LETTERS: IT would be convenient if the 2019-nCoV coronavirus outbreak could be blamed solely on Wuhan’s wildlife markets. However, scientists are struggling to pinpoint the original host of the virus and how it infected people.
This leaves us with two issues to be addressed:
WILDLIFE needs to be protected and measures must be taken by all countries to end wildlife trade, ban the exploitation and killing of wildlife and halt the destruction of wildlife habitats, whether or not the killing of any particular species has an adverse impact on human health and safety; and
TO protect human health, we need to protect animal health and welfare. We need to examine how intensive animal agriculture and low animal welfare standards have resulted in threats to human health, safety and wellbeing.
History shows that not only does eating farmed meat not inoculate humans against diseases, intensive animal agriculture is also a major driver of zoonosis and disease outbreaks, referring to infectious diseases caused by bacteria, viruses and parasites that spread between animals (usually vertebrates) and humans.
If Severe Acute Respiratory Syndrome (SARS), Ebola, West Nile, Nipah, avian influenza and 2019-nCoV viruses were merely transmitted to those who directly handle and consume wildlife, they would not have had the pandemic effects that they did. But wildlife diseases can and do afflict domestic animals, and cross species to humans. Farm animals frequently become intermediate or amplifier hosts for pathogens.
Researchers, including those from the Centre for Global Health Science and Security of Georgetown University, Washington DC, estimate that 70 per cent of zoonotic diseases come from wildlife, and then make the leap from wildlife to humans.
Deforestation and human encroachment into previously forested areas for agriculture have been identified as factors in the spread of zoonosis, as farm and domestic animals come into contact with wildlife and wild birds. The crowded and unhealthy conditions in factory farms then expedite the spread of viruses such as avian influenza, and bacterial pathogens, such as E. coli, Campylobacter and salmonella.
The Japanese Encephalitis virus was transmitted by the Culex mosquito (which feeds on wild birds and mammals) to farmed pigs, which became carriers for the virus and then amplified these infections in humans.
The Nipah virus became an outbreak because virus-infected fruit bats transmitted their virus to the farmed pigs via the consumption of fruit contaminated with bat saliva or urine.
In the case of the Nipah virus outbreak in Malaysia, there was no evidence of direct transmission from bats to humans, and almost all the human cases had direct contact with the infected pigs. Clearly abstinence from hunting, poaching and wildlife products would have made no difference at all in the case of the Nipah virus.
Intensive animal farming is usually characterised by high animal population density and low genetic diversity, both of which are factors that promote increased pathogen transmission and adaptation. Farmed poultry live in conditions that suppress their immunity and make them more susceptible to infections.
Avian influenza virus is reported to be “subclinical or of low pathogenicity in wild birds”, yet become highly pathogenic when transmitted to domestic poultry. A 2010 study published in Veterinary Record reported that a large-scale United Kingdom survey found that battery-cage poultry farms are six times more likely than cage-free farms to be infected with the strain of salmonella, most commonly associated with food poisoning.
The risk of zoonotic diseases must be managed through improvement in farm animal welfare standards, disease management and control measures. These include mitigating measures such as using slower-growing animal breeds, creating diets and management conditions that minimise stress to animals, increasing surveillance and vaccination to monitor and minimise the spread of disease or limiting live animal transportation time.
Other efforts include investing more in research and knowledge transfer to improve farm animal health and welfare standards; reducing non-therapeutic antibiotic use to reduce the risk of antibiotic resistance and encouraging consumers to eat less, or no meat products, or by replacing conventional meat products with higher welfare animal products such as grass-fed beef or free-range or certified humanely raised poultry.
On a personal level, we can reduce and mitigate the risk of zoonotic diseases and infections by choosing a plant-based diet and limiting our exposure to wildlife. At an institutional level, those with the political and economic leverage must reduce and mitigate the said risk by disallowing deforestation and expansion of agricultural activities into forested areas.
There should also be tightening of biosecurity controls in farms and places that process or handle animal products, improving animal health and welfare standards, replacing factory farming systems with more humane and sustainable systems, setting restrictions and guidelines on the transportation of livestock and poultry, and removing barriers and creating incentives for the development, production, and consumption of plant-based foods and lab-grown meat to replace and eventually phase out conventionally produced farmed meat.
WONG EE LYNN
Petaling Jaya, Selangor
The views expressed in this article are the author’s own and do not necessarily reflect those of the New Straits Times