A Positive View of Parasites

A parasite is often to be admired for its ingenuity and persistence, even if it isn’t always attractive. A friend of mine once discovered a worm in his bed. It had come from his own body and had been living there for several months, beginning its tour in the previous March, when it manifested itself by giving him a cough and a bad chest. He found this out later when researching the life of the roundworm, which had apparently completed a convoluted journey round his interior, beginning in the spring. ‘The female roundworm’, he said proudly, ‘lays a quarter of a million eggs a day!’

It is perhaps a good idea to take this sort of positive view of parasitism, because, according to W. H. McNeill, author of Plagues and Peoples, we are all parasites. ‘Most human lives’, he writes, ‘are caught in a precarious equilibrium between the microparasitism of disease organisms and the macroparasitism of large-bodied predators, chief among which have been other human beings,’ the sort involved in ‘war, plunder, enslavement, tax farming’. I particularly like the inclusion of tax farmers in the macroparasitic group. And now the bad news: humans are not a totally successful form of parasite. In the long run, we may be on the way out, because we have not ensured the survival of our host. Seen from McNeill’s point of view, up in God’s position looking down at speck-persons, we have developed too fast and have made something of a cock-up of the ecological balance. The arrival of humans in the temperate regions, he says, was rather like the introduction of rabbits to Australia. This is a horribly satisfying theory for those of us who already tend to the Swiftian view of humans, expressed in perhaps its most extreme form in Gulliver’s Travels by the King of Brobdingnag, who describes humans as ‘the most pernicious race of little odious vermin that nature ever suffered to crawl upon the surface of the earth’. ‘From the point of view of other organisms,’ suggests McNeill in an oddly comforting, matter-of-fact tone, ‘humankind resembles an acute epidemic disease . . .’ ‘Hoorah! Serves us right!’ I often shout out loud while reading, in a rather heavenly, self-flagellatory way, about the ghastly mess we have made of this planet. But oddly enough McNeill’s revelations are not depressing. When one thinks of oneself as just one mini-particle of a greater mass, the self-blame diminishes a little. I am like an ant in a nest. I’m only obeying my instinct, which isn’t anything like as bad as only obeying orders or acting upon my own beastly initiative. Fortunately, not all of us are ghastly. In Ian and Jennifer Glynn’s The Life and Death of Smallpox, some humans come across as rather admirable – people like Lady Mary Wortley Montagu and Edward Jenner who fought heroically to get rid of that appalling disease. Perhaps one needs to read these two books together – for the macro and micro view of humans. The Glynns provide those riveting little details that make one care again. Voltaire admired Catherine the Great for being inoculated while the French fussed and dithered: ‘You have been inoculated with less fuss than a nun taking an enema.’ Not many parasites, as far as we know, can crack such jokes. And we are fairly unique in the parasite world, I would have thought, because we tend to have rows: about methods, causes and remedies, like the row between the ‘vomit’ men and the ‘purging’ men, and the inoculators (who used the smallpox/variola virus to create immunity, which made the subject contagious), and the vaccinators (from the Latin vacca meaning cow), who used cow-pox, which did not. It is things like this that I need to hang on to, so that I can go on being fond of my species. But nasty is always more thrilling than nice and I am gripped by the horror of it all. According to McNeill, and I cannot help but believe him, we are nowhere near controlling microparasites. Or macroparasites, for that matter. Some people may think that because we managed to put paid to smallpox, we are winning. Think again, those people. New and more frightful diseases have burst out: Ebola, Aids, Haemorraghic and Lassa Fever for starters, all of which defy control. Only two summers ago an epidemic of polio broke out in Nigeria, threatening to spread across Central and West Africa, putting 74 million children at risk, and this week I see on the telly that the terrifying encephalitis lethargica is reappearing after an apparent disappearance of eighty years. It seems TB is on the rampage again too, but this time it’s multi-drug-resistant. Those microparasites are still winning. What sort of a world would it have been without them? Without epidemic disease, apparently, Christianity might never have taken off. ‘Care of the sick, even in times of pestilence was for [Christians] a recognised religious duty [and] quite elementary nursing will greatly reduce mortality . . . whereas pagans fled from the sick and heartlessly abandoned them,’ writes McNeill. Gratitude and solidarity therefore flourished among Christians during epidemics, strengthening the faith. Like Buddhism, Christianity also explained suffering. Both started in crowded areas – Jerusalem and India – where there was more disease, and so it is little wonder, McNeill argues, that people coping with such ‘horror and psychic shock’ clung desperately to such philosophies. But he admits this is only speculation. The more we travelled and traded, says McNeill, the better it was for microparasites. Travel meant fabulous conditions for the diffusion of infection. Caravans of traders, itinerant tax collectors and their accompanying soldiers created a ‘bridge of human travellers’. The microparasites hitched a lift all along the Silk Road. They latched on to fur-traders, missionaries and soldiers in Canada, Buddhist missionaries entering Japan, pilgrims in India, slaves shipped from Africa to America; they hung on to beggars and nomads. ‘Famines, migrations, concentrations and dispersals of human flotsam and jetsam, [all provided] fresh opportunities for epidemic disease to diminish populations.’ Sea travel in particular provided  tremendous opportunities. It was quicker, and travellers dispersing disease were stuck on the boat – until the next port; until, for example, all Mediterranean coastal cities were turned into ‘a single disease pool’. And if all that didn’t spread death and disease efficiently enough, there was always biological warfare. In eighteenth-century North America blankets were sent out of the smallpox hospital to spread the disease among the Delaware Indians. A particularly vicious strain of smallpox that emerged in Moscow in 1959 prompted the Russians to collect it and cultivate it for possible future use, say the Glynns, in a rather terrifying finale. ‘By the 1970s, a stockpile of 20 tons of the virus was being kept at Zagorsk – and 20 tons of plague bacillus kept at Kirov.’ Some countries saw eradication as an opportunity. There is ‘a depth of evil and hysteria in the thought that in the aftermath of a nuclear war smallpox should still be there to attack survivors’. But ‘Satan is not calling all the shots,’ they say. I’m not sure about that. So I turn to McNeill, who doesn’t bother much with good and evil, as he appears to believe that the spread of religion is all down to parasites, and provides, at last, a credible explanation for this phenomenon. Better still, those feeling truly, deeply let down by the Labour Party and their weedy version of socialism, can luxuriate in McNeill’s definition of macroparasites. Imperial officers and private landowners, in his view, were the two social classes most directly parasitic upon Chinese peasant farmers. In the Ganges valley, cholera, malaria, dengue fever, kings, armies, landlords and administrators were all sapping the strength of poor labourers. What fun to see those macro- and micro-parasites all lumped together. ‘In the context of the entire human venture upon earth . . . persistent population expansion is exceptional,’ says McNeill. Our growth is probably due to some ‘ecological upset permitting larger numbers of human beings to survive and multiply for a few generations until natural limits again assert themselves’. It’s the word ‘permitting’ that grabs me. Why watch Hammer Horror? These books between them have it all: killer species, spillage from one lethal disease pool to another, creating havoc and destruction among virgin populations. Those of us who watched telly in the Sixties may remember The Quartermass Experiment, in which a terrifying mass of experimental nasty substance grew and grew, swamping and killing everything in its path. It gave me nightmares for years, but McNeill and the Glynns show us Quartermass for real. We are living the nightmare, but at least we know why. McNeill explains, on a grand scale, everything that I always wanted to know about human nature.

Extract from Slightly Foxed Issue 6 © Michele Hanson 2005