Peter Daszak is a disease ecologist and renowned “virus hunter.” He ventures into bat caves in full protective gear to get the animals’ saliva or blood to determine the origins of a virus. During a conversation with me, he was clear: “We are doing things every day that make pandemics more likely. We need to understand, this is not just nature. It is what we are doing to nature.”
Remember, most viruses come from animals. The Centers for Disease Control and Prevention estimates that three-quarters of new human diseases originate in animals.
This coronavirus might simply have come from one of the wildlife markets in Wuhan, China, where live animals are slaughtered and sold, a practice that should be banned around the world. But as human civilization expands — building roads, clearing farmland, constructing factories, excavating mines — we are also destroying the natural habitat of wild animals, bringing them closer and closer to us. Some scientists believe this is making the transmission of diseases from animals to humans far more likely.
The virus that causes covid-19 appears to have originated in bats, which are particularly good incubators for viruses. Scientists are still studying what happened, but in other cases, we have seen how human encroachment can lead bats to look for food around farmland, where they infect livestock — and through them, humans.
There are other paths for pathogens. The most likely one comes directly from our insatiable appetite for meat. As people around the world get richer, they tend to eat more meat. Some 80 billion land animals are slaughtered for meat each year around the world. Most livestock is factory-farmed — an estimated 99 percent in the United States, and 74 percent around the world, according to one animal rights group. That entails crowding thousands of animals inches from each other in gruesome conditions that are almost designed to incubate viruses and encourage them to spread, getting more virulent with each hop. Vox’s Sigal Samuel quotes the biologist Rob Wallace: “Factory farms are the best way to select for the most dangerous pathogens possible.”
Factory farms are also ground zero for new, antibiotic-resistant bacteria, which is another path toward widespread human infections. Factory-farmed animals are bombarded with antibiotics, which means the bacteria that survive and flourish are highly potent. Some 2.8 million Americans are sickened by antibiotic-resistant bacteria annually — of whom 35,000 die, according to the CDC.
And then there is climate change, which intensifies everything — transforming ecosystems, forcing more animals out of their habitats and bringing tropical conditions to places that were previously temperate. Scientific American reports, “The warmer, wetter and more variable conditions brought by climate change are . . . making it easier to transmit diseases such as malaria, dengue fever, chikungunya, yellow fever, Zika virus, West Nile virus and Lyme disease in many parts of the world.” As we change ecosystems and natural habitats, long-dormant diseases can emerge to which we have no immunity.
In May 2015, two-thirds of the world’s population of saigas, a small antelope, died suddenly within a few weeks. A bacterium called Pasteurella multocida, which had long lived in the animal without doing harm, suddenly turned virulent. Why? The Atlantic’s Ed Yong explains that the Central Asian region in which the saiga lives was becoming more tropical, and 2015 was a particularly warm, humid year. “When the temperature gets really hot, and the air gets really wet, saiga die. Climate is the trigger, Pasteurella is the bullet.”
The real scandal is not what China did to us, but what we together are doing to the planet — and what only we together can stop.