Have you heard of the “One Health” movement? If not, you will be soon! As we learn more and more, we’re realising just how connected human health, animal health, and environmental health are. As a result, in recent years vets, doctors and environmental scientists have started working more and more closely… to study the problem and hopefully find some solutions.

What is One Health?

Increasingly, we now understand that most of the new and emerging threats to both human and animal health are a result of environmental and climate change. So, to control the health problems, we must address environmental issues – for example, Anopheles mosquitoes moving northwards due to climate change, bringing Malaria back to northern Europe.
Of course, it’s also true that the most threats to human health are in some way related to animal health – for example, antibiotic resistance; also, most new and “exotic” diseases (like SARS, MERS and Ebola) have an animal reservoir. We call these diseases that can jump from humans to animals “zoonoses”.
As a society, and worldwide, we cannot manage any of these new and emerging threats without considering the other components, because all three (humans, animals and the environment) are inextricably linked.
One Health is a movement and a mindset rather than a project or a single organisation, and it aims to help us see the links between what seem to be entirely separate topics and research areas. By doing so, the hope is we can build healthier humans, animals, and environments.

OK, sounds very noble, but how does that impact us?

Believe it or not, we’re all on the front line of One Health. Here’s a few examples, that really demonstrate the issue:

The parasite Babesia canis is now present and established in the UK. The parasites infect a dog’s red blood cells, causing anaemia and – sadly – often proves fatal. Until 2016 it was not recognised as being native to the UK, but has now emerged.

The parasites are spread by ticks, and it is thought that they reached our shores after a dog either returned from holiday already infected, or was rehomed to the UK from mainland Europe. However, there is a more worrying possibility. Unfortunately, the requirement to treat dogs against ticks before returning to the UK was abolished some years ago, so it is very likely that an infected tick was imported into the UK, establishing colonies of infected ticks.

The primary vector for Babesia is the Ornate Dog Tick, Dermacentor reticulatus. While already present in some areas of the UK, recent research suggests that, probably as a result of environmental and possibly climate change, it’s range is expanding away from the Essex coasts and into our towns and cities – bringing it into contact with more dogs.

This is a really good example of human society and behaviour, in conjunction with environmental changes, altering the distribution of a previously “exotic” disease.

Hopefully, everyone still remembers the great West African Ebola outbreak of 2014-2016, which killed 11,325 people (that we know of). The virus was probably contracted by eating bush-meat – for example, duiker antelope – by poor communities. However, these deer have been a staple of the local diet for many years. The antelope appear to have been infected from Fruit Bats, who live in caves in more remote areas of the region. Humans have recently moved into the area, mining for precious minerals, coming into regular contact with the virus.

So… how much do you REALLY need a new smartphone this year? Many of the raw materials used in these ubiquitous devices are mined in West Africa – and the more demand there is for them, the more chance we expose the local populations to new and exotic diseases.

Of course, diseases can go in the opposite direction too… We are increasingly seeing multiple resistant bacterial infections in pets, one of the most serious is MRSA (methicillin resistant Staphylococcus aureus). This is often harmless on the skin, but if it gets into a cut or a wound, it can cause poor healing, deep infection, and even sepsis. Because it is resistant to so many antibiotics, it is very difficult to treat, in pets as much as in humans. And it’s not as rare as we used to think – one paper suggests that of all Staph infections, MRSA is responsible in 6.6% of dogs, 39.6% of cats, and 83.3% of horse infections.

For many years, it was assumed that MRSA developed in pets due to increased antibiotic use in pets – however, recent research has shown that the vast majority of the cases studied were human in origin. In other words, we are carrying MRSA and then giving it to our pets, a situation known as “anthroponosis”.

Antibiotic resistance is also a major issue – and one that is right in the middle of the One Health movement. Causes include excessive antibiotic use by doctors in people; and excessive antibiotic use by vets in animals (especially farm animals); and dumping of antibiotic contaminated waste by pharmaceutical companies. There isn’t space to go into the issue in detail here – but you can read more on our blog here.

Is this anything to do with the “Disease X” that’s been in the news?

Yes – in all probability, the next major pandemic will be either a zoonotic disease (spread from animals), or due to environmental changes from human activity (climate change or expansion of humans into remote areas of the globe), or probably both.

Are there any solutions?

Yes, there definitely are. If we work together, all of these threats are manageable. And there is some good news – for example, there’s now a serious drive to eradicate human rabies deaths, by vaccinating pet and semi-feral dogs (the most important host in most parts of the world). Called “Zero by 30”, the movement aims to break the cycle of transmission by 2030; you can read more on the Global Alliance for Rabies Control website.

The One Health is a movement that vets, doctors, scientists and all interested parties need to get on board with. After all, we have only one world, and we’re all in this together!

How can I find out more?

As I said above, this is a movement, not a single organisation. However, there are several organisations that are doing great work in promoting the ideals of One Health, and you can read more here:

The One Health Global Network

The One Health Initiative

The World Health Organisation (WHO) page on One Health

A selection of Case Studies from Vets Without Borders