Avian Influenza

 The role of wild birds Poultry Illegal trade  Prevention and control 
Risks to people|Conservation implications

Expert statement - 12th February 2021

Scientific Task Force on Avian Influenza and Wild Birds statement on:

H5N8 (and other subtypes) Highly Pathogenic Avian Influenza in poultry and wild birds. Winter of 2020/2021 with focus on management of protected areas in the African Eurasian region. 

Key points

There are numerous different strains of avian influenza; most circulate in wild birds, but only in some young waterbirds are infection rates sometimes high. These viruses are benign, and at worst cause only mild disease. These “Low Pathogenicity Avian Influenza” (LPAI) viruses also have only mild effects on poultry.

Under the crowded conditions of intensive poultry rearing, however, some variants of the H5 and H7 ‘subtypes’, ultimately derived from wild birds, can evolve into “Highly Pathogenic Avian Influenza” (HPAI) viruses, which can cause massive mortality in poultry. HPAI H5N1 is thus a poultry disease. Currently, it remains extremely difficult for HPAI viruses to infect people, but there is a serious concern the virus may evolve to allow rapid human to human transmission and mortality. Wild birds can also be infected with, and killed by, HPAI viruses but in population terms this is rare. They appear to acquire the virus through contact with infected poultry or with facilities used by them. 

BirdLife seeks the complete removal of the H5N1 highly pathogenic avian influenza virus from the ecosystem – while recognising that the virus is so entrenched now in some regions that this cannot be achieved rapidly. BirdLife is greatly concerned and saddened by the human death toll from the ongoing infection, and by the massive economic loss suffered by those communities affected by the virus and dependent on poultry. We also recognise and share the real concerns about a potential human pandemic.

There are several ways in which H5N1 can be spread within and between countries. It is therefore essential to monitor and control those activities which are known or strongly suspected to spread H5N1. Effective responses need to focus on all of these possible means of spread. They include the movements of infected poultry and untreated poultry products (including manure), the re-use of inadequately cleansed transportation crates, the movements of caged wild birds in trade, and movements of wild birds. Further investigation is also needed of the use of potentially infected poultry manure as fertiliser in agriculture and as feed in fish-farms and pig farms, described by the UN Food and Agriculture Organisation as a high-risk activity.


Outbreaks among wild birds in Europe and Iran during 2006 show that wild birds are capable of carrying the virus to new sites after infection. Many questions remain concerning the effects of the virus on wild birds and how efficiently they can spread it to other wild birds or to domestic poultry, especially over long distances. (See section “The role of wild birds”.)

By contrast, outbreaks in Cameroon, Egypt, India, Israel, Jordan, Niger, Nigeria, Djibouti, Lao and Pakistan in 2006 originated within the poultry industry. Outbreaks in 2007 in Hungary, South Korea, Japan, UK and Thailand, and ongoing outbreaks elsewhere, especially in Indonesia, are also associated with commercial poultry production.

Here, as in most other H5N1 outbreaks, there is strong circumstantial evidence that movements of poultry and poultry products have been responsible. In many of these countries poultry outbreaks occurred almost simultaneously in multiple large-scale poultry operations, indicating that migratory birds were an unlikely agent of the transmission. Moreover, the timing and location of these outbreaks do not match the movements of migratory birds.

For South-East Asia, recent comprehensive analysis of viral lineages concludes that poultry movements were responsible for multiple reintroductions, both within and between countries, and that “transmission within poultry is the major mechanism for sustaining H5N1 endemicity in the region”. (Chen et al., PNAS103: 2845-2850).

Several dead ’wild’ birds in Hong Kong in early 2006 and further cases in 2007 were of birds found in urban areas, away from their natural habitats, or were scavengers in urban areas. There is strong circumstantial evidence that these cases are associated with the deliberate release of captive birds for religious reasons. Birds involved in this trade often pass through ‘wet’ markets, a known and efficient mechanism by which H5N1 is spread. Concern over the importation of H5N1 through wild birds infected in ‘wet’ markets led to an indefinite ban on the importation of wild-caught birds into the European Union, announced in January 2007 and there are now calls for a similar ban on importation of such birds into Hong Kong.

