Ducks are displayed for sale at a market in Phnom Penh April 6, 2006. Bird flu has killed a 12-year-old boy in Cambodia, the impoverished Southeast Asian nation's sixth victim, the World Health Organisation said on Wednesday. REUTERS/Chor SokuntheaBy Marwaan Macan-Markar
BANGKOK, Apr. 11, 2006 (IPS/GIN) -- When a 12-year-old boy became Cambodia's latest victim of bird flu early this month, it only added to the uncertainties for scientists and doctors struggling to head off a possible pandemic.
Health investigators in the boy's village in the south-eastern province of Pre Veng discovered that more than 20 people who had close contacts with the victim had shown no sign of illness from the H5N1 virus. They, like the boy, lived in a neighborhood where "numerous chicken deaths and some duck deaths were noted to have occurred," states the World Health Organization (WHO).
On the other hand, the case of the boy -- who died after gathering dead chickens for consumption in his village -- showed just how potent the avian flu virus can be when it strikes. All six people known to have been infected in Cambodia over the last year have died.
None of the other nine countries where bird flu has killed humans since the beginning of 2004 has Cambodia's 100 percent fatality rate. In Indonesia, 12 of the 13 people infected since January this year died, followed by China, where there have been six fatalities among eight cases, and Azerbaijan, where five of seven cases turned fatal.
In October last year, 20 months after bird flu outbreaks were first reported in Southeast Asia, the fatality rates were hovering around 50 percent, with 62 deaths out of 121 reported cases.
The current human toll is 109 people out of 192 reported infections. Worst-hit is Vietnam, where 42 people have died out of 93 cases, followed by Indonesia, where there were 23 human fatalities out of 30 cases, and Thailand, where 14 of 22 cases ended in death.
This erratic pattern of the virus, though, is prompting U.N. experts to conclude that the H5NI strain of avian influenza is still weak and far from mutating into a strain that could be passed among humans and possibly trigger a pandemic.
"This virus when it infects humans is doing so sporadically," Dr. David Nabarro, the senior U.N. system coordinator for avian and human influenza, told reporters here Monday. "It is very, very infrequent that humans do get infected. And we can't always explain why one person gets it and another person doesn't."
The unpredictable quality demonstrated by this lethal virus is part of its nature, added Dr. Somchai Peerapakorn, an epidemiologist at the WHO's Thailand office. "We are dealing with the influenza A virus that changes with every generation, because it undergoes mutation all the time and randomly.
"We know that the virus is mutating but we don't know when the virus will mutate to give an offspring that is lethal to humans with transmissibility characteristics that will give the human-to-human transmission," he said. "At the moment it is still a bird virus and not a human virus."
But there is little room for comfort, he cautions, given that the WHO has warned that a human-to-human transmission of the virus could kill millions around the world, since humans lack natural immune defense to fight a mutated form of the H5N1 strain. The flu pandemic of 1918, which crossed the species barrier from birds to humans, killed close to 50 million people.
The prospect of such a threat will remain due to another quality of the H5N1 strain of the virus, according to the global health agency. It has the properties to "acquire genes from viruses infecting other animals."
According to animal health experts, human activity holds the key to preventing this lethal virus from remaining in circulation and jumping species. "Human activity (through the trade and marketing of poultry) is the main spreader of the virus," said He Changchui, head of the Asia-Pacific regional office of the Food and Agriculture Organization (FAO).
And the concerted efforts in Thailand and Vietnam to bring avian flu under control are being singled out as examples for other developing countries to follow. "There have been no new outbreaks of animal or human influenza in Thailand over the past five months," said He. "The disease is well controlled. The last outbreak was in October."
In Thailand, nearly half of the country's 76 provinces were hit by the lethal virus during its height two years ago. A combination of government and private sector initiatives, including the use of an army of health volunteers to make regular checks on homes, helped bring the virus under control.
Vietnam's success, according to the U.N. agriculture agency, lies in its countrywide poultry vaccination campaign. "(Poultry) owner compensation schemes have not only helped alleviate economic hardship (but) has also encouraged timely reporting of new avian influenza outbreaks," adds the FAO.
