The history of infection control: Tuberculosis: part two — Finding the cause and trying to eliminate it

Introduction The plot thickens. I mentioned multiple-drug-resistant (MDR) strains of Mycobacterium tuberculosis in part one published in the last issue of this journal. The drastic control measures taken in the US were followed by a reduction in cases, and are recommended in the National Institute for Health and Clinical Excellence (NICE) guidelines on tuberculosis recently published by the Royal College of Physicians (2006). However, we now have extensively drug resistant (XDR) strains, which are also resistant to some of the ‘third line’ drugs used to treat MDR infections. Of 17 690 isolates from reference laboratories throughout the world in 2000 to 2005, 20% were MDR and 2% were XDR. XDR strains were found as far apart as the US, South Korea and Latvia (Morbidity and Mortality Weekly Report, 2006). The potential danger of XDR strains is shown in an outbreak in South Africa, 52 of 53 patients (all with HIV) died within a median of 25 days. All had been in hospital previously, raising the likelihood of nosocomial infection – this was a real ‘wake-up call’ (Lawn and Wilkinson, 2006). However, back to history. Was the disease familial or contagious? Hippocrates mentioned the phthisic diathesis. The occurrence of the disease in families (the Keats’ for example) and the high death rate in small children (grandfather coughing over the baby) suggested a genetic element. Galen thought phthisis was contagious and later Benjamin Marten (1722) wrote in A new theory of consumptions: ‘The original and essential cause may possibly be certain species of animalculi or wonderfully minute living creatures that by their peculiar shape or disagreeable parts are inimical to our nature... Worms and animalculi fretting and gnawing.’