As H5N1 outbreaks continue, there is need for responses to be calm, balanced, prompt and effective. In particular, BirdLife urges:

  • Improved biosecurity at all levels within the poultry industry.
  • Tight controls, backed up by better enforcement, on the movements of all poultry products, including fertiliser and feed made from poultry waste. 
  • A moratorium on trade in wild birds originating from affected regions.
  • Full involvement, collaboration and rapid sharing of information among those with relevant veterinary, medical, agricultural and ecological expertise from around the world.
  • Balanced and accurate public communication strategies by government, relevant agencies and the media. Distorted or sensationalised information can easily give rise to misdirected public hysteria about H5N1 
  • Heightened surveillance of migratory and resident wild birds, with collection of as much ecological information as possible in the case of confirmed outbreaks (see data surveillance document, PDF 1.5 MB, Yasue et al., BioScience 56: 1–7, PDF 123 KB). BirdLife believes that all such results, whether positive or negative, should be published and made freely available to researchers. 
  • More field studies on the ecology of H5N1 in natural environments to improve our understanding of host- or strain-specific pathogenicity, extent or length of viral shedding of H5N1, and the routes of transmission between wild birds.
  • Rapid detection and investigation of deaths of migrant wild birds. Wild bird deaths, sometimes involving large numbers of birds, occur for many reasons other than H5N1 and should not be cause for panic.                                  

In some parts of the world, authorities have proposed attempting to control the spread of H5N1 by culling wild birds, destroying their habitats, or displacing them from breeding and roosting grounds. At best, such measures are ineffective, but they could often make matters worse, as well as distracting from more suitable interventions. They could also add to the stresses already imposed on some species through habitat loss.

The risk of humans contracting H5N1 remains very low. Practically all human cases have resulted from frequent and intimate contact with poultry; but in relation to the number of humans, who have this degree of contact, especially in Asia, the number of known human infections is tiny.

BirdLife believes that greater collaboration between veterinarians, the poultry industry and food, agriculture, health and environment bodies is needed to tackle the threat of avian ‘flu effectively. Ornithological expertise must be sought and utilised in H5N1 outbreaks in wild birds in order to maximise the value of information to be gained. BirdLife participates actively in EU ORNIS committee meetings as well as a task force on avian influenza comprising scientists and conservationists from nine different international organisations, including four UN bodies, convened by the UNEP Convention on Migratory Species(CMS).


The role of wild birds

Despite increased sampling around the world, no fully documented healthy migratory wild birds have tested positive for H5N1; claims to the contrary have lacked essential information (see Feare & Yasue,Virology 3: 96–99).

In early 2006 wild bird outbreaks occurred across Europe, and showed that wild birds are capable of carrying the virus to new sites after infection. How this happens is still unknown. It is possible the birds spread the disease in a ’leap-frog’ fashion by travelling for a short time and passing on infection to another group of birds before dying, and can thereby contribute to the long-distance spread of the virus. There may also be some species that are resistant to H5N1, and capable of infecting other birds without themselves showing serious illness (Feare & Yasue, Virology 3: 96–99). The initial outbreaks in Europe in February 2006, related to forced movements of birds away from the Black and Caspian Sea regions in response to unusually cold weather. These two regions had widespread and sustained H5N1 infection in poultry at the time, and limited biosecurity measures were in place.

Also in early 2006, outbreaks among poultry occurred in Africa (initially in Nigeria). In contrast to the European outbreaks, it seems unlikely that migratory wild birds carried H5N1 to Africa. Strong circumstantial evidence and investigations by government agencies suggest that movements of poultry and poultry products were responsible. The timing and location of these outbreaks do not match the movements of migratory birds. Moreover, in countries such as Nigeria and Egypt poultry outbreaks occurred almost simultaneously in multiple large-scale poultry operations, indicating that migratory birds were not an agent of transmission. If H5N1 had been carried by wild birds to Africa, outbreaks would have been expected in key wetlands for migratory birds, especially in East Africa where there had been surveillance of wild birds over the previous months.

