While the world is preoccupied with one particular type of virus, scientists estimate that there could be trillions of species present on the planet – and that in the ocean one millilitre of water alone will contain several million virus particles.
These viruses don’t have it all their own way, however. Marine ecologist Jennifer Welsh and a team from the Royal Netherlands Institute for Sea Research (NIOZ) recently demonstrated that some sea creatures prey on viruses rather than being infected by them – and claim that by doing so they might have saved humans from many possible viral contagions.
In a laboratory-created environment the researchers examined how 10 different marine animals – including anemones, polychaete larvae, sea-squirts, crabs, cockles, oysters and sponges – succeeded in removing viruses through active predation, filter-feeding or putting up barriers to entry.
The most efficient virus-killers turned out to be sponges. Breadcrumb sponges (Halichondria panicea), which abound in the North Atlantic and Mediterranean Sea, showed that they could remove 98% of viruses in the course of a day – with 94% eradicated within only three hours.
Even when new viruses were added to the water every 20 minutes, the sponges proved able to cope efficiently.
Crabs were the runner-up virus-killers, wiping out 90% over the course of 24 hours. Cockles came third with 43%, with oysters lagging some way behind at 12%.
The scientists conceded that the situation would be more complex for the animals in the wild as a result of all the other animal species influencing their behaviour, currents, temperature and light conditions.
However, they suggest that the natural ability of animals such as sponges to kill viral pathogens could be harnessed, particularly in areas such as aquaculture farming.