Q&A: How 'One Health' can strengthen health systems

The COVID-19 pandemic has highlighted the need to recognize the links between human health and the natural environment, as outlined in the São Paulo Declaration on Planetary Health, which was released in October with over 250 organization signatories from dozens of nations.

“One Health” is an approach in which multiple sectors — including health and agriculture — work together to create and implement programs and policies for better public health outcomes, according to a definition from the World Health Organization. A recent report from Harvard University and international experts found that “Healthcare system strengthening and One Health are essential to jointly advance conservation, animal and human health.”

The approach can also help support pandemic preparedness by preventing the spillover of pathogens from animals to people. Almost three-quarters of all new, emerging, or reemerging diseases affecting humans in this century originated in animals.

Devex spoke to Wendy Harrison, the CEO at SCI Foundation — a nonprofit working to develop sustainable programs against parasitic diseases such as schistosomiasis — about how a one-health approach can help build more holistic health systems and improve pandemic preparedness.

This conversation has been edited for length and clarity.

WHO’s road map for neglected tropical diseases emphasizes the need for a paradigm shift from disease-specific interventions to crosscutting approaches, including animal and environmental health. Why is a one-health approach key to eliminating NTDs?

First of all, when we look at the 20 neglected tropical diseases [in WHO’s portfolio], 10 of those have animals as part of their transmission cycle. So if we are going to tackle these diseases, then we must look at this holistic approach.

A second area is to really look at the resourcing. Many of the communities we work in have poor water and sanitation and poor access to health care. In addition, livestock often play a crucial role in people’s livelihoods, so animal health services are something communities often rely heavily on.

So there’s a real opportunity for those animal health services and the human health services to work together in a much more joined-up way around the distribution of medicines, dissemination of information, and things like surveillance. If you have adequate surveillance for emerging diseases in animals, then the opportunities for early intervention is possible and we can prevent the kind of catastrophic impacts that we’ve seen throughout the COVID-19 pandemic. We know that 75% of emerging ... diseases come from animal origins, so that is a key area.

Many of these communities — often nomadic or pastoralist — are in very hard-to-reach places, and veterinary public health access points are another opportunity to reach those communities. There’s a study conducted in Chad, for example, where they had joint vaccination teams of medics vaccinating people and vets vaccinating not only animals but also people. Interestingly, the vets vaccinated more women and children than the medics did. So that driver for people to seek health care was a very strong one.

How can a one-health approach help stop new animal-borne diseases before they put people at risk? What’s the role of this approach when it comes to improving disease surveillance?

With previous pandemics such as the avian flu and the swine flu, there was a real recognition of this need for early surveillance in nonhuman species. So a number of national governments have set up one-health surveillance units … and really try to capture this information at the very earliest stages.

There has been work to try and build on initially disease-specific interventions to broaden those to have a much more holistic remit, in terms of the diseases that can be picked up. There’s a lot of interesting work being done at the international level but also at the grassroots level — for example, thinking about the use of digital surveillance platforms that can be implemented on simple smartphones.

Going back to the community agricultural health workers, data can be captured at the community level and then collated, allowing for trends in disease to be picked up. There’s a number of initiatives that are really looking to try and bring these different datasets together, and overlaying [data on] the access to water and sanitation on top of animal health data and human health data really is a very powerful tool.

How can a one-health approach ensure that interventions tackle the root causes of diseases in the long term while ensuring local ownership?

[Scholar] Jakob Zinsstag very much encapsulates One Health as a sort of joint risk assessment and joint planning and interventions because that really allows all the different stakeholders to identify the areas where interventions are most effective.

One example is cysticercosis — a tapeworm [infection] ... that has the pig as the intermediate host, where the pigs pick up the parasitic eggs in human feces. The approach that you need to take to assess where the risk points are include water and sanitation, the animal husbandry — so what is the access of pigs to unprotected latrines — but it also very much involves meat and food hygiene and ensuring that meat that is sold is appropriately inspected to ensure it’s safe for human consumption.

What became apparent while working with colleagues from all those different sectors — and very importantly, the community engagement — was that because pigs are scavengers and don’t necessarily have to be fully fed, that’s often the reason people keep pigs; they are a very good source of cheap protein.

So interventions saying “you need to enclose your pig to ensure it doesn't have access to human waste” actually then negates the very reason that the pigs are so useful for the families in the first place. There are many nuanced approaches that we really need to fully understand before we put in place formal disease control approaches that sometimes may not be workable at the community level.

In global health, much funding is targeted to a specific disease such as malaria or HIV/AIDS? How can funding support a more holistic one-health approach?

A lot of work has been done trying to appropriately apportion the costs and benefits across different interventions.

For example, with a disease like rabies, there’s real challenges. … Dog vaccinations have a huge impact on human public health; it’s one of the most cost-effective interventions. However, not many ministries of health want to financially support dog vaccines. And since dogs are not livestock, they are often outside the ministry-of-agriculture remits, so it’s important to have better costing models that really appropriately apportion the costs and benefits.

Nationally, there is some recognition that funding zoonotic diseases in a more holistic way is taking hold. There are some great examples in Kenya, where they have a zoonotic diseases unit that is at the ministerial level, but it has both the Ministry of Health and the Ministry of Agriculture working together.

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