study aimed to identify associated factors and the prevalence of major avian respiratory diseases, including Mycoplasma gallisepticum, Influenza H9, Infectious Bronchitis (IB), and Newcastle disease in poultry farms in the Dakar and Thiès regions of Senegal. Methodology:A cross-sectional observational study was conducted on purposively selected farms with over 1000 birds exhibiting respiratory symptoms. Blood samples (400) were collected for serological analysis, and post-mortem examinations were performed to assess disease prevalence. Additionally, data on biosecurity, vaccination, medication practices, general management, and farm infrastructure were obtained through direct observation. Student t-tests were used to analyze the association between different farming practices and respiratory infections. Findings: The results indicated that proximity to neighboring farms, non-compliant buildings, mixed-age groups, and lack of farmer training were associated with respiratory diseases in the surveyed farms. Serological analysis revealed a high prevalence of Mycoplasma gallisepticum and Influenza H9, each detected in 50% of the farms. Infectious Bronchitis was found in 40% of the farms, while Newcastle disease was detected in 35%. Co-infections were common, with the combination of H9 influenza and Mycoplasma gallisepticum being the most prevalent (33%). Unique Contribution to Theory, Practice and Policy: The study emphasizes the need for targeted interventions, including improved biosecurity measures, vaccination strategies, and farmer training, to control respiratory infections. Strengthening biosecurity protocols and enhancing farmer education will help reduce disease.

Pathogenic avian mycoplasmas show phenotypic differences in their biofilm forming ability compared to non-pathogenic species in vitro

Mycoplasmas are known as the minimalist microorganisms in the microbes’ world. Their minimalist nature makes them highly sensitive to the environmental conditions and limits their ability to survive for extended periods outside their animal host. Nevertheless, there are documented instances of mycoplasma transmission over significant distances and this phenomenon may be linked to relatively unexplored abilities of mycoplasmas, such as their capacity to synthesize biofilm—the predominant mode of bacterial growth in nature. The authors decided to establish a method aimed at inducing the clustering of mycoplasma planktonic cells within a biofilm in vitro and subsequently assess the capacity of certain avian mycoplasmas to synthesize a biofilm. A total of 299 avian mycoplasma isolates were included in the study, encompassing both pathogenic (Mycoplasma gallisepticum, M. synoviae, M. meleagridis, M. iowae) and non-pathogenic species (M. gallinaceum, M. gallinarum, M. iners and M. pullorum). The authors successfully demonstrated the feasibility of inducing avian mycoplasmas to synthetize in vitro a biofilm, which can be visually quantified. The only species that did not produce any biofilm was M. iowae. In general, the pathogenic mycoplasmas produced greater quantities of biofilm compared to the non-pathogenic ones. Furthermore, it was observed that the ability to produce biofilm appeared to vary, both qualitatively and quantitatively, not only among different species but also among isolates of a single species. Future studies will be necessary to determine whether biofilm production plays a pivotal epidemiological role for the pathogenic avian mycoplasmas.

Pathogenic bacteria associated with outbreaks of respiratory disease in Iranian broiler farms.

Multi-causal respiratory infections are more commonly observed than uncomplicated cases with single agents in the commercial poultry industry. Recently, increased mortality rates associated with respiratory clinical signs have been reported in Iranian broiler farms. The present study aimed to determine the spectra of avian mycoplasmas (Mycoplasma gallisepticum, MG and Mycoplasma synoviae, MS) and Ornithobacterium rhinotracheale (ORT) in the broiler farms with the multi-causal respiratory disease (MCRD) from 2017 to 2020. Trachea and lung tissue samples were collected from 70 broiler flocks presenting increased mortality and acute respiratory disease. MG, MS, and ORT were detected by performing polymerase chain reaction with primers complementary to the 16S rRNA, vlhA, and 16S rRNA genes, respectively. Genetic materials of MG, MS, and ORT were detected in five, three, and five of the 70 flocks. Based on the phylogenetic analysis of the complete mgc2 coding sequences, all MG strains formed a distinct cluster along with other Iranian MG isolates. According to the phylogenetic analysis of the partial vlhA gene of MS strains, two isolates were located along with Australian and European strains. In addition, one of them displayed an out-group association with MS isolates from Jordan. Phylogenetic analysis of Iranian ORT strains using a partial sequence of the 16S rRNA gene showed a distinct group among the other ORT strains. The results indicate that MG, MS, and ORT are not predominantly responsible for the MCRD. However, continuous monitoring of poultry flocks could be significant for obtaining valuable information related to different MG, MS, and ORT strains and designing effective control strategies.

