Epidemiological Analysis of Biosecurity Practices and Associated Seroprevalence of Diseases in Non-Commercial Poultry Flocks

NON-TECHNICAL SUMMARY: Poultry diseases can have a major impact on a country's health and financial status. With recent concern over the highly pathogenic avian influenza outbreaks around the world, government agencies are carefully monitoring and inspecting for infectious poultry diseases and zoonotic pathogens. However, there remains no organized inspection or control of non-commercial poultry flocks which have served as the point source of several poultry disease outbreaks. The objective of this study is to obtain baseline data on biosecurity practices in non-commercial poultry on the Delmarva peninsula and to investigate risk factors and potential transmission pathways associated with the seropositivity of the following poultry diseases of potential economic importance such as Salmonella Enteriditis, Mycoplasma gallisepticum, infectious laryngotracheitis, Newcastle disease, and avian influenza. Using a cross-sectional epidemiological approach, questionnaires will be mailed to Maryland Department of Agriculture registered backyard flock owners and live bird market participants. Biosecurity data will be collected along with blood and tracheal/cloacal swab samples from poultry. Serum will be analyzed by the enzyme-linked immunosorbent assay (ELISA) and swabs by Real-Time Polymerase Chain Reaction (RT-PCR). Univariate and multivariate analyses will be used to describe the differences between seropositive and seronegative poultry.

<P> APPROACH: <BR> Objective 1: To describe the presently applied biosecurity measures of non-commercial poultry flocks throughout Maryland, obtained from questionnaire data. Data on currently practiced biosecurity procedures in backyard flocks and live bird markets that may be associated with flock performance will be obtained through a multi-page questionnaire that will be mailed out to Maryland registered poultry owners in May 2011 whose flocks comprise fewer than 1000 birds. Data gathered from the surveys will be entered into Microsoft Excel database and analyzed for statistical significance in correlation to disease prevalence. <P> Objective 2: To determine the prevalence of pathogens and seroprevalence to Salmonella Enteriditis, Mycoplasma gallisepticum, infectious laryngotracheitis, Newcastle disease, and avian influenza from backyard flocks and live bird markets using RT-PCR and ELISA. 2a. Sample Collection Specimen collection will be performed at one time from each bird. Swab samples collected from birds will include both tracheal and cloacal swabs to determine current infection of screened diseases. Blood will also be drawn from each bird and serum processed for the presence of antibodies to surveyed pathogens to establish previous exposure. 2b. Diagnostic Analysis Tracheal samples will be analyzed for Mycoplasma gallisepticum, infectious laryngotracheitis, Newcastle disease, and avian influenza and cloacal swab samples will be examined for the presence of Salmonella Enteriditis by RT-PCR using commercially prepared gene specific primers. Seroprevalence of diseases will be determined using ELISA on stored serum following manufacturer's instructions. <P> Objective 3: To determine the presence of H5 or H7 influenza A subtypes in avian influenza seropositives via real time RT-PCR (RRT-PCR). One-step RRT-PCR assay with hydrolysis type probes will be used for subsequent screening of clinical samples for the H5 and H7 avian influenza virus subtypes. <P> Objective 4: To evaluate statistically significant risk factors and biosecurity measures used in non-commercial poultry flocks. Once disease prevalence and seroprevalence have been determined in surveyed non-commercial poultry flocks, statistical analysis will reveal associations of biosecurity practices/risk factors to the prevalence of disease. Data gathered from the survey will be entered into a database file. Software program (Statistix9 for Windows, Analytical Software, Tallahassee, FL) will be used to analyze the data. <P> Objective 5: To develop extension and educational programs on practical and effective methods of preventing and mitigating poultry disease outbreaks in non-commercial poultry flocks throughout Maryland. Research findings based on objectives 1-4 from this cross-sectional study will identify the presence of important poultry and zoonotic diseases that may be overlooked due to fewer enforced biosecurity regulations and government inspections. These findings will lead to development of new information and educational programs targeted for non-commercial poultry owners.