Tony Martin Globalisation has turned the chicken into the world's
number one migratory bird species http://www.birdlife.org/action/science/species/avian_flu/#6 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 &endash;
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., PNAS, 103: 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&endash;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). (back to top) 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&endash;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&endash;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&endash;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&endash;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. (back to top) 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&emdash;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 &endash; many
reported to be in poor health &endash; 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) (back to top) The widespread illegal trade in cage birds has
transported H5N1-infected birds over large distances. For
example, customs authorities in 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 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 &endash; said to number at least half
a million birds in 2005 alone &endash; in captive birds
released for religious reasons in Hong Kong. (back to top) 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. (back to top) 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. (back to top) 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 Goose Branta 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) &endash; 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
BirdLife Statement on Avian Influenza
Visit below or working links - pdfs, refs and more
Key points
The role of wild birds
Movements of poultry and poultry products
Illegal trade in cage birds
Prevention and control
Risks to people
Conservation implications for wild birds
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 (Important Bird Areas).