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  National Geographic 5 Dec 06
U.S. Bird Flu Detection Plan Is Wild Goose Chase, Study Says
Adrianne Appel

Yahoo News 4 Dec 06
Scientists criticize bird flu search
By Libby Quaid, AP Food and Farm Writer

WASHINGTON - Birds from Latin America--not from the north--are most likely to bring deadly bird flu to the main U.S., researchers said Monday, suggesting the government might miss the H5N1 virus because biologists have been looking in the wrong direction.

The United States' $29 million bird flu surveillance program has focused heavily on migratory birds flying from Asia to Alaska, where researchers this year collected tens of thousands of samples from wild birds nesting on frozen tundra before making their way south.

Those birds present a much lower risk than migratory birds that make their way north from South America through Central America and Mexico, where controls on imported poultry are not as tough as in the U.S. and Canada, according to findings in the latest Proceedings of the National Academy of Sciences.

Nations south of the U.S. import hundreds of thousands of chickens a year from countries where bird flu has turned up in migratory birds or poultry, said A. Marm Kilpatrick, lead author of the study.

"The risk is actually higher from the poultry trade to the Americas than from migratory birds," said Kilpatrick, of the Consortium for Conservation Medicine in New York. Other researchers on the study came from the Smithsonian Institution.

If bird flu arrives in Mexico or somewhere farther south, it could be a matter of time before a migratory bird carries the virus to the United States, Kilpatrick said.

"It's not just a matter of worrying about who you trade with, but it's a matter of thinking about who do your neighbors trade with, and who do your trading partners trade with," Kilpatrick said. "We need to be looking both south and north."

The study concluded that "current American surveillance plans that focus primarily on the Alaskan migratory bird pathway may fail to detect the introduction of H5N1 into the United States in time to prevent its spread into domestic poultry."

The report is the first to combine the DNA fingerprint of the H5N1 virus in different countries with data on the movement of migratory birds and commercial poultry in those countries.

The analysis helped to determine, for example, that the outbreak of bird flu in Turkey likely didn't come from poultry imports from Thailand, as previously thought. Instead, the probable source was migratory birds in Russia, where the virus had similar DNA to the virus in Turkey.

The study found that:
=Bird flu was spread through Asia by the poultry trade.
=Most of the spread throughout Europe was from migratory birds.
= Bird flu spread into Africa from migratory birds as well as poultry trade.

U.S. officials cautioned that the study is not the final authority on the spread and prevention of bird flu.

"When you look at scientific literature, it's a big puzzle. This puts in a few more pieces," said David Swayne, director of the Agriculture Department's Southeast Poultry Research Laboratory in Athens, Ga.

Swayne cautioned that researchers looked only at countries' import restrictions through 2005. "I'm not saying it's the fault of the study; the study is designed to look at what happened in the past," Swayne said. "We have to be very careful not to over-interpret. There is a limit on how recent the data is."

In addition, Agriculture Department officials said they are not focusing exclusively on Alaska. More resources have been spent in Alaska than in other states so far, but testing is happening throughout the lower 48, and the U.S. is even helping Mexico do surveillance, said Tom DeLiberto, the department's National Wildlife Disease Coordinator.

"We have more information now than we did when we designed the surveillance effort last fall," DeLiberto said. "We knew that we had limited information and couldn't design a system that looked at just Alaska," he said. "You have to build a robust system that could cover a lot of different potential pathways. We know as we get more information, we'll adapt our system."

Since the deadly H5N1 virus emerged in Hong Kong in 1996, at least 154 people have died and hundreds of millions of chickens, ducks, geese and turkeys have died or been killed to keep it from spreading.

So far, the virus has killed mostly people who had close contact with sick birds or their droppings, but scientists fear the virus could someday mutate into a form that spreads easily among people.

National Geographic 5 Dec 06
U.S. Bird Flu Detection Plan Is Wild Goose Chase, Study Says
Adrianne Appel

Officials are looking in the wrong place to stop the spread of bird flu to the U.S., a new study suggests.