Similarly, in Asia the movement of wild birds has not been the main cause of H5N1 spread since the virus was first detected in 1996. Prior to April 2005, the small numbers of wild birds found dead or dying with H5N1 in Asia were largely sedentary species that scavenge near poultry, live markets or captive bird populations.

However between April and June of 2005 there were significant die-offs of migratory bird species in Qinghai Lake (north-western China, 6,300 birds) and Erhel Lake (Mongolia, c.130 birds) and some of these birds tested positive for or showed symptoms of H5N1. Although poultry were present in the Qinghai Lake area, there were said to be none around Erhel Lake, leading to enhanced interest in whether wild birds can spread H5N1 over long distances.

It is still unclear how the birds in Qinghai and Erhel Lake were infected by H5N1. Bar-headed Geese Anser indicus were the first species to succumb to the disease and died in the greatest numbers at Qinghai Lake. However deaths from H5N1 in the geese occurred several weeks after their arrival from wintering grounds, suggesting that the source of the H5N1 infection was local. The geese might have contracted the disease from an unidentified poultry source. Another potential route may have been a Bar-headed Goose captive-breeding farm located at the lake, which bred geese for domestication and also released individuals into the wild (Butler 2006), though no H5N1 infections were officially reported there. In 2006, outbreaks reported in wild Bar-headed Geese in north-west China were all close to such release sites. Other species later became infected at Qinghai Lake and there were in total four different strains of the virus isolated from this single outbreak, but whether they acquired the infection from the geese or from another independent source is unknown (Chen et al. 2006). The outbreak was highly localised and no Bar-headed Geese or other wild birds were found dead in wetlands close to Qinghai Lake.

In Mongolia, at Erhel Lake, the main species found dead or dying with H5N1 in July 2005 were Bar-headed Geese and Whooper Swans Cygnus cygnus, and a small number were found to be infected with H5N1. Because this outbreak occurred after the Qinghai Lake outbreaks, researchers have speculated that migratory birds may have carried the virus to Mongolia. Bar-headed Geese and Whooper Swans also died in the Qinghai Lake outbreak, and one of the four strains of H5N1 isolated from Qinghai Lake was also isolated in Erhel Lake. However, both these species would have arrived to breed in Mongolia several months earlier, and during the outbreak the birds would have been near to completing their annual feather moult, during which they are sedentary. Thus it seems unlikely that they carried the virus from Qinghai to Lake Erhel. There were no signs of large mortality events in eight wetlands within 450 km of Lake Erhel and 4,119 H5N1 tests of healthy wild birds carried out during the same period were negative. Although a large number of birds died at Erhel Lake, few actually tested positive for the virus and it was estimated that only 0–1% of the living or dead birds were infected with H5N1. These facts point to the source of H5N1 infection being local to Lake Erhel and that the infected wild birds did not spread the disease to new locations, or even among themselves to any significant extent.

The lack of a trail of dead birds along migratory pathways from infected breeding habitats in Mongolia, China and Russia to southern wintering areas in Asia and Australasia in 2005 and 2006 suggests that migratory wild birds are not spreading the disease long distances between continents during spring and autumn migration. It is possible that in some Asian and Australasian countries where little or no surveillance work has been done, wild bird die-offs have gone undetected. However, in countries such as Japan, South Korea, Philippines, the Netherlands and Finland which are on migration routes from H5N1 outbreak areas in south-east Asia or Siberia, and where there has been extensive surveillance for dead birds at key waterfowl wintering and stopover habitats, there have been no recent cases of H5N1. Japan and South Korea both remained free of the disease after early outbreaks in 2003-4, confined to poultry and scavenging wild birds (crows), were brought under control by closing borders to poultry imports, until early 2007, when commercial poultry operations in both countries were once again infected. With few exceptions, there is limited correlation between the pattern and timing of spread among domestic birds and wild bird migrations.

