Seroprevalence of Mycoplasma gallisepticum in wild birds in Belgium

Mycoplasma gallisepticum is the causative agent of chronic respiratory disease (CRD) in chickens. CRD is characterized by coughing, nasal discharge, sinusitis and severe lesions on the air sacs. Economic losses, due to a decrease in weight gain and egg production, are significant. Moreover, breeder flocks that are infected with M. gallisepticum have to be culled. Mycoplasma species are host restricted but infections with M. gallisepticum, which occur mostly in chickens, also have been detected in other bird species (reservoirs) such as pheasants, partridges, peacocks, ducks, wild turkeys, and house finches. The aim of this study was to investigate whether there were other reservoirs for M. gallisepticum in wildlife. Therefor we analyzed serum samples of wild crows and geese for the presence of antibodies against M. gallisepticum. In 2012, blood samples of wild geese were collected in Belgium. Samples from Canadian geese (Branta canadensis) and Greylag geese (Anser anser) were tested. Samples from carrion crows (Corvus corone) were also collected in 2012. We obtained a total of 192 blood samples of acceptable quality to analyze the presence of antibodies against M. gallisepticum. Ninety-six samples were from crows and 96 were from geese. Antibodies were detected using a Blocking Enzyme Immunosorbent Assay (Svanovir® MG-Ab). Results were read using a photometer at 450 nm. All samples of both wild crows and geese were negative. In this study, it seems like wild crows and geese do not play an important role in the spread of M. gallisepticum in Belgium. However, further investigation in other wild birds is ongoing. Acks: T. Michiels is supported by the Federal Public Service of Health, Food Chain Safety and Environment (RCO-6752 MYCOPLASMA). The study was funded by the Federal Agency for the Safety of the Food Chain. The authors thank Didier Vangeluwe (Belgian Ringing Centre, Royal Belgian Institute for Natural Sciences, Belgium) for providing the samples

Prevalence of Mycoplasma gallisepticum in commerical poultry flocks in Belgium

Mycoplasma gallisepticum is a common cause of chronic respiratory disease (CRD) in chickens, resulting in sneezing, coughing, air sac lesions, decreased weight gain and decreased egg production. It is unknown to what extent Mycoplasma gallisepticum is spread in commercial poultry in Belgium and whether they may act as reservoirs for breeder flocks, in which the disease is officially to be declared. Specific stamping out measures are applied on flocks in which infections with M. gallisepticum are demonstrated. In this study both layers and broilers were investigated. Broiler and layer flocks were selected randomly from the national Sanitrace database. A total of 3660 serum samples were collected from 61 layer flocks and analyzed using a serum agglutination test. Positive results were confirmed using a blocking enzyme-linked immunosorbent assay (Svanovir® Mg-Ab, Svanova). Because of their short lifespan and the slow immunological reaction caused by mycoplasma infection, an alternative and faster method was used in broilers. A total of 840 tracheal swabs were collected from 70 broiler flocks and analyzed with a commercial realtime PCR kit (Adiavet® Myco-AV, Biomérieux). After confirmation with ELISA, 3.3 per cent of the layer flocks tested positive for the presence of antibodies against Mycoplasma gallisepticum. In broilers, 5.7 per cent of flocks tested positive for the presence of DNA of the bacteria. Flocks were considered positive if at least 1 sample gave a positive result. A total of 1.3 % of the laying hens and 0.6 % of the broilers were positive. These findings suggest that in general, the prevalence of Mycoplasma gallisepticum in layers and broilers is low. Further epidemiological studies are ongoing to determine whether layers and broilers may act as reservoirs for MG. Acknowledgements: T. Michiels is supported by the Federal Public Service of Health, Food Chain Safety and Environment (RT 12/4 MYCOPLASMA). The study was funded by the Federal Agency for the Safety of the Food Chain

