INTERVENTION STRATEGIES TO CONTROL AND PREVENT DISEASE OUTBREAKS CAUSED BY AVIAN INFLUENZA AND OTHER EMERGING POULTRY PATHOGENS
Location: Exotic and Emerging Avian Viral Diseases Research Unit
Title: Avian influenza worldwide: current status and successful control tools
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2012
Publication Date: August 2, 2012
Citation: Swayne, D.E., Pavade, G., Hamilton, K. 2012. Avian influenza worldwide: current status and successful control tools. Meeting Abstract. p.15.
OFFLU is the joint World Organisation for Animal Health and Food and Agricultural Organization (OIE-FAO) global network of expertise on animal influenzas. OFFLU aims to reduce negative impacts of animal influenza viruses by promoting effective collaboration between animal health experts. OFFLU puts a strong emphasis on the importance of analyzing and sharing information, and biological material to identify and reduce health threats early. An OFFLU Global Avian Influenza Vaccine and Vaccination research project seek to define the conditions where AI vaccines can assist in control and eradication of H5N1 HPAI in Asia and Africa.
The H5N1 high pathogenicity avian influenza (HPAI) virus emerged in China during 1996 and has spread to infect poultry and/or wild birds in 62 countries during the past 15 years. For 2010-2011, 20 countries reported outbreaks of H5N1 in domestic poultry (n = 11), wild birds (n = 4) or both (n=5). The majority of the outbreaks occurred in Indonesia, Egypt, Vietnam, and Bangladesh, in decreasing order. Domestic poultry experienced 1099 outbreaks involving 292,473 cases, and wild birds had 62 outbreaks involving 698 cases. There was also an H5N2 HPAI outbreak in South African ostriches during 2011. Field outbreaks of H5N1 HPAI have occurred in vaccinated flocks from both failure of the vaccines (i.e. vaccine efficacy) and failure in administration or immune response of the target species (i.e. vaccination effectiveness). Antigenic drift in field viruses has resulted in failure of protection by classic H5 vaccines strains in Mexico, China, Egypt, Indonesia, Hong Kong and Vietnam. This challenge has been met by developing new vaccine strains that provide protection against ever changing HPAI viruses.
A comprehensive review of AI control methods has been completed. From 2002-2010, >100 billion doses of AI vaccine were used in poultry in 15 countries. The majority of vaccine (>90%) was used in China while significant amounts were used in Egypt, Indonesia, and Vietnam. Implementation of vaccination in these four countries occurred after H5N1 HPAI became endemic in domestic poultry and vaccination did not result in the endemic infections. The other 11 countries used less than 1% of the vaccine. Inactivated AI vaccines accounted for 95.5% and live recombinant virus vaccines for 4.5% of vaccine used. Clinical disease and mortality were prevented in chickens, and rural livelihoods and food security were maintained by using vaccines during HPAI outbreaks. Fewer outbreaks of Low pathogenicity notifiable avian influenza (LPNAI) have been reported than HPAI and only six countries used vaccine in control programs which accounted for 8.1% of the total H5/H7 AI vaccine usage.