Marwaan Macan-Markar
BANGKOK, Apr 10 2006 (IPS) – When a 12-year-old boy became Cambodia s latest victim of bird flu, at the beginning of this month, it only added to the uncertainties surrounding this lethal virus that worry scientists and doctors struggling to head off a possible pandemic.
Health workers who conducted investigations in the boy s village in the south-eastern province of Pre Veng discovered that over 20 people who had close contacts with the victim had shown no sign of being ill from the H5N1 virus. They, like the boy, lived in a neighbourhood where numerous chicken deaths and some duck deaths were noted to have occurred, states the World Health Organisation (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, died.
None of the 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 South-east Asia, the fatality rates were hovering around 50 percent, with 62 people having died out of 121 reported cases.
The current human toll is 109 people out of 192 reported infections. The 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.
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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 triggering 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 across the world since humans lack natural immune defence 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 Organisation (FAO).
And the successes in Thailand and Vietnam to bring avian flu under control through concerted effort 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.
Thailand s achievement comes after 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, have contributed to this effort.
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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