Nevertheless some authorities argue that the timing and location of outbreaks in the Black Sea and Caspian Sea in the autumn of 2005 did follow the south-western migration routes of birds. These outbreaks occurred after H5N1 was detected in poultry in Russia and wildfowl in south-west Russia in the summer of 2005. However, there appeared to be no trails of death along this migration route; wild bird deaths appeared to be localised and at least in some instances were restricted to a few individuals from larger flocks. Evidence that wild birds were involved thus remains circumstantial and equally plausible explanations for the spread of avian influenza westwards during the latter half of 2005 are the movements of poultry and poultry products (See section “Movements of poultry and poultry products”). Additionally, there was no return of the virus during the spring 2006 migration period.

One of the key uncertainties relating to the role of wild birds in spreading H5N1 is whether wild birds can carry and spread the disease without showing symptoms. So far, the only published study purportedly demonstrating asymptomatic infection in wild migratory birds was in Poyang Lake, China, where six out of more than 13,000 wild birds tested in China were positive. More studies are needed to assess the generality of this result because the authors did not adequately detail ornithological or field ecological data (such as species identity of the birds found to be positive, exact capture location, or sampling method) (see note on data surveillance, PDF 1.5 MB, Yasue et al., BioScience 56: 1–7).

Many thousands of healthy wild birds have been tested throughout Europe, Africa and Asia and H5N1 has not yet been detected in any. However, this result should also be interpreted with caution because very low infection rates may require much greater sampling effort to detect asymptomatic infection. In addition, recent research (Fouchier et al. 2006 FAO Conference on avian influenza) suggests that some species of dabbling duck experimentally infected with H5N1 do not shed the virus in faeces and do not show symptoms of the disease. The majority of H5N1 testing has been conducted using either faecal or cloacal swabs rather than tracheal swabs (which would be more likely to detect the virus, if present). Thus it is possible that these monitoring efforts failed to detect H5N1 in some species. In future monitoring efforts, tracheal swabs should be used to sample for H5N1 in healthy wild birds. More research on species-specific pathogenicity in wild waterfowl populations is crucial to interpret the apparent spatial and temporal patterns of H5N1 outbreaks.

Understanding of the epidemiology of H5N1 in wild birds, and the behaviour of the virus in the wider environment, remain very inadequate. Most of the research on H5N1 has been on domestic animals in laboratory environments. The ease with which infected wild birds can pass the disease on to other wildfowl or poultry remains an important, unanswered question, although this does appear to have happened, on a small scale, in Europe in early 2006. There is no information on the ability of infected birds to undertake long-distance migration, during which an increasing body of evidence suggests their resistance to disease may be suppressed. The limited evidence that exists suggests tremendous variability in transmission rates and virulence between different host species and different strains of the virus.

Better quality data collection and reporting are crucial to understanding general patterns in outbreaks, possible routes of transmission, and the potential impacts on migratory bird populations. This information can be used to focus contingency efforts, to predict future outbreaks, and to guide effective policy to reduce the economic and conservation impacts of avian influenza.

In the interests of all those attempting to control the spread of HPAI H5N1, BirdLife believes that all surveillance and test data, whether positive or negative, should be published and made freely available to researchers.


Movements of poultry and poultry products

By Shpernik088 (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

Most outbreaks in South-East Asia can be linked to movements of poultry, poultry manure, poultry by-products and accidental transfer of infected material from poultry farms, such as water, straw or soil on vehicles, clothes and shoes. Globally, the most important route of spread remains unrestricted poultry movements. A paper by Chen and colleagues, “Establishment of multiple sublineages of H5N1 influenza virus in Asia: Implications for pandemic control” (Proceedings of the National Academy of Sciences, 21 February 2006) analysed the viral lineages and concluded that poultry movements were responsible for multiple reintroductions in south-east Asia, both within and between countries.

