The following article by Mohsen Shahmanesh examines the social role of viruses and bacteria in four major historical pandemics. It was first published in Weekly Worker.



An earlier pandemic – The Black Death

 We are now in the third year of the Covid pandemic, which has caused the deaths of something like five million people across the world (a very conservative estimate). Which means that now is quite a good time to look back at some of the pandemics previously encountered – and ahead at what they may have in store for us.

In my view pandemics occur during particular moments in history and not only deepen already existing social fissures and currents, but sometimes turn them in a different direction. In other words, they can have a major role in history. To illustrate this I will use five examples of past pandemics which all had political, social and economic consequences that affected human lives.

First of all, though, I would like to say a few words about the place and role of microorganisms in our world. These are often underestimated, because they are invisible. We tend to ignore what is in fact the largest biomass in numbers and in biodiversity. The two microorganisms which I will focus on are viruses and bacteria.

Viruses, as we know, cannot reproduce themselves independently and need a host for that purpose. If we imagine that every single creature on earth had one unique virus, the diversity of those viruses would amount to more than all the other creatures put together. A scientist once calculated that if all the viruses in the world were strung end to end, they would form a chain so long that a beam of light would take over 200 years to go from one end to the other. So we are talking about a huge mass of diverse organisms, most of which are obviously harmless to human beings.1

There is a similar diversity when it comes to bacteria, which do not need a host to reproduce themselves. They are numerous indeed. For example, each one of us will have more microbes in our body than all the cells in our body put together.2 Therefore it is important to think of these micro-organisms when we talk about nature and the biomass that surrounds us.

Let us consider the issue of infection. If a microbe goes from an animal to a human, that is, of course, a biological process. If, however, it survives within that human being and is passed on to someone else, then in addition to a biological process we are witnessing a social process, which could be the beginning of an epidemic; and if it is passed on from region to region, that would be a pandemic. Thus, while the passage from animal to human is biological, the transfer of this microbe or this virus from one human to another is a social process. In other words, pandemics are a reflection of social relations at any particular junction in history. Pandemics are human creations and they in turn affect our social relations.

It is this that provides the basis of what I am about to explore. I will use as examples five pandemics, two of which occurred at the beginning and end of the Middle Ages and were caused by the plague bacterium. We will fast-forward and look at the huge influenza epidemic at the end of World War I. We will then spend a little bit of time talking about the pandemic which occurred during the neoliberal globalisation in late 20th century before coming to Covid-19.

Justinian plague

The first plague we will consider was caused by Yersenia pestis – a bacterium which is found in the flea that inhabits rats and mice. It can be passed on to humans, and can also infect cats and dogs. This conjunction between rats, mice and humans is where the transmission occurs, resulting in a pretty lethal disease with a high mortality rate – particularly the pneumonic variant.

The year is 541 AD. Justinian, Roman emperor from 527 to 565 AD, had initiated a series of wars with the aim of uniting the eastern and western parts of the Roman empire. He sent armies into north Africa and Asia Minor, and over his entire reign there were movements of armies across Europe, north Africa and the Middle East.

In Iran he came up against King Khosrow I (Anushiravan), who earlier had inherited a country in revolt, which he brutally put down by massacring the new religious sect, the Mazdakites, which proclaimed egalitarian – almost communistic – aims. Khosrow initiated his reign by killing over 200,000 of its followers. He too was a conquering emperor, who came up against Justinian in Asia Minor and Syria. His armies fought in the Arabian Peninsula, Yemen and Ethiopia, the Caucasus and central Asia.3

In other words, there was a huge movement of armies over a whole period of time and it is this movement that carried the plague from one place to another. We do not know where it originated – possibly north Africa or Kyrgyzstan – but we know it reached parts of Europe, as well as the Sasanian lands, and caused huge devastation. Roughly 100 million people died during this pandemic – a huge proportion of the population at that time in western Asia and Europe.4 For example, one third of Constantinople’s inhabitants died and it is estimated that 25%-60% of the population of Europe succumbed to the pandemic. This was followed by eight years of Europe-wide famine. Agriculture was totally destroyed – this was the start of the system of crop rotation: eg, wheat, followed by another crop on the same piece of land the next year, then leaving the land fallow the third year. This increased the yield manyfold. The western Roman empire never really recovered after this pandemic, while in Europe we saw the development of feudalism and serfdom.

In Iran quite the opposite happened: the famine and plague resulted in the destruction of the property of large landowners. What this did was to create a new class of smaller landowners called ‘farmers’ (dehqanan), who were in fact a low-ranking aristocracy, in addition to the three already existing classes: namely the aristocracy, the clergy and the commoners. All this resulted in the strengthening of a centralised government and that facilitated the creation of the Silk Road, which opened up trade from China across the Middle East into Europe. When, less than a hundred years later, that route was disrupted because of bandits and the breakdown in civil society, this gave Arab merchants, under the banner of Islam, the opportunity to take over the east-west trade across the Mediterranean and north Africa into Europe.

