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A study published in Nature Communications looks at the genomic screening of 16 UK native bat species to uncover coronaviruses with zoonotic potential.
Prof Alice Hughes, Group Leader Biodiversity Analytics of Terrestrial Ecosystems (BAT) group, University of Hong Kong, said:
“It’s important to note that as we look we will find more coronaviruses in bats, especially horseshoe bats across the entire Old-World. Within this study, Sarbecoviruses (the same virus group as SARS and MERS) were only found in the two horseshoe bats, and horseshoe bats are the likely original source of SARS and MERS. This should not be seen as any cause for alarm; bats co-evolved with coronaviruses, and as yet we are only aware of three that have spilled into humans (SARS, MERS and SARS-CoV2) – and all of these had an intermediate host.
“As yet we are not aware of any direct infection between bats and coronaviruses, and intermediate hosts are still likely to be necessary; within the UK such a precondition is unlikely to be met. There remains a risk across much of the planet, and this will be exacerbated by further habitat loss and roost losses, which can increase the probability of the types of interaction more likely to lead to spillover into an intermediate.
“This study only reconfirms something that bat biologists are largely already aware of, and whilst we certainly need more data, and more biosurveillance, we need to remember that coronaviruses in bats are not new, and spillover into humans (with the potential to then spread between humans) remains incredibly rare.
“Understanding the mechanisms that increase this risk remain the greatest priority, especially as in tropical regions, where many more species of bats are distributed, the potential for spillover is exponentially higher than in regions like the UK.”
Dr Rachael Tarlinton, Associate Professor in the School of Veterinary Medicine and Science, university of Nottingham, said:
“This is mostly uncontroversial, and the work in lesser horseshoe bats reflects the findings of many other European groups. There are however some important differences with other research findings for greater horseshoe bats.
“This work doesn’t address the covid origins debate – these viruses are quite different to SARs-CoV and SARS-CoV-2.
“What is slowly becoming clear from a lot of people’s work on sarbecoviruses in horseshoe bats is that the viruses found outside southeast Asia are really quite different (even in species that have really wide ranging habitats like greater horseshoe bats). SE Asia really does seem to be a hotspot for emergence of sarbecoviruses into new hosts (humans or other species) in a way that isn’t occurring in other regions. The bat ecology of this region is quite different with really high numbers of animals in roosts and a large number of different species and this probably facilitates viruses maintaining “plasticity” to crossing species barriers to keep circulating in lots of different animals.
“It is extremely unlikely that the next coronavirus pandemic will originate in UK bats. Anything is possible and UK bats do have other diseases we need to be careful of in handling or contacting them (like European bat lyssavirus), but these coronaviruses are not particularly high risk for crossing into other species. It doesn’t seem to occur very frequently in Europe (if at all) as we haven’t been finding them in lots of other species or in people, despite a lot of looking for it.
“Our 19 species of bats are regarded as vulnerable from a conservation point of view and handling them or disturbing them requires a Natural England licence (for their own protection). Groups that are monitoring, handling or rehabilitating bats should be taking basic biosecurity precautions (like wearing gloves and cleaning gear between use) for their own and the bats’ general health. People with bats in or near their buildings don’t need to be taking any extra precautions for coronaviruses but as always, if anyone finds dead or injured bats, phoning DEFRA, the RSPCA, vet or wildlife care group is best so that someone trained in safe handling can come and collect it is best for both bat and human health.”
https://www.bats.org.uk/advice/help-ive-found-a-bat
Prof Dan Horton, Professor of Veterinary Virology at the University of Surrey, said:
“We shouldn’t interpret this study as showing that the next pandemic will originate in the UK, or that the risk from UK bats is any higher than we thought previously.
“What it does show is the value of virologists and bat ecologists working together, the need to better understand the risks, and that we have the tools and expertise available to do that.
“We already know there are other viruses in UK bats (including lyssaviruses, that cause rabies) that can, and have, infected people and the risk is well managed through existing guidance and legislation (Bat Conservation Trust website contains useful information). Bats are a crucial part of our ecosystem and need our protection.
“This is a well-designed and robust analysis from a multi-disciplinary team, adding important evidence to help understand the risk of viruses crossing the species barrier into other animals.
