OFFLU aide l'Indonésie pour combattre l’influenza aviaire
29 juin 2010 – The Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (OIE) established a global network of expertise on animal influenza (OFFLU) in 2005, which works to reduce the negative impacts of animal influenza viruses by promoting effective collaboration between animal and human health sectors. In Egypt and Indonesia, where highly pathogenic avian influenza subtype H5N1 (H5N1 HPAI) has become endemic, FAO has undertaken two technical projects under OFFLU’s banner in collaboration with national agencies to understand the characteristics and epidemiology of circulating viruses, determine efficacy of available poultry vaccines, and to develop national systems to monitor viral evolution and support the use of efficacious poultry vaccines as part of a comprehensive strategy to combat HPAI.
In Indonesia, the project for “Monitoring AI virus variants in Indonesian poultry and defining an effective and sustainable vaccination strategy’’ is implemented by FAO and draws upon the resources available in the OFFLU network such as world leading scientists from a range of scientific fields including virology, epidemiology, bioinformatics, vaccinology, laboratory diagnostics, and poultry production.
To gain insight into the viruses circulating in village-based poultry production systems, the OFFLU project conducted biologic and genetic characterization and analysis of 164 H5N1 HPAI viruses isolated from 215 samples collected across 98 districts during 2007 and 2008 in Indonesia. The genetic analysis indicates that all Indonesian viruses characterized to date are found within the virus grouping called “clade 2.1” [World Health Organization (WHO) unified nomenclature], with nearly 80 percent in subclade 2.1.3. This suggests that Indonesia experienced a single introduction of H5N1 HPAI which was followed by subsequent in-country evolution of the virus.
Indonesia’s control strategy for HPAI has nine components, one of which is vaccination of domestic poultry. To further understand the evolution of the H5N1 AI virus in Indonesia and the subsequent impact of vaccines applied to poultry, the OFFLU project pioneered the application of a technique known as antigenic cartography to avian influenza viruses. This technique was developed to characterise human influenza viruses and has been used to facilitate human vaccine strain selection for seasonal influenza viruses since 2002. Using data from a classical technique with a new twist, antigenic cartography employs a mathematical algorithm to quantify the differences among viruses in an important protein produced by the hemagglutinin (HA) gene and visually displays the data in a map format.
The majority of viruses characterised from Indonesian village-based poultry during 2007-2008 cluster together, suggesting that little variation has occurred among this group of viruses; however, a few significant outliers have been detected that represent viruses capable of escaping the protection afforded by current vaccines against H5 avian influenza. Overall, the outcome of biologic, genetic and antigenic analyses of these viruses in Indonesia has contributed to the identification of updated candidate vaccine strains for poultry.
Safe and efficacious poultry vaccines have been developed with these updated strains using reverse genetics (RG) technology. The RG process incorporates a modified HA gene from the candidate virus into a low pathogenic virus backbone improving safety for both application to poultry and for the humans producing the vaccine. This work has also improved the epidemiologic understanding of viruses circulating in village-based poultry across a large geographical area, and has highlighted the need to include representative sampling from all poultry production sectors.
Laboratory capacity building activities and technology transfers are underway to support the rapid and accurate diagnosis of H5N1 HPAI in government veterinary laboratories, and to develop a sustainable mechanism to monitor viruses and identify potential candidates for future vaccines. This is the first coordinated effort of its kind for monitoring of influenza in animals at a national level. The collaborative network of government veterinary laboratories, the Ministry of Agriculture, and private industry along with strong political will, continue these activities to ensure the effectiveness of future vaccination efforts.
To broadly communicate the progress and results from the OFFLU project in Indonesia, four technical review meetings have been conducted in-country with government, industry, and university participation, and several technical teleconferences among experts have been convened to address specific questions and research gaps on poultry vaccination against H5N1 AI. In an effort to engage and inform smallholder farmers, surveys have been conducted to further understand the cost-benefit of vaccinating village-based poultry and the willingness of farmers to pay for vaccinations. Additionally, recommendations on vaccination against H5N1 AI in Indonesia have been provided to the Ministry of Agriculture by FAO, and updated guidance by OFFLU experts on evaluation of vaccines to protect against emergent variant field virus strains is now available at the OFFLU website.
This collaborative effort continues to be a rewarding endeavour for both national and international partners, and sets a standard of cooperation to be worked toward in the global efforts to control transboundary animal diseases such as H5N1 HPAI.