Virus ancestry could help predict next pandemic
Insight into virus evolution helps narrow the range of pathogens that could cause future epidemics.
Virus family history could help scientists identify which strains have potential to become the so-called Disease X that causes the next global pandemic.
A study led by a Roslin Institute scientist has identified 70 virus lineages – groups of related viruses – that pose the biggest risk.
Viruses from other genetic backgrounds are unlikely to cause a high number of infections in humans, the research shows.
The findings will support ongoing efforts to monitor and prepare for future pandemics, including guiding vaccine and diagnostic development.
The research team traced the lineage, or family tree, of 743 distinct species of RNA virus – which carry their genetic information as RNA, similar to DNA – to track how they evolved.
These types of viruses cause many diseases, including the common cold, Covid-19 and measles, and have been responsible for most epidemics, or global pandemics, in recent history.
The study included all RNA virus species that are currently known to infect humans.
Researchers hoped to better understand the potential source of Disease X, a generic term used by the World Health Organization to represent a hypothetical, unidentified pathogen that could pose a significant threat to people.
Monitoring RNA viruses in animal populations could help to identify those that are most likely to emerge and spread rapidly in humans. However, the huge number in circulation makes this extremely challenging and expensive.
Researchers compared the development of strictly zoonotic viruses – those that spread from animals to humans, but not between people – with human-transmissible viruses, which can spread within human populations.
Viruses that can spread within human populations typically evolve separately from strictly zoonotic viruses, the findings showed.
Human-transmissible viruses often emerge when related viruses from the same lineage can already spread between humans.
Strictly zoonotic viruses have historically not led to epidemics in human populations. Having a close relative that can infect humans, but not spread between them, does not appear to increase the risk of epidemic potential.
The research team caution that there is still a chance the next pandemic could come as the result of a strictly zoonotic virus – such as bird flu – or an entirely new virus. However, the findings offer a route to help streamline surveillance for Disease X among the vast number of RNA viruses in existence.
The study is published in the journal Molecular Biology and Evolution: The research team included scientists from the University of Liverpool and Peking University in China.
The study was funded by the EU Horizon 2020 programme and the Biotechnology and Biological Sciences Research Council, part of UK Research and Innovation.
These findings offer helpful insight towards identifying the likely sources of viruses that could give rise to an epidemic, and they are welcome news.
Out of potentially huge numbers of viruses that affect mammals and birds, this work shows we should concentrate our efforts on those viruses that are related to existing human viruses with epidemic potential, which is a considerably smaller number.
Viruses without the right ancestry don't seem to cause epidemics. Out of potentially huge numbers of mammal and bird viruses in circulation, we should concentrate on the ones that are related to existing human viruses with epidemic potential. This research narrows the search for the next Disease X enormously.”
** The Roslin Institute receives strategic investment funding from the Biotechnology and Biological Sciences Research Council and it is part of the University of Edinburgh’s Royal (Dick) School of Veterinary Studies. **