In the European Union, and many other countries world-wide, control measures for Newcastle disease (ND) and highly pathogenic notifiable avian influenza (HPNAI) are imposed by legislation and involve the implementation of stamping out policies with defined restriction zones and severe trade implications. When outbreaks occur, or contingency plans are being drawn up, those involved in control frequently need information on the presence and survival of the viruses in different media and under different circumstances. Similarly, such information is imperative when assessing the risk of trade in different poultry products. Despite this need for such fundamental knowledge the current literature frequently proves inadequate and outdated, resulting in a need for [sometimes extreme] extrapolation from the available data when expert advice is given that directly impacts on policy. It is the sole aim of the proposed work to supply reliable data so that government and international agencies can make more reliable qualitative and quantitative risk assessments for trade and disease control purposes.
This project will continue directly, and build-on, the work and data generated in SE4005 and will use the same viruses: vNDV CK/UK/1453/96, H5N1 A/TY/TY/1/05, H7N1 A/OS/IT/984/00.
This proposed follow-on project aims to cover the following areas:
Part 1. Determine risk-pathways associated with poultry products & associated gaps in data in partnership with the Centre for Risk Analysis (CERA), at VLA Weybridge, and other specialist groups within the VLA.
Part 2. Determine virus survival (expressed as Dt values) in:
a. Poultry commodities for human consumption (muscle (meat), skin, liver & egg products);
b. Other poultry products (including slurry and litter);
c. Water (including sea, brackish, lake water sources);
d. A model representing a commercially relevant pH & temp range;
e. A decaying carcase.
All experiments will involve a time course (approx. 10 points) and a temperature range (approx 4 temperatures). As an example, the poultry commodities for human consumption (2a) work is likely to equate to over 200 infectivity tests and over 400 real time PCR tests.
Part 3. Effect of vaccination on trajectory of virus shedding and the dissemination of (all three) viruses in a domestic poultry host.
Part 4. Pre-clinical ‘window’ of infection in chickens and turkeys. This should be considered in context with the fact that on more that one occasion recently, the source of infection has been purported to be linked to meat obtained from naive birds that were pre-clinically infected (naive birds infected with virus but not showing clinical signs).
It is anticipated that, through completion of this work, we will be able to provide answers with evidence to questions that have been raised as a direct consequence of notifiable avian disease outbreaks in the UK in recent years.