Taking bad viruses with the good

Illustration: Eric Lobbecke

I love viruses, you hate them. You saw “Virus!” and your mind leaps to COVID-19. Then possibly your mind darted to influenza, HIV or Ebola. Of course we worry about these viruses as they can cause us disease and sometimes an excruciating death. It’s these viruses that give the rest their undeserved bad reputation.

The viruses that threaten our health are a tiny fraction of all the other beneficial viruses. Most are vital to our existence on Earth and the sheer number of these good viruses is astonishing.

There are more viruses on Earth than there are stars in the sky. The concentration of the beneficial viruses in freshwater lakes and rivers often exceeds 100,000,000 per millilitre: — that’s 4½ times the population of Australia squeezed into less than a teaspoon of water. Globally, the oceans contain 10 to the power of 30 viruses. On average these are 0.0001mm long, so you can see them only with specialised microscopes. If you lined them all up they would extend for 10 million light years; that’s 100 times the distance across our galaxy. Collectively they would weigh as much as 75 million blue whales.

Viruses are not living organisms. They are an inanimate and unpretentious collection of crystalline chemical units. These units carry a small piece of DNA or RNA with all their genetic information stored in a protein-coated head attached to a coiled collar with legs. When the legs attach to a host the collar compresses, ­injecting the viral DNA or RNA into their target cell.

Viruses have evolved to usually infect only one host type. Viruses that infect bacterial cells, for example, will not infect human cells. Homo sapiens has its own suite of viruses. However, viruses are always mutating and evolving. A virus can sometimes jump the animal species barrier to a human host. COVID-19 is a reminder that nasty surprises can come from the animal kingdom.

Viruses cunningly use their host’s own metabolic machinery to replicate themselves. So viruses are parasites that must have a host cell to replicate. They play a critical role in ensuring that nutrients are completely recycled on Earth so the life cycle we depend on can continue. They also ensure no single species gets out of control to disrupt the global ecological balance. We are not exempt from this process of viral control.

Scientists have long been aware of the threat of viral pandemics. There are dedicated groups of scientists risking their lives tracking down these new viral strains around the globe, trying to prevent or predict the next epidemic and pandemic. It’s not a matter of if there will be another one, rather when and how often can we expect them to occur.

In 2016, after the US led the Ebola response, the Obama White House established the global health security office at the National Security Council. Its aim was to prevent the next viral outbreak from becoming an epidemic or pandemic. By May 2018 the Trump administration destroyed any clear structure and strategy for co-ordinating pandemic preparedness and response. They are paying the price.

How far should a government try to restrict the spread of COVID-19? This is linked to balancing the death rate of individuals against the degree of the destruction to the fabric of our ­society and the health and wellbeing of the community as a whole. Only history can tell us if we struck the right balance. COVID-19 is probably one of the most intensely publicly dissected viral pandemics to date. Death of the elderly features every night on TV. The impression is that the death rate due to the virus is high and indiscriminate when neither is true.

In some sense Australians will never be the same. We will wash our hands often, hopefully all food outlets will permanently have handwashing stations or sanitisers at the front door. We will cough and sneeze into our armpit or tissue. These hygienic practises once were normal etiquette that seemed forgotten.

The next pandemic may well be fatal to all age groups and spread as easily as COVID-19. We have a chance to learn from this outbreak how to better handle the next pandemic without destroying the fabric of our society or the mental and physical wellbeing of many. It won’t then be the end of our world as we know it.

Peter Pollard is a microbial ecologist. His marine and freshwater research has focused on the relationships between microbes (algae, cyanobacteria, bacteria and viruses) and their environments