Updated Sep 2024
Bats play a vital role in ecosystems around the world. They are a diverse group of animals accounting for over 20% of the world's mammals species. Bats contribute to natural and farmed ecosystems, pollinating plants, spreading seeds, and feeding on insects that threaten crops.
In the UK, changes to our bat populations often indicates changes in the health of our wider biodiversity. For example bats suffer when there are declines in insect populations because that's their food, and when habitats such as woodlands, green spaces or farmland are destroyed or poorly managed.
In addition to their important roles in ecosystems around the world, bats (like nearly all mammals), carry microbes including viruses, bacteria or parasites, some of which can potentially infect people. The large variety of bat species around the world host different microbes, and the distribution of potential pathogens varies throughout the range of any given species.
A zoonosis is any disease or infection that is naturally transmissible between another animal species and humans. While the risk of becoming infected with a bat-borne disease is generally low, the consequences of the transmission of these pathogens can be very high. For example, Nipah virus in south east Asia and south Asia and Marburg virus in sub-Saharan Africa can have very high fatality rates and few to no available medical countermeasures. Some zoonoses, such as rabies (the only zoonotic disease associated with bats in the UK), are 100% preventable through vaccination and other methods.
Transmission from wild animals to humans is normally the result of human changes to the environment. For example with bats, destroying or degarding their habitat via deforestation, building development or the intensification of livestock farming can force bats to live unnaturally closer to humans, livestock and pets. This can increase cases of spillover of a disease into human populations, either directly or via an intermediate host such as livestock or pets.
