Some of the most ruthless killers in the world are zoonotic diseases; they account for more than 2.5 billion cases of illness and 2.7 million deaths every year. Prasanna Kannan FRSA explores the evidence and argues that mass veganism is a key preventative measure.
Covid-19, Ebola, HIV, SARS, TB, Zika, even the Black Death – what do these diseases all have in common? They are all zoonotic infectious diseases caused by the transfer of bacteria, viruses or parasites from animals into humans. They often make the jump from other mammals and in some cases can come via intermediate ‘vector’ species. Crucially, although 60% of known infectious diseases are zoonotic in origin, this rises to over 75% in relation to new or emerging infectious diseases. And while zoonotic diseases lead to 15.8% of deaths globally, they account for 43.7% of all deaths in low resource countries, and so have an even greater impact amongst the world’s poorest people.
It is perhaps no surprise that many zoonotic diseases in history have emerged in China. From the Black Death itself (which killed an estimated 75-100 million) through to Covid-19 today, many pandemics have emerged from Chinese live meat markets where numerous animal species are kept in close captivity, leading to an increased probability of vector-based transmission. The fact that wild creatures such as bats, sometimes seen as a delicacy but known to carry many deadly pathogens are in these markets further exacerbates this issue.
However, we will not address this problem if we point the finger at China alone; African bush meat and the mixing of various creatures there is thought to have led to SIV or the Simian form of HIV to make the jump from monkeys to humans, with a similar pathway likely behind Ebola and Zika. And Spanish Flu, the early twentieth century killer that led to more deaths than the World Wars combined, is thought to have originated in the Western Front where various farm animals were kept as food supplies in highly unhygienic conditions.
There are also three trends which mean that even common, domesticated farm animals could help bring about the next deadly pandemic. First is the fact that, due to factory farming methods, animals are held in closer and closer captivity. Second, these animals are given huge amounts of antibiotics to help them survive such close conditions and, third, the fact that increasing deforestation and habitat destruction for farming is bringing us in closer contact with wild animals in a way like never before.
A chicken today is four times the weight it was just 60 years ago; the result of factory farming methods, including the increased use of antibiotics. Indeed, over 70% of all antimicrobials used in the US today goes not to humans but to animal livestock. This makes factory farming sites ideal breeding grounds for deadly new pathogens that are not only zoonotic but also resistant to antibiotics, making them potentially lethal to humans. This is why the deadliest epidemics of this century apart from Covid-19, includes the 2009 swine flu epidemic – which still remains the deadliest having caused up to 575,000 deaths worldwide – and the H3N2 US flu epidemic, both emerged via common farm animals.
Covid-19 may prove to be a warning shot of things to come. Although it is 10 times deadlier than seasonal flu, its case fatality rate is probably close to 1%, based on data from the only controlled study known to us at this time, the Diamond Princess cruise ship. To put this into perspective, tuberculosis has a case fatality rate of 15% and Ebola of 50%. A future zoonotic disease with a case fatality rate even a couple of points higher could be impossible for us to control; after all Spanish flu, which killed up to 100 million in just two years, only had a case fatality rate of 2%.
There is of course a solution to avoid such a catastrophe; human beings decide to no longer consume animal products. Zoonotic diseases are a threat because the pathogens involved are made of proteins that are able to bind to human receptors. Plant-based pathogens on the other hand cannot affect us in this way. There will never be a carrot flu or a lentil flu.
Clearly, it would be impossible to achieve this overnight. But there are a number of intermediate steps we can take towards a plant-based future, which are also steps that can protect us against future zoonotic strains.
Firstly, we must all cut down our meat consumption and treat meat as a luxury like our ancestors did. Not only is this better for our health and wellbeing, it is also the most effective way in which we can reverse factory farming trends that are focussed at increasing livestock yields at any cost. It would also spur even greater innovation and research into plant-based alternatives as well as decreasing habitat destruction.
Secondly, we must preserve and protect non-farm animals and ensure that they are no longer consumed as food products. This can be achieved through a combination of government policy and international cooperation. The ban on wildlife markets in China is a welcome step, though evidence on the ground suggests this is not yet being fully enforced. Strengthening global agreements such as the CITES Treaty for wildlife conservation, ratified by 183 countries but widely flouted, could be crucial in protecting wild species if there is enough pressure and will from our politicians.
Finally, and most important of all, we need greater awareness and a frank discussion of the threat posed by factory farming and zoonotic diseases. We often brush the impact of meat and dairy consumption under the carpet. Yet the clear links it has to climate change and zoonotic diseases are now too important for us to ignore. It is time that we all – individuals, politicians and the media – are clear and honest about the true impact of what we eat.
These solutions are not simple. The lifestyle changes required by us to make them into a reality would be drastic. But they are still the easiest way to safeguard us from a future zoonotic pandemic that could make Covid-19 pale in comparison. Moreover, our demand and capacity for change has shifted dramatically through this crisis. People are more willing than ever to adopt alternative mindsets and to form unlikely alliances to avoid a repeat of this terrible pandemic.
Let us ensure that this also applies to the food we eat and the impact this has upon our planet and our people. Let’s all go vegan before it is too late.
Prasanna Kannan is a member of the Vegetarian Society and formerly managed investments for a global public health foundation. He is currently the founder of a leading real estate fintech and a Housing Fellow with the Winston Churchill Memorial Trust and the National Housing Federation.