Infectious diseases have been the leading cause of death for the human species, and over recent centuries there have been some horrendous pandemics that make Covid-19 so far look pretty small. In this blog I’m going to look at just 3 infectious diseases whose pandemics give Covid-19 some perspective…
Cue wavy lines and wobbly music as we go back in time to the 6th Century…
The first of our “recent” plague pandemics is known as the Plague of Justinian (541-542), which affected the Eastern Roman Empire, especially Constantinople and the Mediterranean region. It is estimated to have killed 50 million people during the initial pandemic and in the 200 years after when it continued to circulate. This was up to a quarter of the World’s population at this time! Justinian I was Emperor of Rome when the pandemic started; apparently he caught the plague but survived.
The next plague pandemic was the Black Death (1347-1353) which killed an estimated 30-60% of the population of Europe, about 100-125 million people! There are thousands of ossuaries (bone collections) in Churches around Europe full of the remains of those killed by the Black Death. The Black Death resulted in a number of social, religious and political upheavals that shaped the future of Europe including movement of people in to cities, decline of the power of the Church and increased power of governments.
The Third Pandemic killed over 10 million people but by this time scientists had worked out that rat fleas were the route by which plague was being spread and therefore control of rat populations helped to stop plague causing as much devastation as it had during the Black Death.
We now know that plague is caused by a bacterium, Yersinia pestis, and can be treated with antibiotics such as Gentamicin, Chloramphenicol, Doxycycline and Ciprofloxacin. Please do not stock pile these drugs or think you can prophylax with them!!
All of these pandemics are thought to have arisen in China and spread via trade routes across Asia and Europe killing a total of about 185 million people (NB then, like now, we consumers are all equally responsible due to our “desire for those traded goods”… this is not a dig at China!). During these earlier pandemics black rats and their fleas where the main cause of plague but in recent times there has been a shift to other types of rats as well as small mammals such as ground squirrels, rabbits and hares and even cats and dogs…
Smallpox is a severe viral infection caused by the viruses Variola minor and the more severe Variola major. Smallpox was the scourge of Europe, especially in the 18th Century. It is highly infectious with each person with smallpox infecting up to 6 others and a mortality of up to 30% for Variola major infection.
In fact Smallpox is so infectious and deadly that between 1492-1600C it is estimated that smallpox killed 90% of the indigenous populations of South America, about 55 million people. Smallpox was introduced into South America by the Spanish Conquistadors and because the indigenous people had never come into contact with the virus and therefore had no immunity the result was catastrophic… it was a virus that allowed the Spanish to “conquer” South America!
One fascinating story about smallpox relates to an outbreak from 1721 in Boston in the United States. As the city came under attack from the latest outbreak of smallpox, a Puritan clergyman called Cotton Mather (who was apparently a notorious character for the prosecution in the Salem Witch Trials) was told of a way of preventing smallpox from Africa by his “enslaved servant”, a man called Onesimus. Onesimus described how it was the practice in Africa to take the fluid from a smallpox lesion and scratch it into the skin of those who hadn’t yet been infected. This caused a mild form of infection which prevented the recipient developing a severe infection; the process was “variolation”.
Despite the widespread attitude of the Church that diseases like smallpox were punishments from God, Mather started to tell people about this way of preventing smallpox. A local doctor, Dr Zabdiel Boylston, looked into the practice further and was so convinced that he started variolating his children and slaves. Variolation went against the medical dogma of the past thousands of years which said that disease was caused by an imbalance in the humours and spread by toxic miasmas, and that its practice violated the laws of medicine, transforming health care practitioners into those who harm rather than heal; so it wasn’t widely used. However, when the epidemic settled it was clear, the mortality in the un-variolated was over 15% and in those who had been variolated it was less than 2%. Needless to say after this variolation became the standard practice for preventing smallpox!
The more “known smallpox story” takes place in 1796 when the UK Physician Edward Jenner, who himself had been variolated as a child, became aware that people who had had cowpox didn’t catch smallpox. He started inoculating people with cowpox to prevent smallpox and so vaccination was discovered… from the Latin “vacca” meaning “cow”! The 1790s not only saw the birth of vaccination but also the establishment of Anti-vaxxers who believed the new process would cause people to develop cow-like tendencies, cow diseases and even sprout horns…
In the end vaccination won through and smallpox was declared eradicated by the WHO in 1980.
