What is ‘One Health’?

‘One Health’ is the concept that animal and human health are interdependent and dependent on the health of the environment they are in human health and animal health are interdependent and bound to the health of the ecosystems in which they exist [1]. The concept aims to foster collaboration and communication between animal and human health services to achieve better public and animal health than either service could achieve individually. Many international and local organisations have already adopted the concept to help improve food safety and prevent emergence of new diseases in animals and humans. The following diagram shows the important complex relationships which need to be considered under a ‘One Health’ umbrella.

Why is this concept important?

Humans and animals interact in many different ways, whether they be companion or farm animals or wildlife. Therefore, it is important that people involved in both animal and human sectors work together to protect human and animal health and ensure food safety and security. The World Animal Health Organisation (OIE) has created an infographic that shows the main areas where the One Health concept can be applied:

• Zoonotic diseases
• Food safety
• Antimicrobial resistance

The recent COVID-19 global pandemic associated with the novel coronavirus SARS-CoV-2, is a good example of why One Health is so important. Experts in human health, animal health, virology, natural history and ecology have collaborated to determine the source of SARS-CoV-2 and to find ways to manage the crisis [2].

Zoonotic diseases

Zoonotic diseases are those transmitted directly from animals to humans or, more rarely, from humans to animals [3]. See our Knowledgebase article for more information on zoonoses.

In order to achieve One Health, animal health services and agricultural industries need to work together to improve disease monitoring in farm animals and prevent disease transmission to people and from people to animals. Effective strategies include:

• Improving the welfare of farm animals by raising them in environments that provide good nutrition, good health, appropriate housing, ability to meet behavioural needs and opportunity for positive experiences
• Improving the overall health of animals to make them more robust and resistant to disease
• Breeding animals with better disease resistance to avoid them being able to acquire and then transmit the disease
• Improving on-farm biosecurity, such as better hygiene and cleaning of equipment
• Regulating movement of farm animals to prevent the spread of disease from one area of the world to another

Food safety

Food safety is the assurance that food to be consumed by people is free from harmful chemicals, toxins and microbes (organisms that cause infectious disease). These may contaminate food through poor hygiene practices at any point in the production chain (‘farm to fork’), or may be in food as a result of general poor health and husbandry of farm animals [4]. Applying the One Health concept to food safety encourages collaboration between veterinarians, farmers and government agriculture staff to:

• ensure good biosecurity practices on the farm and in slaughter houses;
• monitor and prevent contaminants in the milk and meat of animals; and
• notify human health services when there are breaches of food safety that could impact human health.

Antimicrobial resistance

Antimicrobials are important drugs used to treat disease caused by bacteria in both humans, and companion and farm animals. Bacteria can develop a resistance to antimicrobials drugs if they are used frequently and incorrectly. Bacteria that develop a resistance to many commonly-used antimicrobials are called multi-resistant bacteria. These multi-resistant bacteria pose a significant threat to human and animal health, as infections caused by these bacteria cannot be treated by available drugs and, consequently, the person or animal may not recover from the infection.

The One Health allows a collaborative approach by animal and human services to determine how to use antimicrobials effectively without contributing to antimicrobial resistance. Please see our Knowledgebase article on antimicrobial use for more information.

How can One Health be applied?

Applying the One Health model relies on the following:

• Establishing organisations that include experts from both the animal and human health sectors and the agricultural department, or an organisation that co-ordinates collaboration between all sectors.For example, the World Animal Health Organization (OIE) monitors food safety and prevents zoonotic diseases by collaborating with both veterinarians and agricultural departments [4].
• Creating effective routes for communication between these sectors, including advisory groups and meetings;
• Facilitating training of officers in both animal and human health.For example, veterinarians have some training in human diseases. This makes veterinarians better able to advise pet owners and health services on the risk that an animal disease poses to humans, and what can be done to manage that risk [5].

What can you do to help?

• Ensure you keep your pet healthy and practice good hygiene around your pets to keep you and them safe.
• If you keep your own animals to provide you and your family with food, you need to take precautions. Learn about health and safety considerations for keeping layer hens here.
• Enjoy wildlife from a distance to avoid exposure to potentially dangerous diseases.
• Tell your doctor about your pets and their health issues if you think any may be relevant to your health. Learn more about zoonotic diseases here.

Moving forward with One Health

The One Health approach has already been adopted by many large organisations but smaller industries and organisations could still benefit from greater implementation of this approach.

Recently the One Welfare approach has been developed, which encompasses One Health. One Welfare focuses on the overall wellbeing of humans, animals and their environment, including mental health in addition to physical health. This widens the scope of collaboration to tackling climate change, ensuring the mental health of pet owners and farmers, and managing wildlife in a way that also supports their environment. One Welfare has still not been publicly adopted and it is important for us to encourage its adoption so we can broaden our approach to one that fosters sustainability and collective welfare.