Reducing the Economic and Zoonotic Impact of Avian Influenza (REZIAI): delivering novel vaccines and diagnostics from laboratory to the field.

Lead Research Organisation: The Pirbright Institute
Department Name: Avian Influenza

Abstract

Safe and disease-free poultry production systems are crucial for maintaining global food supplies and improving the livelihoods of smallholder farming communities. However, emergence, re-emergence, and continued prevalence of a diverse range of avian influenza viruses (AIVs) in recent years threaten the sustainable growth of the poultry sector. Furthermore, continued circulation of these viruses in birds remains a credible threat for zoonotic infection and pandemic emergence. This is specifically impacting the socio-economic well-being of low-income farmers in the low and middle-income countries (LMIC) such as Vietnam and Pakistan, where a high proportion of the farming workforce are women and young people, and poultry farming is one of the main sources of their livelihood. Control of these viruses presents formidable challenges to public health and veterinary infrastructures. Despite implementing disease control approaches including culling of infected and contact flocks, movement restrictions, and vaccination, viruses continue to cause devastating damage to poultry production in Pakistan and Vietnam. Continuous prevalence of these viruses in birds increases the opportunity for world-wide dissemination through trade and migratory birds. Specific and accurate detection of circulating viruses and vaccination is the key control measure employed to reduce disease impact. However, these viruses evolve over time acquiring antigenic changes resulting in vaccine and diagnostics failure. Therefore, improved disease control is critical for breaking the endemic cycle of these viruses within farming systems.

The work under ZELS programme developed knowledge in how AIVs evade vaccine induced immunity in poultry. The project also developed new vaccine technologies and used avian viruses as vaccine vectors to protect chickens and ducks from avian influenza together with Marek's disease and duck plague respectively. Additionally, we developed diagnostic assays that can be used for rapid detection and differentiation of different AIVs subtypes near the flock-side. We also estimated the zoonotic risks of AIV to farming communities in Vietnam and cost of disease impacting poultry rearing systems in Pakistan.

This project will utilise these data sets, resources and technologies to further improve vaccines and diagnostics and transfer them to the collaborating laboratories in Vietnam and Pakistan. This will increase their capacity and capability to produce in country next generation innovative disease control tools. Estimating losses in the poultry value chain due to AIV infection and the potential benefits of new improved disease control systems will increase the confidence of farmers to new technical solutions protecting animals along with themselves from infectious viral diseases.

Altogether, increasing capacity and capability for local production of improved disease control tools will aid in the reduction of poultry production losses and thus be important for global food security and improved animal welfare, whilst also reducing possible zoonotic transmission to humans. Thus, the proposed research partnership will provide direct benefits to farming communities and substantial indirect economic, public health, environmental and social benefits on a global scale.

Technical Summary

Avian influenza viruses are causing devastating economic losses to the poultry industry in Vietnam and Pakistan. Vietnam has experienced worse zoonotic transmission of AIV H5N1 resulting in over 127 human infections with 64 deaths. Pakistan poultry have been suffering from H9N2 since late 1990s. To reduce the impact of these viruses multiple doses of vaccines are being used, however, in many cases the effectiveness remains suboptimal due to rapid viral evolution. The work undertaken under ZELS programme identified large antigenic diversity among the H5 and H9 viruses isolated from poultry outbreaks in Vietnam and Pakistan respectively. These antigenic variants have the ability to evade vaccine immunity and continue to circulate in vaccinated flocks. Our analysis also observed that the available diagnostics fail to optimally diagnose these emergent variant strains. To address these challenges, we developed novel viral vectors (herpes virus of turkey (HVT) and duck enteritis virus (DEV)-based recombinant vaccines that afford complete protection from a single subtype of viruses. We also developed novel dual recognition element lateral flow assay (DRELFA) device which pairs a nucleic acid aptamer with an antibody for use as a point-of-care platform that can detect and differentiate variant strains of influenza viruses. However, in the field multiple subtypes and multiple antigenic variants persists. Therefore, there is a need to develop tailor-made vaccines and diagnostics that target field variants. This project will utilize the resources generated through ZELS project and implement these technologies at the collaborating laboratories to produce in-country novel vaccines and diagnostics that target emergent variants infecting poultry in a target region. In addition, the project will investigate the disease impact on farmers; realise the socio-economic benefits for the optimal use of different control strategies to protect livelihoods, public health, and food security.

Planned Impact

Endemic prevalence of avian influenza viruses (AIV) in many countries in Asia continues to threaten the sustainability of poultry production systems and the livelihoods in rural communities of Low and Middle- income countries including Vietnam and Pakistan. Although new and improved technologies are most certainly required for better disease control in poultry, the development and deployment of technical solutions will require a multidisciplinary approach, and in-depth understanding of the socio-economic and behavioural factors that drive AIV disease (re)emergence. Many AIV subtypes are 'silent' or of low pathogenicity in poultry yet have the potential to cause significant public health risks. Therefore, the control of AIV can result in conflict between stakeholder communities, where risk mitigation must be balanced with preserving economic livelihoods. Our proposed research will provide integrated and innovative approaches by harnessing expertise in the UK, Pakistan and Vietnam. The research will improve and deliver approaches for prevention and control of AIV. The availability of cost-effective, improved and locally produced disease control tools will contribute to the sustainability of poultry production and improvement of animal welfare, livelihoods and food security. Thus, the strategic objectives of this partnership are aligned with the long-term goals of many stakeholders with an interest in animal health, public health and food security such as Department for International Development (DFID), World Organisation for Animal Health (OIE), Food and Agriculture Organization of the United Nations (FAO), World Health Organisation (WHO), partner institutions, and their national government agencies (BBSRC, MRC, DEFRA).

The outcomes of this research will be communicated to stakeholders via multiple mechanisms. Adoption of the DFID Research Open and Enhanced Access Policy will ensure use of public databases and information sharing. Data and reagents will be shared promptly via peer-reviewed open access journals, through multilingual websites and presentations at conferences and workshops. Public engagement aspects of the project are being facilitated through community forums with farmers groups, and through local TV and radio coverage.

The PIs have experience collaborating with potential beneficiaries outside the immediate academic community, including governmental and non-governmental organizations and the corporate sector.
Knowledge exchange and commercialisation activities will be managed through Business Development Officers who will lead on any detailed identification of and discussions with potential business partners. Socio-economic issues involved in uptake of veterinary vaccines and diagnostics will be evaluated by community-based participatory research activities in farming communities. We are committed to performing high calibre research and to training the next generation of scientists for multi-disciplinary research that addresses priority concerns of global health, infectious disease epidemiology, vaccinology and diagnostics.

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