Infection, Transmission, Pathogenesis and Vaccine Development against Mycoplasma gallisepticum.

Mycoplasma sp. comprises cell wall-less bacteria with reduced genome size and can infect mammals, reptiles, birds, and plants. Avian mycoplasmosis, particularly in chickens, is primarily caused by Mycoplasma gallisepticum (MG) and Mycoplasma synoviae. It causes infection and pathology mainly in the respiratory, reproductive, and musculoskeletal systems. MG is the most widely distributed pathogenic avian mycoplasma with a wide range of host susceptibility and virulence. MG is transmitted both by horizontal and vertical routes. MG infection induces innate, cellular, mucosal, and adaptive immune responses in the host. Macrophages aid in phagocytosis and clearance, and B and T cells play critical roles in the clearance and prevention of MG. The virulent factors of MG are adhesion proteins, lipoproteins, heat shock proteins, and antigenic variation proteins, all of which play pivotal roles in host cell entry and pathogenesis. Prevention of MG relies on farm and flock biosecurity, management strategies, early diagnosis, use of antimicrobials, and vaccination. This review summarizes the vital pathogenic mechanisms underlying MG infection and recapitulates the virulence factors of MG-host cell adhesion, antigenic variation, nutrient transport, and immune evasion. The review also highlights the limitations of current vaccines and the development of innovative future vaccines against MG.

The detection of Mycoplasma sturni and Mycoplasma moatsii from the choana of a barn swallow (Hirundo rustica): a case report

BackgroundMycoplasmas are found in many different species. Until now 26 avian mycoplasma species have been described, but in the most free ranging bird species the prevalence and significance of Mycoplasma spp. is still unclear.Case presentationIn May 2021 a barn swallow (Hirundo rustica) was brought to a veterinary clinic after it hit a window. As part of the routine exam a choanal swab was taken for mycoplasma culture and for the detection of mycoplasmas using a Mycoplasma-genus-specific Polymerase chain reaction.Six single colony subcultures were obtained by the cultivation. Obtained subcultures were investigated by sequencing the 16S rRNA and the 16S-23S rRNA intergenic transcribed spacer region sequence. The 16S rRNA gene sequence from one subculture had a homology of 99.03% and the 16S-23S rRNA intergenic transcribed spacer region sequence of 100% with the sequence of Mycoplasma sturni.The 16S rRNA gene sequence from the other five subcultures shared a homology of 99.89% and the 16S-23S rRNA intergenic transcribed spacer region sequence of 99.81% with the sequence of Mycoplasma moatsii.ConclusionsAccording to the available literature this is the first report about the detection of M. moatsii, in the respiratory tract of a barn swallow. M. moatsii was previously only found in grivit monkeys (Cercopithecus aethiops), Norway rats (Rattus norvegicus) and a mute swan (Cygnus olor). The role of mycoplasmas in barn swallows is still unknown, especially as in the present case both mycoplasma species do not seem to cause clinical symptoms.

Molecular identification and cross-immunogenic study on two field isolates of Mycoplasma synoviae isolated from broilers in five districts of Khyber Pakhtunkhwa.

