The World Health Organisation (WHO) has said that the risk of the H5N1 virus undergoing a lethal mutation is still high. In a report analyzing 205 infections that occurred from December 2003 and April 2006.
Since the human infections have peaked in winter and spring months, the WHO also warned that the same could happen towards the end of this year or early next year. "If this pattern continues, an upsurge in cases could be anticipated starting in late 2006 or early 2007," the WHO said. "Moreover, the widespread distribution of the H5N1 virus in poultry and the continued exposure of humans suggest that the risk of virus evolving into a more transmissible agent in humans remains high."
The agency also compared the current bird flu situation to the 1918-1919 Spanish flu pandemic which killed 40 million to 50 million people "The differences in the age-related case-fatality distribution among H5N1 cases are reminiscent of those observed during previous influenza pandemics, particularly in 1918, where case-fatality rates were higher among young adults," it said.
The report added that children and young adults seemed to be very vulnerable, with maximum deaths occurring in people aged 10 to 29 years. In contrast minimum deaths had occurred in people aged over 50. "The widespread distribution of the H5N1 virus in poultry and the continued exposure of humans suggest that the risk of virus evolving into a more transmissible agent in humans remains high," the report said.
The detailed report can be accessed in this week's Weekly Epidemiological Record.