High seroprevalence of respiratory pathogens in hobby poultry

Seroprevalence studies on respiratory pathogens have been done extensively in commercial laying hens, broilers, and, to a lesser extent, backyard poultry. In Europe, seroprevalence studies in backyard and fancy breed poultry flocks are scarce and limited to a few pathogens, such as Mycoplasma gallisepticum (MG); others, such as Ornithobacterium rhinotracheale (ORT), are missing. A commercial ELISA for detection of antibodies against six selected pathogens was performed on 460 serum samples from chickens across Flanders. Anti-ORT antibodies were, by far, the most prevalent, with a prevalence of 95.4%. Infectious bronchitis virus, Mycoplasma synoviae, and avian metapneumovirus antibodies were found in 75.6%, 76.3%, and 63.5% of the animals, respectively. Antibodies against MG and infectious laryngotracheitis virus were found in 36.7% and 30% of the animals, respectively. These data demonstrate the high seroprevalence of respiratory pathogens among hobby poultry; therefore, it is possible that this group could act as a reservoir for commercially kept poultry

Prevalence of Mycoplasma synoviae in broilers, hobby poultry and wild birds in Belgium

Mycoplasma synoviae has during many years been considered a less important pathogenic species for poultry than Mycoplasma gallisepticum, causing subclinical respiratory infections in broilers. However, the importance of this bacterium and its relevance from a clinical and economic viewpoint has increased since M. synoviae arthritis, amyloid arthropathy, and eggshell apex abnormalities have been reported. Because of vertical transmission of mycoplasma species, there is an official eradication program for M. gallisepticum in breeder stock. Since the implementation of such a program, a decreasing incidence of M. gallisepticum has been observed. However, for M. synoviae, there is currently no such eradication program which may be a cause of dissemination from breeder stock into layer and broiler holdings. During a prevalence study on M. gallisepticum in Belgium, data on presence of M. synoviae in broiler holdings, backyard flocks and wild birds was also gathered. A random selection of poultry herds, proportional to herd density per province, was made based on the active holdings present in the Belgian National Animal Identification and Registration System (Sanitel) data base owned by the Federal Agency for the Safety of the Food Chain (FASFC). At each broiler holding (n=102) 12 tracheal swabs were collected and analysed using a commercial real-time PCR kit (ADIAVET™ Myco AV, Biomérieux). Fifty-six owners of backyard chickens (n=460) were visited and of each owner maximum 10 chickens were sampled. Tracheal swabs from wild birds (n=100) were collected by hunters during hunting season of September – January 2013; and three bird rescue centers were visited and tracheal swabs (n=90) were taken from different species of wild birds common in Belgium. All tracheal swabs were analyzed with RT-PCR (ADIAVET™ Myco AV, Biomérieux). Twenty-seven broiler holdings (26.5%; 95% CI: 18.9-35.8%) tested positive for M. synoviae with a within herd prevalence of 48.8% (95% CI: 43.4-54.2%) and 158 out of 1224 tracheal swabs (12.9%; 95% CI: 11.1-14.9%) were M. synoviae positive. Fifty-four out of 56 owners of backyard chickens had positive flocks resulting in a seroprevalence of 96.4% (95% CI: 87.9-99%) of backyard flocks with a within flock prevalence of 78% (73.9-81.6%). Three hundred and fifty-one out of 460 tracheal swabs (76.3%; 95% CI: 72.2-80%) were positive for M. synoviae. Four samples (one crow and three wood pigeons) obtained during hunting season (4%; 95% CI: 1.6-9.8%) tested positive for M. synoviae. Three samples (one peacock pigeon and two wood pigeons) out of 90 tracheal swabs collected in bird rescue centers (3.3%; 95% CI: 1.1-9.3%) were M. synoviae positive. The prevalence of M. synoviae in broilers is high which could be related to the lack of eradication programs and the possibility of vertical transmission from breeder stock into commercial poultry holdings. In backyard chickens the seroprevalence of M. synoviae is extremely high which indicates that they may act as reservoir for this bacterium from which dissemination to poultry holdings is possible. Further analysis on samples from wild birds in bird rescue centers is ongoing and isolation and typing of strains will be used to determine the possible routes of transmission

Prevalence of Mycoplasma gallisepticum in commercial poultry, hobby poultry and wild birds in Belgium

