New medicine field could help handling endemic and emerging infectious diseases

We may have mortgaged our future by reaching our current health and development levels

According to the article The need of a systems approach to planetary health, published this October, Planetary Health was introduced to better understand and approach the ways human impacts affect the populations health through their impacts on natural systems. Planetary Health offers new ways to: produce an useful evidence base that characterizes complex global environmental and human health relationships; conduct transdisciplinary research with end-users, creating the potential for solutions for transformative change.

To know more about the subject, the Brazilian Society of Tropical Medicine communication team interviewed Dr. Montira Pongsiri, who served on The Rockefeller Foundation-Lancet Commission on Planetary Health. Dr. Montira is currently a Senior Research Associate at Cornell University, and she previously worked at the U.S. Environmental Protection Agency where she developed and led a research initiative on biodiversity and human health that studied the links between anthropogenic stressors, biodiversity changes and infectious diseases transmission.

BSMT: What is meant by planetary health and how different is it from global health and tropical medicine?

Dr. Montira Pongsiri: Simply put, planetary health is the health of human civilisation and the state of the natural systems on which it depends. Planetary health says that we must pay attention to the state of the natural systems upon which human health depends. Unless we dramatically change the way we currently live and impact our natural systems such as our oceans, rivers, forests, and climate, we risk the health of human civilization. We have exploited our natural systems to attain our health and development in the present. In short, we have mortgaged the future in attaining our health and development. While we have made measureable gains in health and development over the last 50 years – increase in life expectancy, significant decline in under age-5 mortality rates, dramatic decline in the percentage of the global population living in extreme poverty – we are experiencing unprecedented global environmental changes (dramatic increase in water and energy use, deforestation, extreme water shortages, climate change with rise in global greenhouse gases, loss of biodiversity) which threaten to reverse these gains and which threaten our prospects for sustainable development. Therefore, urgent, integrated, transformative actions and solutions are needed now to protect present and future generations. Planetary health focuses on increasing understanding of environmental change-human health relationships; and, mobilizing the evidence base on linked environmental change-health relationships to inform integrated policy solutions which address environmental sustainability together with human health and development.

The Rockefeller Foundation-Lancet Commission on Planetary Health  assessed the scale of the risks to human health posed by multiple global environmental changes which we, humanity, are driving. The Commission made the case that we need to address global health and global health practice differently, in a way which integrates an understanding of how our underpinning Earth systems influence the broader determinants of health. Planetary health is different because it starts with the premise that our health depends on the state of natural systems. Importantly, there is agreement that global health can be improved and the course of sustainable development pursued in a positive way if the drivers and consequences of global environmental changes are understood, reflected in policy and planning, and responded to.

Planetary health provides a cohesive, coherent organizing framework for implementing the 2030 Agenda through an integrated approach to planning for achieving health, environment, and sustainable development goals together.

Planetary health presents the opportunity to take multisectoral, systems-based approaches to produce a useful evidence base characterising complex, global and local environmental change and human health linkages in context; and, through multisectoral partnerships, to apply evidence-based strategies to reduce, and perhaps even prevent risks to human health.

BSTM: How do the environmental impacts caused by man damage the health of the population?

Dr. Montira Pongsiri: Let me give you a few examples of the types of environmental change-health relationships which fall under the planetary health framework. This is not exhaustive. Some effects from global and local environmental changes directly affect human health. Climate change leads to extremes in temperature and higher temperatures which cause heat stress and other temperature related illness and death. People living in the Tropics will be especially at risk. By 2050, half of the world’s population will reside in the tropics. Rising temperatures and humidity will make the worlds tropics increasingly unliveable by pushing more people to the thresholds of their physical tolerance.

