ROME – Although more is known today about the role of wild birds in spreading the highly-pathogenic H5N1 avian influenza virus, significant information gaps remain as government and public attention is shifting elsewhere, an international team of experts warns.
"Waning attention to H5N1 HPAI is reducing surveillance and research opportunities, negatively affecting capacity building and coordination between environmental and agricultural authorities, and impacting efforts to further refine understanding of the epidemiology and the ecology of the virus," said the Scientific Task Force on Avian Influenza and Wild Birds in a statement following a review meeting held at Food and Agriculture Organization of the United Nations’ (F.A.O.'s) Rome headquarters.
The task force, established in 2005 and jointly led by F.A.O. and the U.N.E.P.-Convention on Migratory Species, is a collaborative partnership involving 15 international organizations, including several U.N. agencies, other intergovernmental groups and special non-governmental organizations.
"Unfortunately, H5N1 may have slipped off the radar screen for some people, but it continues to be a major problem, especially in Egypt and parts of Asia, where it is having a huge impact on food security and the livelihoods of farmers and local communities," said Juan Lubroth, F.A.O.'s chief veterinary officer.
H5N1 HPAI is has not been restricted to Asia alone, he added, having also occurred in Europe, Central Asia and parts of Africa. Outbreaks of the virus in domestic poultry have been reported in Bangladesh, Cambodia, Romania, Israel, Myanmar, Nepal, Egypt, Indonesia, India, and Viet Nam and in wild birds in China, Mongolia, and the Russian Federation during the past six months,. This week, Bhutan reported outbreaks for the first time and the virus was detected after a three-year absence in Romania in domestic poultry.
Main causes of the disease spreading include poor farm biosecurity and trading of infected poultry. Wild birds play a much smaller role in the H5N1 HPAI ecology — but understanding their role in this disease, and managing the associated risks, poses particular challenges.
The disease has had great and varied conservation implications, including causing thousands of wild birds to die from viral exposure, inappropriate responses including culling of healthy wild birds and destruction of their habitats.
Over the past five years, 750,000 healthy wild birds have been tested for the H5N1 HPAI virus worldwide, either by national authorities, N.G.O.'s and international organizations like F.A.O. Some expected that "wild reservoir" species — birds that can carry and spread the virus without getting sick — would turn up during this process. So far that hasn't been the case. Only an extremely small number of apparently healthy infected wild birds have been found.
F.A.O. has also led efforts to track over 500 migratory wildfowl in various regions with satellite transmitters in order to gather information on their movements and identify possible correlations with avian flu occurrences. No smoking gun emerged from that effort.
This suggests infection of domestic poultry from wild birds is rare and the risk to humans from wild birds is negligible. More testing is needed to firm up this understanding.
Areas highlighted by the task force needing further improvement include:
• Standardization of reporting and sampling methodologies to current best science-based practices.
• Continued and broader surveillance of wild bird populations, along with improving understanding of migration routes, habitat use, and movements.
• Strengthening of capacity do that those conducting outbreak investigations can evaluate the source of virus introduction.
• Education efforts to reduce indiscriminate blame of wild birds for outbreaks in poultry.