Cambodia, on the other hand, is a reason for concern, since villagers are still reluctant to report new outbreaks of bird flu, as was the case in the village where the 12-year-old boy died. A similar situation prevails in another bird flu-infected country, the secretive, military-ruled Burma.
"We are concerned that any weak link could affect the whole system (to control the spread of bird flu)," says Somchai.
Health investigators in the boy's village in the south-eastern province of Pre Veng discovered that more than 20 people who had close contacts with the victim had shown no sign of illness from the H5N1 virus. They, like the boy, lived in a neighborhood where "numerous chicken deaths and some duck deaths were noted to have occurred," states the World Health Organization (WHO).
On the other hand, the case of the boy -- who died after gathering dead chickens for consumption in his village -- showed just how potent the avian flu virus can be when it strikes. All six people known to have been infected in Cambodia over the last year have died.
None of the other nine countries where bird flu has killed humans since the beginning of 2004 has Cambodia's 100 percent fatality rate. In Indonesia, 12 of the 13 people infected since January this year died, followed by China, where there have been six fatalities among eight cases, and Azerbaijan, where five of seven cases turned fatal.
In October last year, 20 months after bird flu outbreaks were first reported in Southeast Asia, the fatality rates were hovering around 50 percent, with 62 deaths out of 121 reported cases.
The current human toll is 109 people out of 192 reported infections. Worst-hit is Vietnam, where 42 people have died out of 93 cases, followed by Indonesia, where there were 23 human fatalities out of 30 cases, and Thailand, where 14 of 22 cases ended in death.
This erratic pattern of the virus, though, is prompting U.N. experts to conclude that the H5NI strain of avian influenza is still weak and far from mutating into a strain that could be passed among humans and possibly trigger a pandemic.
"This virus when it infects humans is doing so sporadically," Dr. David Nabarro, the senior U.N. system coordinator for avian and human influenza, told reporters here Monday. "It is very, very infrequent that humans do get infected. And we can't always explain why one person gets it and another person doesn't."
The unpredictable quality demonstrated by this lethal virus is part of its nature, added Dr. Somchai Peerapakorn, an epidemiologist at the WHO's Thailand office. "We are dealing with the influenza A virus that changes with every generation, because it undergoes mutation all the time and randomly.
"We know that the virus is mutating but we don't know when the virus will mutate to give an offspring that is lethal to humans with transmissibility characteristics that will give the human-to-human transmission," he said. "At the moment it is still a bird virus and not a human virus."
But there is little room for comfort, he cautions, given that the WHO has warned that a human-to-human transmission of the virus could kill millions around the world, since humans lack natural immune defense to fight a mutated form of the H5N1 strain. The flu pandemic of 1918, which crossed the species barrier from birds to humans, killed close to 50 million people.
The prospect of such a threat will remain due to another quality of the H5N1 strain of the virus, according to the global health agency. It has the properties to "acquire genes from viruses infecting other animals."
According to animal health experts, human activity holds the key to preventing this lethal virus from remaining in circulation and jumping species. "Human activity (through the trade and marketing of poultry) is the main spreader of the virus," said He Changchui, head of the Asia-Pacific regional office of the Food and Agriculture Organization (FAO).
And the concerted efforts in Thailand and Vietnam to bring avian flu under control are being singled out as examples for other developing countries to follow. "There have been no new outbreaks of animal or human influenza in Thailand over the past five months," said He. "The disease is well controlled. The last outbreak was in October."
In Thailand, nearly half of the country's 76 provinces were hit by the lethal virus during its height two years ago. A combination of government and private sector initiatives, including the use of an army of health volunteers to make regular checks on homes, helped bring the virus under control.
Vietnam's success, according to the U.N. agriculture agency, lies in its countrywide poultry vaccination campaign. "(Poultry) owner compensation schemes have not only helped alleviate economic hardship (but) has also encouraged timely reporting of new avian influenza outbreaks," adds the FAO.
Cambodia, on the other hand, is a reason for concern, since villagers are still reluctant to report new outbreaks of bird flu, as was the case in the village where the 12-year-old boy died. A similar situation prevails in another bird flu-infected country, the secretive, military-ruled Burma.
"We are concerned that any weak link could affect the whole system (to control the spread of bird flu)," says Somchai.
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