Earlier in this series, we saw how violent clashes between groups of people
can cause outbreaks.
In conflicts like war, the collateral damage to infrastructure
and the precarious living conditions it subjects people to makes outbreaks much likelier.
Although they’re linked to the violence, in these cases,
disease is a sort of terrible side-effect of the conflict itself.
Sadly, there are also times when certain groups might intentionally use an outbreak
to inflict harm on another group of people.
The latter is what we call weaponizing an outbreak,
and it’s been going on for longer than you might think.
In this episode, we’re going to look at when outbreaks become weapons,
from the past to the present, and what we’ve learned from them.
I’m Pardis Sabeti, and this is Crash Course Outbreak Science!
[Theme Music]
Before we get into things,
we should mention up front that this episode goes into challenging topics
involving violence like war, genocide and terrorism.
But we think it’s important to understand the context in which outbreaks are weaponized,
so that we know where the risks lie and how we might stop it from happening.
Historically, people have used naturally occurring outbreaks to hurt certain populations
by making them sick or die from a disease, and from the chaos that follows.
But in modern times, “weaponizing outbreaks” tends to mean artificially releasing a pathogen
to spread and infect a group of people.
Outbreaks can also be weaponized against animals and crops,
to attack resources that people rely on,
but we’re going to focus on the kinds of outbreaks that infect people.
Because they rely on biological mechanisms to inflict harm,
unlike the physical damage from, say, a bullet,
weaponized outbreaks are also called bioweapons.
Like much of the horror that humans are capable of,
there’s no easy explanation for why people want to inflict terrible things on each other.
Answering that is a complex, philosophical and social question
that has been debated for as long as humans have been around.
But history can at least give us the context in which bioweapons have been used
and how they might be used today.
That tends to be the same context as ordinary weapons:
to hurt or eliminate groups of people during a conflict.
Remarkably, people have used bioweapons since long before we knew pathogens,
the germs that make us ill, were responsible for infectious disease,
or even knew what pathogens were!
In 1346, a bacterial disease known as the bubonic plague, or “Black Death”,
had crept into Western Europe.
The victims had flu-like symptoms and “buboes”,
visibly swollen bumps in the armpits or groin, which was usually followed by death.
And at the same time Caffa, a city on the coast of the modern day Crimean Peninsula
was under siege by our favourite exceptional empire here on Crash Course… the Mongols.
Today we know that the plague spreads through a bacterium transmitted by fleas,
but at the time the prevailing theory was that “miasma”,
a kind of toxic cloud, made people sick when they breathed it in.
So, according to historic accounts,
since the Mongols had plenty of access to
the infected corpses of plague victims from their own ranks,
they loaded up catapults with the corpses and hurled them into the city.
As one observer at the time wrote, the intention was to kill off those inside,
because the “intolerable stench” of the corpses’ miasma
would spread the disease into the air and water.
In reality, it’s the bacteria that would have spread to the citizens of Caffa
as they handled the corpses while removing them from the city.
Either way, it’s pretty gruesome stuff...
...And, by the same account at least, it was pretty effective!
People inside the city did become infected and likely because of the Mongols’ efforts.
So we can see that one way that people have weaponized an outbreak
is to attempt to start one that affects your enemies.
Another army tried this over 4 centuries after the Mongols.
In 1763, the British Army was locked in battle with Native Americans at Fort Pitt,
in today’s Pittsburgh, Pennsylvania.
To devastate the Native Americans he was fighting against, the British General Jeffrey Amherst
plotted to spread smallpox by arranging for traders to distribute infected blankets
from a nearby hospital to the Native Americans.
It isn’t clear whether the infected blankets did actually spread smallpox,
and if they did, the death toll was likely less than a hundred people.
But the intention was clear:
to start a smallpox outbreak that would kill the Native Americans fighting against the British.
And sometimes, when a natural outbreak occurred,
colonizers weaponized them by deliberately not helping those affected.
In the early 1860s, a few smallpox cases broke out in today’s Vancouver Island,
and the British colonizers chose not to implement a strict quarantine
or pursue a strong vaccination program,
either of which could have helped kept the epidemic at bay.
And so, it spread to the First Nations people living nearby.
Though efforts were made by some colonizers to help them,
mostly they looked to protect themselves.
When the disease broke out more seriously in the First Nations population,
they were forced out of the town, and their homes were even set on fire.
As one journalist wrote at the time:
“...every precaution is used in order to confine the disease to the natives”,
while celebrating that “Only one death has occurred amongst the whites.”
Over the next year, thirty thousand First Nations people would die,
paving the way for more land to be taken by the colonizers.
Although the colonizers didn't start the outbreak, their inaction,
followed by forcibly removing First Nations people from the towns,
worsened the effects of the outbreak on them and reduced their population,
to the benefit of the colonizers.
As well as driving people from their homes,
forcing a group into a single place with poor environmental conditions can have a similar effect
by encouraging outbreaks to happen.
At the start of World War II in 1939, the Nazis laid siege to the Polish city Warsaw,
damaging the sewage system and contaminating the water supply.
That led to a small outbreak of the bacterial disease Typhus
which eventually disappeared in the summer of 1940.
By then, the Nazis occupied the city.
The Nazis used the potential of another epidemic to justify creating the Warsaw ghetto,
a small section of the city which Jews were forced to live in and forbidden to leave.
They surrounded the whole area with a three metre wall topped with barbed wire
and stopped food supplies from entering, trapping everyone in overcrowded and unsanitary conditions.
The results were catastrophic and led to another, even bigger outbreak of typhus.
The Nobel Prize winning biologist Ludwik Hirszfeld, would later say,
based on his time in the ghetto:
“Typhus was created by the Germans, precipitated by lack of food, soap, and water,
and then—when one concentrates 400,000 wretches in one district,
takes everything away from them, and gives them nothing, then one creates typhus.
