Key Pandemics in History

00:02 So pandemic, this course is all about pandemics, right? Pandemic again is an epidemic that has spread over several countries or continents and usually affecting a large number of people.

00:14 This is a soft qualitative definition but we attempt to, tend to make it a little more solid for administrative purposes.

00:23 So here's some notable pandemics of the modern era going backwards in time.

00:28 Of course right now, the pandemic on everyone's mind is COVID-19.

00:32 And it started in late 2019 when the first cases were detected in Wuhan, China.

00:38 It's caused by the Coronavirus SARS-Cov2.

00:41 And as of the making of this video, it's killed over a million people worldwide and infected over 55 million people.

00:51 Of course the HIV/AIDS pandemic is still with us.

00:54 It's peak years though were between 2005 and 2012.

00:58 After that, effective treatments and control mechanisms were put into place, but it's still affecting many people.

01:04 And you probably know it's caused by the HIV retroviruses and it's killed over 36 million people to date.

01:12 Before that we have the various influenza pandemics.

01:17 In fact, prior to COVID-19, the last pandemic to be declared by the WHO was the 2009 influenza pandemic.

01:27 In 1968, we had a very large H2N2 Influenza A pandemic that killed a million people.

01:34 And in 1956, the Asian flu killed a million people 1889, H2N2 once again killed a million people.

01:43 But the big influenza pandemic we always talk about is the spanish flu of 1918 to 1920.

01:50 That was the H1N1 subtype that killed anywhere from 50 to 100 million people.

01:56 In fact, some people believe it killed so many soldiers during World War I that it was probably a contributing factor to the ending of World War I having taken so many people off the battlefield.

02:09 Today, many of the H1N1 strains floating around are descendants from this flu.

02:15 So these diseases never fully leave us unless they are fully eradicated.

02:20 There's always some genetic semblance of them floating about in their descendants.

02:26 Going further back in time, we can talk about the many worldwide cholera pandemics, including one that's going on today and it's resulted in millions of deaths.

02:38 But it also was the foundation of modern epidemiology.

02:42 In the mid to late 1800s, Jon Snow in England was investigating a cholera outbreak and he didn't know anything about pathogens or what caused diseases but he was able to count And he looked at a neighborhood in London where cholera cases were happening and managed to trace them back to a single water source, the broad street pump.

03:05 This was a medical mystery and he solved this medical mystery using detective work and in doing so invented a whole new science, epidemiology which essentially is medicine using numbers.

03:17 And using numbers, he figured out that this one pumping station was the source of much of the infections of cholera in that neighborhood.

03:25 Maybe you can figure out if that's a common source, point source, propagated type of epidemic.

03:33 Of course, you can't talk about pandemics without talking about various plagues: the plague of London, the black plague, the great plague through the Middle Ages.

03:42 And up to the 17th century, there are 40 outbreaks during that period killed that might have up to 20% of the human populaiton.

03:51 20%, that's extraordinary.

03:55 Smallpox is one of the great plagues of humankind and of course famously, is a disease that we eradicated using vaccines and clever epidemiology.

04:08 Smallpox probably killed around 10 million people and wiped out Native Americans.

04:15 In fact, we think that when Europeans arrived in the new world, it wasn't so much conquistadors killing people that did most of the damage, it was the diseases they brought most notably, smallpox.

04:29 The black death of the 1400s killed perhaps 200 million people.

04:34 In fact, in Venice around that time, they invented the first formal system of quarantine.

04:40 Remember they didn't know what was causing the disease.

04:43 They didn't know about bacteria or pathogens, but they figured out that if infected people were kept away from everybody else, quarantined, they were less likely to propagate the disease.

04:55 And that's an important discovery that we still use today.

04:57 In fact, despite being in the 21st century, many of the techniques we use to control COVID-19 today are based on 19th century efforts and earlier.

05:11 One of the earliest known pandemics, the 'Plague of Justinian', named for the emperor of Byzantium of that time, and that was also the bubonic plague and probably killed between 30 and 50 million people.