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WHO Urges Nations World Wide To Prepare For Virus Outbreak
THE United Nations health agency has called on countries around the world to prepare for a threatened flu pandemic after a study in Vietnam showed signs of greater human-to-human transmission of bird flu."If somebody should need warnings that another pandemic is coming, we've had enough and we should continue very intensively with preparations for pandemic preparedness," the World Health Organisation's (WHO) top influenza expert, Dr Klaus Stohr, said. Fears that a deadlier strain of flu might spread rapidly around the world on a similar scale to pandemics of the last century have been revived, with the emergence of the H5N1 bird-flu virus among humans in Asia. The study of human bird-flu outbreaks in Vietnam until April 2005 suggested an evolution of infections by the H5N1 virus. The WHO, which examined the findings with experts from Cambodia, Thailand and Vietnam earlier this month, also called for an immediate boost in monitoring for possible pandemic influenza in all countries affected by H5N1 in birds. "The changes in the epidemiological patterns are consistent with the possibility that recently emerging H5N1 viruses may be more infectious for humans," a report on the study said. While that meant a greater number of people might be infected by poultry, there was also evidence that human-to-human infections, which have been found several times since the strain was first detected in Hong Kong in 1997, was strengthening, the UN health agency said. "It is possible that avian flu viruses are becoming more capable of human-to-human transmission," the report said. The WHO said the study in Vietnam was not conclusive, however, because of the relatively small number of cases. "The report was in a grey zone. We have enough data as scientists to be concerned, but at the same time we don't have enough to be sure," the WHO's head of communicable diseases, Guenael Rodier, said. Although the implications were not clear cut, "they demonstrate that the viruses are continuing to evolve and pose a continuing and potentially growing pandemic threat," the report said. "The train is going in a certain direction and the recent findings are certainly not going to alleviate our concern," Mr Stohr told journalists. Thirty-six people have died from bird flu in Vietnam since 2003, as well as 16 in Thailand and Cambodia. Human-to-human transmission is believed to have occurred in two clusters of cases in Vietnam and one in Thailand. Concerns have been raised because a pandemic strain may develop through a series of small steps that, taken individually, might not be a clear signal an epidemic was about to start, according to the WHO. The changes seen in north Vietnam included more and larger human clusters of the disease, an increased mean age of the victims and a lower fatality rate. "We do expect that a pandemic virus will adapt better to humans, but will be less severe and transmit better," Dr Rodier said. Analysis of genes from bird and human forms of H5N1 from several countries also suggested changes in the virus, the report said. Dr Stohr said three suspected asymptomatic cases in Vietnam - where people are infected with the virus but do not fall ill - were unusual and it was not clear if they were contagious. "Scientifically it would be quite a surprise if asymptomatic carriers were found," he told journalists. Other interpretations for the trends observed in Vietnam were raised, including transmission through contaminated water or food, or infection from poultry that carried the virus but did not show symptoms, or greater persistence of the virus in the environment. A second human case of bird flu was identified in under a week in Vietnam on Tuesday. Posted by: Spavirt Pheng6042 2005-05-20 |
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