One Health must be at the heart of stronger health systems

Authors: Carolyn Henry, Tim Jesudason and Wendy Harrison, Unlimit Health

One Health must be at the heart of stronger health systems 

Five years after governments promised to “build back better” from COVID-19, health systems remain too focused on responding to crises rather than preventing them. At a time when aid budgets are shrinking and climate and environmental pressures are increasing, this is both a health and an economic failure. 

The lessons of COVID-19 have shown that efforts to strengthen health systems cannot stop at human health services alone.  Instead, it must recognise the interdependence of human, animal, and environmental health and invest accordingly. 

More recent outbreaks demonstrate why this matters. In May 2026, the World Health Organization (WHO) reported a rare strain of hantavirus capable of human-to-human transmission and a new Ebola outbreak in the Democratic Republic of Congo. While unrelated, both illustrate the need for systems capable of detecting and responding to emerging threats before they escalate. 

More than 60% of known infectious diseases are zoonotic in origin, while approximately 75% of emerging infectious diseases originate from animals. Climate change, environmental degradation, deforestation, urban expansion, conflict, and increased global mobility are bringing humans, animals, and ecosystems into closer contact, increasing the risk of future spillover events. Yet the systems intended to manage these risks remain fragmented. Surveillance, financing, governance, and service delivery are often poorly coordinated across sectors, limiting countries’ ability to identify threats early and respond effectively.

A fragmented approach we can no longer afford 

Progress on pandemic preparedness since COVID-19 has been uneven and underfunded. Shrinking aid budgets and geopolitical tensions are putting further strain on international cooperation at precisely the time when stronger coordination is needed. 

The UK government has recognised health systems strengthening as an important foundation for health security. But traditional approaches do not always go far enough in addressing the connections between human, animal, and environmental health. 

One Health Systems Strengthening (OHSS) can help bridge this gap by building coordination across sectors rather than responding to diseases and health threats in isolation. It also recognises that health is shaped not only by access to healthcare, but by food systems, access to water and sanitation services, livelihoods, climate, and the wider environment. 

This is fundamentally an issue of equity. Communities most exposed to these challenges are often those with the least access to quality health services, greatest reliance on livestock for their livelihoods and the fewest resources to withstand a crisis. Resilient health systems must therefore address the conditions that create vulnerability as well as provide services when people and animals become sick. 

Making limited resources work harder 

In a constrained fiscal environment, One Health should not be viewed as an additional demand on shrinking health budgets, but as a way of making existing investments more effective. 

Greater coordination can reduce duplication by enabling sectors to share systems, data, expertise, and infrastructure. Joint surveillance between animal and human health systems, for example, can identify threats earlier, allowing countries to intervene before spillover between different species occurs and outbreaks escalate, into expensive emergencies. 

There is a growing economic case for doing so. A recent joint policy brief from the Food and Agriculture Organization (FAO) and WHO reviewed 97 studies examining the economics of One Health investments and found that around eight in ten reported positive economic returns. The evidence base continues to develop, but the direction is clear: joined-up investment can protect health while making better use of scarce resources. 

One Health also supports universal health coverage (UHC). UHC requires more than ensuring people can access healthcare when they become sick. It needs resilient systems that address the wider factors influencing health and can prevent threats before they reach communities.

What this looks like in practice 

Zanzibar provides one example. Recent workshops convened by the Ministry of Health and supported by Unlimit Health brought together stakeholders from human, animal, and environmental health sectors through the “Four Cs” model: communication, coordination, collaboration, and capacity building. 

This approach has strengthened cross-sector governance while helping make better use of limited resources. It has also highlighted how environmental conditions influence disease transmission and inequality. Poor waste management and inadequate sanitation can create breeding grounds for mosquitoes, while inadequate access to safe water and sanitation continues to drive transmission of parasitic diseases. These connections are not peripheral to health systems strengthening, they are foundational to it.  

From commitment to investment 

The challenge now is moving One Health from rhetoric to implementation. 

For the UK, this means integrating One Health into approaches to health systems strengthening, global health security, UHC, pandemic preparedness, and climate resilience, rather than treating it as a specialist or standalone programme. 

It also means protecting investment in prevention and surveillance as aid budgets tighten, supporting country-led coordination across human, animal, and environmental sectors, strengthening local systems that identify risks before they become crises, and ensuring communities have a meaningful role in decisions affecting their health. 

Funders should similarly recognise One Health as a core component of resilient health systems, not a niche investment. As resources become scarcer and health threats more interconnected, the choice is increasingly clear: continue paying for fragmented responses after crises emerge, or invest in integrated, country-led systems capable of preventing them.  

If pandemic preparedness and universal health coverage are to be credible ambitions, One Health must be part of the foundations of health systems strengthening, not an optional addition.