The four horsemen of the pandemic

by John Quiggin on January 13, 2021

That’s the headline[1] for my latest piece in the Canberra Times. It doesn’t appear to be paywalled, but I’m including the text over the fold.

We are all familiar with images of mud and death in the trenches of the First World War. But it’s only over the past year that many of us have seen photos of the influenza pandemic that raged during the last year of the war and on into 1919. Foreshadowing our own time, they show wards full of sick and dying patients, masked nurses, police and ordinary citizens, and even anti-mask protestors.

The Great War (as it was then called) directly caused the deaths of between fifteen and twenty-two million people, about half of whom were civilians, and a roughly equal number of severe injuries. But the 1918–19 pandemic was even more deadly, claiming the lives of around fifty million people, or roughly 3 per cent of the world’s population at that time. The loss of life was greater even than most estimates of the toll of the Second World, generally regarded as the most deadly event in history.

The link between the Great War and the influenza pandemic was more than a mere coincidence of timing. Massive movements of troops around the world — unprecedented at the time, but foreshadowing our own world of extensive tourist and business travel — were a major factor in spreading the 1918–19 pandemic. And, as with current pandemics, the close proximity of humans and food-producing animals played a major role. But recent research has also pointed to more direct links to the war, including the role of poison gas and the local climate change created by the conflict.

The 1918–19 pandemic was originally called the Spanish flu because of the extensive publicity given to cases in Spain, notably that of King Alfonso XIII, who fell gravely ill. As a neutral power, Spain had not imposed the wartime censorship that prevailed in other European countries.

The first recorded case — involving Albert Gitchell, an army cook at Camp Funston in Kansas — occurred in the United States on 4 March 1918. At this stage it was no more deadly than the usual seasonal influenza epidemic. It was in the trenches and camps of the Western Front that the disease took the deadly form that would kill millions, and particularly young people.

In 2005, a team of researchers led by J.S. Oxford of St Bartholomew’s Hospital in London concluded that the prime culprit was a British base camp at Etaples in Northern France. “The Etaples camp had the necessary mixture of factors for emergence of pandemic influenza,” they wrote, “including overcrowding (with 100,000 soldiers daily changing), live pigs, and nearby live geese, duck and chicken markets (and) horses.” It also had an additional factor: “twenty-four gases (some of them mutagenic) used in large hundred-ton quantities to contaminate soldiers and the landscape.”  

The gases used in the Great War included chlorine, phosgene and (perhaps the most horrible of all) mustard gas, which not only caused disabling blistering but is also highly carcinogenic and mutagenic. The outbreak of flu, particularly deadly to the young men among whom it spread, probably arose from the mutagenic effects of one or more of these gases, combined with repeated transmission from humans to animals and vice versa.

Even more striking is the possibility that soil particles, explosives and other chemicals generated by the continuous bombardment on the Western Front played a role in generating a six-year European climate anomaly characterised by unusually cold and rainy weather — weather that contributed both to the infamous mud of the trenches and to the severity of the pandemic. As well as the obvious effects of cold weather, which weakened immunity and encouraged crowding indoors, the climate anomaly disrupted the migratory patterns of mallard ducks and other birds that were important vectors for the disease.

The existence of the climate anomaly has been demonstrated recently by a team including Alexander More and Paul Mayewski of the University of Maine Climate Change Institute. Using an ice core taken from the European Alps they showed the existence of a six-year period of heavy rain, snow and cold weather, driven by an influx of cold air. As they report, these conditions played a major role in “setting the stage for the onset, spread, and mutation of the H1N1 pandemic, while also increasing all‐cause deaths due to widespread harvest failures and worsening battlefield conditions.”

The researchers showed that mortality increases in times of lower temperatures and higher rainfall. These conditions were present during many of the major battles of the Great War, and may have increased the virulence of the influenza.

As with the war and the pandemic, the researchers suggest that the timing of the climate anomaly was not coincidental. The massive amounts of dirt and dust thrown into the air by continuous bombardment, along with the vast range of chemicals, could have provided the nucleus of rain clouds.  

This was, perhaps, the first instance of a war amplifying its destructive power through climatic effects. Later, during the Second World War, the destructive effects of incendiary bombing were amplified by firestorms, the powerful winds generated when fire consumed all the oxygen in areas struck by bombs. Even worse, though still thankfully hypothetical, is the prospect of a nuclear winter created by the massive fires a nuclear exchange would create.

History does not repeat itself, but it rhymes. In 1914, nationalism and imperialism unleashed the Four Horsemen of the Apocalypse. The pestilence, famine and death unleashed by the fighting was made worse by climate change, itself caused by the war. Now, as the world struggles, and mostly fails, to deal with a new pandemic, the threat of catastrophic warming looms over us all, as does a global failure of democracy. Perhaps we can make better choices than the leaders of 1914 and their millions of enthusiastic followers. But it’s hard to be optimistic. •

fn1. After a series of disasters, I’m submitting my own headlines, with mixed success in getting them used. This one was mine.



Mark Pontin 01.13.21 at 8:52 am

Inadvertent climate modification (and the other factors you cite) worsening the pathogenicity of the WWI trenches is very plausible, and interesting.

But you’re missing the most salient point — as I was always understood it — about what enabled the 1918-19 influenza strain to be bred in the trenches, then spread globally. This is that historically there’d been no way to assemble and maintain such massive troop formations before the WWI-era. Typhus and other diseases had invariably broken out.

It was the then-new drugs that, ironically, for the first time allowed the maintenance of such large numbers of troops in such ghastly field conditions. (Though there were still outbreaks.) Once WWI was over and troops started to be released from the trenches and sent home, they were no longer subject to those medical regimes, such as they were, that had been enforced in the trenches. And that was when the pandemic broke out.

