Mozart's untimely death, at the age of thirty-five, has remained a mystery ever since he passed away in the early hours of December 5th 1791. At the time it was rumoured that he'd been poisoned, and later theories included renal failure and tuberculosis. Yet Vienna's death records show that the most common causes of death among men of his age were tuberculosis, severe weight loss and oedema (an accumulation of fluids), and a group of European researchers have now suggested that he died from a simple bacterial infection.

Eyewitnesses who saw the composer in the days before his death, including his sister-in-law, Sophie Haibel, observed that he was covered in a rash and severely swollen (so badly swollen, in fact, that he was unable even to turn over in his bed). This would seem to support the researchers' theory, as a rash is consistent with a bacterial infection and swelling with oedema. Dr. Richard Zeger, from the Academic Medical Centre in Amsterdam, has compared the infection to the modern-day hospital superbug MRSA.

Austria was at war in 1791, and Vienna was full of soldiers who had been struck down by disease. According to Dr. Zeger's research (which has been published in the Annals of Internal Medicine), the outbreak probably started in a military hospital with poor hygiene before spreading to the wider community. More than five hundred people died of oedema in the months around Mozart's death, and a number of the soldiers had been accomplished musicians which might explain how he came into contact with the infection.