Here is A Brief History of Pandemics. What are pandemics? How do they spread? Some well-known ones in history like the plague, swine flu and Spanish flu.
What were some of the earliest pandemics?
A pandemic is a disease epidemic that has spread across a large region, or even globally.
We have known of pandemics spreading through our communities since we started recording history and now, due to advances in genetic analysis, we can go even farther back. However, these illnesses were not always around. Relatively harmless organisms evolved into dangerous germs in mega-settlements, where people lived in close proximity with each other and their domesticated animals.
One of the earliest and perhaps the most well-known pandemic is the plague. We now know of a 5000-year-old Swedish grave, with the oldest-known strain of Yersinia pestis – the bacterium that causes the pneumonic, bubonic and septicemic plagues. This pathogen may have resulted in the first ever pandemic in human history, which devastated many populations in Europe at the end of the Neolithic (later Stone Age, which started in Seventh millennium BC in Europe and lasted until 1700 BC). There were probably multiple strains of this disease around during the Neolithic.
Humanity has faced various forms of the plague since then. The Plague of Justinian emerged around 541-542 AD, during the reign of Byzantine Emperor Justinian and spread from Egypt to the Middle East, all of the Mediterranean region and finally to North-western Europe. Some historians consider it the deadliest pandemic in human history because of the 25 -100 million deaths that it caused. The Justinian Plague reoccurred for almost two centuries until 750 AD.
The Black Death that manifested during 1346 -1353, spread from Central Asia to the Mediterranean and then to Europe, mainly caused by bites from rat infesting fleas. It kept recurring until 1665, causing approximately 25 million deaths. This is the time of plague doctors with their fascinating beaked masks and costumes. They were not experienced doctors or surgeons but were either young doctors or those who could not establish a successful practice. They never cured anyone. The beaked masks were filled with aromatic herbs to protect them from “putrid air” that was supposed to carry the disease.
From the mid-19th century, a third plague pandemic started from China, causing over 2 million deaths there; 22.5 million people died in India alone (due to a combination of factors including the apathy of British colonial rulers). This plague continued until the development of a vaccine by Waldemar Mordecai Haffkine in 1897, which was successfully trialed in India. The vaccine and antibiotic drugs developed in the 1940s reduced the death rate from the plague but cases continued over the years and still do, in parts of the World, to this day.
What about the Flu Pandemics?
The 1918 Flu pandemic, or the Spanish Flu, was an unusually deadly form of influenza, which lasted from January 1918 to December 1920. It infected 500 million people and killed between 17-50 million (perhaps as high as 100 million). “Spanish Flu” is a misnomer, spread through newspaper articles about the illness of King Alfonso XIII of Spain, which gave the untrue impression that it was particularly acute in the country. Interestingly, in 2007 a meta-analysis of medical journals from that period concluded that it was no more dangerous than previous influenza strains. Rather, poor hygiene, malnourishment and overcrowding promoted a super-infection. Remember, this is just before the end of the First World War. It probably emerged in 1917 at the UK troops staging and hospital camp at Etaples, France or even earlier, in 1915, in Kansas, USA.
The H1N1 virus, which had genes adapted from both humans and birds, caused this pandemic. Some strains of H1N1 are endemic in human beings and cause a small fraction of flu like diseases. Other strains are endemic to pigs or birds and can spread to humans during contact with these animals. Different strains can recombine into new ones.
Swine Flu is common among pigs and sometimes (although this is rare) can transfer to humans. The 2009 flu pandemic lasted from January 2009 to August 2010 and resulted from the mixing of bird, swine and human flu (H1N1) viruses, which further combined with Eurasian pig flu virus. According to some studies, 11% to 21% (around 700 million to 1.4 billion people) contracted the illness, with 150,000 to 575,000 deaths (the seasonal flu results in 250,000 to 500,000 deaths annually according to WHO). The virus jumped to humans in 2008 – first recognized in Mexico – probably through working in close proximity with infected pigs (not by consuming pork products).
And now we have Covid19 caused by SARS-CoV-2 that also jumped from animals to humans. We can only wait and see what its statistics will be.
(Read What are RNA Vaccines?)