Mycoplasma synoviae (MS) is an important poultry pathogen causing heavy economic losses Worldwide. Subclinical persistence of this pathogen is the major issue to control its prevalence. This study aimed to determine the molecular and cross-immunogenicity of MS among broilers in five Districts of Khyber Pakhtunkhwa (KP). This study was conducted by collecting 434 specimen samples from 40 broiler farms and desi poultry in five districts of KP. Specimen samples from the broiler birds (n = 150), broiler farm environment (n = 264), and desi poultry birds (n = 20) were aseptically collected and serially passaged in Modified Frey's broth. The homologous and heterologous antibody reactions were studied in rabbits. Before inoculation into rabbits, the MS isolates were inactivated by formalin and adjuvanted with Montanide. The overall turbidity prevalence in Frey's broth was observed as 109/434 (25.11%) samples, and these turbidity-positive samples were shifted on Frey's agar. After the appearance of classic fried egg colonies, the Biochemical confirmation was supported by the production of catalase and phosphatase, reduction of tetrazolium, film and spot assay, and fermentation of glucose for species differentiation in avian mycoplasma. The MS prevalence percentage was recorded as 2% (9/434) through biochemical tests. The PCR results showed 0.5% MS prevalence with two field isolates (named MS-1 and MS-2). Both MS-1 and MS-2 field isolates showed similar values (42.2) of homologous geometric mean titer (GMT). While the heterologous GMT for MS-1 serum against MS-2 isolate was lower (27.9) as compared to MS-2 serum against MS1 isolate (38.9). No titer was detected in the control group (Group-III). In conclusion, the results indicated the existence of MS in broiler birds and high homologous titers recorded between field isolates, which is a perpetual menace to poultry.

Comparable outcomes from long and short read random sequencing of total RNA for detection of pathogens in chicken respiratory samples.

Co-infections of avian species with different RNA viruses and pathogenic bacteria are often misdiagnosed or incompletely characterized using targeted diagnostic methods, which could affect the accurate management of clinical disease. A non-targeted sequencing approach with rapid and precise characterization of pathogens should help respiratory disease management by providing a comprehensive view of the causes of disease. Long-read portable sequencers have significant potential advantages over established short-read sequencers due to portability, speed, and lower cost. The applicability of short reads random sequencing for direct detection of pathogens in clinical poultry samples has been previously demonstrated. Here we demonstrate the feasibility of long read random sequencing approaches to identify disease agents in clinical samples. Experimental oropharyngeal swab samples (n = 12) from chickens infected with infectious bronchitis virus (IBV), avian influenza virus (AIV) and Mycoplasma synoviae (MS) and field-collected clinical oropharyngeal swab samples (n = 11) from Kenyan live bird markets previously testing positive for Newcastle disease virus (NDV) were randomly sequenced on the MinION platform and results validated by comparing to real time PCR and short read random sequencing in the Illumina MiSeq platform. In the swabs from experimental infections, each of three agents in every RT-qPCR-positive sample (Ct range 19-34) was detectable within 1 h on the MinION platform, except for AIV one agent in one sample (Ct = 36.21). Nine of 12 IBV-positive samples were assigned genotypes within 1 h, as were five of 11 AIV-positive samples. MinION relative abundances of the test agent (AIV, IBV and MS) were highly correlated with RT-qPCR Ct values (R range-0.82 to-0.98). In field-collected clinical swab samples, NDV (Ct range 12-37) was detected in all eleven samples within 1 h of MinION sequencing, with 10 of 11 samples accurately genotyped within 1 h. All NDV-positive field samples were found to be co-infected with one or more additional respiratory agents. These results demonstrate that MinION sequencing can provide rapid, and sensitive non-targeted detection and genetic characterization of co-existing respiratory pathogens in clinical samples with similar performance to the Illumina MiSeq.

Seroprevalence of Mycoplasma Infection in Broiler Population of Assam

The experiment was conducted in the Department of Veterinary Pathology, C.V.Sc, A.A.U., Khanapara, Guuwahati, Assam, India during September, 2020−August, 2021. Avian Mycoplasmosis is a severe threat to the poultry industry. Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) represent the most important Avian Mycoplasma spp. worldwide in the poultry industry. All age groups of chickens and turkeys are susceptible to infection. Most of the outbreaks were recorded between 3rd and 6th weeks of age. The disease is characterized by respiratory rales, coughing, nasal discharge, conjunctivitis, sinusitis and air sac lesions. In the present study, a total of 400 sera were tested for detection of antibodies from 29 farms from 11 different locations of Kamrup (M) and Kamrup (R) district, Assam. For detection of Mycoplasma antibodies, indirect ELISA was performed by using commercially available kits for MG and MS (IDEXX Laboratories). Out of the total samples tested, 13.25% showed sero-positivity for MG and 7.25% showed sero-positivity for MS. Among different age groups, highest sero-positivity was recorded in age group of above 5 weeks (8.5%) and lowest sero-positivity was recorded in birds of age 3−4 weeks (0.75%) for MG. For MS, the highest sero-positivity was recorded in birds of age group of above 5 weeks (5.25%) and lowest sero-positivity was recorded from age 3−4 weeks (0.5%). Season-wise highest sero-positivity was recorded in winter (6.5%), followed by post-monsoon (4.25%), monsoon (1.75%) and pre-monsoon (0.75%) for MG. In case of MS, highest sero-positivity was recorded in post-monsoon (3%), followed by winter (2.75%), monsoon (1%) and pre-monsoon (0.5%).

