A virus, one of millions of deadly killers. Something we have little or no natural resistance to. Something easily spread. Something we have no way of stopping until it strikes. Only after the fact can we identify it, develop immunity to it, or a vaccine for it.
Where do these killers come from? Why do they strike us? What do they seem to happen more frequently? Who is to blame for their spread? The experts are best suited to answer these questions, but the blame is mostly our own.
Reclusive, nocturnal, numerous -- bats are a possible source of the coronavirus. Yet some scientists concur they are not to blame for the transfer of the disease that's changing daily life -- humans are.
Zoologists and disease experts have told CNN that changes to human behavior -- the destruction of natural habitats, coupled with the huge number of fast-moving people now on Earth -- has enabled
diseases that were once locked away in nature to cross into people fast.
All of the exploitative practices in our rush for profits, land to use for farming, land to live on, land that was once wild and filled with creatures from the wild. Our search for exotic wildlife to eat, to keep as pets, or take for fur and organs makes human and wildlife mixing inevitable.
But viruses that are extremely similar to the one that causes Covid-19 have been seen in Chinese horseshoe bats. That has led to urgent questions as to how the disease moved from bat communities -- often untouched by humans -- to spread across Earth. The answers suggest the need for a complete rethink of how we treat the planet.
We already overcrowd our farms with factory techniques that make disease spread between our farmed animals a problem. Sometimes the diseases of poultry and swine cross over into humans. We see bird and swine flu when that occurs. When diseases cross from wild populations into humans, they tend to be more virulent such as COVID-19 and Ebola. These exotic virals may become more the norm than the exception to the rule.
Bats are the only mammal that can fly, allowing them to spread in large numbers from one community over a wide area, scientists say. ...
"When they fly they have a peak body temperature that mimics a fever," said Andrew Cunningham, Professor of Wildlife Epidemiology at the Zoological Society of London. “And so the pathogens that have evolved in bats have evolved to withstand these peaks of body temperature." …
In humans, for example, a fever is a defense mechanism designed to raise the body temperature to kill a virus. A virus that has evolved in a bat will probably not be affected by a higher body temperature, he warned.
"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."
Bats were (are) suspect as a possible vector for Covid-19, and were also inked as potential vectors for Ebola. Think back to where this was traced to. An outdoor market where wildlife was sold. Wildlife that included untold species with the potential to carry diseases people have not before been exposed to. Wildlife that was highly stressed because they were caged, in unfamiliar surroundings, next to other creatures they were afraid of and with hundreds to thousands of people that were not seen in the animals’ natural environments. So we are to blame.
"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.
"Spillovers from wild animals will have occurred historically, but the person who would have been infected would probably have died or recovered before coming into contact with a large number of other people in a town or in a city," said Cunningham.
So we are the ones creating the conditions for zoonotic spillover. The spillover does not need to be direct from animal to human. It could spill from one animal to another and then mutate before being passed along to a third species or more before a human ever picks it up. Our greed, our destruction of habitat, and our ability to move both the animal vectors, and ourselves after exposure across the globe make this undoubtedly just one pandemic of many we will face.
The coronavirus is perhaps humanity's first clear, indisputable sign that environmental damage can kill humans fast too. And it can also happen again, for the same reasons.
"There are tens of thousands [of viruses] waiting to be discovered," Cunningham said. "What we really need to do is understand where the critical control points are for zoonotic spillover from wildlife are, and to stop it happening at those places. —
www.cnn.com/...
Unless we change our practices, we will contribute to our own demise on many fronts. Climate change, deforestation, pandemics, pollution, can all be tied to human overpopulation. Even if we each do our individual best to stop our bad practices, until we convince our elected representatives, the multinational corporations placing profit over the health and life on the planet, and our non enlightened neighbors, change will not happen fast enough. Nature is not the enemy, we in our great multitudes are.