Limited human-to-human transmission of bird flu might have occurred in an Indonesian family but there is no evidence the virus has mutated to allow it to pass easily among people, the World Health Organization said.
Fears of human-to-human transmission pushed down European shares and boosted demand for safe-haven bonds yesterday, lifting benchmark Bund futures to their highest in more than six weeks. The dollar rose against the yen.
Concern has been growing about the case in north Sumatra in which seven family members from a village died this month. The case is the largest family cluster known to date, the WHO has said.
The WHO and Indonesian health officials are baffled over the source of the infection but genetic sequencing has shown the H5N1 bird flu virus has not mutated, the UN agency said on its website (http://www.who.int) on Tuesday. Nor was there any sign of the virus spreading among other villagers.
"To date, the investigation has found no evidence of spread within the general community and no evidence that efficient human-to-human transmission has occurred, the WHO said.
"Sequencing of all eight gene segments found no evidence of genetic re-assortment with human or pig influenza viruses and no evidence of significant mutations," the WHO statement read.
"The human viruses from this cluster are genetically similar to viruses isolated from poultry in North Sumatra during a previous outbreak."
Sick poultry have been the source of bird flu infections for the vast majority of human cases worldwide. The virus can also infect pigs.
Clusters are looked on with far more suspicion than isolated infections because they raise the possibility the virus might have mutated to transmit efficiently among humans.
That could spark a pandemic, killing millions of people.
Financial markets have become worried after the WHO said one of the family members, a 32-year-old father, died on Monday after caring for his ailing son, who also died.
The agency said such close contact was considered a possible source of infection.
Source: China Daily