Why parasites are vital to our existence

A philosophical paper written by University of Johannesburg palaeontology and philosophy of science Professor Francois Durand in 2016 has recently been revived, and proves eerily relevant amid the Covid-19 outbreak.

The pandemic is the latest in a string of age-old plagues, brought on by parasites.

Scientists and conservationists have long warned of people’s unsustainable ways, culminating in an array of diseases that should have humbled mankind when they first emerged.

But instead of heeding nature’s call and halting our forced presence on wild animals and mysterious habitats, we forged on, adapted and continued with brute force to colonise what we thought belonged to us. We did this while not taking into account the intricate relationships within each affected ecosystem.

This brute force has led to, among others, a host of often deadly diseases – from the bubonic plague to malaria, and the destructive cycle continues.

We must be reminded that we are parasites too. Durand explained in his paper that “if an organism does not eat dead organic matter …, if it is not a predator which kills and consumes its prey, and if it does not generate its own food by means of photosynthesis, then the chances are that it is a parasite.”

Essentially, a parasite is something that feeds off other organisms or its produce but does not kill it. He provides the simple example of continually picking leaves off a lettuce plant, in which we consume the young of the plant, without killing it completely.

“Life is something completely different from what we like to think. There is only one species of you, but you consist of 15 trillion cells, only a small amount of which are human. We are just an interlinked sponge of life.”

Durand explained that in most cases, organisms have co-evolved with parasites to be able to tolerate a certain amount and diversity.

Parasites play an important role in the immune systems of their hosts, which makes their presence vital to every level of existence, from individual to populations and ecosystems.

As Durand said: “There are things living on your skin eating dead skin cells, and drinking oils from your eyelashes, to keep you clean. But one parasitoid goes into your body, and you die.”

In humans, parasitic infections such as malaria adversely affect the lives of billions of people every year, and result in the deaths of over one million children.

Witnessing death, destruction and suffering as a result of parasites leaves humans to question the romantic idea they have of nature, which often confuses reality with our idealism.

Deepening our knowledge of the role of parasites could form an integral foundation for humans to further understand nature, its intricate ecosystems, and the role of humankind in it.

Through this, we deepen our understanding of how destructive we are, and what we stand to lose should even one species become extinct – because after understanding the role of parasites, we would know it is never just the loss of one species, but countless others that used it as a host, which feed into other ecosystems.

Looking at the importance of parasites and accepting that human beings are not as great as we imagine could be the first step to every person leading a more sustainable and responsible life.

Durand implored all to start their own food gardens, as a way to start a mini ecosystem, which would give spiders, bees and birds a home and a source of sustenance, and simultaneously solve any pest problems, while feeding humans.

– nicas@citizen.co.za

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