In this war, typhus is the work of the Germans.”
Refusing to recognise that they caused the epidemics,
the Nazis took it as a justification to do even more harm.
During the war, the Nazis would continue to claim the genocide of 3 million Jews in Poland
“was unavoidable for reasons of public health”.
As for the Typhus outbreak in the Warsaw ghetto,
just when it should have gotten worse as winter hit, it actually started receding.
That’s because the Jews inside the ghetto smuggled food in and
ran community kitchens to fight starvation.
They also formed communities of medical workers and taught health education
and hygiene practices in the midst of the war,
implementing their own healthcare initiatives to fight back against the outbreak inflicted on them.
By September 1942, the outbreak was over.
As the war continued, countries like Japan, the US and Britain were using the knowledge of pathogens
to create weapons that could artificially spread a disease.
And shortly after the war, some had even developed bioweapons as we recognise them today.
As best we know, they’ve never been used in an open conflict between countries,
but the general design of modern bioweapons
relies on producing a significant amount of a given pathogen in a lab
and storing it in some kind of vessel,
before releasing the pathogen into a target population to infect them.
It’s likely that would be by dispersing them into the air as a kind of spray
where they could be inhaled or absorbed into
wounds or by contaminating a source of food or water.
The kinds of pathogens used in a bioweapon can be reproduced from naturally occurring ones,
like the viruses that cause smallpox viruses or bacteria that cause anthrax and cholera.
But advances in biochemistry have made the process even more fine tuned.
Scientists can pick particular strains of a disease and even genetically engineer new ones
using gene editing technologies like CRISPR.
That lets them hand craft pathogens with a higher level of infectiousness,
deadliness and resistance to treatment.
Bioweapons have other properties that would make them particularly dangerous.
Unlike other weapons, they could be used stealthily,
making them harder to detect until people are already infected.
What’s more, because the disease can spread,
bioweapons could affect areas far beyond the vicinity of the original attack.
Though that could be a disadvantage if the disease eventually
makes its way back to the attacking force!
After all, the spread of outbreaks aren’t always predictable.
In 1969, the WHO estimated that a single bioweapon attack in a medium sized city
could kill tens of thousands of people.
Given the rising tensions of the Cold War and growing capacity to unleash such an attack,
in 1972, a treaty known as the “Biological and Toxin Weapons Convention”
was signed and ratified by most of the world’s countries, including the US and the Soviet Union.
It prohibited the development, production,
and stockpiling of pathogens for anything other than peaceful purposes.
Today, the convention is still the final word as far as it’s signatories are concerned
but unfortunately, it hasn’t been enough.
States have continued to develop bioweapons,
and the availability of biochemical techniques mean that smaller groups like terrorist cells
could potentially develop a bioweapon,
as part of a bioterrorist attack.
Plus, there’s always the risk of an accident.
In 1979, a plume of anthrax spores was accidentally released
from a secret bioweapons facility in Sverdlovsk, a city in the Soviet Union.
It drifted over fifty kilometres and killed at least sixty-six people,
the deadliest human outbreak of inhalation anthrax ever.
Even when they’re working with viruses for peaceful purposes, like vaccines,
there’s a risk labs might also have samples stolen and turned into a bioweapon,
or simply mishandled and let loose!
So naturally, there are strong security measures for labs that handle dangerous pathogens,
from limits on who can access them to security protocols for moving samples around.
This is called biosecurity.
That’s just one part of a lab’s overall biorisk management,
the strategies that help prevent accidents and attacks, keeping everyone safe.
We can also regularly monitor areas that are likely targets of an attack, like water supplies,
for pathogens that could lead to an outbreak,
so that we can quarantine them or cut off the source if we find any,
which could stop an attack quickly.
We can also make it easier to trace the source of an attack
to make it easier to respond and harder for the attackers to remain anonymous.
That makes a bioweapon less appealing to use.
For example, analysing the genes of a weaponized pathogen as it spreads
could give us clues as to where it came from, based on the mutations it develops.
This could give us a kind of breadcrumb trail to trace back to the original case,
and where the attack may have started.
Finally, research is continuing on how to prepare in case such an attack happens.
Like other kinds of outbreaks, it means developing the capacity to spot an outbreak early on,
recognize the disease causing it, stopping it spreading any further
and having treatments to help infected patients.
While a lot of this work happens in a lab, sometimes,
governments even act out simulations of outbreaks to practice
and see how well their strategies would work in the real world!
All of this can help reduce the impact of an outbreak, and even stop them in their tracks.
As we mentioned earlier, there’s no easy explanation for why people
weaponize outbreaks to hurt each other
and frankly, it’s upsetting to think about.
But by learning about threats like these and the ways we can respond to them,
we can also express the best of humanity’s qualities by coming together
and helping stop outbreaks, wherever they may arise.
And tackling these challenges is exactly what we’ll be covering
through the rest of the series.
We at Crash Course and our partners Operation Outbreak
and the Sabeti Lab at the Broad Institute at MIT and Harvard
want to acknowledge the Indigenous people native to the land we live and work on,
and their traditional and ongoing relationship with this land.
We encourage you to learn about the history of the place you call home
through resources like native-land.ca
and by engaging with your local Indigenous and Aboriginal nations
through the websites and resources they provide.
Thanks for watching this episode of Crash Course Outbreak Science,
which was produced by Complexly in partnership with Operation Outbreak
and the Sabeti Lab at the Broad Institute of MIT and Harvard—
with generous support from the Gordon and Betty Moore Foundation.
If you want to help keep Crash Course free for everyone, forever,
you can join our community on Patreon.