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Monday, October 31, 2005

Wild Bird Monitoring Schemes for Europe

The October 21 issue of Science has a good news article highlighting continued debate about the role of wild birds in carrying and transmitting H5N1 avian influenza virus. The article refers to a proposal by Erasmus University of Rotterdam virologist Albert Osterhaus to create networks in Europe and elsewhere to test wild birds for the virus.

A related story in the same issue (subscription required) describes the work of virologists monitoring birds in the Netherlands, including Vincent Munster at the Erasmus Medical Center and Ron Fouchier. The story reports that the researchers have "applied for European Union funds to expand the network across Europe."

These researchers published an outline of this approach earlier this year in the journal Nature. They argue that,

"To obtain a better global picture of the threat posed by avian flu, it is imperative to investigate the virus in wild bird populations. Wild birds, particularly migratory ducks, geese and shorebirds, are the natural reservoir of influenza A viruses, which can infect other avian and mammalian species7. But information about flu in wild birds is still limited. A widespread and integrated approach is needed to understand the dynamics, epidemiology and pathogenesis of these virus infections in wild birds, and the potential routes of virus transmission."

They propose that
"the immediate duties of our proposed task force are fourfold. First, to gain insight into the global picture of flu, taking into account temporal and geographical variation of the virus, in the different species involved (wild birds, poultry, humans, other domestic animals such as pigs, horses and cats, and other wild animals such as seals, cetaceans and tigers). Second, to prioritize research and integrate knowledge of different disciplines on influenza virus infections. Third, to advance intervention strategies for animal outbreaks and human cases. And fourth, to translate knowledge into policy advice, emphasizing the integration of human and animal health strategies."

The also argue that surveillance and monitoring can help reduce not only the threat of an avian influenza pandemic, but also save millions of dollars, with an estimated cost of $1.5 million/year to establish and run the network, as opposed to the hundreds of millions of dollars spent each year to combat the spread of H5N1 in several Asian countries.

Wild Bird Monitoring In Singapore

According to the Gulf Times, agencies in Singapore are monitoring wild birds for H5N1 bird flu viruses. The story reports that the state-run Agri-Food and Veterinary Authority (AVA), as well as the National Parks Board "have an ongoing surveillance programme to test for avian flu in wild birds at reserves. Nets are set about at various locations in the early morning and late evenings. The AVA said it then collects blood and stool samples from the birds and tests them for the deadly H5N1 strain.
The tests have turned up negative to date."

According to the Wild Singapore Website, the AVA "now tests migrating birds twice a month instead of once during the migratory season of September to March."

The reports do not indicate which species are being monitored.

Africa Bird Flu in Financial Times

University of London Professor E.G. Nisbet commented in the Financial Times this weekend about the likelihood of waterfowl carrying H5N1 avian influenza to Africa. He mentioned Garganey as a possible carrier and transmitter of the virus, a possibility I mentioned here last week.

Friday, October 28, 2005

H5N1 High Risk birds in Europe

An EU press release from last month suggests that member states should enhance surveillance for avian influenza viruses in wild birds this winter. States are requested to identify species of wild birds presenting higher risk based on--
a) origin and migratory flyways,
b) numbers in the EU, and
c) likelihood of contact with domestic poultry

A provisional list of higher risk birds included the following 15 species: White-fronted Goose, Bean Goose, Mallard, Gadwall, Northern Pintail, Northern Shoveler, Eurasian Wigeon, Common Teal, Garganey, Common Pochard, Tufted Duck, Northern Lapwing, Ruff, Black-headed Gull, and Common Gull.

As many of these birds are occasional vagrants to Eastern North America from Europe, if H5N1 becomes endemic in the European population of any of these species, there is a remote chance that one of these birds could carry the virus to North America during fall migration.

However, if H5N1 is to be carried to North America by wild birds, it is still more likely to arrive via Alaska, where populations of many more Asian birds cross over to nest in Western Alaska, and where populations of a few North American species (such as Sandhill Crane) cross over into Siberia during the breeding season.

