Risk Wise

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direct contact between wild birds and poultry kept outside, or by

indirect contact with contaminated materials. While there is no direct

evidence that wild birds have carried the virus long distances on

migration,

analysis of genetic sequences and other indirect

evidence suggests that wild birds are likely to have contributed to

the spread.

The relative importance of different modes of infection

transfer, however, is unclear in the present state of knowledge.

Poor planning in response to ever increasing human populations

and development pressures has led to the increasing loss or degra-

dation of wild ecosystems, which are the natural habitats for wild

birds. This has resulted in closer contact between wild populations,

domesticated birds such as chickens, ducks, geese, and other domes-

tic birds, and humans and has thus provided greater opportunities

for the spread of HPAI H5N1.

The interplay between agriculture, animal (domestic and wild)

health, human health, ecosystem health, and socio-cultural factors

has been important in the epidemiology of the virus.

Minimizing the spread of HPAI H5N1

There is wide international consensus that attempting to control

HPAI through responses such as culling or disturbing wild birds, or

destroying wetland habitats is both unfeasible and diversionary, and

thus should not be attempted, not least since it may exacerbate the

problem by causing further dispersion of potentially infected birds.

Resolution IX.23 of the Ramsar Convention on Wetlands states that:

“The destruction or substantive modification of wetland habitats

with the objective of reducing contact between domesticated and

wild birds does not amount to wise use as urged by Article 3.1 of the

Convention, and also may exacerbate the problem by causing further

dispersion of infected birds.” This statement is supported in

Resolutions 8.27 and 9.08 of the United Nations Environment

Programme’s Convention on the Conservation of Migratory Species

of Wild Animals (CMS) and Resolution X.21 of the Ramsar

Convention.

Currently, wildlife health problems are being created or exacer-

bated by unsustainable activities such as habitat loss or degradation,

which facilitates closer contact between domestic and wild animals.

In the case of HPAI H5N1, healthy wild wetlands will limit the

number of waterbirds that enter agricultural areas.

The key to the control of HPAI remains control and prevention in

the poultry sector,

with long-term solutions being to separate

poultry rearing operations and wetlands used by wild birds so as to

avoid shared access and cross-contamination. Wild birds and poultry

occurring in the same region should not use the same wetlands or

have direct contact with each other. Runoff from domestic poultry

operations should not pollute wetlands used by wild birds. Farmers

can help to reduce the risks of direct transmission among poultry

and cross-infection between wild and domestic birds, such as improv-

ing hygiene and biosecurity standards in farms and during the

transportation of birds.

Many advocate the need to move to markedly more sustainable

systems of agriculture with significantly lower intensity systems of

poultry production so as to reduce the risk of avian influenza and

other bird diseases. These need to be more biosecure, resulting in

far fewer opportunities for viral cross-infection and thus patho-

genic amplification. There are major animal and human health

consequences (in terms of the impact on economies, food secu-

rity and potential implications of a human influenza pandemic)

of not strategically addressing these issues. However, to deliver

such an objective in a world with an ever-growing

human population, and with issues of food-security

in many developing countries, will be a major policy

challenge.

Risk of misinformation and adverse policies

The spread of HPAI H5N1 is of public concern and

receives much media attention. Yet a widespread misun-

derstanding of the issue remains, especially regarding

the different ways in which the virus might be spread.

Misinformation has led to wild birds being automati-

cally blamed, which creates public fear and thus

political pressure for ill-advised and disproportionate

policies such as the culling or disturbance of wild birds

or the destruction of wetland habitats. The principal

modes of transmission, such as the trade in poultry and

poultry products, the trade in cage birds and human

movements no doubt play a far more significant role in

the spread of HPAI H5N1. In some cases, these modes

of transmission have been underestimated and do not

receive proportionate exposure in the media. We need

to present an accurate and balanced view that acknowl-

edges there are multiple vectors whose relative

importance can change, depending on the area or

outbreak concerned.

Direct action to reduce the risk of spread and

infection in wildlife

Early detection is essential for the control or eradication

of HPAI H5N1, hence rapid reporting of infection

remains central to international and national control

strategies. Comprehensive surveillance programmes

including wildlife surveillance are essential for better

understanding the disease, monitoring its development

and contributing to early warning systems. Wild bird

surveillance programmes should incorporate the results

of risk assessments that have identified those species

likely to be at higher risk of carrying HPAI H5N1, as

well as the best strategic design (including optimal selec-

tion of sampling sites) and methods of sampling these

species.

National veterinary services should be

upgraded to the standards of the World Organization

for Animal Health (OIE).

The development of global early warning systems,

which incorporate the results of national and interna-

tional surveillance programmes, should be a high

priority, and aim for the following attributes:

• Open and transparent participation of relevant

parties

• Targeted active and passive surveillance and other

data-gathering

• Web-based output allowing the rapid dissemination

of open-access data and information deriving from

surveillance systems

• Integration of surveillance results with geographical

and other data to facilitate integrated responses and

risk management

• Meta-data allowing full analysis and interpretation

of results in order to facilitate appropriate responses