“Good Old” Influenza
Moving into the 20th Century there have been some particularly nasty influenza pandemics. By now most people have heard of the 1918 influenza pandemic, often erroneously referred to as “Spanish-flu”. It had nothing to do with Spain, they just reported it first, in fact it is more likely to have been originally from the US but as the US were our new allies it would have been deemed bad politics to call it “American-flu”. In fact the Spanish called it “French-flu” as they understood it started first it France. Maybe we can learn lessons from this unhelpful “name calling” with regard to singling out Wuhan and SARS‑CoV‑2!
The 1918 influenza pandemic is thought to have started in the military camps of Etaples in Northern France at the end of the First World War. These camps were a mixture of soldiers from all of the Allied countries as well as the animals used to feed them. It is likely that influenza brought over by our North American allies was mixed with swine flu and avian flu from the animals and birds to create a “new” influenza virus by the process of antigenic shift. When these armies where then disbanded and sent back to their respective countries they rapidly disseminated the “new virus” around the world with devastating consequences. Influenza continued to wax and wane over the next couple of years, with at least three waves of infections all taking their toll.
It has been estimated that 500 million people (a third of the world’s population!) became infected with this “new virus”, resulting in approximately 50 million deaths! That’s about the same as the Black Death. One of the most striking aspects of the flu pandemic was the high mortality in young people, probably because they lacked any immunity from earlier, similar pandemics such as that from “Russian-flu” in the 1890s (which killed over 1 million people). In fact the 1918 influenza pandemic killed more people than the preceding War.
There was no treatment, no vaccines, and the World was only just recovering from the War. People were told to wear face masks and to stop shaking hands, lockdowns of schools, businesses and theatres were ordered and hygiene strongly emphasised… sound familiar?! In fact in some places in the US there were fines and prosecutions for people who didn’t wear face masks. It is likely that the pandemic ultimately came to an end because the majority of people had had the infection and herd immunity had reached sufficient levels to stop the virus circulating.
But did you know there have been two further influenza pandemics in the 20th Century; in 1957 and 1968? “What” I hear you cry, “But that’s really recent and NO, I didn’t know!” The 1957 pandemic was known as Asian-flu and killed about 2 million people; and the 1968 pandemic was called Hong-Kong-flu and killed about 1 million. Both were thought to have originated in China but it’s not certain.
One thing I find very strange about these two pandemics is that I can find no one who remembers them. Everyone I speak to knows nothing about them. When I have tried to tell this to my parents who were born in 1941 they strongly deny it ever happened as they had never heard anything about it! I suspect there is a good reason for this… the media.
Back in the 1950s and 1960s we didn’t have the torrent of 24/7 news outlets that we have today. Then news was “reported back” from correspondents overseas, it was retrospective, earnest and factual. Non-essential Note: the first newspapers in Europe were handwritten affairs circulated weekly in Venice from 1566. Now the news is everywhere and you can’t escape it. Also, the news these days is sensationalised whereas there was a more reserved approach in the past (just look at an “old news real” of the BBC reporting even in the 1980s, hilariously stuffy!); it wasn’t seemly to be dramatic on the news, added to this people didn’t have the worldwide connections or means to travel like they do nowadays. As far as I can tell no one took much notice of these reported pandemics. Nowadays, with media companies competing for our attention, everything has to be “unfolding”, “instant” and “dramatic” or we too (probably) wouldn’t pay too much notice either.
So these are some of the most striking historical epidemics and pandemics but there are plenty of others; Ebola in West Africa in 2013, HIV since 1981 and then there’s Cocoliztli which killed 15 million in Mexico in the 1500s?!? Who’s heard of that one…?! [“Please take his medical history book off him”, I hear you cry!]
…actually I hadn’t heard of that last one until I starting looking at smallpox and I still don’t know what it is… maybe there’s a future blog in that?!?….