Molecular Detection of Mycoplasma Gallisepticum and Mycoplasma Synoviae Infection in Poultry

In Pakistan, production of poultry has been evolved as a good alternate of beef and mutton. In this study multiplex PCR approaches were adopted to differentiate and detect avian mycoplasma in a single PCR reaction as a step forward in the economization of PCR detection. From the total of 25 samples, 25 (100%) had a positive Mycoplasma isolation result. The biochemical test yielded the highest number of isolations, with MG accounting for 10/25. Commercial DNA-based PCR kits have been developed as a result of recent advancements in diagnostic techniques for Mycoplasma infections. Tetracyclines, fluoroquinolones, tilmicosin, tylosin, spiramycin Infections should be reduced as much as possible.

Percent positivity and phylogenetic analysis of Mycoplasma gallisepticum and Mycoplasma synoviae in commercial poultry from the different States of India.

Background and Aim:The Indian and global poultry industries suffer significant economic losses due to Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) infections, which adversely affect egg production, hatchability, weight gain, and feed efficiency in farms, thus decreasing the overall production efficiency. This study aimed to determine the percent positivity and phylogenetic analysis of MG, MS, and co-infection of both mycoplasmas in commercial poultry farms across different states of India from 2017 to 2021.Materials and Methods:A total of 3620 tracheal or choacal swabs were collected from breeder and layer farms showing clinical signs of avian mycoplasma infections from commercial poultry farms across India, and the percent positivity for MG, MS, and co-infection of both mycoplasmas were determined by Polymerase chain reaction using the 16S rRNA and vlhA genes amplification, respectively. Phylogenetic analysis was carried out by sequencing the mgc2 and vlhA genes of 2 samples of MG and 24 samples of M. synoviae to gain insight into the genetic variability of Indian strains. The data were then compared with other Indian strains, vaccines strains, and strains from other countries.Results:Our data shows the percent positivity of MG, MS, and co-infection of both MG and MS was 6.43%, 23.61%, and 15.49%, respectively. The phylogenetic relationship between MG and MS was determined using the vlhA and mgc2 genes, revealing two samples of MG and 24 samples of MS clustered with other Indian strains. M. synoviae MSM22 and previously studied M. synoviae MGS 482 clustered with vaccine strain M. synoviae MS-H.Conclusion:Mycoplasma synoviae infections in breeder, layer, and in both is predominant compared to MG across the states investigated in India. Sequenced samples of MG and MS showed evolutionary relationships with the previously studied Indian strains of MG and MS. These findings support our view that monitoring chickens for avian mycoplasma infections are of paramount significance. It further lends credence to the contention that such information will pave the way for the development of a home-grown vaccination control program and thus safeguard the poultry sector against mycoplasma infections.

