Monday, March 20, 2023

Raccoon Dogs, Pigs, Birds, Most of Your Diet, and Other Vectors of Zoonotic Disease

by Michael C. Dorf

As Republican politicians continue to push the improbable (but not completely ruled out by the evidence) hypothesis that the COVID-19 pandemic originated in a lab leak (or, in the fever dreams of their conspiracy theorists, as a bioweapon), new evidence has emerged suggesting a specific species as the more likely zoonotic origin: DNA from the (illegal) Wuhan live animal market that has been the focus of the most attention points to raccoon dogs as a possible source. I say "possible" because the evidence is raccoon dog DNA and COVID-19 in samples taken from the live market very early in the pandemic; it's possible that the raccoon dogs were infected after COVID-19 had already begun to spread from some other source, but given that other coronaviruses can spread from raccoon dogs to humans, the raccoon dog hypothesis merited a recent story in The NY Times.

Let's begin with the obvious: raccoon dogs (which are closely related to foxes, wolves, and dogs but not raccoons) are adorable (although definitely not suitable as pets).

At this point in our tale, I expect readers to feel outrage at the fact that some people in China eat raccoon dogs and other cute animals, including the kinds of dogs many people keep as pets. That is outrageous on moral grounds--slaughtering and eating a raccoon dog or a Labrador retriever feels only a step removed from cannibalism. It is also alarming on public health grounds, given the tendency of deadly diseases to jump from the particular sorts of wild animals that some people in China regard as delicacies to humans.

So be outraged. But try not to be selectively outraged.

The next and likely more deadly pandemic probably won't be caused by a coronavirus but by a new strain of influenza that jumps from pigs, birds, or, as with H1N1, both. Flu pandemics tend to be deadlier than the recent (and let's be honest, ongoing) COVID-19 pandemic. They are also almost invariably zoonotic in origin. Annually circulating flu viruses mutate from year to year, and while they are deadly in a small percentage of people with various vulnerabilities, most people who get the flu merely experience about a week of unpleasantness. By contrast, flu pandemics occur when a new (or newly circulating) flu virus emerges against which existing immunity (and the flu shot, which needs to be readied months in advance) is largely ineffective. These novel flu viruses can be simply novel in humans, as when "swine" flu or "bird" flu jumps species, or, worst of all, a new cocktail that combines genetic material from flu viruses that previously infected two or more species.

In parts of Asia, historically chickens or ducks were raised in close proximity to pigs, creating opportunities for viral mixing. That phenomenon poses greater dangers when the animals are themselves raised in intra-species close quarters--so-called concentrated animal feeding operations (CAFOs) or more colloquially, factory farms. Short of a bioweapons lab, it would be hard to come up with better conditions for the emergence of new deadly diseases than massive chicken or duck CAFOs in proximity to pig CAFOs.

Of course, even when pigs, chickens, and other animals are raised separately, their close proximity and sheer numbers create enormous vulnerability. The minks (also an adorable animal) who recently caught bird flu on a Spanish farm might well have been infected by a wild bird such as a goose or duck that in turn might have caught it from one of the roughly 50 billion chickens raised for slaughter around the world each year. The mink outbreak is itself very concerning and could portend a similar species jump to pigs or other mammals raised by humans for food.

So far I've been discussing viruses. As readers are probably aware, many farmers provide prophylactic antibiotics in the feed for the animals they raise. Antibiotics work against bacterial infections but not viral ones. But of course animals raised for food are vulnerable to such bacterial infections--especially so given how closely they are typically confined. Hence, the practice of dosing all the animals with the antibiotics. That approach increases the likelihood that each animal survives to slaughter, but it also increases the likelihood that antibiotic-resistant strains of disease evolve.

What is to be done? The blindingly obvious answer is that human beings should stop eating other animals and their products, and not just out of self-interest. After all, whether an animal is adorable or not should be completely irrelevant to the moral question of whether to exploit, slaughter, and eat that animal--although, for the record, cows, chickens, and pigs are gentle and often adorable animals. 

I'm tempted to stop there. I didn't become a vegan because of the public health risk modern animal agriculture presents, but it is certainly a sufficient reason for veganism on a population-wide basis. I recognize, however, that most people won't go vegan, at least not right away. Even so, at the individual level, greatly reducing individual meat (and other animal product) consumption would be a start. Collectively, we need, at a minimum, stricter laws and stricter enforcement of existing laws that aim to reduce the breeding and spreading of deadly diseases.

One would think that self-interest would suffice to bring people onboard in efforts to reduce the likelihood of another deadly zoonotic pandemic. Towards that end, greater recognition of the danger should help. Unfortunately, there is a shared interest between the PRC leadership and Republicans in the U.S. in avoiding the truth. Republicans who want to vilify China are pushing the unlikely lab leak/bioweapon theory, while the Chinese government implausibly pushes back against each and every theory according to which COVID-19 originated in China (which it nearly certainly did). Lost in the shuffle are thousands of raccoon dogs as well as billions of chickens, pigs, and other animals raised for slaughter--as well as the humans who who will be infected by the diseases their conditions incubate, whether or not any particular individual human consumes animal products.