Nine out of 10 Hong Kong patients suffering from atypical pneumonia were infected with a coronavirus, a comprehensive medical study has found.
A clinical analysis of 50 local patients, conducted by University of Hong Kong microbiologists, found 45 out of 50 patients were infected with a coronavirus.
The results come as international experts race to identify the pathogen causing the outbreak.
Old age, underlying illness, poor liver function and delays in treatment with a combination of the antiviral drug Ribavirin and steroids, were found to be the main risk factors in the deterioration in health for people infected with Severe Acute Repiratory Syndrome (Sars).
The patients, aged between 23 to 74, were admitted to three different public hospitals between late February and late March.
A total of 19 patients, of a mean age of 50, had received intensive care and ventilatory support. The mean day of deterioration from the onset of symptoms was 8.3 days.
Yuen Kwok-yung, the University's chair professor in microbiology, told the South China Morning Post last night that the most significant finding was that coronavirus was the primary cause of Sars.The World Health Organisation had said that Sars could be caused by more than one virus. Other kinds of virus have been linked with the outbreak. The Chinese University has earlier isolated paramyxovirus in some Hong Kong patients, while the Chinese Centre of Disease Control and Prevention believed chlamydia was the cause.