Some health effects from environmental change are ecosystem-mediated. For example, higher concentrations of atmospheric CO2 can lead to significant reductions in the amount of zinc, iron and protein in grain crops like rice and wheat, which has important implications for nutritional security.  Another example of an ecosystem mediated effect is the risk of vector-borne diseases like malaria. Forest loss and land cover change (e.g. road development) can lead to changes in the abundance, composition and/or distribution of disease-carrying mosquito vectors which can affect the risk of transmission of disease to people.  Then, there are the indirect health effects from global environmental changes like coral reef destruction and urbanization processes which are more difficult to characterize and quantify, but which, over the long term, may be among the most important.

BSMT: We have experienced a series of epidemics, new diseases being discovered and others reemerging at a frightening speed. Can we say that they would be consequences of disorganized population growth, unbridled deforestation, climate change and even global economic development?

Dr. Montira Pongsiri: More than half of all recognized human pathogens are zoonotic, and almost all of the most important human pathogens are either zoonotic or originated as zoonoses before adapting to humans. The emergence of epidemics is related to food/agricultural systems, and they occur especially in areas where there is environmental disruption and where there is increased overlap between people and infectious agents. So, we need to consider the system in which disease emergence occurs – the drivers of change, their impacts, and feedback relationships. This means improving our understanding of how ecological factors as well as behavioral factors play a role in disease emergence. This kind of systems-based understanding can help us to address the upstream drivers of environmental change rather than just the health consequences.

BSMT: How could the creation of this new field of medicine planetary health contribute to avoid such impacts?

Dr. Montira Pongsiri: As mentioned, planetary health presents the opportunity to take a multisectoral, systems-based approach to 1) understand the complex interconnections between the condition of natural systems and human health and 2) to develop strategies to reduce and perhaps even prevent risks to human health –by improving our stewardship of our natural systems. This is a departure from traditional global health and medical practice. This is also the opportunity.

BSMT: How can the population help planetary health?

Dr. Montira Pongsiri: Actions are needed at multiple levels – by individuals, households, communities and governments – to address environmental changes affecting health and sustainable development. Community health workers and health care providers can play an important role to increase awareness of critical environmental change-health relationships. Increasing awareness can help individuals and their communities reduce their health risks from changing environmental conditions.

BSMT: What is the role of doctors, researchers and journalists in the study and practice of planetary health?

Dr. Montira Pongsiri: We need integrated actions and solutions now. What’s really exciting about planetary health is that it can enable us to work together differently – in the ways that we produce science, and in the ways we apply that science to improve decisions and policies on the ground. For researchers, this means that we should design research studies which start with a known policy need, then carry out that research with end-users like policymakers and health practitioners who can help accelerate the application of scientific understanding to solve problems. Journalists and teachers can improve understanding of the critical interconnections between global and local environmental changes and human health. Increased awareness can help reduce risks at individual and community levels. The key is working together in new ways based on the recognition that the environment and health are should be addressed together.

BSMT: Do we still have time to save Planet Earth?

Dr. Montira Pongsiri: We have agency, and there are solutions within reach. The Rockefeller Foundation-Lancet Commission report outlined just some of the solutions:

• Nearly 30% of all food produced is not eaten. Almost 30% of the world’s total agricultural lands is used to produce food that is never eaten! We must reduce the exploitative use of our finite land resources, and we must reduce food waste.

• We can invest in ecosystem-based strategies to increase disaster resilience. For example, restoring wetlands, coral reefs, and mangroves can protect coastlines from the damaging effects of extreme events at much lower cost compared to engineered solutions. There are economic co-benefits to these investments as well.

• We cannot address planetary health without addressing our underlying resource use. There will be an estimated 10-12 billion people on earth by the end of the century. This growth will be accompanied by greater demands for resources. Increasing access to modern family planning can help reduce population growth.  There are co-benefits of providing modern contraception such as reducing maternal mortality.

• We can move towards a more circular economy, where we reduce waste and increase recycling – essentially, this means using limited resources much more efficiently than we currently do.

• We need to account for health in development policy decisions so that it becomes standard practice to assess, monitor, and plan for likely health impacts of land use, planning and other policy decisions which affect natural systems.

• And finally, related to the governance challenge just described, we need to carefully consider taxes and subsidies so as to disincentivize practices related to adverse health impacts.

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