Why it’s impossible to separate human, non-human and the environment
In the old view of health, humans, other animals and the environment didn’t have much to do with each other. In the new view, the three can barely be separated – what affects any one of the three affects all.
At the end of the movie Contagion (this is not a spoiler!), you see a bulldozer clearing a patch of trees for a new pig farm. In clearing the land, it displaces a bat colony, and one of the bats, who’s harboring a virus, drops a piece of banana onto the ground. One of the pigs eats the banana, and in the next frame, a slab of pork that was once the pig, lands in restaurant kitchen, where it’s being handled by a chef. And off we go …
It’s the nightmare scenario for a pandemic flu. And it’s basically just waiting to happen. That’s the opinion of doctors and scientists who keep track of viruses emerging from forests and other wildlife domains as we humans invade their space and come in contact with bugs and microbes that we have never encountered before but can now carry around the world in a matter of hours.
From HIV to SARS to bird flu and swine flu, these viruses have become a serious threat to human health globally.
“We now stand at the precipice of health care transformation where disease prevention and health promotion in people, animals, and our environment have become a critical strategic need,” writes Dr. Lonnie King, Director of the National Center for Zoonotic, Vector-borne, and Enteric Disease at the CDC.
Dr. King is one of a new breed of doctors and scientists who recognize that there can be no separation between the human health care and the care of other animals and the environment. We are all part of one intricate ecosystem, each influencing the others all the time.
In the most practical of ways, how we humans treat other animals and their homes has a direct impact on our own lives and health.
In the Nipah virus, art imitates life
Diagram by One Health
The plot of Contagion is based on the real-life story of Nipah, a virus that swept through pig farms in Malaysia 12 years ago. Bats who harbored the virus found themselves displaced by new pig farms, and began to infect the pigs with a virus that the pigs, in turn, passed on to the farmers. And while the Nipah virus appeared harmless to bats, it was 70 percent lethal to humans. Millions of pigs were slaughtered in an attempt to control what could have become a global pandemic.
In recent weeks, there’s been an uptick in bird flu.
“We’ve been relatively lucky that bird flu does not easily transfer from person to person,” said James Hughes, a professor of medicine and public health at Emory University. “But with an opportunistic mutation or two, an avian virus could be more easily transmitted to humans and then between humans.”
Just as happens after floods and hurricanes that turn out not to be catastrophic, it’s easy to get complacent when a flu scare turns out not to be a disaster.
“There are many, many examples of old diseases returning with a vengeance,” Hughes said. “If you haven’t learned to expect the unexpected, you haven’t been paying attention.”
A third-world municipal dump is the perfect breeding ground for zoonotic disease
Pigs have turned out to be an almost perfect host for these mutations. A virus that has been limited to one particular species of wildlife, and that would have a hard time infecting humans, can often easily find a good new home in a pig.
And because pigs are also physiologically quite similar to humans in many ways, the newly mutated virus can then make the easy leap to a third strain that can be deadly to humans.
That’s what happened in the outbreak of swine flu in 2009, when pigs at a U.S.-owned factory farm in Mexico picked up bird flu from some migrating flocks, enabling the virus to take on a new form that was then transmitted to factory workers. It wasn’t, for the most part, a killer strain. But that was basically another lucky break. How many of those can there be before we hit the anti-jackpot?
In the 2006 outbreak of E. coli from spinach fields in California, it wasn’t the spinach that was to blame; it was bacteria from a cattle operation upstream that found their way into the water supply and onto the spinach – a very simple interaction among animals, the environment and us humans.
Climate change is a major factor
Climate change is a factor, too. More and more animals in the wild are on the move as they seek out cooler climates and try to escape the growing number of droughts, floods and heat waves that leave them without homes and food. These include small insects like ticks and mosquitoes that area also carrying diseases to new locations.
All of this is bringing together scientists from different domains of human, non-human and environmental health.
One organization at the forefront of this is One Health, which is “dedicated to improving the lives of all species – human and animal – through the integration of human medicine, veterinary medicine and environmental science.”
While the primary focus of organizations like One Health is protecting humans, there’s a recognition that unless we protect other animals and the whole ecosystem, we simply cannot protect ourselves. What’s good for them is good for us, and what’s bad for them can be even worse for us.
Companion animals may be at risk
No animals are exempt from the overall danger. During recent outbreaks of bird flu and swine flu, there were reported cases of companion animals contracting the viruses.
Tracey McNamara was a veterinary pathologist at the Bronx Zoo when, in August 1999, a disease she’d never seen before started causing birds of all kinds to literally fall out of the sky. West Nile Virus had arrived in the western hemisphere. One of her concerns is that people who don’t interact much with wildlife but who have pets at home is that these, too, could be at risk – and could then pose a risk to humans.
“The next infectious disease could emerge in a dog or a cat, or maybe some exotic species housed at a zoo,” she said.
Meanwhile, bird flu is still being incubated on farms and in markets that are perfect places for disease to spread.
Chickens and other birds are crammed together in cruel and filthy conditions, where they also pass the virus to ducks, geese and swans as they migrate around the world.In 2006, New Scientist reported that bird flu had become “the biggest outbreak of an animal disease ever recorded.” It’s only grown since then.
The scientists of One Health and other organizations want to prevent these diseases before they can take hold. More than anything else, that’s going to mean bringing an end to cruel farming practices and fostering a new relationship of respect toward all animals.