Black Death

Let us now move forward about eight centuries, to Europe in 1346 AD. States like Venice and Genoa actually had control of the trade in the Mediterranean and we believe that it was through this that rats were carried in ships from north Africa across the entire continent. The plague, known as the Black Death, went as far north as Denmark and as far west as England. There is data regarding its effects on the Mediterranean and at least part of the Middle East, which was also devastated.

It is likely that between a quarter and a third of the European population died and about one-tenth of all the farms and villages in Europe disappeared. The population fell to below what it was half a century earlier (1290s) and it took at least a century and a half before it came back to where it was before. Merchants whose capital had been least damaged were able to form a new landlord class, while the previous feudal rulers were ruined. This meant that peasants were liberated, and in western Europe serfdom never came back.

The result was that this now freely mobile labour came into the cities, and the labour shortage momentarily drove up wages, stimulating innovation in technology and production. Only merchant capital was not really damaged, so the former merchants were now able to invest not just in land, but also in industry, where they became part of the new industrial capital. You can see an example of this in the Welser family in southern Germany, who, from being flax merchants, expanded into flax farming and the production of linen cloth, which the family sold and exported.5

The system of banking developed: for example, the Medici family in Italy became wildly rich as a result of the new mobility of capital across Europe. The power of the state was enhanced, as it was able to collect more taxation. Over the next decades the rise in the price of labour was repeatedly suppressed by the state, with consequent resistance from below. Capitalist relations, which before the pandemic had already developed in the bosom of feudal relations, were now spreading across Europe.6

H1N1 influenza

Now let us go on to World War I and the spread of the influenza virus. The genes of the so-called Spanish flu originated partly in swine and partly in birds – a particular characteristic of influenza, as well as some other viruses, where bunches of genes can be exchanged between one species and another, creating a new species. This reconstitution gives it greater flexibility.

The flu pandemic was probably caused by the development of mutations that were not only much more infectious, but also more lethal. The normal seasonal flu that we see every year today kills around 0.01% of those infected, but back then the mortality rate was between one and three percent. That still does not sound too high, but, because millions of people were infected, the actual number of deaths was very high.

The social background to this pandemic was the wartime troop movement – not just across Europe, but from colonies in Africa, Asia and across the world. The blockade of European ports by the Allies produced mass hunger across Germany, weakening the population and making them more susceptible. And, of course, there were social upheavals, not least the Russian Revolution.

It is likely that the influenza virus originally came from the USA, once America joined the war in 1917. It may be that it developed in US pig farms and was brought over to Europe by the US troops. Infection among troops ensured that it spread rapidly across Europe, Asia and Africa. We are talking about the deaths of 50-100 million people as a result – much more than those who died as a result of the conflict itself.

This was particularly true in places outside Europe: India lost an estimated five percent of its population, Iran between eight and 20 percent – not just as a direct result of the virus, but also the famines associated with it. In Europe 0.5-1% of the population died.

The US, being further away from the war, was damaged much less than Europe – not just from the destructions of war, but also from the influenza pandemic. In fact the USA – already the largest capitalist economy in the world – now became even more powerful following this pandemic. The disparity between capitalism in Europe and in America was accentuated as a result of the slaughter caused by the pandemic, as well as the damage of war itself. Across Europe there was huge social turmoil, with the rising of the working class through strikes as well as revolutions. Even Switzerland came near to civil war.

The difference in the mortality rate was reflected in Asia, where anti-imperialist movements were stimulated after the war – partly accentuated by the different effects of the pandemic in Europe and Asia. Just to give you an example, the Indian Congress, which until then had limited its demands to reforms within the colonial system, from then was calling for independence. There were strikes across Asia – for example, in sugar factories in Java and among British plantations in Assam. In Iran the pandemic, which, as I said, had killed between eight and 20 percent, weakened the hold of feudal landowners and regional power bases, paving the way for Reza Khan – later Reza Shah – to create the modern state that we have today.


Let us move on now to a little later in the 20th century. In the early decades of the century a retrovirus living in our closest relative, the chimpanzee, in Cameroon, was probably repeatedly passed across to humans through the consumption of bush meat. The chimpanzee SIV virus is a construct of two different monkey retroviruses that must have passed over to the chimpanzee some time before. Until the middle of the century, HIV and the illness it caused, Aids, was probably restricted to this or that family in isolated villages. Now this virus suddenly began to spread across Africa and in a very short period of time it became global. So what was it that caused a virus that had been localised in a corner of Cameroon to become a global pandemic?

