The Interdependence of Human Health and the Health of Planet Earth

Human and wildlife wellbeing are inextricably linked (Fig. 1). From medicine, to food production, to disease; human health depends on the health of the ecosphere. Wildlife has aided our success and livelihoods since the beginning of human existence: it has provided us with food, clothes, shelter, and even the oxygen we breathe! Yet, our response has been to destroy what essentially created us. From exploitation in the medicinal industry to deforestation, to the devastating impacts of climate change, we have endangered and destroyed thousands of species [1]. It is now evident that this destruction is impacting human lives too; it has been said that the effects of climate change and habitat destruction (which is increasing the incidence of zoonotic disease) are harmful to humans [2,3]. The World Wildlife Fund (WWF) President Carter Roberts, also described the situation to be detrimental to humans and animals alike [3]. The concerns raised emphasised the need for immediate action to restore the planet by tackling climate change and deforestation as well as conserving vulnerable species. 

Figure 1 - The Interdependence of Human Health and the Health of Planet Earth.
By Kiera McCabe, Youth STEM Matters Artist.

Wildlife in the Pharmaceutical Industry

Figure 2 - Pharmaceuticals. Credit: Michał Parzuchowski via Unsplash.

The pharmaceutical (Fig. 2) industry relies heavily on plants and animal products to manufacture medicine. Up to 75,000 plant species have been screened for use in the production of drugs [4]. How many of these species are endangered? How many of these are we putting at risk? Codeine, for example, is one of the most widespread and vital analgesic drugs (pain killers) used in adult pain management and, in small quantities, is an antitussive (cold remedy). It is actually made from a plant called Papaver somniferum (more commonly referred to as ‘poppy’) [5]. Imagine if this plant became endangered, or worse, became extinct? That’s not to say there are no alternative options for painkillers or flu remedies, but the damage it would cause in the medicinal world and on human health would be substantial. By utilising technologies and methods that synthetically produce compounds, we could potentially avoid endangering plant species further.

Many innovative systems already exist, from combinatorial chemistry to computer-based molecular modelling design. However, we know natural products are truly revolutionary and vital in the pharmaceutical world. If we reduce the pressures imposed by the needs of increasing human population and regulate demanding markets that use overharvesting of plants and other species to make produce, we could potentially create a world where both humans and plants thrive.

Plants are not the only natural product used in pharmaceuticals. Many argue that pharmaceuticals are negatively impacting animal populations too. This is particularly evident in the globalisation of Traditional Chinese Medicine (TCM), which has the potential to threaten already endangered species, such as rhinos and pangolins, due to their use in the practice [6]. After celebrating World Pangolin Day on 20th February, we need to remember the devastating fact that all eight species of pangolins are endangered, and this ‘earth dragon’ (as it is referred to in illegal trading) must be protected from  its use in medicine, among other things [7, 8]. There is a need to seek different solutions to experimental research, to preserve and conserve the vulnerable animal populations.

The use of animal specimens in medicine is known as zootherapy [9]. It is said that little consideration, in terms of endangerment, is given when choosing the animal to use. In countries such as Nigeria, where zootherapy is common, it is threatening biodiversity even further [9]. A study conducted in North-Eastern Brazil found that 51 animal species were used in the treatment of a large number of diseases [10]. The popular and widespread use of animals for these purposes is not only harming wildlife populations, but is causing other environmental issues, including an accumulation of waste and toxins. Furthermore, many toxic chemicals commonly used in this practice are harmful to human health. 

Animal Testing in Medicine

Scientists also use animal products to understand human physiology, as seen in clinical trials during the development of vaccines and other medicines [4]. Scientific processes sometimes use animals as experimental models in tests that would otherwise be too risky on human subjects [11]. A balance must constantly be maintained to avoid exploiting natural resources to the breaking point, where the depletion and decimation of plant and animal communities occurs. It is imperative, therefore, to acknowledge the importance of wildlife - plants and animals alike - and realise the significance of protecting biodiversity.

