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Source: http://www.jsonline.com/story/index.aspx?id=735618
Scientists study spread, worry about hot spots
By SUSANNE RUST
srust@journalsentinel.com
Posted: April 6, 2008
Although media coverage of bird flu has dwindled in the past couple of years, the virus is still smoldering, experts say.
Since 2003, 373 people have been infected with the avian flu, known as H5N1. More than 60% of those people have died.
And while researchers are still closely monitoring the disease, many are beginning to question whether it will become the pandemic they predicted a few years ago.
In 2006, at the flu's peak, there were 115 human cases. In 2007, that number dropped by 25%, to 87 human cases.
"The virus has had millions upon millions, if not trillions of opportunities to evolve" into a pathogen that could jump easily between people, said William Schaffner, a flu expert at Vanderbilt University in Nashville, Tenn.
So far, it hasn't.
Since the beginning of this year, there have been 24 confirmed cases and 19 deaths.
But both Schaffner and Dennis Maki, an infectious disease expert at the University of Wisconsin-Madison, say the debate about what this virus will do is far from resolved.
"My own belief is it won't become the pandemic" many had originally anticipated, Maki said. "It's had a lot of opportunities to evolve over the last five years. Yet we've had less than 1,000 cases worldwide."
But, he added, "it would be very dangerous to say never."
In the meantime, health officials are closely monitoring the disease and keeping a wary eye on two countries: Egypt and Indonesia.
According to the World Health Organization, Egypt is the only country where the incidence of the disease in people has been on the rise. In 2006, there were 18 cases in this North African country. In 2007, that number had jumped to 25.
The country has been particularly susceptible, experts say, because of its location on a major migratory bird route and the widespread practice of people living within the country who keep domestic fowl near their homes.
Researchers think migratory birds brought the virus into Egypt, where it jumped to domestic birds, such as chickens and ducks.
But the real concern is in Indonesia, where the government has done little to stop the spread of the disease.
Maki said countries such as South Korea, Vietnam and Malaysia have been ruthless in their fight against the virus: They have culled and vaccinated birds, as well as stopped the movement of domestic birds in affected regions.
Maki and Schaffner say the Indonesian government hasn't followed suit, and if the virus were to mutate and become a lethal disease that could be passed easily from person to person, it would be there.
Although the virus has not become a human scourge, the disease is now endemic in birds throughout Europe and Asia. Just last week, officials in Switzerland detected the disease in several migrating birds.
Poultry are suspects
However, Schaffner said while researchers had thought just a few years ago that migrating birds were the primary contributors to the spread of the disease, many now think it is the commercial movement of domestic poultry that is the key.
He said researchers are discovering that domestic birds may be able to harbor the disease for extended periods, without showing signs of illness. Most wild birds become sick quickly.
"You'd be surprised at how much international movement there is of chickens," Schaffner said.
That may be why the Western hemisphere has, so far, been buffered against the spread of the disease, he said. If the major mode of transmission was wild, migrating birds, we should have detected it in North America by now.
Transoceanic distribution of commercial poultry isn't as common as movement within continents.
Both Maki and Schaffner stressed that pandemic awareness and readiness must remain a priority for governments worldwide.
"We have to continue to plan and maintain the infrastructure to respond to outbreaks, whether it is pandemic flu, bioterrorism or new infectious diseases like SARS," Schaffner said.
Scientists study spread, worry about hot spots
By SUSANNE RUST
srust@journalsentinel.com
Posted: April 6, 2008
Although media coverage of bird flu has dwindled in the past couple of years, the virus is still smoldering, experts say.
Since 2003, 373 people have been infected with the avian flu, known as H5N1. More than 60% of those people have died.
And while researchers are still closely monitoring the disease, many are beginning to question whether it will become the pandemic they predicted a few years ago.
In 2006, at the flu's peak, there were 115 human cases. In 2007, that number dropped by 25%, to 87 human cases.
"The virus has had millions upon millions, if not trillions of opportunities to evolve" into a pathogen that could jump easily between people, said William Schaffner, a flu expert at Vanderbilt University in Nashville, Tenn.
So far, it hasn't.
Since the beginning of this year, there have been 24 confirmed cases and 19 deaths.
But both Schaffner and Dennis Maki, an infectious disease expert at the University of Wisconsin-Madison, say the debate about what this virus will do is far from resolved.
"My own belief is it won't become the pandemic" many had originally anticipated, Maki said. "It's had a lot of opportunities to evolve over the last five years. Yet we've had less than 1,000 cases worldwide."
But, he added, "it would be very dangerous to say never."
In the meantime, health officials are closely monitoring the disease and keeping a wary eye on two countries: Egypt and Indonesia.
According to the World Health Organization, Egypt is the only country where the incidence of the disease in people has been on the rise. In 2006, there were 18 cases in this North African country. In 2007, that number had jumped to 25.
The country has been particularly susceptible, experts say, because of its location on a major migratory bird route and the widespread practice of people living within the country who keep domestic fowl near their homes.
Researchers think migratory birds brought the virus into Egypt, where it jumped to domestic birds, such as chickens and ducks.
But the real concern is in Indonesia, where the government has done little to stop the spread of the disease.
Maki said countries such as South Korea, Vietnam and Malaysia have been ruthless in their fight against the virus: They have culled and vaccinated birds, as well as stopped the movement of domestic birds in affected regions.
Maki and Schaffner say the Indonesian government hasn't followed suit, and if the virus were to mutate and become a lethal disease that could be passed easily from person to person, it would be there.
Although the virus has not become a human scourge, the disease is now endemic in birds throughout Europe and Asia. Just last week, officials in Switzerland detected the disease in several migrating birds.
Poultry are suspects
However, Schaffner said while researchers had thought just a few years ago that migrating birds were the primary contributors to the spread of the disease, many now think it is the commercial movement of domestic poultry that is the key.
He said researchers are discovering that domestic birds may be able to harbor the disease for extended periods, without showing signs of illness. Most wild birds become sick quickly.
"You'd be surprised at how much international movement there is of chickens," Schaffner said.
That may be why the Western hemisphere has, so far, been buffered against the spread of the disease, he said. If the major mode of transmission was wild, migrating birds, we should have detected it in North America by now.
Transoceanic distribution of commercial poultry isn't as common as movement within continents.
Both Maki and Schaffner stressed that pandemic awareness and readiness must remain a priority for governments worldwide.
"We have to continue to plan and maintain the infrastructure to respond to outbreaks, whether it is pandemic flu, bioterrorism or new infectious diseases like SARS," Schaffner said.