http://www.swissinfo.org/eng/international/ticker/detail/UN_sees_high_risk_of_more_easily_spread_bird_flu.html?siteSect=143&sid=6860878&cKey=1151690988000
By Stephanie Nebehay
GENEVA (Reuters) - The risk of bird flu mutating into a form more easily spread between people is still high and there could be an increase in human infections at the end of the year, the World Health Organisation (WHO) warned on Friday.
In a report analysing more than 200 known bird flu cases, the United Nations agency identified three peaks in human infections since 2003, all concentrated during the winter and spring seasons in the northern hemisphere.
"If this pattern continues, an upsurge in cases could be anticipated starting in late 2006 or early 2007," the WHO said, adding that further analysis was needed.
"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," it said.
While the avian virus, which has spread to some 50 countries, remains mostly a disease of birds, experts fear it could mutate into a more transmissible form and spark a pandemic killing millions of people.
The WHO study of human cases of H5N1 between December 2003 and April 2006 -- during which 203 people caught the disease, and 113 of them died -- concluded that children and young adults were most vulnerable to dying after exposure to the strain.
SPANISH FLU
It said the pattern of infections was "reminiscent" of that seen during the 1918-1919 Spanish flu pandemic which killed 40 million to 50 million people worldwide -- mainly young adults.
Confirmed human cases in the recent bird flu outbreak ranged in age from three months to 75 years.
But the highest proportion of bird flu cases occurred among those aged 10 to 29, with the typical victim being hospitalised four days after falling ill. Some 73 percent of patients aged 10 to 29 died from the virus.
More than half of patients died five days after being taken to hospital -- nine days after onset of symptoms, the study found. People aged 50 and older had the lowest fatality rate.
"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.
Dr. Fred Hayden, a medical officer at the WHO's global influenza programme, said there was some evidence of the virus having "environmental hardiness" to survive cool temperatures, leading to a concentration of cases in winter.
Hayden told Reuters it was important to take seriously the threat from avian flu to all ages.
"Certainly mortality is high in all age groups. Even the case-fatality rate for 50 years and older which is the lowest, is still 18 percent which is an enormous toll. But it is even higher in adolescents and young adults," he said.
Hayden said it was important for the U.N. and national health authorities to share more epidemiological and clinical data as they aim to defend themselves against a common threat.
"There's a lot of information in this document, it is an important summary of what we have learnt to date. But a lot can't be addressed because information is not complete," he said. "One goal is to be more systematic in capturing information as we go forward and several efforts are in place."
<HR>
By Stephanie Nebehay
GENEVA (Reuters) - The risk of bird flu mutating into a form more easily spread between people is still high and there could be an increase in human infections at the end of the year, the World Health Organisation (WHO) warned on Friday.
In a report analysing more than 200 known bird flu cases, the United Nations agency identified three peaks in human infections since 2003, all concentrated during the winter and spring seasons in the northern hemisphere.
"If this pattern continues, an upsurge in cases could be anticipated starting in late 2006 or early 2007," the WHO said, adding that further analysis was needed.
"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," it said.
While the avian virus, which has spread to some 50 countries, remains mostly a disease of birds, experts fear it could mutate into a more transmissible form and spark a pandemic killing millions of people.
The WHO study of human cases of H5N1 between December 2003 and April 2006 -- during which 203 people caught the disease, and 113 of them died -- concluded that children and young adults were most vulnerable to dying after exposure to the strain.
SPANISH FLU
It said the pattern of infections was "reminiscent" of that seen during the 1918-1919 Spanish flu pandemic which killed 40 million to 50 million people worldwide -- mainly young adults.
Confirmed human cases in the recent bird flu outbreak ranged in age from three months to 75 years.
But the highest proportion of bird flu cases occurred among those aged 10 to 29, with the typical victim being hospitalised four days after falling ill. Some 73 percent of patients aged 10 to 29 died from the virus.
More than half of patients died five days after being taken to hospital -- nine days after onset of symptoms, the study found. People aged 50 and older had the lowest fatality rate.
"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.
Dr. Fred Hayden, a medical officer at the WHO's global influenza programme, said there was some evidence of the virus having "environmental hardiness" to survive cool temperatures, leading to a concentration of cases in winter.
Hayden told Reuters it was important to take seriously the threat from avian flu to all ages.
"Certainly mortality is high in all age groups. Even the case-fatality rate for 50 years and older which is the lowest, is still 18 percent which is an enormous toll. But it is even higher in adolescents and young adults," he said.
Hayden said it was important for the U.N. and national health authorities to share more epidemiological and clinical data as they aim to defend themselves against a common threat.
"There's a lot of information in this document, it is an important summary of what we have learnt to date. But a lot can't be addressed because information is not complete," he said. "One goal is to be more systematic in capturing information as we go forward and several efforts are in place."
<HR>
The year will be half over tomorrow.