In vitro susceptibility of Mycoplasma iowae isolates to antimicrobial agents

ABSTRACT Mycoplasma iowae, a potential re-emerging avian pathogen mainly affecting turkeys, has been reported from many parts of the world. Poor hatchability, embryonic death, joint and skeletal abnormalities, poor ossification, runting-stunting, poor feathering and airsacculitis may be observed in infected flocks. The reduction of the severity of clinical signs and short-term control of M. iowae are performed by antibiotic treatment. However, M. iowae develops resistance more rapidly and is considered to be more resistant to antimicrobials than other avian pathogenic mycoplasmas. The aim of the present study was to determine the in vitro susceptibility of 101 M. iowae isolates and strains to ten clinically important antimicrobial agents, and to analyse and compare the susceptibility patterns of isolates of various origins and from a wide time-period. The examined reference strains showed high susceptibility to all antimicrobials except for spectinomycin. Low concentrations of tiamulin, florfenicol and oxytetracycline inhibited the growth of the clinical isolates. Nevertheless, slow tendency of increasing minimum inhibitory concentration (MIC) values was observed over time in the case of the above mentioned agents, while MIC values of enrofloxacin showed relatively rapid changes. Spiramycin, erythromycin, tilmicosin, tylosin, lincomycin and spectinomycin did not inhibit the bacterial growth in most of the cases. Isolates originating from captive game birds showed similar susceptibility profiles to isolates from industrial turkey hosts. The widely detected low susceptibility of M. iowae isolates to macrolides, lincomycin and spectinomycin, and the increase of MIC values of frequently used antimicrobials against this pathogen, emphasize the importance of targeted antibiotic therapy. RESEARCH HIGHLIGHTS Antimicrobial susceptibilities of 101 Mycoplasma iowae isolates were determined. Minimum inhibitory concentrations were determined by broth micro-dilution method. Tiamulin, oxytetracycline and florfenicol showed low MIC values. Isolates rapidly adapted to antimicrobial pressure.

Molecular detection of respiratory avian mycoplasmosis associated bacterial and viral concurrent infections in the poultry flocks

Respiratory tract infections are of serious concern to the poultry industry. The present study was aimed to delineate the extent of respiratory avian mycoplasmosis associated bacterial and viral concurrent infections in the poultry flocks. A total of 146 poultry flocks of Haryana and Rajasthan, India, suspected for chronic respiratory disease (CRD) were screened for avian mycoplasmas, Newcastle disease virus (NDV), infectious bronchitis virus (IBV), and avian pathogenic Escherichia coli (APEC) by conventional polymerase chain reaction (PCR) assays. A total of 49.31% (72/146) flocks were found positive for Mycoplasma infection. Of the Mycoplasma-positive flocks, 80.55% (58/72) represented pathogenic avian mycoplasmas (MG and/or MS), while 19.44% (14/72) flocks were positive for commensal avian mycoplasmas (other than MG and MS). A correlation was deduced between avian mycoplasmosis and bacterial and/or viral co-infections. The results revealed that 17.24% (10/58) flocks had only avian mycoplasmosis infection. However, in the remaining flocks, the avian mycoplasmosis was associated either with APEC infection [17.24% (10/58)], IBV infection [43.10% (25/58)], or both APEC and IBV infections [22.41% (13/58)], respectively. Further epidemiological studies on respiratory avian mycoplasmosis associated concurrent infections with other pathogens are recommended to assess circulating strains, risk factors, and economic losses.

Development of two novel SYBR green-based quantitative PCR assays for detection andquantification of Mycoplasma gallisepticum and Mycoplasma synoviae

Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are considered the most pathogenic and economically devastating avian mycoplasmas. A definite MG and MS diagnosis depends on three main approaches, including isolation and identification, demonstration of specific antibodies, and detection of genetic materials. A fast and precise diagnosis technique is an indispensable prerequisite to prevent and control avian pathogens more effectively. This study aimed to develop and validate convenient SYBR green-based quantitative PCR (qPCR) assays using genome specific primers to rapidly detect and quantify MG and MS. Two sets of primers were designed based on the highly conserved regions of mgc2 and vlhA genes in MG and MS, respectively. The efficiencies of both reactions were calculated around 96% with a detection limit of as few as 10 copy numbers of DNA/μL in a sample. The standard curves showed linearity over a dynamic detection range of 6 log units from 10$^{1}$ to 10$^{6}$ DNA copy numbers/μL without any significant variations in inter- and intra-assays. The melting temperatures of the amplicons for MG and MS were determined to be 79.90 °C and 80.79 °C, respectively. The results showed that only MG and MS were detected as a single melt peak without cross reaction with other non-targeted pathogenic agents. The developed assays were further applied to the 60 swab specimens from commercial poultry with unknown MG and MS statuses and compared with the conventional PCR assays. The current assays detected 1 and 11 samples as MG and MS, respectively. However, five MG and three MS positive samples were tested positive in gel-based assays. The protocols developed here have the potential for use as a diagnostic research tool to detect and quantify MG and MS in clinical samples. Furthermore, the proposed qPCR techniques can provide an alternative approach for diagnosis and surveillance in epidemiological studies.

