One Health: Bats, a Source of New Pandemics

While bats are, through no fault of their own, a reservoir of zoonotic diseases with pandemic potential, it is human activity that is driving an increase in cross-species contact and raising the risk that pathogens will emerge in humans. The One Health initiative brings together global bodies in the fields of animal health, environmental health, and human health to develop solutions that will benefit everyone.  

Bats: A Reservoir of Zoonotic Diseases

Experts now estimate that 60% of all emerging human infectious diseases originate in animal populations. Bats are no exception. As carriers of numerous viruses, bacteria, and fungi that infect humans, they are the source of the Ebola, rabies, Marburg, and Nipah viruses. There’s no denying it: they are the perfect reservoir hosts for emerging zoonotic agents. But why are they such key players?

Beyond the fact that these small animals fly and live in conditions that promote the rapid and widespread transmission of pathogens, they have a low body temperature that allows them to tolerate viruses that would cause serious illnesses in humans. Thus, with the exception of viruses in the rabies family, bats rarely develop clinical signs. The bat’s innate immune response has unique properties that allow it to withstand viruses and coexist with them.

Chiroptera can therefore harbor an incredible diversity of pathogenic viruses. But what is the purpose of this? Researchers believe that these flying mammals may use certain asymptomatic viruses as a defense against other pathogens or diseases. Primary viral infections may provide protection against subsequent infections by related viruses. Furthermore, these infections promote a continuously activated antiviral state that is always on the alert and therefore more responsive. Not to mention that it is also possible that certain bat viruses possess oncolytic properties. These viruses, in fact, have an extremely long lifespan relative to their size and rarely develop tumors.

Bats are therefore an important model for studying the mechanisms by which viruses remain asymptomatic, which could have numerous implications for human medical research. The four bat genomes currently being studied are vital resources for the scientific community in studying host-pathogenic interactions on a global scale.

Health for All

Although bats have adapted to living with many pathogens, if these were to infect other mammals, as has happened in the past, it could have serious consequences. Needless to say, the current context of COVID-19 and the pandemic caused by the SARS-CoV-2 coronavirus is well known. The challenge, therefore, is to predict when and where these viruses will jump from one species to

another one and potentially trigger a pandemic.

The best way to do this is to study diseases in animals, find cures in animals, and stop them in animals before they even reach humans. To prepare for and respond to a new pandemic, it is therefore necessary to develop new, integrated, and collaborative health approaches on a global scale. This is the concept of “One Health.”

The One Health initiative is a movement launched in the early 2000s that promotes an integrated, systemic, and unified approach to public health, animal health, and environmental health at the local, national, and global levels in order to better prepare for and address emerging diseases with pandemic potential. This approach assigns a major role to veterinarians and personnel who are in regular contact with domestic and wildlife, as well as the environment.

For the World Organization for Animal Health, its implementation requires “new mechanisms that enable all these stakeholders to share information and act in a coordinated manner, in coordination with public health officials—who in our member countries most often work under the auspices of ministries of health, whether as government employees, local government staff, or private practitioners.” The synergy between animal health, public health, and the environment will contribute to improved animal and human health worldwide.

Preserving animal health protects human health

The One Health initiative is all the more important given that current circumstances are bringing human and animal populations ever closer together. As the destruction of natural habitats caused by urban or agricultural expansion forces bats to enter human settlements, it has become urgent to limit interactions between bats, humans, and livestock and to monitor diseases across different animal populations.

While there will always be emerging zoonotic diseases, we can limit their transmission, especially if we know which pathogens are most frequently responsible. Without singling out bats in particular—since they are by no means the only ones responsible for this kind of worst-case scenario—let’s focus our efforts on the health of the ecosystems around us. So let’s start by avoiding close contact with animals, for example by stopping bat meat consumption and the destruction of their habitat.

And if the medical, economic, and media repercussions of previous pandemics have taught us one thing, it is that we must closely monitor animal diseases and maintain a suitable ecosystem for the wild animals that live alongside humans. Preserving animals and ensuring the protection of their habitats also protects human populations from potentially deadly pandemics that threaten our society today.