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A descriptive epidemiology study of the occurrence and control of Salmonella in duck breeding and production. - OZ0343

Description
In recent years, there has been an increase in interest in using duck eggs for cooking, particularly in cakes but also in fresh form, for which undercooking is the norm as a result of the rubbery texture of well cooked duck eggs. Although duck eggs only account for a small proportion of UK egg sales, there has been a significant growth in sales over the past few years. Recent Salmonella outbreaks in the UK and Ireland have been linked to a specific strain of Salmonella Typhimurium (DT8), which is associated with ducks. This strain appears to have a special ability to contaminate duck eggs.
As reports of Salmonella in ducks in the UK currently rely upon voluntary submissions from the industry, it is difficult to compare data from different years and to get a clear picture of any trends. As there is currently no intention to introduce targets for Salmonella in ducks throughout the EU, more robust information about the Salmonella situation in GB would be desirable in order to help reduce the risk of further outbreaks of duck-associated salmonellosis. Also, sampling methods for duck houses have not been compared and validated so far, and different methods are currently used by the industry for taking voluntary samples. Because of the higher moisture of litter in duck housing, the different behaviour of ducks compared to other poultry, the differences in litter management and possibly differences in flock prevalence, sampling methods which are currently used for chicken and turkey flocks are likely to prove less practical and sensitive for detecting Salmonella in ducks. This project, therefore, aims to assess a selection of sampling methods against an intensive sampling ‘gold standard’ method for detection of Salmonella infection in duck flocks to determine the optimum and most cost-effective sampling methodology (01).
A longitudinal epidemiological study (02) of Salmonella and its control in breeding, laying, rearing and fattening duck holdings and hatcheries will be carried out; this will provide detailed information on the persistence of Salmonella present and the effectiveness of control measures, including egg sanitisation methods. This will enable advisory material to be produced to target key biosecurity areas within the duck industry.
The efficacy of 4 Salmonella Typhimurium vaccination programmes, currently available but not widely used in ducks will be investigated (03). If specific available vaccination programmes can be shown to be protective against Salmonella, this would provide a good starting point for biosecurity advice and publication of the findings should help stimulate greater vaccine uptake.
Representative Salmonella strains isolated from surveillance, the sampling and longitudinal studies will be studied by VNTR and sequenced to identify virulence genes (04). These will be compared to strains from historical outbreaks in order to identify if new more egg invasive strains may have arisen and disseminated beyond GB.
Overall, this project will provide Defra with a clear and detailed view of Salmonella in the duck industry and the areas and methods for improvement in terms of the control of Salmonella.
Objective
The overall aim of the project is to provide a clear and detailed understanding of Salmonella in the UK duck industry. The project has been divided into four objectives.
Objective 01 – Assessment of optimum sampling methods for detection of Salmonella infection in duck flocks (100% AHVLA)
This work package is designed to provide data on the presence of Salmonella within the duck industry and to provide definitive data on the limits of detection of currently used and optimal survey and routine monitoring samples to provide guidance to Defra, EU and Industry on future surveillance options for Salmonella.

Objective 02 – A descriptive longitudinal epidemiological study of Salmonella and its control in duck holdings and hatcheries (100% AHVLA).
This work package will comprise of longitudinal investigational field studies aimed at identifying routes of dissemination and factors involved in persistence of Salmonella on duck farms.

Objective 03 – In vivo study to investigate the efficacy of 5 Salmonella vaccination programmes in ducks. This work package is designed to determine the efficacy of five Salmonella vaccination programmes in Salmonella challenged laying ducks and two routes of challenge administration (AHVLA 100%).
Project Documents
• EVID4 - Final project report : OZ0343 - EVID4   (709k)
• ANX - Annex : 21-Better control of salmonella Advice leaflet   (1589k)
Time-Scale and Cost
From: 2012

To: 2015

Cost: £510,729
Contractor / Funded Organisations
A H V L A (Animal Health and Veterinary Laboratories Agency - AHVLA)
Keywords
Animals              
Disease Control              
Epidemiology              
Fields of Study
Animal Health