Across Africa there were two elements. Firstly, the growth of mining of tin, gold, diamond, copper and other minerals. Alongside that, and related to the growth in mining, was the improved transport, with the wealth of this virgin land now being plundered. The Congo river became navigable, which allowed workers from Cameroon to go down into the mines in the Congo. Then there were the roads that were built to move what had been mined into the ports, from where it could be exported to Europe, America, etc. So, effectively, it was the combination of mining and transport that provided the backdrop to the spread of the virus. But who got it?

In Africa a quarter of all workers were migrants. In South Africa and other countries they were often housed in single-sex dormitories away from their families for weeks and sometimes months, and they were serviced by commercial sex workers during the period when the men were away from their families. Studies showed that the incidence of HIV infection was higher, the longer the men stayed away from home. The women who were left behind had no work, while even the rudimentary social welfare services that had existed in some African countries were dismantled at the behest of the International Monetary Fund through its promotion of privatisation.7

For women – the lowest rank within the social structure – there was often no other work except selling their own bodies. In this the IMF had the help of company managements. One example was in the Ivory Coast, where every weekend the bosses would bus in loads of commercial sex workers (CSWs) to a large industrial farm, where on average each CSW serviced 25 men. So you can see how everything was set up to facilitate the transmission of the virus from one person to another.

Lorry drivers, who were transporting the products of these mines, were the other group of people involved in that transmission. For example, the nearer you lived to the route of the highways through Uganda and Kenya into Mombasa, the higher the rate of HIV was likely to be in CSWs. Like migrant workers, when the drivers went home, they passed it on to their wives and families.

Besides unprotected sex, HIV is also transmissible through the sharing of blood, or from mother to child – these are the only three ways it can be transmitted from one person to another. The HIV pandemic spread to east Asia and later to eastern Europe through the rise in substance abuse. In the far east, HIV appeared in huge numbers of needle-sharing drug addicts. These were the years of the huge rise in transnational drug smuggling and an exponential growth of drug addiction in the far east – Burma, Thailand, etc. And, later on, when the Soviet bloc collapsed, eastern European states encountered the spread of drug addiction and the sharing of needles.

The cause of all this was neoliberal globalisation, which created a highly mobile workforce and trillions of dollars of floating money – some of which was used in illegal drug and human smuggling across borders, and now accounts for a significant portion of global trade. According to the United Nations, for instance, today there are 21 million men, women and children across the world who have been trafficked and, effectively, are slaves.8

These are the sort of mechanisms through which a virus which was previously very localised can become globalised – changes in both economic policy and relationships between humans.

One particular consequence is that, since the HIV pandemic, almost every new drug that is not a ‘me too’ item has been produced in laboratories or universities funded by public money. Similarly the vaccines used today against Covid have also been developed by public money. Once a new drug or vaccine is seen to be a useful addition to production, it is handed over to big pharma. I am not aware of a single major drug group over the recent years that has not been developed along this pathway.

Another observation that the HIV pandemic revealed was a change in social behaviour – something which almost certainly also occurred in previous pandemics. We saw an interesting combination of solidarity and distrust. Distrust of official information – which, in the case of HIV, was a denial that the HIV virus causes Aids. In South Africa this became the official government position, resulting in millions of people in the country contracting the virus.

You can, of course, see such attitudes very much in the current pandemic, where larger and larger sections of the population are effectively denying the existence of this particular infection. The other side of the coin of denial is risk-taking: we saw that with HIV and we see it today with Covid.


We could look at today’s pandemic by asking, ‘What is this world that we’ve created that makes it so much easier for that microorganism to move from person to person, region to region, and very rapidly become a pandemic?’ Remember, it only took a couple of months for the Covid virus to envelop the entire world in a most amazingly rapid spread.

You could answer that with the word ‘mobility’. We are in a world where everything is mobile: production, commodities and humans. Human beings have always been the most mobile of all mammals and, of course, technology and the way we organise these days has accentuated that to almost insane levels. For instance, there were 38.9 million flights and 4.2 billion passengers in 2019 alone – ideal for the global transmission of an infectious virus.

The other aspect that assists the movement of a virus from an animal source into humans is industrial farming. Let me give you one concrete example. Previously there were one million pig farms in the United States, but now there are 100,000: in other words, there has been a tenfold reduction, even though the production of pork has actually expanded. The cramming together of all those pigs results in more favourable conditions for the transmission of a virus. Remember that the H1N1 influenza virus was a combination of genes from swine and birds.

Just to give an idea of the volume of meat that is produced globally, there are 1.5 billion cattle, one billion pigs and 20 billion poultry globally – half of which are produced in industrial-type farms. These are, if you like, a petri dish ready for the mixing together of viruses from different species. The farm animals are not only in close contact with each other, facilitating the transmission of infective agents, but also with other wild animals, such as birds, rodents, etc. There are potentially numerous viruses that are able to adapt themselves to be transmitted to a human host in this way.

