June 5, 2020

 

Livestock industrial farming at risk for new diseases

 

 

Some scientists warn on the industrial farming of livestock, which are also breeding grounds for mass production of new diseases, TodayOnline reported.

 

Industrial farming of livestock may offend the sensibilities of many people, with animals crushed into pens where they are barely able to stand up, among other distressing images.

 

Three years before the virus that causes COVID-19 started making people sick in China, another novel coronavirus began circulating in the southeast of the country. It was fatal, but its victims were 25,000 piglets, not humans.

 

That outbreak was swiftly followed in 2018 by a scourge on a much larger scale—the Ebola-like African swine fever, which does not infect humans but killed at least 100 million pigs as it raged across China. It threw the country's pork industry into crisis and sent the price of China's favourite meat soaring. The disease is still spreading in Asia.

 

This flurry of outbreaks and the possible link between the COVID-19 human pandemic to China's wildlife trade has pressed the authorities to tighten rules.

 

In addition to a ban in February on trade of wildlife for human consumption, China said it would revise or enact several laws related to the control of diseases in or linked to animals over the next two years. Some regulations, like those updating the animal epidemic prevention law, would be introduced "as soon as possible", said Zhang Yesui on May 21. Zhang is the spokesman for the National People's Congress, the country's legislative body.

 

China aims to plug the holes that experts say have escalated past problems - low standards of biosecurity, lack of oversight and responsibility, as well as local government cover-ups of outbreaks. Biosecurity covers methods to prevent disease outbreaks in animals as well as to protect crops from infections and pests.

 

But veterinary epidemiologist Dirk Pfeiffer says with animals this is not just a China issue; it is a bigger global problem around the competing demand to raise livestock to feed growing populations and of managing the disease risks for animals and humans that come with the expansion of meat production.

 

"This is the real story—the connection between our food systems, our meat production and infectious disease," said Pfeiffer, a professor at City University of Hong Kong. Meat from the wildlife trade was only one piece of a much bigger picture, Pfeiffer said, pointing to the vast scale of livestock production that came with economic growth.

 

"It's a numbers game—the more dense the biomass, the more opportunity for spread of infectious disease," he said. Livestock—which makes up 60% of the biomass, or total weight, of mammals globally—compares with just 4% for wild animals, according to researchers at the Weizmann Institute of Science in Israel in 2018.

 

The way livestock is raised in industrial-scale farming not only skews biodiversity, it also creates a pathogen bomb for potential disease outbreaks, experts say.

 

"Cheap chicken, cheap cow, it's the creation of a pathogen factory … [it] looks like an efficient system, but the costs of failure—and the risk—is high," said Richard Kock, a professor of wildlife health and emerging diseases at the University of London's Royal Veterinary College. "It sits there as a time bomb."

 

Pathogens can get into livestock farms in many ways, including via feed or water contaminated with viruses from bat or bird droppings or humans coughing and sneezing.

 

But in large-scale, high-density farms, the viruses can spread quickly through the ranks of cows, pigs, or poultry, with ample opportunity to mutate, recombine and otherwise "practise their ability to invade cells", including those of humans, Kock said.

 

This threat may be recognised but it is not being sufficiently monitored, said Gregory Gray, an infectious disease epidemiologist and professor at Duke University.

 

"We are artificially increasing our human risk from some pathogens, because they are allowed to thrive in these domestic animals, and we don't have a good pulse on it," he said.

 

An example: the H1N1 influenza in 2009, the first flu pandemic in 40 years, was first identified in the United States and only later linked to pig farms in Mexico.

 

The risk of disease broadens as the domestication of animals expands, such as the breeding farms for "wild" animals in China, which may have had a role in the current COVID-19 pandemic, Kock said.

 

The World Health Organiation has said that since the 1970s about 70% of emerging pathogens came from animals, which it calls a "burgeoning threat" because "animals are intensively farmed, transported for trade and kept in close contact with other species and humans in market places".

 

The Food and Agriculture Organisation of the United Nations (FAO) puts it this way: "Economic growth is accompanied by an increase in consumption of animal products; changes in livestock production increase the potential for new pathogens to emerge, grow and spread from animals to humans on a global scale."