ON THE MARCH
Fight against bird flu is a hit-and-miss affair across Asia
By Frank Zeller, Agence France-Presse
HANOI
Bird flu is on the march again across Asia as winter ends, but the battle against the killer virus is being hobbled by stark differences between the region's diverse countries, health experts warn.
While Vietnam and Thailand have been hailed as models in the fight against avian influenza, new cases in hotspot Indonesia and population giant China have highlighted concerns the disease will be hard to stamp out.
Many Asian nations have learned much since the H5N1 strain erupted in Asia in 2003, spreading as far as Europe and Africa last year, but gaps remain and the threat of a pandemic remains real, epidemiologists say.
New human infections in China and Laos and recent animal cases in Myanmar, Pakistan, Afghanistan, and Hong Kong are reminders that the virus "is still entrenched," said Peter Cordingley, press officer for the World Health Organization (WHO). "If you take a broad look at the region, I would say it's pretty much the same as last year, when we saw bird flu move all the way to Africa," he said. "We're seeing signs of that already. We're seeing human cases in Egypt, and inside Asia the virus is obviously becoming quite active."
Bird flu is now popping up in new areas, and risk factors for transmission have increased, said He Changchui, the Asia-Pacific head of the Food and Agriculture Organization (FAO) based in Bangkok. "Last year it seemed we had more association with migrating wild birds, but this year we are also finding trade and the movement of poultry across borders played a very large role," he said. "The virus doesn't know any borders, and due to globalization and increased border trade and more regional integration in goods flows and people travelling, we can easily carry a virus from one country to another."
Yet while some countries, aided by international aid and know-how, have set up extensive surveillance networks, new laboratories, vaccination drives, and education campaigns, other countries lag far behind.
"Without any doubt Indonesia is ground zero globally for bird flu," said Cordingley about the archipelago nation that leads the world's death toll with 63 out of the 167 bird-flu deaths confirmed by the WHO. "The virus has a firm grip on large parts of the country and we're very concerned about Indonesia," he said.
The FAO's He agreed that while "there are some capabilities there, Indonesia is too big a country, and due to the decentralization, more reporting and streamlined information are required."
Cordingley said "some countries have done very well, such as Vietnam and Thailand. But they're seeing cases in poultry, so clearly there's still a big fight to be fought in those two countries."
China, Indonesia, and Vietnam all face similar risks because of their high densities of people and poultry, said Jeff Gilbert, the FAO senior technical adviser on bird flu in Vietnam. "Everything is turning over so fast that you have new and susceptible flocks all the time," he said.
But even the best efforts of rich nations do not guarantee safety. "Japan and Korea certainly jump on it from a height," Gilbert said. "They're doing the Rolls Royce approach, and if they're doing that and still having issues, then the poorer countries will definitely have issues."
Surveillance remained patchy in Cambodia and Laos, which reported its first human case of bird flu. "In Laos there are remote regions without very good surveillance systems in place," said He. "You don't know if something happened there."
Cordingley said many farmers in Indonesia and elsewhere remained ignorant about the threat: "If you own chickens anywhere in this region you have good reason to be cautious around them." On the broad risk of bird flu, he said, "[w]e're careful not to tell people that this is out of control, because it's not out of control."
But he said fear remains that bird flu "jumps to a human being and mutates and turns into a pandemic strain. If it is as virulent in a pandemic form as it is at the moment then quite clearly we would have a public health catastrophe on our hands." M
Global flu pandemic could rival death toll of WWII
PARIS
A global pandemic of a novel, contagious, and lethal form of influenza could kill as many people in a year as died in World War II, according to an estimate by The Lancet.
In a calculation based on mortality from the "Spanish flu" pandemic that ran from 1918 to 1920, US researchers believe 62 million people could die in a space of 12 months if a similar pathogen emerged today. The vast majority of deaths-96 percent-would occur in the developing world.
The study, led by Harvard University professor Christopher Murray, is based on death registration data to estimate deaths from the 1918 pandemic in 27 countries. These data were then extrapolated to the worldwide population of 2004. But gains in prosperity and access to medical care since 1918, as well as changes in the size and age of the populations of countries, were taken into account.
Murray's team believes that between 51 and 81 million people could die, making an average of 62 million, if a similar pandemic were to occur, on the basis of 2004 data. Historians estimate the death toll from World War II at between 50 and 62 million.
The 27 countries included the United States, European nations, Argentina, India, and the Philippines.
The safest place to be would be Denmark, where there would be excess mortality-that is, an increase above the normal death rate-of 0.2 percent over 2004. At the other end of the scale would be India, where the excess mortality would be more than 20 times higher, at 4.39 percent.
The study coincides with the scare surrounding H5N1 bird flu, which is lethal and contagious among birds. The fear is that this virus could acquire genes that would make it easily transmissible among humans, creating as in 1918 and in two other flu pandemics last century a novel pathogen against which no one would have natural immunity.
Murray said the high death toll and its preponderance in developing countries was explained by the different access to vaccination, antiviral drugs, and speedy treatment with antibiotics to treat secondary infections such as pneumonia.
"The predicted mortality today for India is lower than in 1918 because there has been significant advances" in Indian prosperity since then, Murray said. "The predicted mortality for sub-Saharan Africa, though, is probably quite similar to what it was in 1918 because there hasn't been that big a change in per capita income."
But, he said, "[w]e saw a strong relationship between mortality and income in 1918-20, and it was such a strong relationship that there's nothing to suggest that also won't hold true if something like that happened again."
Murray said the findings raised worrying questions about pandemic preparedness in poor countries, such as early provision of antivirals that can slow the spread of a pandemic and swift distribution of a vaccine to deal with the new virus. "Much of the global policy attention on early detection, surveillance, national pandemic preparedness plans is going to benefit high-income and maybe some upper-middle-income countries," he said. "There really hasn't been, I believe, enough attention on practical things that low-income and lower-middle-income countries can do and that is where most of the harm will come."