Molecular-based monitoring of live vaccines in dust samples from experimental and commercial chicken flocks and its potential use as a screening test

Despite the high cost of vaccination programmes, conventional methods to evaluate vaccine uptake are often impractical and costly. More recently, molecular-based testing of poultry dust has been used to monitor the “take” of Marek's disease virus and infectious laryngotracheitis virus (ILTV) live vaccines. This study aimed to provide proof-of-concept for detecting other poultry pathogens by using molecular detection of vaccine microorganisms in poultry dust of vaccinated flocks. Dust and choanal cleft and cloacal swabs were collected from chickens vaccinated against avian encephalomyelitis virus (AEV), fowlpox virus (FPV), Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) using live vaccines in an experimental flock. Dust samples were collected weekly from 5 commercial breeder or layer flocks from day-old up to 25 weeks of age. These flocks were vaccinated against Newcastle disease virus (NDV), infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), ILTV, fowl adenovirus (FAdV), MG and MS. Samples were tested for nucleic acids of these microorganisms by PCR or reverse transcriptase PCR. Genomes of all targeted vaccines were detected in dust samples from the experimental and commercial flocks except for FPV, which was detected only in the experimental flock. FAdV was detected in unvaccinated commercial flocks. These findings suggest that PCR detection of target organisms in dust samples has potential as a relatively simple and inexpensive population-level test to monitor vaccine take and/or pathogen status in chicken flocks. Further studies comparing the detection of each of these microorganisms in poultry dust with individual birds samples are required to validate this approach.

Influence of Escherichia coli endotoxemia on danofloxacin pharmacokinetics in broilers following single oral administration.

As a fluoroquinolone antimicrobial agent, danofloxacin is mainly used to treat avian bacterial and mycoplasma infections. The pharmacokinetic characteristics of danofloxacin are usually explored in healthy animals, while those in endotoxemic broilers are still rare. This study aimed to investigate the pharmacokinetics of danofloxacin in endotoxemic broilers induced by Escherichia coli (E. coli) lipopolysaccharide (LPS) after single oral administration. Ten healthy 5-week-old Arbor Acres (AA) broilers with similar body weight (BW) were randomly and equally divided into LPS and control groups. The LPS group was intravenously injected with an LPS of E. coli O55: B5 at 2.5mg/kg BW, and the control group was intravenously injected with the same volume of sterile saline. Danofloxacin was administered orally at a dose of 5mg/kg BW immediately 1h after the intravenous injection of LPS or sterile saline. Rectal temperature was measured at predetermined times points in all broilers, and plasma and serum samples were taken. The interleukin-6 (IL-6) levels in serum samples were detected by the enzyme-linked immunosorbent assay (ELISA) kits, and danofloxacin concentrations in plasma were detected through the high-performance liquid chromatography (HPLC) method and subjected to a compartmental analysis using Phoenix software. The LPS challenge led to biphasic adaptive changes in broiler body temperature and increased the levels of IL-6. Compared with the control group, LPS treatment significantly prolonged the time to the peak concentration (LPS: 8.75±3.88h; Control: 3.20±2.20h). However, there were no significant differences in the other pharmacokinetic parameters between both groups.

A Computational Reverse Vaccinology Approach for the Design and Development of Multi-Epitopic Vaccine Against Avian Pathogen Mycoplasma gallisepticum.

Avian mycoplasma is a bacterial disease causing chronic respiratory disease (CRD) in poultry industries with high economic losses. The eradication of this disease still remains as a challenge. A multi-epitope prophylactic vaccine aiming the antigenic proteins of Mycoplasma gallisepticum can be a capable candidate to eradicate this infection. The present study is focused to design a multi-epitope vaccine candidate consisting of cytotoxic T-cell (CTL), helper T-cell (HTL), and B-cell epitopes of antigenic proteins, using immunoinformatics strategies. The multi-epitopic vaccine was designed, and its tertiary model was predcited, which was further refined and validated by computational tools. After initial validation, molecular docking was performed between multi-epitope vaccine construct and chicken TLR-2 and 5 receptors, which predicted effective binding. The in silico results specify the structural stability, precise specificity, and immunogenic response of the designed multi-epitope vaccine, and it could be an appropriate vaccine candidate for the M. gallisepticum infection.

