Title: Assessment of the threat of game birds as “reservoirs” of avian paramyxovirus (APMV) 1 infection for farmed poultry
Funder: Department for Environment, Food and Rural Affairs

Abstract: Description Newcastle disease, caused by avian paramyxovirus type 1 (APMV-1), is one of the most devastating diseases of poultry. Game birds, such as pheasants and partridges, are known to be susceptible to infection with NDV. However the infection dynamics of NDV between game birds and chickens remains unknown. This work builds on a programme of research and aims to inform policy decisions directly through I) improvement in our ability to predict or control incursions and risk pathways for introduction and/or maintenance of infection ; II) improvement in earlier detection of NDV infection across all production sectors; III) an evidence base to support a future reduction in the length of time businesses remain under official restrictions when NDV incursions occur and; IV) reduction in costs to either government and/or industry through early detection, targeting of field activities where there is greatest risk for effective control and proportionate intervention based on a scientific evidence base to minimise cost. The information generated will be of use to both animal health officials and will be made publicly available to a wide range of stakeholders, including the Game & Wildlife Conservation trust, via peer-reviewed publication in scientific and special interest forums such as seminars, papers and websites. Previous work at the AHVLA investigating infection dynamics of NDV in game birds has shown highly infectious but subclinical infection in these birds. This taken together with field observations from two separate UK outbreaks in this sector suggests that scanning surveillance programs are inadequate and these birds pose a significant risk to the galliforme and game bird poultry industries through subclinical propagation and spread of this notifiable disease. However, the susceptibility of game birds to emergent ND viruses and the transmission dynamics of these viruses between game birds and galliforme poultry, as a potential reservoir, remains unknown. This highlights a significant knowledge gap in the effective control of this disease which poses a threat to the maintenance of disease freedom within the UK. An improved understanding of how these birds contribute to the dissemination of this notifiable disease would greatly enhance assessments of risk to the UK poultry population and improve intervention strategies, including fit-for-purpose diagnostic capabilities to complement surveillance programs. The notifiable avian disease control strategy for Great Britain states that “under legislation there is provision for the imposition of a compulsory vaccination zone in the event of an outbreak”. Knowledge of vaccination options for the game bird industry would assist in these control strategies for NDV incursions. Contemporary avian paramyxoviruses and pigeon paramyxovirus (an antigenic variant of APMV), displaying the highest risk to poultry populations, will be selected to determine their ability to infect pheasants and partridges. Inter-species infection and transmission studies with APMV and PPMV, using novel co-housing methodology developed at the AHVLA, will be performed using pheasants, partridges and chickens to determine the potential of these game birds to act as reservoirs. PPMV infections will determine whether game birds act as vectors and/or enhancers for infection of chickens with PPMV. The ability to prevent such infection and interspecies transmission events will be assessed through vaccination-challenge studies in both chickens and game birds using contemporary ND viruses. This approach will use current commercially available and widely used NDV vaccines to generate the samples and data needed to validate current AHVLA NDV diagnostic protocols for their use in game birds and thus enhance the laboratory toolbox for surveillance, diagnosis and control of NDV is these species. Objective 1. Assess the threat of game birds as “reservoirs” of APMV-1 infection for susceptible farmed poultry 2. Define possible role of game birds as intermediary hosts for PPMV-1: can PPMV-1 from columbiformes change and adapt differently in game birds presenting greater threat for infection of farmed galliformes compared to those viruses transmitting directly 3. Assess the potential effectiveness of vaccination as part of a control strategy for dealing with outbreaks/incursion of virulent NDV in the game bird sector 4. Ensuring alignment between rapid diagnostic tools for early detection and the kinetics of infection in game bird species infected with NDV


Research activity codes: 2.2 FACTORS RELATING TO PHYSICAL ENVIRONMENT
Health categories: INFECTION