“They detected the genomes of coronaviruses related to (but not identical to) ones that have infected people, from a small sample of bat faeces. This corroborates previous findings from others.
“They then made safe artificial versions of those viruses (‘pseudoviruses’ that can’t be passed on) and tested whether they could bind to human cells in the laboratory, and using computer models.
“Although one of the new viruses was able to bind special cells that have an abnormally high amount of human ACE2 receptor (the same receptor SARS-CoV-2 uses), it was 17-fold lower than SARS-CoV-2 itself, and when they tried with ‘normal’ human cells the same virus was not able to bind to them.
“As the authors point out the study is reiterating that there is potential for viruses found in the faeces of bats to infect humans which is something we knew before.
“The range of species tested is very comprehensive (16/17 UK species) but the sample size is too low to draw conclusions about how many bats are likely to actually carry these viruses, and also whether there are other viruses they might have missed.
“The samples were all faeces- so we don’t even know for certain if the viruses were actually infecting the bats which the faeces came from. Most of the other viruses they found do not infect mammals.”
Prof Graham Smith, Lead Scientist for Wildlife at the National Wildlife Management Centre, Animal and Plant Health Agency (APHA), said:
“The authors point out that about 70% of emerging human diseases originate from wildlife. Globally, bats account for around 20% of all wild mammals, so finding a number of viruses in British bats, specifically coronaviruses, is not unexpected.
“Relatively little work has been undertaken to identify viruses (or other pathogens) in wildlife and there is a limited understanding of how many pathogens circulate in British mammals, yet alone globally. This study is novel in trying to assess the zoonotic potential of these coronaviruses. The potential ability for binding to the ACE2 receptors is an indicator of zoonotic potential, but we do not know how strong this relationship is, and we do not know how many other such pathogens are circulating in other mammals (e.g. rodents).
“This is therefore a welcome first step in understanding the viral biome in wildlife but further studies are needed to assess whether coronaviruses in bats have zoonotic potential and the risk of cross-species transmission of coronaviruses to other mammal species. A focus on bats however, may lead to adverse public reaction when they may not act as reservoir hosts for more pathogens than other wildlife. The risk to public health remains very low.”
Dr Olivier Restif, Senior Lecturer in Epidemiology at the University of Cambridge and Chair of the British Ecological Society Parasite and Pathogen Ecology and Evolution Special Interest Group, said:
“Emerging diseases are a growing threat to humanity and there is now clear evidence that climate change and environmental degradation are creating new opportunities for pathogens to jump between species, including from wildlife to people and domestic animals. However, outbreaks of such zoonotic diseases remain relatively rare, and we still have limited understanding of the underlying risk factors. Rodents and blood-sucking insects have long been known sources of diseases, and bats have more recently been added to the list of wildlife reservoirs.
“This study should not raise concerns about the risk of coronavirus outbreaks from bats in the UK, which remains extremely low. None of the viruses found in this study share sufficient characteristics with the COVID-19 virus to cause any concern. Furthermore, the mere presence of viruses in bats is not sufficient to generate pandemics. Direct transmission of any pathogen from bats to people anywhere in the world remains extremely rare, and hasn’t happened in the UK for 20 years (with one casualty in 2002 caused by a bite from a bat infected with a different kind of virus).
“Very little is known about the risks posed by bat viruses, which ones could infect people and how they can be transmitted. This study aims to improve our scientific understanding of these questions, with a specific focus on coronaviruses, a hugely diverse group of viruses found in all mammals. A very small number of these can cause severe disease in people and occasionally spread to pandemic proportions (SARS, MERS and COVID-19). This study helps us understand how the huge genetic diversity of coronaviruses found in bats may contribute to the risk of spillover and outbreak in human populations.
“The scientists recovered genetic material (RNA) from multiple coronaviruses in bat faeces across the UK, and compared their sequences and properties to those of other coronaviruses known to cause disease. Importantly, they did not grow or handle actual coronaviruses (which had been previously destroyed as part of the standard safety protocol), but only used the genetic information. In laboratory conditions, they tested the ability of one specific virus protein to attach to human cells, which is a prerequisite for virus infection. Only one of the bat virus sequences tested displayed this ability, providing useful scientific information on the diverse biological activities of bat coronaviruses.