A study of rural chicken farmers, diseases and remedies in the Eastern Cape province of South Africa

The source of emerging diseases and antimicrobial resistance is of increasing interest to epidemiologists. This paper looks at village chickens as such a source. In addition, infectious diseases constitute a major challenge to the growth and profitability of the rural poultry sector in Sub-Saharan Africa. A serological survey was conducted to estimate the apparent seroprevalence of selected chicken diseases in the Eastern Cape Province of South Africa alongside a sociological survey of poultry farmers and the remedies most commonly used to prevent diseases in their flocks. Sera collected from village chickens (n = 1007) in the province were screened for specific antibodies against Newcastle disease (ND), avian influenza (AI), avian infectious bronchitis (IB) and Mycoplasma gallisepticum (MG).The overall seroprevalence of ND, AI, IB and MG in the province was found to be 69.2 % (95 % CI 51.9−86.5%); 1.8 % (95 % CI 0.2−3.4%); 78.5 % (95 % CI 74.9−82%) and 55.8 % (95 % CI 41.3−70.3%) respectively with clustering found at the District level. Cross hemagglutination inhibition (HI) tests indicated that the chickens were exposed to the ND vaccine. AI ELISA-positive samples were tested using HIs against the H5, H6 and H7-subtypes, but only H6-specific antibodies were detected. Avian influenza strains shared the common ancestor responsible for the 2002 chicken outbreak in KwaZulu-Natal Province.The majority of chicken farmers were females and pensioners (69 % and 66.1 % respectively) and had a primary school education (47.1 %). Traditional remedies were commonly used by farmers (47.15 %) and among the remedies, Aloe plant (Aloe ferox Mill.) or ikhala (Xhosa) was the most commonly used product (28.23 %) for preventing and reducing mortalities among village chickens.The findings stress the importance of village chickens as a substitute for social welfare and highlight the exposure of village chickens to important chicken pathogens. The economic impact of these pathogens on the development of this sub-sector needs further investigation. Village chickens are a potential source of virulent Newcastle disease virus (NDV) because of the lack of vaccination and biosecurity. They may serve as amplification hosts which increases the probability that virulent NDV could spill over into commercial poultry flocks due to large amounts of circulating virus. The zoonotic threat of circulating H6N2 viruses raise concern due to their mutation and reassortment among chickens and a potential movement of infected birds within the province. Finally, the use of antibiotics by untrained chicken farmers constitute another major concern as it could serve as a source of antimicrobial resistance (AMR).

Avian Mycoplasma gallisepticum and Mycoplasma synoviae: Advances in diagnosis and control

Both of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) infections are the most common Mycoplasma infection in domestic poultry. The disease is associated with economic losses in poultry. MG and MS are commonly spread within chickens (Gallus gallus domesticus) and turkeys (Meleagris gallopavo domesticus) flocks; however, they are frequently isolated from quails (Coturnix coturnix) and several avian species. Diagnosis of MG or MS infections is confirmed by isolating the organism in a cell-free medium or directly detecting its DNA in infected tissues or swab samples. Serological tests are also widely used for diagnosis. However, advances in molecular biology represented a rapid and sensitive alternative to the traditional culture methods requiring specialized techniques and sophisticated reagents. Several Mycoplasma molecular diagnostic tests are implemented: including polymerase chain reaction (PCR), Random Amplified Polymorphic DNA (RAPD), arbitrary primed polymerase chain reactions (AP‐PCR), and Multiplex real-time polymerase chain reaction (Multiplex MGMS). Current control practices against Mycoplasma infection include intense biosecurity, biosurveillance, medication, and vaccination. However, the egg-borne nature of avian Mycoplasma infection complicates controlling the infection. This review focuses on the advances in diagnosis and control of avian Mycoplasma infection, especially MG and MS infections.