The Amazon & Your Health
The number of emerging infectious diseases has quadrupled in the last fifty years 1. While there is no single reason for this increase, habitat destruction and wildlife trade are crucial causes.
As a biodiverse region with rising deforestation, some experts fear that the Amazon is in danger of becoming the world’s next disease hotspot. Why does this happen and what can we do about it?
Wildlife Trade and Livestock
Wildlife trade is a multibillion-dollar industry. There is a lucrative market for Amazon animals, including macaws, crocodiles, snakes, lizards and many mammals, especially primates. As one of the largest importers of wildlife in the world, the U.S. plays a crucial role in this economy 2.
This practice is not only unsustainable and harmful to ecosystems, it also poses a huge hazard to human health. Over 60% of emerging diseases are zoonotic, meaning they jumped from non-human animals to humans 3. HIV-1, the virus responsible for AIDS epidemic, spilled into humans from Chimpanzee bushmeat 4.
Wildlife trade not only increases our exposure to foreign pathogens, it also creates new ones. When different species are kept together in captivity, infectious agents recombine, as was the case for SARS and possibly Covid-19 5.
While they may originate in wild animals, most pathogens jump to humans by livestock 6. The expansion of industrial farming, which is associated with inhumane treatment, overcrowding and exposure to wild animals, has increased zoonotic transmission in recent decades 7.
Sustainably regulating wildlife trafficking and uncontrolled cattle farming in the Amazon rainforest are essential if we want to reduce the outbreak of disease.
Habitat destruction is a critical factor in the spread of infectious disease. Research suggests that deforestation and other land-use changes are responsible for up to 31% of emerging diseases 8.
Why does this happen? As we encroach into natural habitats, we are more likely to come into contact with pathogens from wild animals, who often are forced to adapt to urban settings.
Additionally, habitat destruction tends to weaken natural buffers and strengthen disease vectors.
In the United States, booming populations of American robins and mice, who thrive in lawns and fields, are the main vectors for West Nile virus and Lyme disease respectively (1). In the Amazon, deforestation creates ideal breeding grounds for mosquitoes. One study found that increasing deforestation by 10% increased malaria cases by 3%, causing tens of thousands of cases (although malaria outbreaks have been shown to reduce clearcutting over time 9.
Zoonotic diseases from wildlife are most likely to emerge in biodiverse, tropical regions with growing development 10. This puts the Amazon at high risk, making it more important than ever that we responsibly care for this rainforest.
A Global Medicine Cabinet
Keeping the Amazon rainforest standing not only prevents the spread of pathogens, it also provides modern medicine with cures for disease. About one quarter of all modern drugs directly use plant compounds, and many more are synthetic imitations of plant materials 11.
The Amazon rainforest harbors roughly 50,000 known plant species 12, over 10% of the world’s known plant diversity 13. Given that only a small fraction of these species has been studied, scientists have only scratched the surface of the Amazon’s medicinal potential. Already, Amazon compounds have been used in drugs to treat malaria, glaucoma, and leukemia, to name a few.
Traditional ecological knowledge (TEK) has provided modern medicine with some of the most widely used pharmaceutical agents (14). Indigenous people in the Amazon have been utilizing rainforest plants for millennia. One study showed that indigenous people on the upper Negro River in the Brazilian Amazon utilize fifty-five different plant species for malaria alone 15.
Amazonian tribes also benefit our health for a second reason: they steward about one quarter of the Amazon, helping to prevent disease outbreaks associated with deforestation.
For these reasons, we are indebted to Amazon tribes and have an obligation to defend their sovereignty and combat biopiracy, the exploitation of indigenous knowledge for corporate profit.
- Robbins, J. (2012, July 14). The Ecology of Disease. The New York Times. https://www.nytimes.com/2012/07/15/sunday-review/the-ecology-of-disease.html
- Smith, K. M., Zambrana-Torrelio, C., White, A., Asmussen, M., Machalaba, C., Kennedy, S., Lopez, K., Wolf, T. M., Daszak, P., Travis, D. A., & Karesh, W. B. (2017). Summarizing US Wildlife Trade with an Eye Toward Assessing the Risk of Infectious Disease Introduction. EcoHealth, 14(1), 29–39. https://doi.org/10.1007/s10393-017-1211-7
- Phillippe Grandcolas, & Jean-Lou Justine. (2020, April 29). Covid-19 or the pandemic of mistreated biodiversity. The Conversation. https://theconversation.com/covid-19-or-the-pandemic-of-mistreated-biodiversity-136447
- Gao, F., Bailes, E., Robertson, D. et al. Origin of HIV-1 in the chimpanzee Pan troglodytes troglodytes. Nature 397, 436–441 (1999).
- Rachel Nuwer. (2020, February 19). To Prevent Next Coronavirus, Stop the Wildlife Trade, Conservationists Say. The New York Times. https://www.nytimes.com/2020/02/19/health/coronavirus-animals-markets.html
- Jeanna Bryner. (2012, July 6). 13 Animal-to-Human Diseases Kill 2.2 Million People Each Year. Live Science. https://www.livescience.com/21426-global-zoonoses-diseases-hotspots.html
- Jones, Bryony A et al. “Zoonosis emergence linked to agricultural intensification and environmental change.” Proceedings of the National Academy of Sciences of the United States of America vol. 110,21 (2013): 8399-404. doi:10.1073/pnas.1208059110
- Robert Kessler (EcoHealth Alliance). Outbreak: Modern Parallels. https://www.ecohealthalliance.org/2018/05/outbreak-modern-parallels
- Andrew J. MacDonald, Erin A. Mordecai. (2019). Amazon deforestation drives malaria transmission, and malaria burden reduces forest clearing. Proceedings of the National Academy of Sciences Oct 2019, 116 (44) 22212-22218; DOI: 10.1073/pnas.1905315116
- Institute of Medicine (US) Forum on Microbial Threats. Microbial Evolution and Co-Adaptation: A Tribute to the Life and Scientific