Waterbird culls and wetland drainage could worsen spread of Avian Influenza, BirdLife warns
BirdLIfe International [1] today warned that hasty responses to Avian Influenza based on incomplete or unsound data
could do great damage to birds and other biodiversity, while actually raising the risk to people and to the economically
important poultry industry. BirdLife International’s Partners throughout Europe, such as the RSPB (BirdLife in the UK),
are working or preparing to work with their governments to monitor migratory wild bird populations and to provide
scientific data and expert guidance.
Recent outbreaks of the highly pathogenic H5N1 strain of avian influenza [2] in Europe have occurred along migratory
flyways (including the Danube delta, a great gathering place for migratory waterbird) during the autumn migration. There
is no concrete evidence that migratory birds have helped transmit the disease between countries or regions, but the
possibility cannot be ruled out.
The spread of H5N1 within and beyond South-east Asia appears attributable to movements of infected poultry [3, 4, 5].
The patterns of spread are not consistent with the timing and direction of movements of wild birds
BirdLife International strongly opposes any suggestion that wild birds should be culled as a way of controlling the
spread of the disease, on grounds of practicality and effectiveness, as well as conservation. Any such attempts could
spread the virus more widely, as survivors disperse to new places, and healthy birds become stressed and more prone to
infection. The World Health Organisation, Food and Agriculture Organisation and OIE (the World Organisation for Animal
Health) agree that control of avian influenza in wild birds by culling is not feasible, and should not be attempted.
Similarly, attempts to drain wetlands to keep waterbirds away are also likely to be counterproductive, as well as
disastrous for the environment, the conservation of threatened species, and for vital ecosystem services such as flood
control and water cleansing. Birds will seek alternative staging places and waterbirds forced to fly further and endure
more crowded conditions along their migration route will be more prone to infection. Some Asian and Middle Eastern
governments are reported to be already formulating proposals for draining wetlands.
The most efficient control techniques involve improved biosecurity, to reduce the likelihood of contact between poultry
and wild birds or infected water sources. Further measures include stricter controls or even bans on movements of
domestic poultry, and on wild bird markets. Countries should also ban imports of wild-caught birds from infected areas.
Such measures should be introduced worldwide.
BirdLife International therefore welcomes the recommendations by the European Commission that surveillance and
biosecurity measures at poultry farms in the European Union should be strengthened, and that the Member States and
experts have been advised to increase resources and efforts to monitor migratory bird species.
“We would like to offer our expertise in the Member States through our Partners and invite the EU state administrations
to contact our Partners in country for help especially with the wild bird monitoring programmes,” said Dr Clairie
Papazoglou, BirdLife International’s Head of EU Policy,.
BirdLife International’s Director of Science, Dr Leon Bennun, stressed the importance of informed and balanced judgement
in responses to the threat of avian influenza, and in the public dissemination of information about it. “It is important
that discussions of the issues relating to avian influenza should differentiate between the real problems caused by the
spread of the disease within bird populations, especially within the poultry industry, and the theoretical risks of a
human pandemic.”
ENDS
Notes
[1] BirdLife International is a partnership of people working together for birds and the environment. It promotes
sustainable living as a means of conserving birds and all other forms of biodiversity and is the leading authority on
the status of birds and their habitats. Over 10 million people support the BirdLife Partnership of national
non-governmental conservation organisations and local networks.
[2] There are at least 144 strains of avian influenza, many of which circulate in wild birds at low levels. Most strains
are mild and are designated ’Low Pathogenicity Avian Influenza‘ (LPAI). But a few ’subtypes’ can cause massive mortality
in poultry and are designated ’High Pathogenicity Avian Influenza‘ (HPAI).
Wild birds can also be infected with, and killed by, HPAI viruses. They appear to acquire the virus through contact with
infected poultry or with facilities used by them.
Subtype H5N1 evolved in poultry from Low Pathogenicity Avian Influenza viruses that were probably acquired from wild
birds. Conditions in poultry flocks (such as crowding, and prolonged contact with faeces, saliva and other bodily
secretions) keep the viruses circulating as they evolve
[3] The current series of outbreaks began in 2003 in South-east Asia, where a dramatic increase in intensive poultry
production is sometimes combined with poor hygiene and bio-security in small “backyard” enterprises. Domestic ducks are
commonly turned out to feed in rice fields alongside waterbirds during the day, and confined with other poultry at
night. Birds from different areas are brought together in networks of poultry markets, and often transported hundreds of
miles.
[4] Within south-east Asia, movements of poultry and poultry products are known to have been involved in the virus’s
spread among flocks and between countries. Outbreaks in China, Kazakhstan and southern Russia are connected by major
road and rail routes. The “transmission routes” between outbreaks in Asia do not follow migratory flyways. Many of these
outbreaks also occurred in summer, when birds are moulting and do not fly far.
[5] There are several ways through which H5N1 might be transmitted, including movements of poultry (and feathers),
migrating birds, the trade in wild-caught birds, and the movement of soil/mud on wheels and feet. The relative
importance of each of these factors in the transmission of H5N1 is unknown, but to date, all outbreaks that have been
investigated have been traced back to poultry movements.