There is a long road ahead of us before we return to any semblance of “pre-COVID” life. During the roll-out stages of a new vaccines, we remain at the mercy of this easily transmissible virus. We tele-work, stay connected through the Internet and by text, and we plan. We plan for future family visits, hypothetical gatherings with friends, or a summer trip. Always wishing, this has to end soon! But will it?
As the climate warms, biodiversity shrinks, and our planet shifts outside of a natural homeostasis, we have to admit that while we might conquer COVID-19 in the near future, there are still many diseases risking to spillover. As a global community, we need to unite around a holistic, multi-sectorial response to address future emerging diseases and pandemics, namely: the One Health approach.
Inherently interconnected, humans, animals and ecosystems do not merely co-exist, they are co-dependent. A change in one ricochets, and transforms the others. Scientific studies have shown that 60% of existing human infectious diseases are zoonotic, transmitted from animals to humans, including West Nile, rabies or salmonella.
Furthermore, the majority of recently emerging infectious diseases, such as AIDS, Ebola or MERS, originated from an animal source.
The COVID-19 pandemic has underlined the intrinsic link between humans, animals and the environment
Zoonotic diseases do not travel only in one direction. While the animal source of COVID-19 remains still unknown, the virus strain is genetically similar to a coronavirus circulating in Rhinolophus bats. Equally mysterious is how the virus jumped to humans, either from bats directly or through an intermediary host. A new more worrying trend is that the virus continues to jump, from humans to new animal species.
While the COVID-19 pandemic is currently sustained through human-to-human transmission, the high frequency of human infection has increased animal exposure to the virus. Animals that have close contact with humans, such as house-hold dogs and cats, or even zoo tigers with human handlers, have become infected with COVID-19 virus. However, these animals have not been shown to transmit to the virus back to humans. When new animals become infected with COVID-19, it is an opportunity for the virus to mutate in its new host. Cats and dogs seem to be a dead-end for the virus, but sometimes when conditions are just right within other animal species the virus can evolve rapidly.
The media coverage of mink cases during the past month has portrayed the tenacity of COVID-19 in its search for new susceptible hosts. Farmed mink are particularly vulnerable to COVID-19 partially due to the realities of industrial farming. Close contact between mink at such high numbers would never occur naturally in the wild, presenting an opportunity for the virus to spread through concentrated mink populations like wildfire.
As a virus adapts to a new host species, viral evolution accelerates, and every transmission is a new opportunity for viral mutation. The new strains developed on mink farms in Denmark caused international concern when they then passed back into humans. Therefore, due to preventative measures based on the results of national risk assessments as well as by application of the precautionary principle, millions of mink were culled by national authorities worried by an establishment of a new animal reservoir of the virus.
A One Health approach to protect the health of all
The COVID-19 pandemic has awoken the need for longstanding and sustainable One Health collaboration. Countries need to reconsider animal, human and environmental health as a unified, holistic entity. The health and protection of the environment and of animals, should also be prioritized as a means of ensuring human health. The establishment of a new animal reservoir of COVID-19 could hinder our abilities to control the virus and could spur future spillovers of the virus back to humans, as well as endanger the health and security of many other animal species. In this vein, the OIE has released guidelines and recommendations for safely interacting with wildlife, companion animals and farmed animals susceptible to COVID-19. These guidelines are meant to provide for increased safety of animals, and to complement human health guidelines published by the World Health Organization (WHO).
To promote One Health, the Tripartite, a collaboration between the OIE, the WHO and the Food and Agriculture Organization of the United Nations (FAO), shares common objectives in the prevention and control of health risks at the human–animal–ecosystem interface. Acknowledging the importance of maintaining a global perspective and foresight on wildlife health and biodiversity, the United Nations Environment Programme (UNEP) has recently joined the partnership to enlarge the ecological and environmental health component. The four organisations have recently agreed to set up a One Health High-Level Expert Council to collect, distribute and promote reliable scientific information on the links between human, animal and environmental health. The Council will work to avoid future sanitary crises by assisting countries in making appropriate decisions.
Forging a new path for the future
Nobody knows what the future holds, but we do know that emerging diseases will continue to pose a serious threat to humans, animals and our environment. The risks posed by such ever-evolving pathogens will not disappear. Therefore, we must improve our preparedness and response for future outbreaks of newer, and perhaps, even more serious disease risks, by following a One Health approach.
Let COVID-19 be a wakeup call to the international community that further collaborative work is needed to ensure the health and safety of our planet.