Additional monitoring of live and apparently healthy birds is needed, and though this provisional list of higher risk European birds is a good initial guide for testing, the announcement today of H5N1 in a heron in Romania underscores the need to test additional wetland birds for the virus.

Mallards and Avian Influenza Viruses in Northern Europe

A study recently published by the CDC examines H5 and H7 influenza strains found in Mallards in the Netherlands and Sweden. Since many of the strains they found in Mallards were closely related to more pathogenic strains that caused outbreaks in Europe, the authors claim that "the minor genetic and antigenic diversity between the viruses recovered from wild birds and those causing HPAI outbreaks indicates that influenza A virus surveillance studies in wild birds can help generate prototypic vaccine candidates and design and evaluate diagnostic tests, before outbreaks occur in animals and humans."

Since low pathogenic avian influenza (LPAI) strains can become precursors to more dangerous HPAI strains, a proactive approach to avian influenza management would involve widespread testing of birds for all avian influenza A viruses, not just testing of sick birds for H5N1.

Monitoring for H5N1 in Israel

A USA Today story from yesterday has Yossi Leshem, an ornithologist and director of the International Center for the Study of Bird Migration at Latrun, claiming that their six banding stations are not enough to effectively carry out surveillance for avian influenza H5N1 virus in Israel. According to the article, Leshem stated that "at least a dozen additional banding stations are necessary."

If at least 18 banding stations are needed to keep an eye out for H5N1 in the small state of Israel (20,840 square miles), how many stations would be needed to find and track the virus in the United States (3,537,441 square miles)?

The pressing need for widespread and extensive monitoring of avian influenza (and other zoonotic viruses) is a challenge and opportunity. Will we build a one-time wind-gauge to find and identify H5N1 when it comes to North America, or will we create a system of continual, long-term monitoring that will help us track emerging viral storms for years to come?

Avian influenza stories

I've recently been quoted in a couple avian influenza stories, the latest on the National Geographic website.

That article slightly overstates the risk of H5N1 transmission from wild birds in Africa by stating that "many" birds that may carry H5N1 are now arriving in Africa. More correctly, "some" birds that may carry H5N1 are now arriving in Africa. While many birds "may" have the virus (we need more testing), only a few birds nesting in central Asia (where the virus was found in wild birds this summer) make it all the way to sub-Saharan Africa. Of the species found infected in Asia that make it to Africa, the most likely candidate for virus transmission may be Garganey (see my post below)--though still no direct evidence that this species is carrying the virus out of Asia.

At the end of this article, Gary Allport did a good job describing the migration and potential threat of transmission from wild Mallards.

The second article is a press release put out by the Wild Bird Feeding Industry. Lots of interesting info there for people worried about getting bird flu from bird feeders or birds in their backyards. The skinny on that is: no real threat right now, but wash up after potentially coming into contact with bird droppings.

Bird Flu test results from Alaskan wild birds

According to the latest report, no H5N1 found in Alaska. But only 290 of 4,500 samples have been screened so far. Lets keep our fingers crossed.

Wednesday, October 26, 2005

H5N1 bird flu already in Africa?

An interesting report from last year found that ostriches in South Africa were testing positive for antibodies to H5 virus. However, apparently the virus they had been infected with was H5N2, not the H5N1 virus that we are currently worried about birds carrying to Africa. How many other birds in Africa have already experienced H5N2 infections, and how will that impact their ability to withstand potential future H5N1 infections? Have birds with H5N1 already reached Africa in past years? Unfortunately, we know very little about the extent and distribution of H5 infections in birds. Since the first H5 virus to be detected (H5N3) was from a tern in South Africa in 1961, some forms of H5 virus have apparently been in Africa for as long as we've known about them.

With media speculation about H5N1 being carried to Africa by migratory birds, there has been little discussion of the exact mechanism for this to take place. Mallards, which have been shown in the lab to be able to harbor and transmit some H5N1 genotypes without showing signs of infection, are found in marshlands in North Africa, but are not as common throughout the continent. Most Mallards in Africa are also probably from Western Europe, where the virus is not yet thought to be widespread.

