Before Covid-19: Other deadly epidemics
The coronavirus pandemic took just three months to spread around the world, creating an unprecedented health crisis by its sheer size and scope.
However, it was not the first to rock the world with its massive death toll.
Here are several major epidemics which made their mark on history.
- The plague -
Mainly transmitted by fleas on rats, a bacteria called Yersinia pestis was the cause of the first pandemic officially recorded by historians.
Called the Justinian Plague, it struck around the Mediterranean basin and Europe from the 6th to the 8th centuries, wreaking large death tolls in cities.
A second plague broke out at the end of the Middle Ages. The Black Death started in Europe in October 1347 in the Sicilian port of Messina, brought in by ships from Genoa which had been infected when visiting Crimea.
In the space of several months, the disease spread across Italy and France then through the rest of western Europe, leading by 1351 to the death of an estimated 30 percent of the European population.
Resurgences of the plague continued right up to the late 18th century. The Great Plague of London in the 17th century killed one fifth of the capital's population, while another in the early 18th century wiped out a quarter to one-third of the inhabitants of Marseille and Provence in France.
Cholera : This disease, caused by bacteria transmitted by dirty water, results in severe diarrhoea which can lead to death.
Cholera ravaged Europe's major cities in the 19th century. In France alone hundreds of thousands died in outbreaks from 1848 to 1849 and 1853 to 1854.
Cholera epidemics have also struck other parts of the world, especially underdeveloped countries such as in Haiti in 2010 following an earthquake, where it killed 10,000. The World Health Organization (WHO) estimates that cholera kills around 100,000 people every year.
Smallpox : With its highly contagious sores, smallpox was for centuries a terrible scourge, especially for young children.
Brought in by European colonisers, the smallpox decimated indigenous communities on the American continent.
Over the 20th century the illness is estimated to have killed more than 300 million people, more than all the armed conflicts over the century.
It has been totally eradicated thanks to a worldwide vaccination drive led by the WHO after World War II.
Flu : The Covid-19 toll is often compared to that of deadly seasonal flu, though the latter rarely makes the headlines.
Globally, seasonal flu accounts for up to 650,000 deaths, according to the WHO.
In the 20th century, two major non-seasonal flu pandemics -- Asian flu in 1957-1958 and Hong Kong flu in 1968-1970 -- each killed around one million people, according to counts carried out afterwards.
Both pandemics occurred in different circumstances to Covid-19, before globalisation intensified and accelerated economic exchange and travel -- and with it the rapid spread of deadly viruses.
The greatest catastrophe of modern pandemics to date, the flu pandemic of 1918-1919 -- also known as Spanish flu -- wiped out some 50 million people according to research published in the 2000s.
In 2009, the H1N1 virus, or swine flu, caused a global pandemic and left an official death toll of 18,500.
This was later revised upwards by the medical journal The Lancet, to between 151,700 and 575,400 dead.
AIDS : AIDS is by far the most deadly modern epidemic: almost 33 million people around the world have died of the disease, which affects the immune system.
First detected in 1981, no effective vaccine has been found.
But retroviral drugs, when taken regularly, efficiently stop the illness in its tracks and heavily reduce the risk of contamination.
This treatment has helped bring down the death toll from its peak in 2004 of 1.7 million deaths to 690,000 in 2019, according to UNAIDS.
Ebola : The death toll from the new coronavirus is already far higher than that of the haemorrhagic fever Ebola, which was first identified in 1976 and in its latest 2018-2020 outbreak killed nearly 2,300 people.
In four decades, periodic Ebola outbreaks have killed some 15,000 people, all in Africa.
Ebola has a far higher fatality rate than Covid-19: around 50 percent of people who are infected die from it, and this has risen to 90 percent in some of the epidemics.
But Ebola is less contagious than other viral diseases, namely because it is not airborne but transmitted through direct and close contact.
Dengue fever, chikungunya, Zika : These three diseases are all transmitted by mosquito bites, in particular from the tiger mosquito.
Dengue fever and chikungunya have similar symptoms and both can have serious complications: an attack on the nervous system in the case of chikungunya and haemorrhaging for dengue fever.
Zika often causes no symptoms in infected people, but the virus can be dangerous for babies inside their mothers' womb and cause severe brain problems in children.
In 2015 a Zika epidemic hit Latin America, particularly Brazil. Several thousand malformed babies were born in the country.
Stealthy killers : The hepatitis B and C viruses also have a high death toll, killing some 1.3 million people every year, most often in poor countries.
Malaria also causes 400,000 deaths per year.
And tuberculosis,an illness caused by a bacteria which affects the lungs, causes around 1.5 million deaths per year.