Live animal or ‘wet’ markets may have played a major part in sustaining the virus in south-east Asia, according to the UN Food and Agriculture Organization (FAO), World Organisation for Animal Health (OIE) and World Health Organisation (WHO). They were identified as the source of the H5N1 infection in chicken farms in Hong Kong in 1997 when approximately 20% of the chickens in live poultry markets were found to be infected. The same situation was seen in Vietnam, where the circulation of H5N1 in geese in live bird markets in Hanoi had been documented three years before the 2004 outbreaks in chicken farms (FAO/OIE/WHO Consultation on avian influenza and human health: Risk reduction measures in producing, marketing, and living with animals in Asia, Kuala Lumpur, Malaysia, July 2005).

There is also a huge international trade in poultry—both legal and illegal. The legal trade involves millions of hatching eggs and poultry being shipped to destinations world-wide. For example, prior to the outbreaks in Egypt, the country was reported to export 180 million day-old-chicks plus 500,000 mature fowl a year. Almost 12 million live chickens were officially imported into the Ukraine in 2004 and more than 16 million into Romania. In Turkey, one factory has the capacity to produce over 100 million hatching eggs per year, many of them exported to Eastern Europe and the Middle East. Outbreaks in 2006 in India, Nigeria and Egypt originated within the poultry industry, and there is strong circumstantial evidence that movements of poultry and poultry products were responsible. Similarly, the re-emergence of the disease in 2007 in Thailand, South Korea and Japan was within the commercial poultry sector.

For obvious reasons, little information is available on the extent of the unregulated and illegal poultry trade. However, in February and July 2006, it was revealed that poultry meat is being illegally imported from Asia into the USA; in October 2005 3,000 chickens were intercepted by Italian customs after being smuggled into the country from China; and in November 2005 the UK authorities revealed that large quantities, possibly hundreds of tonnes, of chicken meat had been illegally imported from China, having been fraudulently relabelled before being sold on to food manufacturers across the country. In February 2006, 20 kg of chicken tongues from China were found by customs in Rio de Janeiro, Brazil, and 21 tonnes of (mainly) poultry meat from China were confiscated in southern Spain. There are numerous reports of extensive smuggling of poultry – many reported to be in poor health – across the land border between China and Vietnam. In central Vietnam, up to three-quarters of the poultry tested in December 2006 were positive for the virus. These indicate continuing lapses in border controls, despite the widely publicised risks. Illegal poultry movements are reported to be extensive in central Asia. In 2005, Ukraine’s State Department of Veterinary Medicine said there had been substantial illegal re-exportation of meat from Ukraine to Russia from third countries.

Also needing closer investigation is the widespread practice of using poultry manure (chicken, duck and other poultry faeces) and other poultry by-products (e.g. dead birds, feathers) in agriculture and aquaculture as fertiliser, and in untreated form as food for pigs and fish. Poultry infected with the H5N1 virus excrete virus particles in their faeces. Avian influenza viruses may not be deactivated for several weeks inside organic matter such as faeces. Therefore, putting untreated faeces from infected birds into fish ponds and on to fields as manure provides a potential new source of infection. Although recognised as early as 1988, the risks of this practice for spreading influenza viruses have been little investigated. The sole European H5N1 case in the second half of 2006 concerned a captive Black Swan Cygnus atratus(an Australian species) that died of the disease at Dresden zoo in August. The cygnet hatched in April 2006 and lived on an ornamental pond. The artificial feed used at the lake is considered one of the possible sources of the virus.

Chicken faeces have been used as fertiliser in aquaculture operations in Russia and Eastern Europe as well as south-east Asia. Poultry faeces are also spread onto agricultural land and discharge inevitably runs off into waterways. The collection and transport of untreated poultry manure could be a highly effective way of spreading the virus. The FAO recommends “that the feeding of poultry manure/poultry litter should be banned in countries affected by or at risk from avian influenza, even if correctly composted, ensiled or dried with heat treatment.”

