“But why does the disease transfer in the first place? That answer seems simpler, says Cunningham, and it involves an alien phrase that we will have to get used to, as it is one that has changed our lives -- "zoonotic spillover" or transfer.
"The underlying causes of zoonotic spillover from bats or from other wild species have almost always -- always -- been shown to be human behavior," said Cunningham. "Human activities are causing this."
When a bat is stressed -- by being hunted, or having its habitat damaged by deforestation -- its immune system is challenged and finds it harder to cope with pathogens it otherwise took in its stride. "We believe that the impact of stress on bats would be very much as it would be on people," said Cunningham.
"It would allow infections to increase and to be excreted -- to be shed. You can think of it like if people are stressed and have the cold sore virus, they will get a cold sore. That is the virus being 'expressed.' This can happen in bats too.
In the likely epicenter of the virus -- the so-called wet-markets of Wuhan, China -- where wild animals are held captive together and sold as delicacies or pets, a terrifying mix of viruses and species can occur.
"If they are being shipped or held in markets, in close proximity to other animals or humans," said Cunningham, "then there is a chance those viruses are being shed in large numbers." He said the other animals in a market like that are also more vulnerable to infection as they too are stressed.
"We are increasing transport of animals -- for medicine, for pets, for food -- at a scale that we have never done before," said Kate Jones, Chair of Ecology and Biodiversity at University College London.
"We are also destroying their habitats into landscapes that are more human-dominated. Animals are mixing in weird ways that have never happened before. So in a wet market, you are going to have a load of animals in cages on top of each other."”
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I hope factory farmers are watching all this carefully moo.
