Most of the emerging infectious diseases in the world are caused by zoonoses, vertebrate animals then transmitting their disease to humans. Among the group of mammals, bats are the animals that transmit zoonotic viruses the most. Coronaviruses (CoVs) that infect humans, such as SARS-CoV-1 and SARS-CoV-2, which bats carry, have caused large-scale epidemics in recent times.
A survey conducted by experts from the University of Cambridge (United Kingdom) offers a possible explanation for the spread of these viruses. And climate change plays a key role in this theory: Global greenhouse gas emissions over the past century have made southern China a hotspot for coronaviruses, fueling the growth of forest habitat favored by bats, the authors say.
In the image above, a graphic description of the phenomenon is made. There has been a change in the global distribution of bats, mainly in Yunnan province in southern China and neighboring regions of Myanmar and Laos: climatic conditions have increased the number of species in an area. The mentioned region coincides with the possible spatial focus of carriers of SARS-CoV-1 and SARS-CoV-2.
Changing the distribution of bats: a new habitat
Among the consequences of climate change in China is the growth of plants and trees in places that shouldn’t be. Rising temperatures, sunlight and carbon dioxide have changed southern China’s natural habitats. Where there used to be tropical scrubland, there are now tropical savannas and deciduous forests. At present, many species of bats are housed in this environment which have found a suitable place for their vital development.
About 40 species of bats moved to Yunnan Province, leading to the creation of about 100 other types of coronaviruses transmitted by bats.
As a result, the study authors constructed a map of global vegetation from a century ago, using data on temperature, precipitation, and cloud cover. Later, they worked with information on the adaptation of bat species in different types of vegetation to be able to calculate the global distribution at the beginning of the 20th century. Comparing this with the current distributions, they realized the great richness in species and the increase in the number of species that has occurred over the last century.
“Understanding how the global distribution of bat species has changed due to climate change may be an important step in reconstructing the origin of the COVID-19 outbreak“said Dr Robert Beyer, researcher in the Department of Zoology at the University of Cambridge and first author of the study.
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