Mycoplasma gallisepticum is a pathogenic species for poultry and responsible for major economic loss. It is a common cause of chronic respiratory disease and can result in a variety of different symptoms such as coughing, nasal discharge, sinusitis, airsacculitis, decrease in egg production, and increase in embryo mortality in layers, reduction of weight gain and downgrading of carcasses in broilers. Because of the possible vertical transmission, infected breeder flocks should be depopulated in order to prevent further spread. Despite high hygienic measures, outbreaks in breeder flocks still occur and to date the exact route of spread into the breeder farms is not known. Because knowledge about the prevalence of M. gallisepticum in poultry holdings (other than breeders) is currently lacking in Belgium, the aim of this study was to determine the prevalence of M. gallisepticum among layer, broiler and turkey holdings, as well as in other bird species (backyard poultry, racing pigeons and wild birds) that are commonly present in Belgium and could possibly act as reservoirs for this bacterium. A random selection of poultry herds, proportional to herd density per province, was made based on the active holdings present in the Belgian National Animal Identification and Registration System (Sanitel) data base owned by the Federal Agency for the Safety of the Food Chain (FASFC). At each layer holding (n=87) and turkey holding (n=17) 60 blood samples were collected and serum was analyzed using a rapid plate agglutination test (MG-RPA test, Soleil diagnostics). Positive sera were confirmed with a blocking ELISA test (Svanovir® Mg-Ab kit, Boehringer Ingelheim Svanova). Due to the slow immune response that occurs during mycoplasma infection and the shorter life span of broilers, real-time PCR was performed to test the presence of M. gallisepticum DNA (ADIAVET™ Myco AV, Biomérieux) on 12 tracheal swabs per broiler holding (n=102). Samples of other origins include: blood samples of racing pigeons (n=56) taken during consultation at the Faculty of Veterinary Medicine (University of Ghent); fifty-six owners of backyard chickens (n=460); sera from 2012, taken from wild crows and geese (n=192); tracheal swabs from wild birds (n=100) collected by hunters during hunting season of September - January 2013; and finally,seven bird rescue centers were visited and blood samples and tracheal swabs (n=197) were taken from different species of wild birds. All serum samples were analyzed using the Svanovir® Mg-Ab kit and all tracheal swabs were analyzed with RT-PCR (ADIAVET™ Myco AV, Biomérieux). Two layer holdings (2.3%; 95% CI: 0.6-8%) were positive after confirmation with ELISA with a within herd prevalence of 39.2% (95% CI: 30.9-48.1%) and 47 out of 5220 serum samples (0.9%; 95% CI: 0.7-1.2%) tested positive. Eight broiler holdings (7.8%; 95% CI: 4-14.7%) were positive with a within herd prevalence of 34.4% (95% CI: 25.6-44.3%) and 33 out of 1224 tracheal swabs (2.7%; 95% CI: 1.9-3.8%) tested positive. Seventeen turkey holdings were sampled and all serum samples were negative for M. gallisepticum. Fifty-six serum samples from racing pigeons tested negative for M. gallisepticum. 73.2% (95% CI: 60.4-83%) of backyard flocks were M. gallisepticum positive with a within flock prevalence of 48.8% (95% CI: 43.6-54.1%) and 169 out of 460 serum samples (36.7%; 95% CI: 32.5-41.2%) were positive. One sample (wood pigeon) obtained during hunting season (1%; 95% CI: 0.2-5.4%) and 4 samples (two herons, one duck, and one magpie) obtained from bird rescue centers (2%; 95% CI: 0.8-5.1%) tested positive for M. gallisepticum. Ninety-six samples from crows and 96 samples from geese, collected in 2012, were negative for M. gallisepticum antibodies with ELISA. The prevalence of M. gallisepticum in commercial poultry is rather low, although in broilers a higher prevalence is found than in layers. This could be due to analysis method (RT-PCR vs serology). In backyard chickens there is a very high seroprevalence of M. gallisepticum which indicate that they may act as a reservoir for this bacterium which may disseminate into commercial poultry holdings. Further isolation and typing of strains will be used to determine the possible routes of transmission