As the coronavirus spread rapidly through the world, scientists worked to identify the source of the disease. According to the Centers for Disease Control (CDC), the exact origin is still not known; however, the virus is similar to one found in bats, and the first cases of the coronavirus were linked to a wildlife market, where bats were killed and sold. In wildlife markets, sometimes called “wet markets,” a variety of species are kept in highly cramped quarters, not unlike on factory farms. At some wildlife markets, customers can purchase an animal to be slaughtered on the spot. Such wildlife markets exist around the world, including in the United States.
People may worry less about the transmission of a virus from animals to humans if they don’t eat wildlife. However, the conditions on factory farms — where most of U.S. animal products originate — are similar to those of wildlife markets, and could be the source of the next pandemic. In fact, the H1N1 influenza outbreak of 2009 originated in an industrial pig farm in North Carolina, the Nipah virus was also transmitted from pigs to humans, and the H5N1 avian influenza was transmitted from poultry to humans.
Zoonotic diseases, diseases that can spread from animals to humans and vice versa, are a major public health concern, with the CDC estimating that over 60% of known infectious diseases are zoonotic.
A recent paper by Humane Society International identifies five primary pandemic risks associated with intensive agriculture:
- Virus ‘spillover’: when expansion of farms into previously wild areas brings wild and domestic species together.
- Viral amplification: where novel viral strains are created through confining vast numbers of stressed animals indoors.
- Farm concentration: where dense geographic concentration of farms increases the risk of pathogens spreading.
- Global live animal trade: where huge numbers of live animals are transported between countries and continents, allowing pathogens to spread even further.
- Live animal markets, agricultural fairs, and auctions: where “hubs” are created such that animals from many different places are brought into proximity with the public, where viruses can proliferate.
In terms of viral amplification, during swine flu or avian flu outbreaks factory farms can particularly act as evolution vessels. Many diseases that start in wildlife, such as birds or bats, are not viable in humans at first, but when introduced to hog and poultry farms, viruses are able to evolve over time to be able to infect humans.
As noted above, intense concentration is a major pandemic risk factor. In this sense, hog and poultry farms are the kinds of environments that are ideal for a disease to move and evolve quickly through a population. To ensure quality control, animals are virtually genetically identical, making for less variation wherein less susceptibility to a virus could emerge. Animals are also packed tight, with numbers typically well into the thousands, within a containment area with little to no space in between animals. Additionally, they are stressed, and therefore have weakened immune systems. Pigs, and often poultry, are genetically similar enough to both wildlife and humans, so they act as the ideal evolution center for viruses to transform from a wildlife disease to a zoonotic one.
The problems are not limited to factory farms where animals are killed for food. Evidence shows that the coronavirus has spread on mink fur farms in Europe and in the U.S., where hundreds of millions of wild, fur-bearing animals are confined in small, barren, wire cages for their entire lives. Wild mink in Oregon and Utah have also tested positive. In Denmark and the Netherlands, farmed mink spread the mutated virus to humans—the only known animal-to-human transmission outside the original source. To protect public health, European governments took the drastic step of killing nearly 20 million mink at infected farms, which still remain reservoirs for the virus.
A final concerning factor for transmission and a pandemic outbreak is that factory farms regularly overuse antibiotics. Many factory farms prophylactically administer low doses of antibiotics in animals’ feed, and the CDC notes that 70% of all antibiotic use in the U.S. is on factory farms. About half of the antibiotics used are practically identical to those used in humans.
Regular low-dose antibiotic use can lead to extreme health risks for both humans and animals. As portions of the antibiotics aren’t fully metabolized, they will show up in manure, which can make its way into water systems. Also, although the consistent presence of antibiotics is provided in an attempt to maintain healthy animals, the reality is that it can create more serious illnesses. Strains of pathogenic antibiotic resistant bacteria, for example, are transferable to humans though handling of meat or manure.
To decrease the health risks that come with factory farming, we encourage consumers to demand better welfare and regulations for the farms. The USDA and the World Health Organization have taken steps to oppose antibiotic use and set stricter governance for how antibiotics can be used. However, until animals are given proper spacing, food, enrichment, and even genetic variation, the problem of emerging zoonotic diseases will persist.
- Wildlife Markets and the Coronavirus, MSPCA
- The Fur Trade, MSPCA
- An HSI report: The connection between animal agriculture, viral zoonoses, and global pandemics, Humane Society International (September 2020)
- COVID-19 and Animals, Centers for Disease Control
- Understanding CAFOs, Centers for Disease Control
- Coronavirus: Fear over rise in animal-to-human diseases, BBC (July 6, 2020)
- Factory farms and pandemics, U.S. PIRG website
- Coronavirus could drive the last nail into the mink fur trade, CNN (October 18, 2020)
- Federal legislation, MSPCA
- Farmers and animal rights activists are coming together to fight big factory farms VOX (July 8, 2020) This article includes information about S. 3221/H.R. 6718, the Farm System Reform Act.
- Question 3 Prevails with 78% of the Vote, MSPCA