As the world attempts to recover from COVID-19, we need a proactive, integrated approach to prevent future pandemics. Photo by Slava on Unsplash
Prior to COVID-19, “One Health” seemed an elusive concept except in the circles of infectious disease professionals. Today, it is more relevant than ever to the global population, but what exactly is it?
At its core, “One Health” links animal health to human health from the perspective of zoonotic diseases. It describes the complex relationships that occur among factors that influence human health, animal health and their ecosystems.
To fully grasp the importance of the concept, it is necessary to understand where new diseases come from.
Zoonotic diseases are those transmitted from animals to humans. It is estimated that as many as six out of 10 human infectious illnesses originate from animals. Humans can also infect animals: reverse zoonosis.
Emerging infectious diseases (EIDs) can be caused by recently evolved pathogens that have been introduced for the first time into the human population, the most familiar and current example being SARS-CoV-2, the virus behind COVID-19. EIDs may also extend to previously occurring infectious diseases that are gaining momentum once again by having an expanded geographical range, impact or even a higher occurrence. As many as 75 per cent of human EIDs are zoonotic and are generally associated with wildlife.
With so many variables involved, it’s clear that an integrated health approach is needed, drawing on expertise from numerous disciplines.
In a recent publication in One Health in 2021, Canadian experts recommended three possible areas: zoonoses and chronic diseases; social determinants of zoonoses; and the effectiveness of the health system in their prevention and control.
So how do zoonotic diseases become established in humans in the first place?
The answer lies in the complex interactions among humans, animals, evolving pathogens and their environment.
Globalization, a marvel of the modern world, offers greater access to trade, travel and migration – and a higher risk of pathogen exposure. Activities such as illegal animal trade and “bush meat” consumption can result in human exposure to exotic wildlife pathogens.
Human-induced climatic changes that lead to a rise in global temperatures can also increase risk of exposure to exotic pathogens by affecting animal migration. These changes can influence emergence of vector and water-borne diseases. Deforestation and wildlife habitat encroachment provide more opportunities for contact among humans and animals.
Other factors that favour the emergence of new diseases include destructive agricultural practices, global conflict connected to population displacements and insufficient public health infrastructure.
By their nature, RNA viruses such as SARS-CoV-2 can mutate very quickly, giving rise to the appearance of new strains. For example, variants have arisen in the months since the beginning of the pandemic that appear to spread more easily and affect younger people.
Another issue is antimicrobial and antibiotic misuse which has also been implicated in EID emergence.
Long gone are the days of operating in medical knowledge silos. It is glaring that a more concerted, transdisciplinary approach to global health has become necessary. This means efficiently sharing critical information quickly. We need to get better at pathogen surveillance in both animals and humans.
By: Shirene Singh
Currently, I am a Medical Writer with over 5 years of experience as a university educator and an infectious disease researcher, with a focus on vaccinology and viral immunology. A lifelong goal of mine has been to contribute to knowledge translation by leveraging my scientific and medical background. My passion for writing includes global health concepts, immunology and strategies for infectious disease control.
LinkedIn Profile: www.linkedin.com/in/shirenesingh