Garganey, a small Asian teal, may be a more likely candidate to carry H5N1 to Africa. While the virus has been found in a Garganey in Russia, it is not known how extensive the virus is in Garganey populations, or how well these birds are able to withstand, carry, and transmit H5N1. If these ducks are able to carry and transmit the virus along their migratory route, they may carry it to Africa, where large flocks spend the day on large lakes and move into rice fields to feed at night. Garganey in Africa reportedly stay well clear of human settlements, so they may not pose an immediate health risk to people, but if they can transmit H5N1 to other local birds, there may be a greater risk of the virus spreading to other birds and even humans.

These are a lot of ifs, but in order to gauge the possibility of H5N1 spreading in Africa, monitoring of Garganey flocks might be a good place to start.

But for real effective virus monitoring, we need a global commitment to widespread surveillance of all wild birds.

Goose and Gulls

Last night I stopped by a pond near my home to see a Greenland race Greater White-fronted Goose in a flock of 60 Canada Goose. This is a fairly rare bird in this part of the world, and has arrived a bit earlier than most reports. The bird is smaller than a Canada Goose, with bright orange legs and beak. Fun to see something walking around your neighborhood that spent this past summer in Greenland.

At work this morning, I finally found 2005 yard bird #103--three Herring Gulls flying over with a flock of 86 Ring-billed Gulls. Still hoping to have a Lesser Black-backed Gull fly through sometime this year. The best place in North America to see Lesser Black-backed Gulls, an uncommon bird in most of the Northeastern United States is Peace Valley Park a few miles from here.

Tuesday, October 25, 2005

US Plan for Bird Flu Testing

Bloomberg has a story about the U.S. plans to monitor birds for the arrival of H5N1 in North America. The article reports that ten species have been tested in Alaska--Pacific Black Brant; Emperor Goose; Northern Pintail; Steller's Eider; Rock, Dunlin, Western and Sharp-tailed Sandpipers; Black Turnstone, and Bar-tailed Godwit. Birds considered for testing in the Eastern United States include Canada Goose and Snow Goose.

While its good that a range of birds are being tested, the testing may not be wide enough to find other avian influenza strains in other species--a concern since the virulent strain of H5N1 probably developed in the bird markets of Hong Kong when genetic material from a quail virus combined with material from a duck virus. If other bird species carrying other virus strains become infected with the current H5N1 virus, further mutations may arrise that prove deadly to additional species.

The UN Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention) has called for
--global surveillance of avian influenza in wild birds,
--regulation of animal markets--
--suspension or restriction of the global wild bird trade
--improved standards in poultry farms
--identification of precise migratory routes of waterbirds and the highest risk locations along different flyways

Saturday, October 22, 2005

Bird Flu in Wild Birds

I've been working overtime trying to keep up with the latest news about H5N1 bird flu in Asia and Europe. The latest updated statement from National Audubon is here.

More and more evidence is coming in of wild birds being found infected with H5N1, increasing the possibility that wild birds may be spreading it from Central Asia to Europe. However, since domestic ducks can also transmit the virus without showing signs of infection (see abstract of latest study here), legal and illegal movement of domestic ducks is another potential source of virus transmission that we may not have a good handle on.

Latest reports of wild birds with H5N1 include Mallard, Garganey, Great-creasted Grebe, Green Sandpiper, and Coot in Russia, Bar-headed Goose and Whooper Swan at Erhal Lake in Mongolia, and a boat intercepted off the coast of Taiwan held an illegal shipment of cage birds out of China that included mynahs, a black-naped orioles, and Chinese nightingales infected with H5N1. Whooper Swans have also tested positive for H5N1 in Croatia and Romania. Right now, most testing for H5N1 occurs when sick birds are found. That's a good way to help confirm H5N1 outbreaks, but does little to help understand where the virus is, the full range of species it is infecting, and the risks of transmission to other domestic and wild birds.

