Tuesday, May 02, 2006
Experts say bird flu virus survives longer
Influenza experts across the globe are urging nations not to lower their guard against the H5N1 bird flu virus, saying it now survives longer in higher temperatures and in wet and moist conditions.
Scientists previously found the virus to be most active and transmissible among birds in the cooler months from October to March in the northern hemisphere, and many people were hoping for some respite in the coming summer months.
But influenza expert Robert Webster warned against complacency and underestimating the H5N1 strain of the bird flu virus, which made its first documented jump to humans from birds in 1997 in Hong Kong, killing six people.
“When we tested the virus in Hong Kong from 1997, the virus was killed at 37 degrees Celsius (98 Fahrenheit) in two days. The current H5N1 is still viable for six days at 37,” said Webster, from St Jude Children’s Research Hospital in the U.S. city Memphis.
“H5N1 at room temperatures can stay (alive) for at least a week in wet conditions,” Webster told Reuters on the eve of a bird flu conference organized by the Lancet medical journal in Singapore.
“One of the often overlooked facts about influenza is that it’s more heat stable than people realize, especially under moist, damp conditions ... Don’t trust it,” he said.
Webster said heat-stable strains of the H5N1 bird flu virus were already circulating in ducks in Vietnam, Indonesia, China in 2004 and 2005 and experts would have to test if this trait was in the variants now circulating in India, Africa, Europe and parts of the Middle East.