WHO Reports Mutation in Human-to-Human Bird Flu
Saturday, June 24, 2006
JAKARTA, Indonesia, June 23 -- The World Health Organization has detailed the first evidence that a person probably caught the bird flu virus from a human, then passed a slightly mutated version to another person. But experts said Friday that the genetic change does not increase the threat of a pandemic.
The H5N1 mutation occurred in a 10-year-old Indonesian boy who was part of the largest group of infected people ever reported, according to an investigation. The first of those people to contract the virus is thought to have been infected by poultry. It is thought that she passed it to the boy and five other blood relatives.
The boy is thought to have infected his father, who had the same mutation, according to the report obtained by the Associated Press. Only one infected family member survived.
"It stopped. It was dead end at that point," said Tim Uyeki, an epidemiologist with the U.S. Centers for Disease Control and Prevention in Atlanta.
Uyeki, who was part of the investigating team, stressed that viruses are always slightly changing and that there was no reason for this mutation to raise alarm because the virus has not developed the ability to spread easily among people.
David Nabarro, who oversees bird flu issues for the United Nations, said the findings nevertheless emphasized the importance of continuous monitoring of the H5N1 virus in humans and poultry.
"We were fortunate in that the change that took place did not result in sustained human-to-human transmission," he said by telephone Friday. "This is a vivid reminder of the need to keep a very close watch on what the virus is doing."
Experts fear that the H5N1 virus will eventually mutate into a form that spreads easily among people, potentially sparking a global pandemic. The current virus remains hard for people to catch, and most human cases have been traced to contact with sick birds. Scientists believe limited human-to-human transmission has occurred in a handful of other clusters, all of which involved very close contact.
The WHO report was distributed during a three-day meeting in Jakarta attended by some of the world's top bird flu experts. Indonesian officials called the closed-door session to ask for help in coping with the virus, which has infected more people this year in their country than anywhere else -- last month killing an average of one person every 2 1/2 days.
Keiji Fukuda, acting director of WHO's global influenza program in Geneva, said the cluster in Indonesia last month drew international attention because of its size. Otherwise, he said, it resembles family clusters observed elsewhere.
"What we're really looking for is the kind of human-to-human transmission which can cause large neighborhood outbreaks and big community outbreaks," he said. The virus on Sumatra island did not spread beyond the eight blood relatives; no spouses were infected.
William Schaffner, a bird flu expert at Vanderbilt University in Nashville, called the mutation "noteworthy but not worrisome." Generally it takes a series of mutations in a bird flu virus to increase the danger of a pandemic in humans, he said by telephone.
Schaffner said it is remarkable that scientists were able to discover a mutation that occurred in a remote village. That's the result of intense surveillance linked with "21st-century laboratory virology," he said.