A course with a difference

Around 10,000 years ago, humans began to domesticate animals. This development—along with the domestication of crops—spread throughout Africa, Asia and Europe, and triggered a steady and unabated increase in the population. But this came at a price: humans living in close proximity to livestock became susceptible to new infectious microorganisms, which crossed the species barrier from animals to cause a range of hitherto unknown diseases. Among these was one of mankind's deadliest companions: Mycobacterium tuberculosis . Humans only gained the upper hand in the fight against tuberculosis (TB) in the second half of the twentieth century. The enormous growth in wealth and the agricultural revolution that took place in developed countries alleviated poverty and malnutrition, two of the most important risk factors for the disease. But it was the availability of antibiotics that allowed physicians to embark on the worldwide eradication of TB. It seemed that mankind was finally ridding itself of one of its most deadly scourges after smallpox and plague.![][1] However, TB is on the rise again. It is still the most significant cause of death by a single infectious agent: a staggering one‐third of the world's population is infected with M. tuberculosis . According to the World Health Organization (WHO; Geneva, Switzerland), approximately two million people die from the disease every year, and there are nearly nine million new cases. Only HIV, which kills around three million people annually, has a higher mortality rate. In fact, M. tuberculosis and its close relative M. avium are an increasingly important cause of death in immunocompromised AIDS patients.> &TB is on the rise again. It is still the most significant cause of death by a single infectious agent: a staggering one‐third of the world's population is infected with M. tuberculosis One important factor for the re‐emergence of TB is that … [1]: /embed/graphic-1.gif