Although statistics suggest that the chance of any individual living in Toronto catching Sars is still remote - it is a city of many millions and the numbers affected are relatively small - there is still a risk. The risk of unnecessary travel from affected areas is not only to the host family but also to those en route. Furthermore, there is the obvious consideration that every effort is being made to prevent it from spreading to the UK. Business travel to Toronto, or visits on compassionate grounds such as funerals, are justifiable, but I would have thought that holidays are not. It would be perfectly reasonable to ask your friend to postpone her trip.

A friend of mine is due to take part in a charity walk along the Great Wall of China in a couple of weeks. She is unsure as to whether she should go or not. What is your advice? Name and address withheld

Although only a small part of China is affected by the Sars outbreak, any visit to the country at this time, unless it was at least important, if not necessarily essential, would seem to be a mistake. I don’t think your friend should go. Remember that the perceived risk is always greater than the actual risk, so that many of your mutual friends will spend a very uncomfortable ten days after her return from a potentially infected area.

Is there anything one can do (in an air-conditioned working environment) to avoid catching this virus from a colleague who has been in close contact with a Sars victim? Name and address withheld

Your colleague who has been in close contact with the Sars victim shouldn’t be working in an air-conditioned office. Once someone is aware that they have been in close contact with a victim they should be sitting at home for the next ten days. Transmission of viruses of the Sars type are reduced by frequent hand washing and a reduction in the amount of face/nose/lip scratching and touching.

I have been in West Wales over Easter and have come back with shivers, eye sockets hurting and totally exhausted. Usually I am fine. What is the big difference between Sars and flu? Mary Heaney, London

The most important difference is that there is at the moment no Sars in West Wales. The essential differences between the Sars virus and flu are that the high fever and cough with extreme breathlessness are noteworthy features of the former. The patient is much more gravely ill far quicker with Sars than with flu. In flu, the greatest danger is from secondary infection in vulnerable patients. In Sars, the severity of the attack doesn’t seem to be related, as in flu, to age.

My son, who is domiciled in Hong Kong, is planning a wedding here in the UK in June. He has invited about 20 friends and relations from Hong Kong and Singapore to attend, and is concerned at any repercussions which may result if his guests infect any other people in the hotel where they will be staying. Could the hotel take any legal action if such a disaster occurred? Should he postpone until the situation clears? Name and address withheld

Yes. I would suggest that 20 friends and relatives from Hong Kong and Singapore, if they were normally domiciled in Hong Kong, would not be welcomed by fellow guests at your son’s wedding. The alternative would seem to be either to postpone the wedding, or to have a smaller wedding without the Hong Kong contingent, and a large party at a later, safer time. The hotel might have a case against you if you knowingly subjected other guests to a risk and you hadn’t handed on your doubts to them. The decision should be theirs, as they are responsible not only to your party but also their staff and others staying in the hotel.

I am pregnant and in my second trimester. My worry about Sars is that there is not enough information on its impact on pregnant women. Is it safe to wear masks? What if I am working in Singapore - do I need to quarantine myself when I return to Australia? I have two young toddlers in my house. Aileen Kueh, Australia

There is unlikely to be much information about Sars and pregnancy, as it has been recognised for only a few months. The first report in the UK was in The Times in February. High fever in late pregnancy is, or was, a comparatively frequent cause of premature delivery or miscarriage. This has been an obvious effect of previous outbreaks of flu. Masks are of limited value in preventing viral diseases. They should be frequently changed, with hand washing after the change. If you have to work in Singapore, which seems rather regrettable, it would be better if you would quarantine yourself after you get back from Australia.

You don’t say whether the young toddlers in your house are your own, but whoever are the parents, it would be unfair to subject them to a risk, however remote.

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