science

One Health Model

One Health Model is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand One Health Model rather than just read about it. In short: In 2017, the U.S. Government defined one health as "a collaborative, multi-sectoral, and transdisciplinary approach --- working at the local, regional, national, and global levels -- with the goal of achieving optimal health outcomes recognizing the interconnection between people, animals, plants, and their shared environment" (CDC, 2025).

Key takeaways

One Health Model belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect One Health Model to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of One Health Model from memory before moving on to harder problems.

Reference excerpt

In 2017, the U.S. Government defined one health as "a collaborative, multi-sectoral, and transdisciplinary approach --- working at the local, regional, national, and global levels -- with the goal of achieving optimal health outcomes recognizing the interconnection between people, animals, plants, and their shared environment" (CDC, 2025). The concept of One Health is the unity of multiple practices that work together locally, nationally, and globally to help achieve optimal health for people, animals, and the environment. When the people, animals, and environment are put together, they make up the One Health Triad . The One Health Triad shows how the health of people, animals, and the environment is linked to one another. Each element affects and is affected by the others. For instance, diseases transmitted from animals can impact human health, while environmental factors like pollution or climate change can influence both animal and human health. With One Health being a worldwide concept, it makes it easier to advance health care in the 21st century. When this concept is used, and applied properly, it can help protect people, animals, and the environment in the present and future generations.

Background The origins of the One Health Model dates as far back as 1821, with the first links between human and animal diseases being recognized by Rudolf Virchow. Virchow noticed links between human and animal disease, coining the term "zoonosis." The major connection Virchow made was between Trichinella spiralis in swine and human infections. It was over a century later before the ideas laid out by Virchow were integrated into a single health model connecting human health with animal health. In 1964, Calvin Schwabe, a former member of World Health Organization (WHO) and the founding chair of Department of Epidemiology and Preventive Medicine at the Veterinary School at the University of California Davis, called for a "One Medicine" model emphasizing the need for collaboration between human and wildlife pathologists as a means of controlling and even preventing disease spread. This model sought to bridge the gap between human health and animal health, advocating for a more integrated approach to preventing and controlling diseases that impact both humans and animals." It would be another four decades before the One Health became a reality with the 12 Manhattan Principles, where human and animal pathologists called for "One Health, One World." This was coined by the Wildlife Conversation Society in 2004 where a symposium was held with experts and organization at Rockefeller University. The One Health Model has gained momentum in recent years due to the discovery of the multiple interconnections that exist between animal and human disease. Recent estimates place zoonotic diseases as the source 60% of total human pathogens, and 75% of emerging human pathogens. Greater awareness of food safety concerns has also prompted further support of the One Health Model. More than 60 percent of pathogens globally originate from the environment. In Canada over 10 million illnesses per year are food-borne. This is expected to have an economic impact on the country, costing $3.7 billion yearly. These illnesses highlight the need for a 'One Health' approach that addresses public health concerns and reduces the economic costs associated with disease outbreaks. The One Health Model can significantly minimize these costs and improve health outcomes by promoting early intervention and collaboration across sectors.The One Health Model has been introduced as a method to encourage intervention as early as possible, which has previously been overlooked but remains impactful to many economies. In the more recent years, the One Health Model has been applied to the COVID-19 global pandemic. The COVID 19 global pandemic consisted of human, animal, and environmental influences and transmission pathways. This exacerbated the value of the One Health model as multiple sector in medical, environmental health, public health, physicians, veterinarians, and researchers were challenged to work together to improve public health outcome.

Applying the One Health Model The One Health Model can constantly be applied with human and animal interactions. One of the main situations where One Health can be applied is with canine and feline obesity being linked to their owners and their own obesity. Obesity in canines and felines is not good for them nor is it good for humans. The obesity of humans and their animals can result in many health problems such as diabetes mellitus, osteoarthritis, and many others. The only solution for this issue is to encourage owners to have a healthy lifestyle for both them and their animals. Zoonotic Diseases is another situation that the One Health model can be applied to. This is talked about more in the Zoonotic Disease section.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with One Health Model

Start with the simplest possible case. Write down what One Health Model claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to One Health Model before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about One Health Model ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of One Health Model

In research: One Health Model appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses One Health Model in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: One Health Model is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1821 introductions, Human–animal interaction, Medical models, so understanding it makes those chapters shorter.
In everyday life: Look for One Health Model outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study One Health Model in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what One Health Model means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain One Health Model out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is One Health Model in simple terms?

Why does One Health Model matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study One Health Model?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on One Health Model.