Virus deadlier than predicted, expert warns

A leading health expert has warned the Sars virus is twice as deadly as previously thought, although less infectious.

Professor Roy Anderson, of Imperial College London, said detailed analysis of the virus's effects in Hong Kong suggested that Sars – sudden acute respiratory syndrome – killed 10 per cent of those infected, double the latest World Health Organisation (WHO) estimate. But he added that the virus was less infectious than previously believed, deriding "doom and gloom" predictions about its global threat.

His revised death rate figure, accepted by the WHO, came as health ministers from across Asia decided that the threat from Sars justified even tougher controls on air travel and new quarantine rules for the region. They agreed a package of draconian new rules, including banning passengers showing suspicious symptoms from boarding aircraft, extended screening of passengers at international airports, and health declaration forms to be signed by visitors from affected countries.

The virus meanwhile claimed further medical and political casualties yesterday, as the death rate worldwide reached 294. Seven more deaths were reported in China, where the Health Minister, Zhang Wenkang, became the latest politician to resign after the furious criticism of China's sluggish response to the crisis. The country's Sars death toll now stands at 122, with 154 new cases confirmed yesterday.

However, there were signs in Hong Kong that the outbreak was waning after 17 new cases emerged – the lowest daily rate this month. Nevertheless, a further six deaths, including that of the territory's youngest victim, a 28-year-old computer engineer, took Hong Kong's fatalities from Sars to 121.

In Taiwan, about 480 furious health workers were locked into a military barracks after the virus was found in their hospital, putting more than 1,100 patients and staff into quarantine.

In Singapore, where 21 people have now died, plans to electronically tag infected people were confirmed.

Meanwhile, Professor Hugh Pennington, an expert microbiologist at Aberdeen University, warned that at least one Sars outbreak within the UK was highly likely. Britain had escaped relatively unscathed, with only six, non-fatal, cases reported so far. A suspected seventh case was given the all-clear yesterday in Sheffield.

But Prof Pennington predicted that an infected traveller would land in the UK, undetected, and spread the disease within their family or workplace.

Emergency disease control plans would then swing into action, with at least one hospital in the infected city dedicated to Sars.

The Health Protection Agency, the UK's main disease control authority, has sent an expert in communicable diseases to Toronto to study the city's response to the outbreak, and said valuable lessons had been learnt from the Canadian and Asian experiences.

The consultant arrived on Friday to study Toronto's decision to quarantine hundreds of people exposed to the virus, as well as its closure of Sars-affected hospitals, in case the same tactics have to be used in Britain.

Toronto's authorities, meanwhile, launched a Can$10m (£4.3m) advertising campaign to lure back tourists, insisting the city was safe.

Attempts to play down the global danger posed by Sars were rejected at the Asian ministerial summit by Shigeru Omi, the WHO's Asian regional director, who called it an "unprecedented" threat.