new I do not agree with many of the health ministry's actions in relation to the Severe Acute Respiratory Syndrome (Sars) outbreak. Nevertheless, I also do not agree with o­ne of the issues raised by Tai Lo Chin's letter.

It appears that he is suggesting that the distinction between probable and suspected cases is an invention of Health Minister Chua Jui Meng. Although I do not have a background in immunology or the medical field, it is my understanding that the distinction between a probable case and a suspected case is clearly defined for every recognised disease.

A document from the WHO website clearly lists the distinction for Sars.

Of course, in terms of quarantine and other such issues, I believe there is no difference in the recommendation between a probable and suspected case. And obviously, a suspected case should be investigated until it can be 'upgraded' to a probable case or determined to be something else.

In most countries, and I agree this is advisable, suspected Sars cases are reported in the media and to the WHO. However, it is my understanding that the WHO and most health ministries and departments, do not consider Sars to be confirmed present in a country until a probable case is identified.

The WHO in their daily report of cases clearly state that with most countries except the US, o­nly probable cases are listed.

I would like to recommend that readers visit the WHO website as it does provide some information which the health ministry is apparently reluctant to reveal.

It might also be helpful for readers to gain some basic understanding of viruses in general and the differences between viruses and bacteria.