Steve Ainsworth did not discuss tuberculosis as a candidate for the bug of the millennium award (Yorkshire terrier, 6 January).

TB was referred to as the white plague, and Grange states that it has almost certainly caused more suffering and death than any other infection.

There is evidence of spinal TB in remains from the neolithic, preColumbian and early Egyptian periods.

In the 17th and 18th centuries TB caused one quarter of all adult deaths in Europe.

The happy prediction in the 1970s that TB would be eradicated (in developed nations) by 2010 is already a very old joke, with incidence rising and the added joy of the emergence of multi-drug resistant strains worldwide.

In 1993 the World Health Organisation declared TB to be a global emergency .

But you also need an award for the most promising newcomer in preparation for the year 3000 prize.

HIV, as you mentioned, would have to be the current front-running virus.

But for sheer cunning and adaptability, and to inject a note of realism for todays NHS, the overall winning newcomer would have to be MRSA (methicillin-resistant Staphylococcus aureus ). The current worldwide MRSA epidemic has been going for about 25 years.

Aided by the collective carelessness, complacency, ignorance and lack of interest of clinicians, managers, planners and politicians (and some microbiologists, I'm sorry to say) it has inexorably spread throughout hospital and residential care settings, leaving chronically infected patients in its wake.

Watching people die of untreatable infection, despite having given them the best care available, is not funny.

Enough of the population are now carriers for sporadic cases to occur in the community, and vancomycin resistant strains have recently been found. We have casually thrown away all the advantages that should have flowed from past centuries advances in hospital care, surgical techniques and antibacterial drug development. Perhaps that should merit a special award in itself.

Dr Susan Bragman Consultant microbiologist Greenwich Healthcare trust