Investigating the virosphere

While we might have heard all we ever want to know about viruses in the last few years, the truth is, known viruses represent less than zero point one percent of the estimated total of viruses out there. Claire Concannon meets a team from the University of Otago trying to increase our knowledge of virus diversity, so that we can better understand their evolution.

All of us can list at least a few viruses. Probably more now than three years ago. Coronavirus, influenza, ebola, zika, chickenpox, monkeypox, human immunodeficiency virus (HIV) - there are plenty going around.

But the viruses we know about couldn't even be described as the tip of the iceberg when it comes to virus diversity. It's more like one frozen raindrop resting right at the top of an unfathomably giant continent of ice.

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"It's mind-blowing how many viruses we still have to discover, around like 99.99% of the virosphere is still to be discovered," says PhD student Stephanie Waller.

Waller is currently investigating native New Zealand species to figure out what viruses are associated with them. She is focusing in particular on tuatara, mokomoko (skinks and geckos), tuna (eels) and pekapeka (bats).

Waller's work on cloacal swab samples from tuatara from Takapourewa Stephens Island has already revealed potentially 50 new viruses. She is hoping this work will build on our knowledge of virus diversity and help us to figure out how viruses jump to new hosts.

That is the key question in disease emergence, according to Waller's supervisor and senior lecturer Dr Jemma Geoghegan, who says only knowing a tiny fraction of virus diversity and the hosts they associate with, limits our understanding.

Geoghegan has been a key member of the team of scientists behind sequencing Covid-19 cases to inform New Zealand's pandemic response. But before the pandemic, and alongside her research identifying variants, Geoghegan is very much focused on how viruses evolve.

" is really about trying to understand the diversity of viruses in nature to then understand the mechanisms behind virus host jumping and spread into new hosts," she says.

In Geoghegan's lab in the Department of Microbiology at the University of Otago, other researchers are specifically focused on disease-causing pathogen puzzles.

Such as, identifying the underlying pathogens causing two sicknesses in the endangered hoiho (yellow-eyed penguin). …

Go to this episode on rnz.co.nz for more details