The world has experienced many pandemics throughout history, such as cholera, typhus, smallpox, measles, tuberculosis, leprosy, malaria, yellow fever and human immunodeficiency virus (HIV/AIDS). There have also been many influenza-related pandemics, the most recent being Pandemic H1N1 influenza 2009 also referred to as swine flu. Over time, many of these diseases have been controlled through the use of vaccines.
The World Health Organization has a six stage classification to describe how a new influenza virus moves from the first few infections in humans to become a pandemic and what countries should do to prepare for and respond to a pandemic. It begins with the virus mostly infecting animals, with a few cases of animals infecting people, then moves through to the stage where the virus begins to spread directly between people. A pandemic is then declared when infections from the virus have spread worldwide.
The word 'pandemic' is a Greek word, with 'pan' meaning 'all' and 'demos' meaning 'people'. Throughout history, there have been many pandemics, spreading infectious diseases such as smallpox and tuberculosis. More recent pandemics include the HIV/AIDS pandemic and the Pandemic (H1N1) influenza 2009, commonly known as swine flu.
Australia also has its own system to describe each phase of a pandemic, in addition to the World Health Organisation classification system. The Australian pandemic phases describe whether the virus is spreading overseas or in Australia and what Australia plans to do as the disease enters and spreads throughout the country. A disease or condition is not a pandemic just because it is widespread or kills many people, it must also be contagious or infectious.
Pandemics throughout history
There have been several significant pandemics throughout history:
Plague of Athens, 430 BC
Suspected outbreak of typhoid fever which continued for over four years.
Antonine plague, 165-180 AD
This ancient pandemic, believed to be either smallpox or measles, was brought back to the Roman Empire by troops returning from campaigns in the Near East (now known as the countries of Turkey, Syria, Iraq, Israel, and Jordan). The disease resulted in up to 2000 deaths per day in Rome, which was only one quarter of the people infected. The total number of deaths has been estimated at five million.
Plague of Justinian, 541-750 AD
This was the first recorded outbreak of the bubonic plague. It was reportedly responsible for eliminating a half of Europe's population between 550 and 700.
The Black Death, mid 1300 AD
'The Black Death' refers to the outbreak of bubonic plague in Europe in the mid 14th century. Bubonic Plague was spread by fleas that lived on plague infected rats. These rats travelled across Europe on trading ships, spreading the disease.
The Black Death was one of the most devastating pandemics in history and came to Europe in October of 1347, spread swiftly through most of Europe by the end of 1349 and on to Scandinavia and Russia in the 1350s. It returned several times throughout the rest of the century. The Black Death is estimated to have killed 30 to 60 per cent of Europe's population.
Third Pandemic, mid 1800 AD
This outbreak of bubonic plague started in China, spreading to all inhabited continents and killing ten million people in India alone.
First Cholera Pandemic 1816 - 1826 AD
This pandemic began in Bengal then spread across India. It extended as far as China, Indonesia and the Caspian Sea.
Twentieth century influenza pandemics
In the twentieth century, the world experienced three influenza pandemics:
The Spanish flu 1918
The Spanish flu swept across the world between 1918 and 1919. It tended to affect areas for up to 12 weeks and then would suddenly disappear only to return several months later. More people died during this pandemic than in the First World War. Worldwide, at least 50 million people are thought to have died. It has been estimated that about 25 per cent of the world's population was infected.
The Asian flu 1957
Although the proportion of people infected was high, the illness was relatively mild compared to the Spanish flu. The first wave of this pandemic was concentrated in school children and the second in the elderly. It is estimated that the Asian flu resulted in two million deaths.
The Hong Kong flu 1968
This pandemic affected mainly the elderly and is thought to have resulted in approximately one million deaths worldwide.
As well as the influenza pandemics, there have been other types of pandemics that have occurred in the twentieth and twenty-first century. One example of this is:
The acquired immune deficiency syndrome (AIDS) pandemic is a widespread disease caused by human immunodeficiency virus (HIV).
HIV/AIDS has emerged as one of the greatest global threats to the human population. HIV/AIDS was first recognised in 1981. Since then, it has led to the deaths of more than 25 million people, making it one of the most destructive diseases in recorded history. In addition to this, an estimated 33 million people are now living with HIV/AIDS worldwide, with five million of those in the Asia-Pacific region.