Breakthrough could halt pandemic
Meanwhile, researchers in the United States believe they have found an easily produced vaccine for H5N1 that could halt a feared pandemic.
Dr. David Ho of the Aaron Diamond Aids Research Center in New York says the vaccine would be "easy to produce, fast to produce and as broadly protective as possible," according to the South China Morning Post.
The report said tests on mice had shown the animals had produced the antibodies necessary to fight the disease.
The report said Ho claims to have overcome the problem of manufacturing enough of the vaccine to get it out fast enough to halt a pandemic. The process involves copying genetic material from flu-virus protein and combining it with antibodies to help stimulate the immune system.
"These days gene synthesis and cloning can be done in a week so you just substitute the genes and use the same technology," Ho was quoted as saying. M AFP
LONG FIGHT
It could take 10 years to reduce the risk of bird flu in Southeast Asia
JAKARTA
Significantly reducing the risk of deadly bird flu in Southeast Asia, the region hardest hit by the virus, could take up to a decade, said the United Nations official heading the global fight against avian influenza.
In an interview with AFP, David Nabarro said changing traditional farming practices across the vast region to reduce the risk of a human pandemic emerging would take several years and a huge political commitment.
However, he said the virus does not appear to be mutating into a form easily transmissible between humans.
"During the time that I've been in this job, I have seen no increase in the risk of a pandemic," he said. "The virus does not seem to have evolved in ways that suggest that it's moving towards being more transmissible between humans, the risk is staying about the same," he said in Indonesia, the nation hardest-hit by avian flu.
Scientists fear that the deadly H5N1 strain could mutate into a form easily transmissible between humans, sparking a pandemic that could kill millions. H5N1 has resurfaced in humans in Indonesia after an apparent lull with five deaths this year, and in poultry outside the region, including, for the first time, in Britain.
Awareness of the threat has increased hugely as well as the need for effective responses from the government, said the doctor, who has headed efforts to fight the disease since September 2005.
"I've seen a huge increase in awareness of problems of highly pathogenic avian influenza, the need for a strong animal health sector, good veterinary services and an effective response in individual countries and in the regional level, particularly in this region, and globally," said Nabarro. "It's not a level where I can say everything's fine, but what I am seeing is things moving in the right direction in most countries, which is immensely gratifying because it's a sign that things are moving well together, that people are prepared to work with each other for the common good."
"The problems that have been faced around bird flu, or avian influenza, are really quite serious in this country," Nabarro said. "The more virus there is in the poultry, the more likely it is that humans will get infected. Fortunately not many are getting infected, but still we've seen quite a lot this year and last year. Secondly, the more virus there is in poultry, the more likely it is that the virus will change and perhaps reach the point where it's capable of being transmitted easily from human to human and that this would give us the potential for an influenza pandemic."
But improving biosecurity-separating humans and animals, improving hygiene and making the public understand the threat of diseases leaping from birds and animals to humans-is going to take time.
"These require changes in practices that have been frankly going as they have for a very long time, so the United Nations' recommendations for transforming the way livestock are reared, will probably take several years and possibly even as much as 10 years to put into practice in this region."
Vaccine can cut severity of attack
Meanwhile, a study published in PLoS Medicine (www.plosmedicine.org), sugests that immunity to seasonal, garden-variety flu viruses may offer some protection from bird flu. The H5N1 bird flu virus is different from the seasonal H1N1 and H3N2 influenza virus strains to which most humans are exposed each year and develop antibodies to.
Prof. Richard Webby and colleagues at St. Jude Children's Hospital in Tennessee wondered whether immunity to N1 human virus strain and the vaccines developed to protect against it could also provide protection against H5N1, which contains the closely related N1 protein strain.
The researchers immunized mice with DNA that caused their cells to make the neuraminidase from an H1N1 virus found in seasonal flu outbreaks. They then examined the immune response of the mice to the proteins of a seasonal flu virus strain and to the H5N1 bird-flu virus isolated from a patient in Vietnam in 2004 who had been in contact with infected birds.
Most of the mice responded to the DNA vaccine by making antibodies that recognized the human N1, and a few also made antibodies against bird N1. All the vaccinated mice survived infection with a man-made flu virus containing N1, and half also survived infection with low doses of a man-made virus containing the bird N1 from an infected Vietnamese patient.
The researchers then tested blood samples from 38 human volunteers for their internal ability to inactivate neuraminidase from an H1N1 seasonal flu virus and two H5N1 bird flu viruses. They found most of the samples were active against the protein from the H1N1 virus, and eight or nine also inhibited the protein from both H5N1 viruses, the researchers said. M AFP
The state of play
PARIS
As of March 1, 167 humans have been confirmed dead and at least 150 million farm birds have been culled worldwide since concern over bird flu began to rise four years ago. The vast majority of cases to date have been recorded in Asia, but early in 2006 the viral disease began showing up in Europe, the Middle East, and Africa.
As defined by the World Health Organization (WHO), avian influenza is a contagious disease of animals caused by viruses that normally infect only birds and, less commonly, pigs. "Avian influenza viruses are highly species-specific, but have, on rare occasions, crossed the species barrier to infect humans," the WHO says.
The virus strain that has caused the most worry, due to its potential to affect humans, is known as H5N1. However scientists say that there are so far few cases of it being spread from humans to other humans, a key precondition for an epidemic.
People heavily exposed to contact with live animals, or involved in slaughtering them, are believed to be most at risk. However, the disease cannot be caught by eating cooked meat, health experts say. M AFP
|