For more information see BirdLife’s March 2006 report, Fish farming and the risk of spread of avian influenza (PDF, 200 KB)


Illegal trade in cage birds

The widespread illegal trade in cage birds has transported H5N1-infected birds over large distances. For example, customs authorities in Chinese Taiwan have intercepted two consignments of infected birds being smuggled from mainland China. An outbreak of H5N1 at a bird quarantine station in the UK may also be attributable to smuggled birds ‘laundered’ into a legally imported consignment, since the species concerned, Silver-eared Mesia Leiothrix argentauris is not a native of Chinese Taiwan, stated as the origin of the consignment. In 2004, a pair of Mountain Hawk-eagles Spizaetus nipalensis smuggled in hand luggage from Thailand to Belgium was found to have the disease. The most likely source of infection in captive birds is at live animal ‘wet’ markets in Asia, where domestic and wild-caught birds are kept in close proximity, posing a high-risk of cross-contamination. This is likely the source whereby dead ’wild’ birds found in Hong Kong in early 2006 and again in early 2007 were infected. There is evidence they were part of the extensive trade – said to number at least half a million birds in 2005 alone – in captive birds released for religious reasons in Hong Kong.


Prevention and control

By Don Becker [Public domain], via Wikimedia Commons

It is important that preventive measures for H5N1 concentrate on better bio-security—surveillance and testing of poultry, controlling the movements and sale of poultry, poultry products and cage birds, regulating the use of poultry manure used in aquaculture and agriculture, and stepping up national and international efforts to control the illegal trade in poultry, poultry products and captive wild birds. In particular, surveillance should include domestic ducks, since it is known they can carry the virus asymptomatically and infection in them could therefore easily pass undetected. Increasingly, experimental laboratory research on transmission routes, infection rates and H5N1 survival rates in the environment suggest key differences in the behaviour of H5N1 from other avian influenza viruses, related to adaptations to a poultry environment rather than in wild birds. The commercial poultry industry has led to the genesis of the current HPAI H5N1 and played an important role in the spread of the disease. Focusing on wild birds alone is misplaced and a potentially dangerous diversion of energy, effort and resources.

The best veterinary advice concerning issues such as confinement of free-ranging flocks and vaccination should be sought and followed. Vaccination may be effective—providing there is adequate antigen in the vaccine. Poor-quality vaccines stop the signs of the disease but allow the virus to continue replicating, spreading and evolving. There is continuing debate among virologists, veterinarians and politicians over the merits of vaccination (see FAO website or Nature Magazine for more discussion on vaccination).

In 2005 and 2006 some government officials advocated culling or flushing wild birds from habitats and destroying habitat or nests to reduce the risk of transmission of H5N1 to poultry or humans. The World Health Organisation, Food and Agriculture Organization and OIE (the World Organisation for Animal Health) agree that culling wild birds is not a feasible or effective approach to control the disease, and should not be attempted. Attempts at culling or flushing could make the matters worse and birds could spread the virus more widely. Better surveillance of wild birds, and more research on the behaviour of the virus in wild bird populations, are very important. In some countries, there is an urgent need to improve the capacity to detect and report wild bird deaths and details of H5N1 outbreaks.

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Risks to people

Although H5N1 can cause serious disease in people, the virus is hard to catch. Transmission from birds to human remains difficult, usually involving prolonged and intimate contact, and so far the virus rarely, if ever, spreads from person to person. This type of close-contact human to human transmission is thought to have occurred in North Sumatra where six family members died of H5N1. A major concern is that it might evolve into a form that is transmitted easily between people, thereby facilitating a pandemic.

In the last 100 years there have been at least three major pandemics of human influenza A in humans, which killed many people around the world. The origins of these deadly virus strains remain uncertain, but at least two are thought to have arisen when avian ‘flu and human influenza viruses came together, possibly in pigs, and reassorted their genetic material. Continued outbreaks of H5N1 increase the chances of this happening again, especially as the current strain of H5N1 is exceptional in that it can pass directly from poultry to humans, without an intermediate host.

Almost always, human infections have occurred in people who have been closely associated with poultry. Given the substantial number and distribution of outbreaks in domestic poultry and waterfowl, there have been relatively few cases in people (see WHO for up to date statistics http://www.who.int/csr/disease/avian_influenza/en/index.html), indicating that the transmission of the virus from poultry to man remains inefficient.