Add to this our assault on nature. Today, there is no part of nature which is virgin any more. Humans have gone into every single virgin forest that existed – in the Amazon, in Africa, in Indonesia, etc – and by going into those regions humans come into contact with new species of micro-organisms which had hitherto had no contact with humans. Such a scenario also creates opportunities for the creation of new viruses. Although the vast majority of new viruses we encounter will not cause disease in human beings, the odd one does – and, provided it is capable of passing from one human to another, we have the conditions for another epidemic or pandemic.

Wars and tourism provide additional mechanisms for the dissemination of infections. Since World War II, there has not been a single year when there has not been a war somewhere in the world. Moreover, looking at population mobility and movements, in 2019 alone 33.4 million people are estimated to have been uprooted, and in 2020 the UN estimated that 280 million people live somewhere that is not their country of birth – currently international migrants represent about 3.6% of the world’s population.9


The current Covid-19 pandemic is our third coronavirus pandemic, following SARS and MERS, both of which actually did not spread as widely. The reason this particular coronavirus is so successful is its highly infectious nature. We have in epidemiology what we call R0(the ‘R value’) – the figure relates to the number of people one single already infected person can in turn infect. Delta’s R value is between three and four, and, in one study, six (almost as infectious as measles), but the new variant, Omicron, appears to be even more infectious, more capable of transmission, than even Delta. If you multiply that figure in your head, you can perhaps understand how rapidly the Delta variant, which is now taking over the whole world, can spread.

In summary Covid is a highly infectious virus which, proportionally does not actually kill a huge number of people. That is actually an advantage for a virus, when it comes to its ability to spread: if a huge number of people are killed, that makes it easier to identify and isolate the patient, making it easier to control the spread. That is why influenza is so efficient: it kills relatively few people. When it comes to the current virus, it kills less than 0.15% of people under 60 and three percent of those over 60. If this is compared, for instance, to SARS, with 10% mortality, and Ebola, which kills over 80% of those infected, the difference is marked.

So, yes, it is efficient – in the sense that it spreads because it kills a relatively small number of people – but, if you multiply the R value by millions, the number of deaths is actually huge. Of course, we are not just concerned about fatalities, but debilitation and long-term consequences in a significant proportion – 10% or so – of those infected.

What will be the long-term effects of this latest pandemic? Obviously, it is too early to say, but we can look at some of the effects that have already taken place, such as changes in work habits and perhaps even in chain production: where previously commodities might depend on parts produced in five or six different countries, that may well change now. This pandemic has broken the supply chain across the world: half the global economy ground to a halt for a period. I personally think that this pandemic has accentuated the weakening of US global hegemony, which was already on the wane before Covid.

It is interesting to look at what has happened to the Centre for Disease Control and Prevention (CDC), the US federal agency. In all previous pandemics, such as that of the Ebola virus five years ago, the entire public health community across the world would follow the directions of the CDC, as they had in previous epidemics and pandemics. But where is the CDC in this particular pandemic? This says a lot about the inability of the US to deal with even its own problems, let alone act as a guide to the rest of the world. While the CDC dealt very effectively with Ebola and SARS, we are in year three of Covid-19 and its lead has been non-existent. We still do not have a global response. Whenever a new Covid variant appears, each country goes its own way. This is very telling, when it comes to the structure of the capitalist world and its development.

I have not said anything about the relationship between global warming and the development of viruses and bacteria. That is a huge field in itself and, while the two are obviously quite interrelated, the subject needs much more work and research.

In the meantime, let me sum up what I am arguing: pandemics are human-made; they are the child of social, economic and political relationships.

If we take Rosa Luxemburg’s famous statement that we face “either barbarism or socialism”, I believe we can now refine that “barbarism” more clearly. My personal take is that, while nature is treated as a commodity, while our assault on nature continues, and until we change radically and fundamentally the way we live collectively, we can confidently predict that Rosa’s “barbarism” will rise out of a chain of global pandemics and terminate in the victory of one part of nature over humankind.

  1. See N Wolfe The viral stormLondon 2011.↩︎
  5. com/how-pandemics-past-and-present-fuel-the-rise-of-large-companies-137732.↩︎
  7. See, for example, my article ‘Aids and globalisation’:↩︎

This article was first posted at:


also see:-


1. Imperialism is responsible for Omicron – Sam Carliner, Left Voice (USA)

Imperialism is responsible for Omicron

2. Herd immunity: myth and reality – Socialist Democracy (Ireland)

3. Capitalism is a virus – Left Voice (USA)


4. Capitalism and workers : plus ca change – Karl Marx