See forex —

“…Generalized vaccination against contagious diseases, one of the major inventions of the 20th century, became indispensable during the First World War. The vaccines developed before and during the conflict made a great difference in the lives of the soldiers: up until then, epidemics (along with gangrene, typhus, etc.) had been one of the main causes of death in wars. A law of March 28, 1914, made the typhoid vaccine obligatory for the whole French army, and for good reason: in the first 14 months of the war, 100,000 cases of typhoid fever were declared, with a mortality rate of over 20 percent. The tetanus vaccine was also used; it had been developed for Canadian troops ….”

And so on.


John Quiggin 01.13.21 at 9:57 am

Very interesting points. The first influenza vaccine wasn’t developed until 1938

But you’re right in making the point that without vaccination against other diseases, the war might have been unsustainable.


Peter T 01.13.21 at 10:16 am

Depressingly, high attrition through disease does not make war unsustainable. It just stretches it out longer. The French Revolutionary and Napoleonic Wars spread typhus from Cadiz to Moscow and led to as many deaths proportionate to population as World War I. They just did it over 30 years instead of six.

For those interested in the links between climate and pre-industrial human activity, William Ruddiman’s Plows, Plagues and Petroleum is a good read.


notGoodenough 01.13.21 at 12:34 pm

One contributing factor to the spread and severity of the influenza pandemic may have been the desire for secrecy by the various powers to prevent morale loss and to “continue as usual”.

President Wilson signed the sedition act, and officials lied continuously about the scope and severity of the pandemic. One headline in the Philadelphia Inquirer (October 15, 1918) read “Scientific Nursing Halting Epidemic” – while in that week alone, 4,597 people in Philadelphia died of flu-related illnesses (quite possibly a result from the Liberty Loan Parade held in September – which was, to use the modern vernacular, a “superspreader” event). The misinformation led, naturally, to mishandling and slowed efforts to address the situation.

In short, officials used their positions of authority to downplay severity in an attempt to bolster attention for that which they considered more important, and – as a result – many people died who otherwise might have lived. Commenters may draw their own parallels, should they wish.


DavidtheK 01.13.21 at 12:55 pm

If I’m remembering my history reading correctly, there were also two other significant animal vectors. Rats were a very big problem in the trenches. And despite the growth in mechanization, there were still existing cavalry units with horses and in some cases horses were still being used as transport animals. When they fell in battle, they were left undisposed and unburied especially if it was no man’s land between opposing trenches. That must have provided a host for a whole lot of nasty microbes.


passer-by 01.13.21 at 1:16 pm

Minor quibble, but WWII did cause more deadly casualties. 50 million dead would be a very low estimate for WWII (while it is more of a higher estimate for the flu), for which estimates range from 60 to 85 million dead.

And for what it’s worth, disease has routinely been the first cause of attrition / death during wars, even if you count only military loss (even more so if you count civilian loss, but illness-related civilian death in war is not necessarily counted as war-related, even if the epidemics are clearly linked to the war situation).


Edward Gregson 01.13.21 at 4:42 pm

I’m not sure nuclear winter is particularly well-supported at this point.


Kenny Easwaran 01.13.21 at 5:43 pm

One other interesting point I’ve heard about the 1918 pandemic (perhaps from the Wikipedia article, so take it with a grain of salt) is that while normal conditions put selection pressure on influenza to become less virulent, the wartime conditions put selection pressure on it to become more virulent. In normal conditions, when people are feeling sicker, they are more likely to stay home and not spread the virus. But in wartime conditions, when people are feeling sicker, they are more likely to be sent home from the front and thus spread the virus through all their travel nodes.


ccc 01.13.21 at 6:06 pm

The 1918–19 pandemic was a zoonotic pandemic, just like most other pandemics. Its was caused by human exploitation of non-human animals. Will John Quiggin’s article mention that? No, because he keeps evading that crucial point.


John Quiggin 01.13.21 at 11:43 pm

@9 “And, as with current pandemics, the close proximity of humans and food-producing animals played a major role.”


John Quiggin 01.13.21 at 11:44 pm

Also The Etaples camp had the necessary mixture of factors for emergence of pandemic influenza,” they wrote, “including overcrowding (with 100,000 soldiers daily changing), live pigs, and nearby live geese, duck and chicken markets (and) horses.”


nastywoman 01.14.21 at 6:46 am

but… probably?
there were very few… ”parties” during the First World War?


nastywoman 01.14.21 at 7:26 am

Which reminded me:
”Why Weddings Are the Perfect Superspreader Event – › health-news ›
– and that I used to go to so many weddings each year – that by having two of them in Russia two years ago – we perhaps avoided another… war?


nastywoman 01.14.21 at 1:11 pm

”In normal conditions, when people are feeling sicker, they are more likely to stay home and not spread the virus. But in wartime conditions, when people are feeling sicker, they are more likely to be sent home from the front and thus spread the virus through all their travel nodes”.

which made me think that ”all their travel nodes” are the major problem? –
As even in Germany – a country which was pretty successful in the beginning to control the Virus – came skiing season you just couldn’t hold these Germans back anymore and they were traveling in hoards to ”the skiing battle fields” –
which could make you think – that the joy of traveling through the 21 century could be feven more deadly than any ”travel nodes” in war?


ccc 01.15.21 at 10:46 am

Please, no further comments from you on any of my posts – JQ


PD 01.15.21 at 8:27 pm

Even before the pandemic, it has been estimated that about 50% of Allied casualties in the Gallipoli invasion were caused by disease, rather than enemy action.


bad Jim 01.16.21 at 6:19 am

A trivial riposte to DavidtheK: even in WWII the Germans relied upon horses for transport of supplies. As far as I know, horses and humans share diseases less than some other pairs of animals.

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