Infectious disease

1. Infectious disease – those spread by contact with infected people or animals, through airborne inhalation, or by water or food – are still threads to us today. The influenza virus for example infects a staggering 5 million people worldwide every single year, travelling from person to person in airborne droplets, and causing chills, fever, sore throat, runny nose, headaches and muscle pain.

2. The flu virus changes gradually by a process known as antigenic drift. As the virus replicates, single nucleotide errors occur in the viral genome, causing minute changes to the proteins that coat the outside of the virus. The immune system recognizes these proteins to detect and destroy the infection, so as they change, the ability of the body to recognize the virus decreases, preventing people from building up immunity. Not only does the virus make continual, subtle changes to its genome and proteins, but it also occasionally develops huge mutations.

3. Spanish Flu is a truly global pandemic, some believe that this influenza virus, which emerged in 1918, killed as many as 40-50 million people around the world. The Black Death is an infamous bubonic plague outbreak swept across Asia into Europe with a total death toll of roughly 100 million.

4. Flu virus can definitely cause a pandemic in the future. As for other diseases, it is hard to predict. The human immunodeficiency virus has raged since the early-Eighties. This pandemic has claimed around 25 million lives. Approximately 34 million people currently have HIV across the globe. Could a pandemic end humanity? It could. But there are medical and allied sciences like epidemiology and modelling are so strong now. It is unlikely a pandemic would wipe out humanity, but it could cause huge damage, particularly in some areas of the world with weak health infrastructure.