What we really need is a comprehensive, systematic, and long-term program to survey avian viruses in multiple species across the globe. Checking for viruses only when we find sick birds is like taking a wind speed reading during a hurricane--valuable info, but not as valuable as the ability to track, predict, and prepare for a hurricane when it is still at a distance. Right now, there is a potential hurricane of avian influenza--but we don't have a good idea of when and where it might strike. We don't know how many bird already have H5N1, where those birds are, and what other avian influenza strains are out there that it might swap genes with.

Imagine hurricane predictions without doppler radar. That's just about where we are at with avian influenza tracking right now. Researchers in Alaska are testing waterfowl for the virus, including Steller's Eider, Emperor Goose, and Northern Pintail. Canada has started a system to survey mallard flocks for avian influenza viruses--but what about other waterfowl and shorebirds species? With more reports of Passerines (song birds) testing positive for H5N1, maybe we should be testing more widely? A United States Interagency Working Group is working on a plan to test for H5N1 across the United States in response the the current threat--but what is needed is a longer-term plan to not only test for H5N1, but to track all avian influenza strains. We don't just need a way to track this influenza storm, but future storms as well.

More New Yard Birds

A Palm Warbler, an Orange-crowned Warbler, and a White-crowned Sparrow were new yard birds at work on Thursday. Lots of migrants were found in the region, with heavy movements caught on radar each night this week. Rain this weekend is keeping me in, but should be good time to look for migrant ducks--including scoters--on local lakes. Winter is coming, but lots of birds on the move.

Friday, October 14, 2005

Bird Flu

One of the fun things about living with birds is that sometimes we even share the same germs. In the case of avian influenza, this has become somewhat of a problem, with millions of people around the world starting to wonder, in some sort of Hitchcockian fashion, if birds are going to kill them.

The good news is that so far, most people are at very little risk from avian influenza or "bird flu". While the virus is spreading towards Europe, there is little evidence that wild birds are spreading the virus. And the virus is not easy to catch from birds, and is even harder to catch from other humans.

For a statement on the relationship between wild birds and avian influenza, with some good links, see this statement by the National Audubon Society.

New Yard Birds

After a week of rain, it let up a little this morning so I took a walk around the office (160 acre farm) and found a couple new birds for my 2005 yard list. The most expected was a Great Blue Heron. These are common in the area, and we even have a creek on the property, but so far this is the first one I've seen here this year. It was merely flying overhead and didn't stop.

I also found a Winter Wren down in a tangle of multiflora rose, but the best bird was a single Rusty Blackbird. These birds are becoming much more rare, they're population has plummeted. According to recent analysis of Christmas Bird Count records, Rusty Blackbirds have experienced a 5.2% annual decline, a total decline of 86% over 39 years, a loss of nearly 13 million Rusty Blackbirds since 1965/66. They breed in the boreal forests up north, and winter in the SE United States. This one was probably just moving through. Nice way to start the day.

Rusty Blackbirds have a variable plumage depending on age, sex, and time of year. A photo of a bird that looks like the one I saw this morning is online here.

Thursday, October 06, 2005

Pine Run

Stopped by Pine Run on the way to work this morning. 23 species, including a nice juvenile Bald Eagle. Otherwise just the common local stuff, though Canada Goose numbers are increasing as we get closer to winter (over 500 there this morning). Still 11 Pectoral Sandpipers on the mudflats. For gull fans, 2 Lesser Black-backed Gulls were joined there this morning by 9 Ring-billed Gulls.

Tuesday, October 04, 2005

Honey Hollow

This past weekend I took my three kids for a morning of salamander catching in the creek at Honey Hollow Education Center here in Bucks County, PA. The kids enjoyed turning over rocks and catching larval red-backed salamanders and small crayfish--as well as the green frog I caught. For me, I also enjoyed my first Pileated Woodpecker I've seen in Pennsylvania, as well as a furtive Winter Wren. The woodpecker let out with its insanely wild call (listen here) from nearby as we were playing in the creek, and I got a fleeting look as it disappeared through the trees. Not a great sighting, but a neat wild experience nonetheless.
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