(ORDO NEWS) — A study led by scientists at Ludwig-Maximilian University Munich has identified an important factor in the spread of coronavirus infection in bats.
The work showed that bats in habitats disturbed by human activity are more likely to become infected with coronaviruses than bats in intact ecosystems.
Bats in human-disturbed ecosystems experience constant stress and weaken their immune systems.
Over the past 20 years, coronaviruses spreading in wild bat populations have led to three major outbreaks in humans: SARS in 2002, MERS in 2012 and COVID-19.
The latest outbreak caused an ongoing global pandemic today. This has drawn increased attention to zoonoses – infectious diseases that are transmitted from animals to humans.
It is now clear that land use change is a major driver of the increasing incidence of pathogen transmission from wildlife to humans.
These are the so-called zoonotic side effects. This is partly the result of changes in the abundance and distribution of zoonotic disease carriers and greater contact between wildlife and humans.
Why do bats get sick
A study led by Dr. Vera Varmuth from the Department of Evolutionary Genetics at the Ludwig Maximilian University of Munich found that bats in human-dominated habitats are more likely to become infected with coronaviruses than bats in untouched human ecosystems.
The scientists statistically linked more than 26,000 bats from more than 300 species with coronavirus infections to land cover and land use data using a meta-analysis method.
“Land modification often means the loss of important wildlife resources. In the case of bats, this could be feeding grounds or suitable wintering grounds,” Varmut says.
That such a loss of resources can lead to chronic stress in wildlife has been repeatedly proven.
If bats cannot find places to roost or find less food in degraded habitats, they experience chronic stress. It weakens the immune system.
“The negative impact of chronic stress on the mammalian immune system is well known. Our results clearly show that animals in disturbed ecosystems become infected more frequently.
The more an area is exposed to human influence, the higher the likelihood of infection of bats living in this area with coronaviruses, ”Warmut notes.
There are three main land uses that lead to the degradation of wild ecosystems and the spread of coronavirus infections in bats: agriculture, deforestation and energy production, including mining.
These three species are the main threat to bats worldwide due to the negative impact on two of the most important bat habitats: forests and caves.
Bats are reservoirs for viruses and the main animal hosts of coronaviruses. Environmental stress has a significant impact on the incidence of coronavirus infections in bats.
Scientists believe that to successfully control the risks of infection spread, it may be necessary not only to monitor the presence of pathogens in the wild, but also their prevalence in animal hosts.
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