The Impact of Marine Pollution

Humans do not impact wildlife and human health exclusively on land and in the air, but in marine realms too. Improper disposal of factory waste affects marine wildlife, therefore it also has negative consequences on the human species. For example, mercury that is disposed of in water bodies is absorbed by fish; eating poisoned fish leads to mercury poisoning, and if a pregnant woman consumes this fish, the unborn baby risks developing neurological disorders [12]. Pesticides can also bioaccumulate, that is, be absorbed by an organism before it can be degraded to a less toxic form [13]. Ingestion of products (plant or animal) contaminated with such chemicals are dangerous to human health and cause a wide variety of problems, ranging from mild to severe. 

Fish and other aquatic life can also end up consuming microplastics that are often disposed of in water bodies. Microplastics are often found in cosmetics and toothpaste that are washed down in filtration systems that ultimately drain into seas and oceans [14]. While arguments suggest that microplastic contamination of fish may not affect humans (as the particles are confined to the digestive system, as opposed to the muscular system that is eaten), the potential threat to humans cannot be overlooked [15]. Toxicity to humans ultimately depends on the concentration and composition of the microplastics, and further research could come up with tangible results of the effects on humans [16]. This shows how human activities are harming wildlife, and how our actions have consequences that affect us too. 

Deforestation: The Destruction of Wildlife and Humans

Figure 3 - Deforestation. Credit: gryffyn m via Unsplash.

Deforestation (Fig. 3) creates space for human infrastructure and food production, but this comes at a cost to wildlife and our planet, which in turn impacts human health.  One direct result is the displacement of animal populations. This migration of animals from their natural habitats has been found to affect disease patterns. Perhaps, the incidence of zoonotic disease transmission (where pathogens are transmitted from animals to humans) can be attributed to habitat displacement. As animals are displaced, they may seek shelter in human habitats, bringing the two close enough to transmit diseases more frequently. In South America, this issue is devastatingly evident. Here, malaria epidemics have risen from the migration of Anopheles darlingi mosquitoes to ‘foreign’ habitats [17]. This is just one example of many that clearly illustrate how dangerous human initiated animal displacement can be to human health.

Deforestation also causes biodiversity loss and enhances the greenhouse effect [18]. Trees that are cut down release carbon dioxide into the air when they are burnt, and this greenhouse gas causes global warming [19]. Currently, strategies to combat these negative effects while  limiting vegetation removal and animal displacement involve strict regulations for the agricultural, mining, and infrastructure industries. These regulations are in place not only to protect wildlife, but to ultimately protect humans too. However, we clearly need further initiatives to protect the biosphere. Governments and bodies of power must recognise the damage deforestation has on both wildlife and human wellbeing, furthermore, they must act on it. Education is another powerful tool of change.  By raising awareness for the implications of deforestation on humans; scientists, industries and the public may pave the way to alternative practices, and safeguard the biosphere.

Conclusion

There are multiple threats to the health of both people and planet, but there are also many ways to conserve the planet, wildlife, and, ultimately, human health. We can each play our part by calling on governments and local politicians to create policies and regulations to protect the earth, alongside the implementation of in-depth monitoring of these regulations to ensure companies are abiding by them. We could also boycott businesses involved in deforestation, plastic pollution, and fossil fuels - all of which are often unethical and inequitable. Global participation in adopting policies such as ‘The Green New Deal’, a climate proposal aimed at combating global warming and reducing the use of fossil fuels, will see such initiatives making the impact they need to [20].

We are interdependent - humans, plants and animals all need one another. We must undo this harm, and act in line with the UN Sustainable Development Goals 3, 13, 14 and 15 - Good Health and Well-Being, Climate Action, Life Below Water, and Life on Land, respectively. In order to protect our planet and preserve human health, we need to acknowledge the importance of wildlife and be more successful and efficient in our approaches to environmental conservation.

We could all benefit from playing our part in our various communities and spheres of influence, remembering that a small effort, such as not littering in water bodies, could go a long way to a healthier, wealthier, and more sustainable world. It is a matter of urgency that we do what we can to conserve the planet so that future generations may also experience the marvellous wonders of the earth and appreciate its beauty. A worldwide effort is required - let us challenge ourselves to do something unanimously, something that we can all agree is necessary for the betterment of life on Earth. We could then enjoy life and all it has to offer, by looking after life on land and water, and everything else in between! 

References

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