Finding a solution to the Chinese riddle that is the SARS virus is a race against time, writes Dr Muiris Houston, Medical Correspondent
We now have a fair idea what causes it. We are learning more about how it is transmitted. However, despite just a single case in the Republic, SARS is now officially a world epidemic with no definitive treatment yet available. Not surprisingly, the Department of Health is advising individuals not to undertake non-essential travel to SARS-infected areas in south-east Asia and Canada.
Almost four weeks after the World Health Organisation (WHO) issued a global health alert about SARS, the number of cases continues to rise. World attention has focused on Hong Kong and China; however, closer to home in Ontario, SARS has got a firm grip on the most heavily populated province in Canada.
The seventh Canadian victim of SARS died in Toronto on Thursday. Dr James Young, the Ontario Commissioner of Public Safety, said the infection of the 57-year-old woman was linked to the original outbreak in Toronto's Scarborough Grove Hospital and was not a sign that the disease was spreading to the general population.
Nevertheless, with 178 probable and suspect cases recorded so far in the province it is clear that the outbreak continues to smoulder in a country with one of the best developed health systems in the world.
SARS fears have seen Toronto cancel a major conference of international cancer specialists although the official line is that the city is safe to visit, with the risk to the general public remaining extremely low.
At Toronto's International Pearson Airport, screening for SARS started on April 1st. Health Canada officials hand all departing passengers a health alert notice, advising people who meet certain criteria to defer their flights. These criteria include: having SARS symptoms (fever, cough, shortness of breath and difficulty breathing); having been in contact with a SARS-affected person in the last 10 days; and having visited a health facility that has been identified by public health officials as being affected by SARS.
Health officials have placed thousands of people in the city - including one of Canada's leading infectious disease experts - in isolation in an attempt to stop the spread of the disease. On Wednesday, a man and a woman who refused to isolate themselves were formally placed in 10-day quarantine after they were found in a shopping mall without a face mask.
Commenting on the situation in Canada, Dr Darina O'Flanagan, director of the National Disease Surveillance Centre here, says: "The experience in Toronto has demonstrated the ease of transmission of this agent in a hospital setting. Ontario has declared a provincial emergency, requiring the closure of the affected hospital and has invoked quarantine laws to control the outbreak. It is important in Ireland that we don't become complacent and face the risk of a similar outbreak. We need health professionals to remain vigilant."
With just one case in the Republic - a man treated in Mayo General Hospital after he returned from Hong Kong - we are escaping the worst. But ongoing vigilance by health professionals is vital and people who travel here from areas such as Hong Kong, Guangdong, Singapore and Toronto must keep in mind the possibility of SARS and seek help early if they develop flu-like symptoms. All but essential travel to Hong Kong and Guangdong province in China should be postponed, according to WHO.
SARS has a death rate of 3 to 4 per cent, three times the death rate of "regular" influenza. Death is by respiratory failure - the victims' lungs are overwhelmed by pneumonia to the point where mechanical breathing assistance is required. It is almost certainly caused by a new strain of coronavirus, which can survive on contaminated objects like door handles for a number of hours. But if SARS transmission evolves to mimic that of influenza, then it may be impossible to contain without vaccination and a proven treatment.
Writing in the New England Journal of Medicine, Dr Julie Gerberding, director of the US Centre for Disease Control and Prevention, offered this observation: "If we are extremely lucky, the epidemic will be controlled, develop a seasonal pattern that will improve prospects for regional containment or evolve more slowly than it has in the early stage. If the virus moves faster than our scientific, communications and control capacities, we could be in for a long difficult race. In either case, the race is on. The stakes are high. And the outcome cannot be predicted."