The Review 2008

23 The study was based on information about exercise frequency collected for 24,656 people who died in 1998. The information spanned the 10 years before death. The researchers said the results suggested people who never or seldom exercised should be encouraged to get more active.There was also evidence of an ‘open window’ theory that frequent exercise might temporarily weaken immunity against infection, thereby increasing the risk of contracting diseases. The study was suppor ted by theArea of Excellence scheme, as well as funding from the Health and Health Service Research Fund and the Hong Kong Council on Smoking and Health, and published in May 2008 in the international online scientific journal, PLoS One , of the Public Library of Science. The Review 2008 • Research Why H5N1 is So Deadly – And How It Might Be Treated HKU researchers have unlocked a key to the question of why H5N1 infection is so lethal in humans and identified a path to treating it. H5N1, a form of avian flu, kills up to 80 per cent of its victims and the high mor tality rate has been a worry. What if this virus develops the ability to spread more quickly and sets off a pandemic? Researchers from Microbiology, Pathology, Bio- chemistry and Paediatrics, working with scientists from the Hong Kong University of Science andTechnology and Siriraj Hospital in Bangkok, found H5N1 infection rap - idly triggered high levels of COX-2, a substance that sets off a ‘cytokine storm’. This is an exaggerated immune response that causes inflammation and damage to the lungs and is the most deadly complication of H5N1. Most impor tantly, the researchers found selective inhibition of COX-2 could reduce the severity of inflam - mation in H5N1-infected tissues.They then tested avail - able treatments to see if any could achieve this effect. A combination of the anti-viral drug zanamivir and two drugs that modulate the immune response, celocoxib and mesalazine, was found to increase the survival rate of infected mice to 52 per cent. Significantly, this treatment was administered 48 hours after infection, mimicking real-life situations because most patients do not present for treatment until two to four days after they are infected. Current treatment regimes only work best within the first 36 hours. “Triple therapy offers some hope for surviving the devastating consequences associated with a pandemic influenza outbreak,” the authors said, adding that their findings offered a sound theoretical and experimental basis for fur ther study. The results on triple therapy were published in Proceedings of the National Academy of Sciences while the work defining the role of COX2 in H5N1-triggered cytokine cascades was carried in the Journal of Infectious Diseases . Both were published in 2008. In addition, two research papers published in the journals PLoS Pathogens and Virology in September 2008 described the emergence and subsequent evolutionary dynamics of the H5N1 virus. Exercise and Flu: Only in Moderation Moderate exercise can reduce the risk of dying from influenza when compared with little or no exercise. But surprisingly, heavy exercise does not seem to offer the same benefit. Scientists from the School of Public Health, Depar tment of Community Medicine and Depar tment of Microbiology found people who exercised at most three times a week for 30 minutes or more reduced their mor tality risk by 4.2 per cent to 6.4 per cent. People who exercised less than once per month, or four times or more per week, did not receive the same benefits. 22