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One Health: Theory to Action

Updated: Apr 25, 2021

Written by Celina Tang, Sukham Brar and Paula Magbor

Edited by Jocelyn Tan and Kyla Finlayson

“One Health is a collaborative, multisectoral, and transdisciplinary approach - working at local, regional, national, and global levels - to achieve optimal health and well-being outcomes recognizing the interconnections between people, animals, plants, and their shared environment.” - One Health Commission.

The concept of One Health can be challenging to understand for those hearing about it for the first time. With that being said, we hope to clear up this confusion with our One Health Blog Series! We have compiled information from the One Health 3300A course at Western University, taught by Dr. Frisbee, Dr. Oleo Popelka, and Dr. Kiser, as well as other online resources, to produce this introduction to One Health post.

History and Rationale Behind One Health

The history of One Health dates back all the way to when Hippocrates (460 BCE–367 BCE) identified the interdependence of public health and an environment that is clean. Centuries later, Calvin Schwabe (1927–2006) released a book on ‘One Medicine,’ indicating that human and veterinary medicine are deeply interconnected and that there is no fine line that separates the two. Afterwards, the introduction of ecosystem health to this concept led to the creation of One Health. While the term ‘One Health’ is relatively new, the concepts and principles behind it are not. There has and continue to be threats and issues that arise from the intersection between animals, humans, and ecosystems.

With regards to the original rationale for One Health, the focus was on infectious diseases. Approximately 60% of these diseases recognized in people are due to multi-host pathogens that can move across species lines. Approximately 70% of emerging human infectious diseases are zoonotic.

Zoonotic Diseases

With the increase in emerging and re-emerging infectious diseases, using a One Health approach to tackle these health challenges has become essential. You may have heard the term "zoonotic" get used a lot in recent years to describe many of these diseases, but what does it actually mean? Zoonotic diseases, also known as zoonoses, are infectious diseases that spread from animals to humans or vice versa, in what is known as reverse zoonosis. This spillover event has caused the outbreaks of many infectious diseases, such as the Ebola virus disease, avian influenza, and is even suggested to be the source of the current COVID-19 pandemic.

The rapid growth of the human population, resulting in the loss of natural habitats to accommodate this increase, has created more opportunities for these spillover events. With an estimated 7.8 billion people currently worldwide, and the UN's projected 9.7 billion people by 2050, addressing these health challenges involves collaboration between experts in different fields beyond human health. That is where One Health comes into action.

Over the next few blog posts, we will be doing a deep dive into the role of One Health in each of the three pillars: human, animal and environmental health (so stay tuned)! For now, to see this approach in action, let us investigate a quick case study on Rift Valley Fever (RVF) in Africa.

Application of One Health Pillars: Rift Valley Fever

RVF is a viral zoonosis prevalent in countries along the horn of Africa. Mosquito vectors transmit the disease to livestock, which infects humans either by direct contact or aerosol exposure. Human-induced drivers of climate change have created environmental changes, such as more frequent El Niño events, that support the breeding grounds of mosquitoes that carry the RVF virus, leading to increasingly severe and frequent outbreaks in animals and humans. This poses significant health challenges to humans and livestock, as well as socio-economic, cultural, and social changes in livestock farming communities.


Stay tuned for more posts that will be released in the coming months to gain a better understanding of each of the One Health pillars!

If you are interested in learning more about One Health from professionals in the field, check out our Professor Lecture Series, featuring Dr. Stephanie Frisbee and Dr. Gerald McKinley, on Tuesday, November 10 at 6PM. Our Facebook event page contains more information and can be found here.

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