“This study should not raise concerns about the risk of coronavirus outbreaks from bats in the UK, which remains extremely low. There is no evidence that any of the viruses identified by this study could cause disease or even on outbreak in the UK. In fact, all but one virus were shown to be unable to recognise human cells in laboratory conditions, suggesting they would be innocuous. The health risk posed by the one virus shown to recognise human cell receptors remains uncharacterised.
“This study adds to our understanding of the diversity of bat coronaviruses from around the world, and helps us to rule out most of them as potential zoonotic risks.
“A pandemic originating in UK bats remains extremely unlikely. None of the viruses found in this study share sufficient characteristics with the COVID-19 virus to cause any concern. Furthermore, the mere presence of viruses in bats is not sufficient to generate pandemics. Direct transmission of any pathogen from bats to people anywhere in the world remains extremely rare, and hasn’t happened in the UK for 20 years (with one casualty in 2002 caused by a bite from a bat infected with a different kind of virus). In the UK, avoiding physical contact with bats remains, as with any other wild animal, the best way to avoid any risk of disease.
“Being near bats isn’t risky provided you do not touch them. In the UK, people usually encounter bats outdoors at night or indoors where bats are roosting. Common sense hygienic precautions should prevail: do not handle bats (or any other wildlife) unless trained to do so safely, and avoid close contact with their dejections. Please consult the UK Bat Conservation Trust (https://www.bats.org.uk) for expert public advice on what to do if you find bats indoors.”
Dr Julian Tang, Clinical Virologist, University of Leicester
“Essentially, this study looked for coronaviruses in UK bat species and found several coronavirus species, 2 of which were new.
“The study could quite easily have stood alone without the pandemic context, which is extensively discussed in the long Introduction.
“The authors then tested how easily these bat viruses could infect laboratory cell-lines expressing human cellular receptors such as hACE2 that we know is used by SARS-COV-2 (the virus that causes COVID-19) – the idea being that if the virus can infect cells carrying human cell receptors, then it could easily infect humans, which then creates that human-to-human transmission capability for epidemic or pandemic potential.
“This debate about how much we should be concerned about such a potential pandemic risk has been explored before for avian A/H5N1 influenza (the cause of recent bird deaths around the UK), earlier, around 10 years ago:
“You could argue that these bat coronaviruses have been around for many years, and we have had three animal-to-human (zoonotic) coronavirus crossover events over 20 years: SARS (2003), MERS (2012) and COVID-19 (2019).
“Is three events over 20 years a lot or a little or somewhere in between? Should we be a bit worried that this might recur? Moderately worried? Or very worried? And what practical actions should such levels of worry correlate to?
“Such viruses enter human populations via animal-human interfaces – direct (like hunting/consuming them for food), or more indirect (like their contamination of surfaces that you then touch – or other animals that you then touch or eat).
“But with current global dietary and farming habits, it is not possible for all populations to cut all ties with these animal sources – including all secondary/intermediate sources (and we don’t even know what these are in all cases). So, as the authors suggest, we can only enhance our vigilance and surveillance of potential cross-over events, and there are now many websites devoted to this now, such as ProMed: https://promedmail.org.”
Dr Benjamin Neuman, Professor of Biology and GHRC Chief Virologist, Texas A&M University, said:
“Viruses are everywhere, and we ignore them at our peril.
“Studies like this shine a light on the swirling possibilities and near misses all around us that go unnoticed because they are too small to see.
“These viruses do not appear to be new; they look like very ordinary branches from the tip of a very long bat coronavirus family tree.
“I like to think that each time we shine a light on a fresh trove of viruses hiding in plain sight, the world gets a little bit safer, though of course that has more to do with how we use the information, going forward.
“This is a very nice paper that takes the first few steps toward understanding the potential for native European bat viruses to infect humans.
“This is not a report of a new pandemic, or even a single human infection; only a piece of important information that had escaped notice.”
‘Genomic screening of 16 UK native bat species through conservationist networks uncovers coronaviruses with zoonotic potential’ by Cedric C. S. Tan et al. was published in Nature Communications at 4pm UK time on Tuesday 27 June.
DOI: 10.1038/s41467-023-38717-w
Declared interests
Dr Benjamin Neumann: “No conflicts of interest to report.”
Dr Julian Tang: “No competing interests related to this study.”
For all other experts, no reply to our request for DOIs was received.