The report predicts that bird flu will likely spread to the Americas through infected poultry. This poultry may then infect local wild birds, which could carry the disease from Latin America or Canada to the United States.

The U.S. is currently testing thousands of wild birds in Alaska, because authorities believe the flu is likely to be carried from Asia to the U.S. by migrating waterfowl.

The new report, from the New York-based Consortium for Conservation Medicine, studied migration patterns and the bird trade. The study suggests that birds migrating from Siberia to Alaska are unlikely to carry the virus and that few of those birds ultimately fly farther south.

"We share very few migratory birds with Europe and Siberia. There are ducks and geese that winter in Siberia and molt in Alaska, but they don't come down here," said research scientist A. Marm Kilpatrick, co-author of the study.

The U.S. has also been trying to keep the disease at bay by testing and quarantining all poultry imported from infected regions of Europe, Asia, and Africa.

But there is very little poultry trade between Asia and Europe and the U.S., Kilpatrick said, so the risk of the U.S. getting infected that way is very low. Furthermore, few birds migrate between Europe and the Americas, Kilpatrick added.

A far greater risk is that many countries in Latin America import poultry from infected regions of Europe and do not have strict testing and quarantine systems in place, Kilpatrick said.

In addition, more than four million birds migrate annually between the U.S. and Latin America. "If your neighbor gets the virus and birds migrate, you're at risk,'' he said.

His team's research appears in today's issue of the Proceedings of the National Academy of Sciences.

Triple Threat

The H5N1 avian virus originated in Hong Kong and spread rapidly through much of Asia before continuing to Africa and Europe. It is fatal to birds and can be transmitted to humans through close contact with birds, for example, on poultry farms.

So far the disease has killed 151 people, but the virus in its current form cannot be transferred from human to human.

In his team's current research, Kilpatrick found that the virus spread through Southeast Asia primarily through the poultry trade, but migrating birds were mainly to blame for carrying the disease from Asia to Europe.

"The question now is, How will it get to the U.S.,?" Kilpatrick said.

Ken Rosenberg of Cornell University's Laboratory of Ornithology was not involved in the study, but he agrees that testing birds in Alaska may not protect the U.S. from the virus.

"To my knowledge, all the testing has been negative. They haven't found it coming in through birds that way,'' Rosenberg said. Rosenberg thinks it's possible that the virus will come to the U.S. from Latin America, not through migrating birds but through the legal or illegal pet-bird trade.

Mulit-Nation Plan Is Key

Kilpatrick's team found that the virus has spread easily so far due to both the global trade in birds and the migration of wild birds, chiefly geese, swans, and ducks. The team examined the spread of the virus into 52 countries.

In each instance the researchers determined whether transmission occurred through the legal poultry trade, the wild-bird trade, migrating birds, or some combination of these. The scientists also estimated the number of birds that enter or leave a country, how many of them were likely infected, and how long the birds remained contagious.

The team then ran genetic tests on the viruses found in infected birds, which helped reveal how the virus spread from region to region.

Turkey, for example, has a thriving poultry trade with Thailand as well as a heavy influx of migrating birds from Russia. Scientists weren't sure which pathway brought the virus to the country.

"But then we took a look at the [genetic] isolates, and they were much more related to Russia," Kirkpatrick said. This led his team to conclude that the likely source of bird flu in Turkey was Russian migrating birds.

The case of Turkey may offer a lesson the U.S., Kilpatrick suggested.

An effective way to keep the U.S. free from bird flu would be to work with Latin American countries on a regional system of testing and quarantining imported poultry, he said.

"If we want to be as safe as possible, we would want all our neighbors to have the same safeguards we do," Kilpatrick said.

His team has not heard from U.S. policymakers about the suggestions put forward in the new study. But Kilpatrick said he hopes decision-makers will refer to the research when considering future bird-flu prevention plans.

"If you're going to make policy decisions, it's best to look at data,'' he said.
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