Activities such as birdwatching and feeding garden birds are completely safe if simple common sense precautions are followed. These include avoiding touching carcasses of wild birds, and washing hands with soap and water after filling or cleaning bird feeders. Both measures are advisable as birds can carry other potentially dangerous pathogens. The best veterinary advice should be followed on appropriate quarantine periods in areas where there have been H5N1 outbreaks, particularly in the vicinity of water bodies since avian influenza viruses can survive a long time in water (up to 100 days depending on pH, salinity or temperature) and faeces; it is recommended that people avoid swimming in infected water bodies.

In countries where H5N1 outbreaks have occurred, people working with poultry or other captive birds need to take stricter precautions, to minimise the risk of carrying infection to the birds they work with. They should avoid direct contact with wild birds and should also avoid contact with water from ponds and other sources which are used by wild birds, as much as possible.


Conservation implications for wild birds

H5N1 could be damaging to species that are already threatened, and/or congregate in just a few localities. At least two globally threatened bird species have already been affected. There may be other threatened species that have been infected but not detected because the majority of wild bird outbreak reports do not identify the species involved. In February 2006, the virus was isolated from a dead Red-breasted GooseBranta ruficollis in Greece. This is of concern as 90% of the world population of 88,000 is confined to just five roosts in Romania and Bulgaria, both affected countries. Another globally threatened species – Black-necked Crane (Grus nigricollis) – died in the Qinghai Lake outbreak in north-west China in the summer of 2005 (Chen et al. 2006). Moreover it is also estimated that between 5% and 10% of the world population of Bar-headed Goose perished at Lake Qinghai, China, in spring 2005, although how many of these were farmed birds is not known. In May 2006 more than 600 Bar-headed Geese allegedly died of H5N1 in Qinghai and Xizang provinces in north-west China.

However, the total number of wild birds affected has so far been small and, in contrast to the high infection rates in poultry operations, at present the virus does not appear to be efficiently transmitted by wild birds in a natural environment. Very many more birds die of other, commoner, avian diseases each year. For example, a recent report from Niedersachsen state in north Germany showed that less than 0.1% of the 7,000 dead birds brought into labs for testing this year were infected with H5N1.

Rather than the direct mortality of H5N1 on wild birds, perhaps the greater threat to wildlife is the misguided attempts by governments and the public to cull or destroy habitats to control the disease. There have been reports in the media of wild birds being demonised. In some countries politicians have called on hunters to wipe out or frighten away incoming migrant birds. Some governments have reportedly revived plans to drain wetlands, under the pretext of denying waterfowl landing and breeding places. Nests of birds, such as Barn Swallow Hirundo rustica and House Martin Delichon urbica, which breed in close proximity with man, have been destroyed in the mistaken belief that this measure will lessen the risk of contracting avian influenza. These measures put wild birds and other biodiversity in jeopardy.

BirdLife International is a member of a task force on avian influenza comprising scientists and conservationists from nine different international organisations including four UN bodies, convened by the UNEP Convention on Migratory Species (CMS). The task force seeks much better data and information on the cause of the spread of the disease and will contribute to a rapid reporting system of avian influenza outbreaks and surveillance around the world. In early April 2006, top scientists with expertise ranging from ecology and ornithology, to virology and veterinary medicine met to examine the latest information on avian influenza, define gaps in our understanding of the virus, and provide recommendations on approaches to reduce the socioeconomic and environmental impacts of avian influenza (see www.cms.int/avianflu/conclusions_rec_ai_seminar.pdf). The CMS task force has recently published a leaflet on Avian Influenza and Wild Birds, available from: http://www.aiweb.info/document.aspx?DocID=5

At the end of May 2006 BirdLife International also participated in an FAO and OIE scientific conference on avian influenza in wild birds. One outcome of these discussions has been the Global Avian Influenza Network for Surveillance (GAINS), a collaborative programme to improve data on avian influenza epidemiology in wild birds. BirdLife is a partner in GAINS and is currently collecting field data on the baseline numbers of sick or dead birds at key wetlands .

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