The importance of understanding zoonotic diseases, infectious diseases that pass from animals to humans,social structures and pressures that lead to the increasing risk of these diseases emerging has never been more important than now, in light of COVID-19. With the UK in its third national lockdown, the question of how to prevent epidemics such as this in the future is vital. Understanding the relationship between loss of forest, poverty, and health will play a key role in finding solutions. This blog will look at three central factors in the increasing risk of zoonotic diseases posed by deforestation: urbanisation, agricultural practices, and the ecosystem services provided by forests. From this, an understanding of how to effectively prevent future pandemics such as COVID-19, as well as potential strategies to reduce poverty and promote environmental wellbeing, emerges.
Zoonotic diseases and epidemics
A handbook published by the World Health Organisation (WHO) in 2018 titled "Managing pandemics'' outlines the threat of epidemics in the 21st century and their risk factors (1). Central to the risk of epidemics emerging is the way in which new lifestyles spread diseases further through the destruction of wildlife habitats. The destruction of wildlife habitats creates the conditions for the emergence of new diseases to which humans have little resistance - this can become the basis for the transmission of zoonotic diseases and potential epidemics such as COVID-19 (1). Zoonotic diseases pose a serious threat to human health - accounting for over 60% of all infectious diseases (1). Examples of zoonotic diseases other than COVID-19 include Ebola, SARS, MERS, Dengue, Malaria, HIV/AIDS, Zika, and Swine flu.
Urbanisation and increasing animal-human interactions
The increasing interactions between humans and animals due to deforestation provide opportunities for pathogens found only in animals to jump to human hosts. Though increased contact with wildlife may initially seem lovely, it can lead to many issues such as habitat loss, wildlife trade, forest fragmentation, forest fires, and an increased risk of zoonotic diseases. Through increased globalisation and urbanisation, the pressure that cities are placing through expanding into surrounding wildlife is increasing. This is leading to more people living in peri-urban conditions, acting as a bridge between wildlife and dense cities (1). This places more people in close proximity to wildlife and works to spread these zoonotic diseases faster - unfortunately, these peri-urban areas are also those that tend to be poorer with less access to health care facilities, meaning that diseases can spread even further before being detected.
Impact of agricultural practices
In addition to increasing urbanisation, agricultural practices are further pressuring forests. Much of the world's rainforests are in the Global South and in the poorest areas, where forests can act as the main sources for subsistence survival - providing food, shelter, fuel, and other by-products. There is also increasing pressure on agricultural workers to clear more land to produce more crops (2). The limitations of agricultural technology and resources such as fertilisers have also led to land becoming barren and thus even more clearing of land through shifting cultivation. In fact, the largest global drivers of deforestation and loss of habitats has been cited as the conversion of forest for agricultural land to grow commodities such as palm oil, soy, beef, gold, and rubber (2). This shows the way in which, not only are humans coming into contact with wildlife and zoonotic diseases more through urbanisation and decreasing wildlife habitats, but the habitat available to animals is decreasing, forcing the animals into contact with humans.
Loss of ecosystem services and biodiversity
Further to this, forests provide a range of ecosystem services, such as carbon storage and air purification, but also, more relevantly, disease regulation. With the degradation and loss of forests, their capacity to check the spread of disease is reduced, meaning that methods usually used to monitor forests and their risks is reduced (3). The impact of this is further increased through the biodiversity loss experienced with deforestation (3). Biodiversity loss is associated with increased pathogen transmission and disease outbreaks due to changes in the distribution of predators and competitors which can lead to abnormally high densities of animals. With this increased density of hosts for a disease organism, the spread of the disease increases and the risk of spreading zoonotic diseases such as COVID-19 is enhanced.
Addressing both deforestation and poverty together
However, when looking to understand the interactions of poverty and deforestation in health, it is important to look at the larger structures that create the settings in which people need to look to destruction of habitat to survive. An interesting attempt to combat the correlation between deforestation and poverty was performed in Indonesia with a welfare program (4). This poverty-alleviation program provided insurance against harvest failures, thus guaranteeing an income for farmers and reducing their need to destroy forests. Additionally, with the supplemented income, it was found that the community turned to goods from the market rather than ones sourced through deforestation, supporting industries that protected the environment (4). They also found that this program was as effective as other efforts that focussed specifically on conservation. This demonstrates the ways in which fighting poverty and protecting the environment are not conflicting priorities, rather, they are goals which work together to improve poverty, environment, and health.
One Health
In order to understand the interaction between poverty, health, and deforestation, it is important to look at the larger structures that connect these issues. Only through this, can solutions begin to be found - one of these is the idea of "One Health" which focuses on addressing health threats atthe animal, human, and environmental interface (5). The implementation of ideas such as this needs to be carried out in multiple sectors in order to ensure protection against future zoonotic disease epidemics.
References
Sophie Baldwin is a final year Sociology HSPS undergraduate at Jesus college. She has a particular interest in the relationship between the environment, poverty, and global health.
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