COVID-19 calls for renewed look at livestock farming

Poor sanitation facilities, unsafe disposal of factory waste at animal farms pose a problem by providing breeding ground for pathogens.

By Meenakshi Sushma
Published: Thursday 09 April 2020

The novel coronavirus disease (COVID-19) pandemic has raised questions on the health of industrial livestock farms. While illegal trade of wild animals comes up in conversations around the origins of the epidemic, animal farming practices usually take a backseat. 

Poor sanitation facilities and unsafe disposal of factory waste at animal farms pose a problem — by providing a breeding ground for pathogens, according to a study published in Nature.

Regular doses of antibiotics are required in industrial animal farms to prevent animals from getting sick. The use of antibiotics is so rampant that pathogens eventually become resistant to them, leading to the rise of medicine-resistant superbugs.

Callous livestock farming practices have now called for attention to increasing the risk of global disease in times of COVID-19.  

According to the report, thousands of pigs died in four factory farms in China's Qingyuan county in 2003. They were affected by a coronavirus strain which was identical to the one found in horseshoe bats within the neighborhood.

The study found that it was the industrial way of farming pigs which prompted spread of infection. Transmission to humans was ruled out initially, but subsequent laboratory tests showed that such transmission could have been possible.

The novel coronavirus (SARS-CoV-2) is likely to infect animals that contain Angiotensin-converting enzyme 2 (ACE2), according to a study published in Science Direct.

ACE2 is an enzyme attached to the outer surface of cells in lungs, arteries, heart, kidney and intestines. The animals that could potentially be infected include civets, pigs, pangolins, cats, cows, buffalos, goats, sheep and pigeons. Most of them are industrially farmed in China.

The ACE2 enables the binding of SARS-CoV-2 in these animals as well as humans.

So did SARS-CoV-2 jump from animals?

The scientists from Scripps Research Institute recently published a genomic sequencing analysis of the SARS-CoV-2 virus in journal Nature. Through this analysis, they narrowed down to two scenarios.

The first scenario suggested that the virus evolved from within humans. This is possible when a less pathogenic form of the virus gets transmitted in the human body from an animal.

It evolves within the human body through an extended period of stay and undetected human-to-human transmission.

The second scenario suggested that the virus evolved within an animal host and got transmitted to humans, as happened in the case of Severe acute respiratory syndrome, which jumped from a civet. However, in this case, pigs acted as an intermediate host.

Similarly, the Middle East respiratory syndrome (MERS) virus came from a camel that had strains of coronavirus.

If we consider this scenario the Scripps researchers think that it is most likely that the initial transmission would have occurred from bats to an intermediate animal host, where the virus then evolved to its current form.

If the industrially farmed animals fall under the category of the intermediate host — or even the source — it could lead to a spread of a new type of viral or bacterial spread.

“This reality has been completely ignored by governments and the big meat companies they are beholden to,” non-profit GRAIN quoted Rob Wallace, an evolutionary biologist, as saying.

The situation calls for a renewed approach to livestock farming practices. To understand why viruses are becoming more dangerous, one must investigate the industrial model of agriculture and more specifically, livestock production.

This kind of investigation is urgent in the wake of epidemics such as COVID-19, Wallace said.



Subscribe to Daily Newsletter :
Related Stories

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.