Do bats hold the secrets to fighting future pandemics?
Pipistrelle Bat (Pipistrellus pipistrellus) held in a hand to give an indication of size. Scientists have determined that unique immune adaptations linked to bat flight could open new avenues to combat deadly viral diseases, including those behind past pandemics
A growing body of research, highlighted by a recent study in , continues to shed light on why bats seem to host a 'greatest-hits' collection of dangerous viruses without becoming seriously ill. While many other mammals (including humans) suffer devastating consequences from pathogens passed on by bats, these winged mammals generally remain healthy.
Bats have long been implicated as reservoirs for viruses that occasionally spill over into human populations. Multiple pathogens, ranging from SARS-related coronaviruses to Ebola, Marburg, Nipah, Hendra, and rabies, can be traced back to bats. Yet these viruses tend to coexist in bat populations without causing severe disease, whilst transmission to other species (including humans) can lead to devastating outbreaks.
🚨Bat1K Paper Alert🚨We’re excited to share "Bat genomes illuminate adaptations to viral tolerance and disease resistance", JUST published in Nature! 🦇📜Work led by Bat1K executive committee member @hillermich and @_AriadnaMorales🔥https://t.co/uptjW3xUyB
— Bat1k Genome Project (@bat1kgenomes) January 29, 2025
The most infamous recent example is SARS-CoV-2 — the virus behind the COVID-19 pandemic. Although the precise route from bats to humans remains debated, the closest known relatives of SARS-CoV-2 have been identified in bat populations in China. Earlier outbreaks, such as SARS (2002–2003) and MERS (2012–present), were similarly traced to bat coronaviruses, with civets (for SARS) and camels (for MERS) suspected as intermediate hosts.
Despite carrying high-profile pathogens, bats themselves seldom become ill. Why?
The new study provides further insight into a hypothesis that has been gaining ground: when bats evolved the ability to fly, they underwent genetic changes that also reshaped their immune systems. Flight is metabolically taxing, generating considerable oxidative stress at the cellular level. However, bats have evolved robust DNA repair processes and mechanisms to temper inflammation, preventing the collateral damage one might expect.
In most mammals (including humans), inflammation serves as a double-edged sword, an effective defensive response against infection, but potentially lethal when it spirals out of control. Bats appear to have optimised this balance, using immune pathways that restrain viral replication without triggering the excessive inflammation (which contributed to severe COVID-19 cases). Though rare exceptions exist, and bats are not universally immune to all viruses, they have largely achieved a sort of evolutionary truce, harbouring viruses with minimal harm to themselves.
Ireland is home to nine bat species, all insectivorous and primarily active at night. Unlike certain tropical or subtropical bat species, Irish bats typically do not congregate in very large colonies nor frequently interact with large mammals, reducing the likelihood of serving as significant zoonotic reservoirs.
- The common pipistrelle (Pipistrellus pipistrellus), the most widespread bat in Ireland, has not been linked to any known human viral outbreak.
- Leisler’s bat (Nyctalus leisleri), often regarded as Ireland’s largest resident bat, also has no documented history of transmitting dangerous pathogens to humans.
- The Lesser horseshoe bat (Rhinolophus hipposideros), distinguished by its characteristic nose shape, is likewise not associated with major human-infecting viruses.
The risk of contracting a serious disease from Irish bats remains negligible, while their ecological benefits, such as pest control are substantial.
Deciphering how bats modulate their immune responses could revolutionise our approach to pandemics.
Researchers are especially interested in how bats suppress viral replication without unleashing harmful inflammatory responses. Harnessing or mimicking these molecular pathways in humans could pave the way for therapies that prevent life-threatening immune overreactions seen in diseases like COVID-19.
Meanwhile, monitoring the viruses carried by bats could serve as an early-warning system, providing an opportunity to intervene before a pathogen jumps to another species. Importantly, it is human activities, including deforestation, wildlife trade, and habitat encroachment that increasingly bring bats (and the viruses they carry) closer to people. Conservation and responsible environmental management are therefore crucial first lines of defence against new zoonotic diseases.
Bats, remarkable as the only truly flying mammals, epitomise a delicate balance between hosting viruses and remaining largely unharmed. Their ability to tolerate pathogens that ravage other species provides a tantalising model for enhancing our own defences against viral threats. To realise the potential of bat-inspired immunological solutions, however, scientists, conservationists, and policymakers must collaborate to protect bat habitats and conduct research responsibly.
To prevent the next global pandemic, bats are more ally than foe. By examining their evolutionary makeup, we may uncover new methods to disarm dangerous pathogens, long before they pose a catastrophic risk to humanity.
