Anne Kelso

“The term ‘influenza’ is often used loosely to describe respiratory illness caused by a wide range of viruses, including respiratory syncytical virus, parainfluenza viruses, rhinoviruses and adenoviruses as well as influenza viruses themselves. Although all of these viruses can cause significant disease, true influenza has a special place in the world of communicable diseases for two reasons. First, seasonal influenza imposes a substantial health and economic burden every year and is thought to be responsible for about 250,000–500,000 deaths per annum around the world. Second, and more importantly, new influenza viruses emerge sporadically and cause global pandemics of unpredictable timing and impact.The most severe of these in modern history, the Spanish influenza pandemic in 1918–1919, is estimated to have killed 50 million people or 2.5% of the world’s population over a few months. As far as we know, this was the most severe pandemic of any infectious disease to have affected mankind over such a short period …”