Worldwide risk of animal-to-human disease spread remains high
Regardless of how the COVID-19 pandemic started, it’s clear that deadly diseases can jump from animals to humans – and a new report from Harvard Law School and New York University finds we’re not doing enough to prevent another animal-borne virus from becoming the next global pandemic.
The study, which looked at common forms of animal-human interactions in 15 countries including the United States, found dozens of examples where viruses could make the leap. Researchers argued that simple policy changes could dramatically reduce the risk of such disease crossover.
Too much of the focus so far has been limiting the damage after a pathogen has already made the jump from animals and begun to spread among people, like Ebola did in 2014, SARS-CoV-2 in late 2019 and bird flu is threatening to do, said Ann Linder, the report’s lead author.
But pathogens are incredibly tiny – 10,000 times smaller than the head of a pin, she said – and can be highly contagious. “By the time you realize that there’s something going on, that outbreak may have metastasized past the point where it can be contained.”
Instead, said Linder, associate director of policy and research at the Animal Law & Policy Program at Harvard Law School, “we really need to shift our mindset and our focus on(to) preventative policy. We can’t be chasing down these outbreaks after the fact.”
That’s why she and her colleagues have spent the last four years looking for weak spots, areas of animal-human interactions where viruses could potentially leap from one to the other. Unfortunately, they found a lot of them.
Linder said her biggest concerns include industries that are “poorly regulated or not regulated at all.”
In the U.S. alone, the report flags the exotic pet trade, live animal markets, bat guano harvesting, guinea pig and ferret farming, coyote and fox urine production, roadside zoos, animal fighting, fur farming, commercial farming and many other potentially dangerous settings.
“The general understanding is that the more frequent such interactions are, the (more the) risk of disease transmission heightens,” said Suresh Kuchipudi, chair of infectious diseases and microbiology at the University of Pittsburgh School of Public Health.
The report proposes a handful of policy changes in 15 countries, spanning Africa, Asia, the Americas, Europe, the Middle East and Australia. They include enhanced regulation and monitoring of animal markets and their supply chains; improved public health protections across the livestock industry, the wildlife trade and wildlife farming industries; and policies that support sustainable agricultural practices.
Kuchipudi said it’s a matter of balance between food security, economics and the health of animals and people.
“Can we stop all animal operations?” No, he said. “It’s not a solution and also not appropriate.”
But risks can be reduced, particularly when people are made aware of them, through reports like this one, Kuchipudi said.
He also said known risks should be reduced through procedures like pasteurizing all milk and milk products, processing animals carefully and either avoiding petting zoos or making sure children wash their hands thoroughly after touching animals and don’t kiss them.
Such precautions are also important for the animals, Kuchipudi said, recalling many pets caught COVID-19 from their human families.
“We really need to recognize that by protecting our animals we protect our (own) health. And vice versa,” he said.
So-called zoonotic diseases have always existed – smallpox, HIV/AIDS and last year’s monkeypox outbreak are additional examples – but researchers think they’re becoming more common as interactions between humans and animals increase with climate shifts, urban expansion, global travel and other changes.
The report points out that these problems don’t just happen in far-off lands, said Kuchipudi, who was not involved in the study. “We always think this must be happening in some other part of the world,” he said. “We have the same sort of activities right in our backyard. The risk exists regardless of the geography and cultural practice.”
The report flags the U.S. mink industry as one that should be better regulated or eliminated because it poses a risk to human health and its products are unnecessary luxuries.
The mink industry disagrees with the finding that its industry is unsafe.
Mink farmers are careful stewards of both public and animal health, said Challis Hobbs, executive director of Fur Commission USA, the organization that represents U.S mink farmers.
Mink are sold through auction houses and must be certified and follow biosecurity standards to go to market, he said via email.
Early in the COVID-19 pandemic, American mink farmers, at their own expense, helped develop and deliver a vaccine to protect mink from catching the SARS-CoV-2 virus, Hobbs noted.
In the U.S., mink farms participated in weekly testing for the SARS-CoV-2 virus for a period and now test sporadically, Hobbs said. “We continue to work closely with federal, state, and local agencies to take all necessary precautions to protect humans and wildlife and prevent the spread of diseases,” he said.
Dr. W. Ian Lipkin, a professor of epidemiology at the Columbia University Mailman School of Public Health, who was not involved in the research, called the viral spread from animals to humans “a global problem.”
Lipkin has long pushed for shuttering wet markets like the one in Wuhan, China and following more stringent safety procedures at scientific research laboratories.
Lipkin said he also remains concerned about the overuse of antibiotics in animal agriculture, which increases the risk that these essential drugs won’t work when people need them.
Inexpensive genetic analysis can now be used to quickly test animals to see what pathogens they carry that might pose a risk to humans, he said. People who work closely with animals can also get their blood tested to see if they carry antibodies indicating they’d previously been infected with an animal-borne virus.