BirdLife: wild birds “victims not vectors” of H5N1

press release, with plenty of info in footnotes:

BirdLife International 08-12-2005 [1] As the year draws to a close, millions of wild birds have flown to their wintering sites across, Asia, Africa, Europe and the Americas without the widely predicted outbreaks of H5N1 bird flu associated with their migration routes. [2]

“The most obvious explanation is that migrating wild birds are not spreading the disease,” said Dr Michael Rands, Director & Chief Executive of BirdLife International.

“Migratory wild birds were blamed for spreading bird flu west from Asia, yet there’s been no spread back eastwards, nor to South Asia and Africa this Autumn. The limited outbreaks in eastern Europe are on southerly migration routes but are more likely to be caused by other vectors such as the import of poultry or poultry products. The hypothesis that wild birds are to blame is simply far from proven,” said Dr Rands. [3, 4] “Wild birds occasionally come into contact with infected poultry and die: they are the victims not vectors of H5N1 bird flu.”

BirdLife maintains that better biosecurity is the key to halting the spread of bird flu.

In particular, BirdLife is urging governments and relevant agencies to concentrate their efforts on the poultry and cage bird trades and to impose the following prevention measures:

* Banning the movement of poultry and poultry products from infected areas [5] * Banning the use of untreated poultry faeces as fertiliser and feed in fish-farms and in agriculture [6] * Restricting the international movement of captive birds in trade [7]

“Implementing measures like these are proven to work,” says Dr Rands. “For example, Malaysia and South Korea both experienced bird flu outbreaks through importing infected poultry products, but stamped the disease out and have remained disease free through improved biosecurity. In the mean time, hundreds of thousands of waterbirds have arrived to winter in, or migrated through South Korea, and many migrant waders have passed through Malaysia.”

“Better biosecurity is the key to controlling the disease’s spread,” said Dr Rands. “But the virus can rapidly mutate, so it’s important to monitor wild bird populations to look for evidence of new strains arising.” [8]


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] On 28 November, the Dutch agriculture ministry announced it was planning to lift restrictions preventing contact between free-range poultry and migratory birds. “The peak of the bird migration season is finished by mid-December, and also no infected birds have been found in our monitoring of wild birds,” the ministry said. This is the first official admission that the bird flu epidemic widely predicted for this autumn and winter, as migratory waterbirds moved south and west into Europe, has not materialised.

[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 biosecurity in small “backyard” enterprises. Birds from different areas are brought together in networks of poultry markets, and often transported hundreds of miles.

[4] 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.

[5] 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 were moulting and not capable of flight.

Live animal markets have played a major part in spreading the virus, and were identified as the source of the HPAI H5N1 infection in chicken farms in Hong Kong in 1997. In Viet Nam, the circulation of HPAI H5N1 in geese in live bird markets in Hanoi was documented three years before the 2004 outbreaks in chicken farms.

HPAI H5N1 has been found in duck meat imported from China into South Korea, Japan and Taiwan. Poultry are still 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 a major haul of illegally imported Chinese poultry was recently discovered in the UK.

[6] Domestic bird waste is widely used as food and fertiliser in fish farming and in agriculture, yet infected poultry are known to excrete virus particles in their faeces. The use of untreated faeces in fish farming was recently described by the United Nation’s Food and Agriculture Organization as a “high risk production practice”. Russian fish farms have begun using chicken faeces as fish farm fertiliser, and this practice is employed in Eastern Europe where poultry faeces are also spread onto agricultural land. The Government of Vietnam has warned local residents against the risk of dumping tonnes of chicken faeces into rivers and lakes as fish food; one boy has died of bird flu after swimming in a river where infected chicken carcases were discarded. In October, Mute Swans died at fish farms in Croatia and Romania.

[7] Customs in Taiwan have intercepted two consignments of infected birds being smuggled from mainland China. In 2004 a pair of Mountain Hawk-eagles smuggled in hand luggage from Thailand to Belgium were found to have the disease, and in the UK recently imported captive birds died of bird flu in quarantine.

[8] Around 16,000 live wild birds all tested negative for the disease in Hong Kong since 1997. Pakistan has tested 700 migratory birds and found no traces of HPAI H5N1. 2,500 migratory shorebirds recently tested in New Zealand and 173 shorebirds tested in Australia were all negative for HPAI H5N1. 20,000 birds (comprising 250 species) in Europe in tests dating back to 1986 (mainly in the Netherlands) all proved negative for HPAI H5N1. “Several thousand birds” tested in Alaska during summer 2005 were all negative for HPAI H5N1. Nine dead Jungle Crows, adjacent to a poultry outbreak in Japan in 2004, tested positive for HPAI H5N1 out of around 5,000 birds tested; the remainder were negative. More than 5,000 waterfowl specimens tested in Korea in 2003–2004 were all negative for HPAI H5N1. One dead Whooper Swan, out of 850 birds tested in Mongolia in August 2005 was positive for HPAI H5N1; the remainder were negative. In Thailand in 2004, HPAI H5N1 was detected in two dead crows at an outbreak site, but 23 live crows and 55 live pigeons at the site where negative. Further testing in the above countries and elsewhere is on-going, but results are not all available currently

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Dr Leon Bennun, Director of Science, Policy and Information for BirdLife International, on BBC website - [url=]Reality takes wing over bird flu[/url] - includes:

Fuelled in part by alarmist press reports and by the attempts of government agencies to draw blame away from farming, there are now calls for drastic measures against wild bird populations.

I believe these measures would put some species at risk of extinction, without having any effect on the spread of avian flu.
If wild birds had been spreading the disease across continents there would have been trails of outbreaks following migration routes; but this hasn't happened.

The "wild bird" theory for the spread of H5N1 also provides no explanation as to why certain countries on flight paths of birds from Asia remain flu-free, whilst their neighbours suffer repeated infections.

What is striking is that countries like Japan and South Korea, which imposed strict controls on the import and movement of domestic poultry after initial outbreaks, have suffered no further infections. Myanmar has never had an outbreak.

In fact, countries which have not yet developed a large-scale intensive poultry industry have also been largely spared. The UN Food and Agriculture Organization (FAO) reports that in Laos, 42 out of 45 outbreaks affected intensive poultry units.
Factor in the global nature of the poultry industry, and the international movement of live poultry and poultry products both before and after the Asian outbreaks, and we have the most plausible mechanism for the spread of the virus between places which are not connected by the flyways of migratory birds.

The timing and pattern of outbreaks has been largely inconsistent with wild bird movements; but they have often followed major trade routes.
Some of the agencies attempting to monitor and control avian flu, such as the FAO, seem to have been reluctant to draw attention to the role of intensive agriculture, because of the impact on national economies and on access to cheap sources of protein.
For this and other reasons, the role of migratory wild birds in the transmission of the disease has been exaggerated, and further sensationalised in the press.
In fact, H5N1 outbreaks in wild birds have so far mostly burned themselves out without culls or other human interventions.

Some of the world's most threatened birds may be put at risk. But there is also the near-certainty of damage to ecosystem services on which people and economies depend.
BirdLife is calling for an independent inquiry into the spread of H5N1 which gives due weight to the role of the global poultry industry, and maps both official and unofficial poultry trade routes against the pattern of outbreaks.

It may also be time to take a long, hard look at the way the world feeds itself, and to decide whether the price paid for modern farming in terms of risks to human health and the Earth's biodiversity is too high.