1500 new viruses identified

By Tara Shaw

Almost 1500 new viruses have been discovered in a pioneering study, it was published in the journal Nature last week.

An international research team of scientists from China and Australia made the discoveries whilst researching the viruses which infect invertebrates – the group of animals which do not have backbones, including insects, snails and worms.

Genetic analysis was carried out on over 220 invertebrate species, most of which had never been screened for viruses before. The data from this allowed the team to identify at least 1,445 distinct virus genomes – strains of viruses which had previously never been seen.

A virus is a small infectious agent that replicates inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants through to microorganisms including bacteria.

They are typically made up of a core of genetic material, such as DNA or RNA, surrounded by protective coats made up of proteins and fats. When a virus comes into contact with a host cell, it inserts its genetic material into the cell, taking over the cell’s functions and sometimes destroying the cell itself. Viral diseases in humans take a wide range of forms, from the common cold, herpes and chickenpox to AIDS and Ebola.

At the moment, most of the research carried out on viruses tends to be biased towards those which cause disease in humans or are economically important, such as those which affect crops. However, as viruses exist in every type of life form around the world, the research group believed that focusing on the “virosphere” of a different group might help improve our understanding of how they work.

Until now, little has been known of the nature of viruses in invertebrates. However, they are often vectors – carriers which transfer an infection from one host to another – of viruses which can infect vertebrates such as humans and other animals

The work carried out by the team revealed that there was a lot of genetic divergence between the newly-discovered strains and those which have already been described. This means that the invertebrate viruses are very different to the ones we already know about, and the study highlighted that there is no cause for alarm for human health. However, the results also revealed a lot about how viruses evolve and select their hosts, including the discovery that many viruses which infect vertebrates originate from those in invertebrates.

The study has helped to highlight how much we still have to learn about viruses and how they work – information which could have huge benefits for our understanding and prediction of emerging infectious diseases.

The research team believes that the next step should be to survey a range of different animal groups in the same way in the hope that they may reveal even more.

Viruses are everywhere and in everything, and we may have only just scratched the surface of their diversity.