29 June 2005
U.N. Team Finds No Widespread Bird Flu Infection in Humans, June 29, 2005 (Testing in Vietnam indicates virus has not mutated, scientists report)
By Charlene Porter
Washington File Staff Writer
Washington – An international team of scientists completed a survey in Vietnam June 29 finding that their worst fears about the development of a bird flu pandemic have not yet come true. The dangerous H5N1 virus that has swept through poultry flocks in 10 nations has not changed into a form that is easily transmissible between humans.
“What was reported to the government is that, according to preliminary findings, they could not find any indication showing that the virus has actually extended its range in humans,” said World Health Organization (WHO) representative Hans Troedsson, according to news accounts. “The most important thing is that we could rule out that there was an immediate, imminent pandemic.”
Because the avian influenza virus is still so widespread in the region, the team concludes that the risk of a broader influenza pandemic is still real. WHO headquarters in Geneva reports that the team recommends no change in the current assessment that a risk of severe disease among humans with a high fatality rate is still present.
The team was looking to find signs that H5N1 had mutated to become a virus that is easily transmitted between humans through contact as casual as a cough or a sneeze. If that were to happen, health experts fear a global flu pandemic could result, killing tens of millions of people. The predicted death toll is high because this particular flu strain has rarely occurred in humans, and immunity to it would be very low.
In surveying data submitted by national health authorities in the region, WHO reports that human-to-human transmission is likely to have occurred in two isolated cases involving very close contact among family members. Infection that occurs in this manner is not considered “effective transmission” by disease experts and does not signal that the virus has taken on a form that will allow it to move readily through a community.
Vietnam has experienced the greatest number of human cases of bird flu since the emergence of the virus was first documented in late 2003. Vietnam’s Ministry of Health confirmed a new case June 28 in the northern province of Ha Tay, for a total number of 87 human cases with 38 deaths.
Thailand and Cambodia are the only other countries to report human cases of avian influenza. Together, the three nations have confirmed a total now of 108 cases, but experts have expressed some doubt as to whether the total is accurate. Inadequate health care and disease surveillance in rural areas of these nations may result in human cases going undetected, experts fear.
Surveillance is an important technique for understanding the disease in both human and animal populations. Another WHO team in China urged officials to increase efforts to test birds and humans who have had contact with a saltwater lake where 5,000 migratory birds and geese have died since early May. H5N1 is the apparent culprit in those deaths, and other birds that survived might carry the virus far and wide on long-distance migratory routes. No human cases of the disease have been reported in China.
Japanese agricultural officials also have reported the appearance of another highly infectious strain of bird flu on six farms in Ibaraki Prefecture, and they are in the process of culling some 25,000 birds. This outbreak is the first among Japanese commercial flocks since mid-2004.
