An influential study has found that the new strain of H1N1 flu virus behaves more like a pandemic strain than regular seasonal flu.
Nickkita Lau and Reuters
Wednesday, May 13, 2009
An influential study has found that the new strain of H1N1 flu virus behaves more like a pandemic strain than regular seasonal flu.
The study by scientists at the Imperial College London also says its severity is comparable to the 1957 pandemic of H2N2 Asian flu, which killed an estimated two million people globally.
Hong Kong University microbiologist Ho Pak-leung said the fatality and infection rates of the virus may have been severely underestimated.
Ho also warned of a possible mutation of the virus which could trigger an even more extensive outbreak.
Researchers reported in the journal Science that the virus is transmitted more easily and affects young adults more often than annual flu strains.
"I think the most important thing we found was the rate of spread and the extent of spread is similar to what has been seen in previous pandemics," said Christophe Fraser of Imperial College London.
They estimated 23,000 individuals had been infected in Mexico by late April, giving a fatality ratio of 0.4 percent based on confirmed and suspect deaths reported.
Clinical severity appears to be less than that seen in 1918 but comparable with that in 1957.
Looking at the pattern in La Gloria in the state of Veracruz where the outbreak is believed to have originated, the researchers said it looked as if the virus was transmitted human to human over 14 to 73 generations - meaning one person infected another, who infected another, up to 73 times.
Ho said the fatality rates announced by the World Health Organization and health authorities, particularly in the United States, are still relatively low.
He suspects that a huge number of people may have been infected with the swine flu virus and that they have not been accurately diagnosed because they have not undergone tests.
Ho also expressed concern over a mutation of the virus before its characteristics are fully understood.
He said if the animal virus has mutated into a human virus after generations of transmission among humans, the threat of a widespread outbreak is even higher.
Source: http://www.thestandard.com.hk/news_detail.asp?pp_cat=13&art_id=82060&sid=23822376&con_type=1 
