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Posted By: Heather M. Hylton, MS, PA-C
April 07, 2020
Several years ago, I was fortunate to hike in the Zambia bush where I was accompanied by a naturalist who spoke of the many issues related to wildlife trade and poaching, and in particular, the prospect for spillover of pathogens from one species to another—namely, animals to humans. This spillover presents the opportunity for the emergence of global pandemics, just as we have seen with the worldwide spread of COVID-19. In fact, Johnson et al suggest that these viruses have the potential to infect "diverse host species [and] signal emerging disease events with higher pandemic potential."
The Washington Post highlights the spillover issue in a recent article by Karin Brulliard, shining light on factors contributing to this problem, which include the wildlife trade as well as human infringement upon animal habitats. The article goes on to say that there are several commonalities among the geographic areas at highest risk for a spillover event: large population, diversity of plants and animals, swift changes in the environment, and the presence of bats and rodents which likely serve as reservoirs to various pathogens.
It is suspected that in the case of the COVID-19 pandemic, a bat served as the initial reservoir, perhaps passing the virus on to the pangolin, a species largely considered endangered by the International Union for Conservation of Nature and Natural Resources. Pangolins are found on the African and Asian continents, are largely revered for their scales and meat, and are known to be hunted illegally. Brulliard notes that part of the concern associated with animal trade is the handling of these exotic animals and general lack of testing for organisms that could present health risks to humans.
Similarly, the encroachment of humans onto animal habitats is likely a major factor in human illness, such as Lyme disease. Changes in animal habitats can drive more human-animal contact, providing the opportunity for increased transmission of microorganisms that can potentiate illness in humans.
At the time of this writing, there are close to 1.3 million documented COVID-19 cases according to the Johns Hopkins Coronavirus Resource Center's case map. It is safe to assume there are many, many more undocumented cases. To prevent the next pandemic, it is critical to think more broadly about our current practices and policies that lead to increased human-animal contact and to address them appropriately, collaboratively, and globally. We have multiple examples of human illness potentiated by this jump of pathogens from animals to humans and must address this, not only to prevent illness and save lives, but to also appropriately sustain wildlife and their natural environments. Without global commitment and cooperation, the cycle of events leading to pandemics is likely to continue.
- Brulliard K. The next pandemic is already coming, unless humans change how we interact with wildlife, scientists say. www.washingtonpost.com/science/2020/04/03/coronavirus-wildlife-environment/. Accessed April 7, 2020.
- International Union for Conservation of Nature and Natural Resources. Pangolin. www.iucnredlist.org/search?query=pangolin&searchType=species. Accessed April 7, 2020.
- Johns Hopkins University and Medicine. COVID-19 map.coronavirus.jhu.edu/map.html. Accessed April 7, 2020.
- Johnson CK, Hitchens PL, Evans TS, et al. Spillover and pandemic properties of zoonotic viruses with high host plasticity. Scientific Reports. 2015;5:Article 14830.