By the time a high-impact zoonotic disease reaches a hospital ward, it is already too late.
Global health systems are highly effective at tracking human-to-human transmission. They test, isolate, trace contacts, and treat patients. However, these systems are activated only after infection has already occurred—after a pathogen has crossed from animals into people, adapted, and begun to spread.
This reactive posture exposes a fundamental weakness: global health systems are designed primarily to respond to emerging zoonotic diseases, not to prevent them. Recent advances in genomic analysis have made this gap even clearer. Evidence now shows that many outbreaks are driven not only by sustained human-to-human transmission but also by repeated spillover events—fresh introductions of pathogens from wildlife or livestock into human populations.
This means that even when transmission chains are interrupted, the underlying risk remains. Pathogens continue to circulate silently in animal populations, creating new opportunities for spillover. Outbreak control alone cannot eliminate this risk; prevention must begin where diseases originate.
The World Health Organization’s Director-General captured this reality during a recent briefing on Ebola: “The outbreak had a big head start… we are still trying to catch up.”
That phrase—catching up—has become the defining characteristic of global outbreak response. The lesson is clear: unless surveillance shifts upstream, the world will remain perpetually behind the next emerging threat.
During the recent Ebola outbreak caused by the Bundibugyo virus (BDBV), the virus gained an early advantage because initial cases were not promptly detected in health facilities. Its symptoms closely resembled common illnesses such as malaria, allowing transmission to continue unnoticed. By the time the outbreak was recognized, response teams were forced to catch up with a disease that had already spread through communities.
The Blind Spot: Where Spillover Happens
Most emerging infectious diseases originate at the wildlife–livestock–human interface. Expanding agriculture, environmental degradation, climate change, and growing population pressures are bringing people, livestock, and wildlife into increasingly close contact.
These are not remote or marginal landscapes. They are productive ecosystems that sustain livelihoods, food production, and local economies. Across much of Africa—including Uganda and the Democratic Republic of the Congo—they are central to everyday life.
Yet surveillance systems remain overwhelmingly focused on hospitals, laboratories, and human cases. They are not designed to routinely monitor ecosystems, animal health, or the points of interaction where pathogens first cross species barriers.
This is the world’s greatest surveillance blind spot—and it is precisely where the next outbreak is most likely to emerge. Without integrating ecological and veterinary surveillance into national disease monitoring systems, global health security will remain incomplete.
From Pilot to Practice: Uganda’s Experience
Encouragingly, there are signs that this thinking is beginning to change.
In late 2021, Uganda established a wildlife veterinary diagnostic laboratory in Queen Elizabeth National Park with support from the United States Government. The facility was created to strengthen early detection of zoonotic diseases at their source.
It enables:
- Detection of pathogens in wildlife before they spill over into humans or livestock.
- Surveillance across the wildlife–livestock–human interface.
- Earlier warning and more targeted interventions.
Ugandan authorities have described this investment as marking a “new era in disease surveillance and prevention.”
Such initiatives demonstrate that upstream prevention is not merely aspirational—it is practical and operational. However, isolated pilot projects are not enough. They must be scaled up, institutionalized, and fully integrated into national surveillance systems.
FAO and the One Health Imperative
This is where the Food and Agriculture Organization of the United Nations (FAO) plays a pivotal role.
Through its leadership in advancing the One Health approach, FAO supports countries in integrating animal health, environmental monitoring, and agrifood systems into broader health security frameworks. This includes strengthening veterinary services, improving early detection of zoonotic threats, and promoting coordinated surveillance across sectors.
Globally, FAO, together with the World Health Organization (WHO), the World Organisation for Animal Health (WOAH), and the United Nations Environment Programme (UNEP), leads implementation of the One Health Joint Plan of Action. The plan calls for stronger surveillance and coordinated action at the human–animal–environment interface.
In Uganda, FAO’s work in livestock health, agrifood systems, and ecosystem management places it in a unique position to help address disease risks where they actually emerge.
Ultimately, FAO’s contribution is to shift the focus from responding to disease outbreaks to managing the systems that generate disease risk in the first place. Achieving this transformation, however, will require sustained political commitment and long-term investment.
The Hard Reality: Risk and Culture
Any credible strategy for preventing spillover must also confront a difficult reality: disease risk is not only ecological—it is social.
In many communities, bushmeat hunting, trade, and consumption are deeply embedded in livelihoods, food security, and cultural traditions. Attempts to eliminate these practices outright are unlikely to succeed and may instead drive them underground, making associated risks even harder to monitor and manage.
A more pragmatic approach is needed.
This is not about endorsing illegal hunting or unregulated wildlife markets. Rather, it is about recognizing local realities and managing public health risks more effectively. The objective is not to erase cultural practices but to reduce the likelihood that they lead to disease emergence.
That means applying the same public health principles used for other animal-source foods by:
- Promoting safer handling, processing, and preparation practices.
- Strengthening hygiene and inspection standards where appropriate.
- Expanding veterinary oversight and surveillance.
- Supporting community awareness, engagement, and behaviour change.
Risk can rarely be eliminated entirely, but it can be substantially reduced. Embedding these measures within community-led initiatives will also strengthen trust and improve long-term sustainability.
From Catching Up to Getting Ahead
The evidence is unmistakable: spillover is not a rare event. It is continuous, dynamic, and becoming more likely as human, animal, and environmental systems become increasingly interconnected.
Yet global investment remains disproportionately focused on responding after outbreaks occur.
This imbalance is no longer sustainable. Upstream, integrated surveillance grounded in the One Health approach offers a more effective path forward. By linking human, animal, and environmental health systems, it enables earlier detection, more targeted interventions, and far more cost-effective prevention.
Uganda’s experience demonstrates that this shift is both feasible and impactful. The challenge now is to move beyond isolated successes and scale these approaches nationally, regionally, and globally.
Without that commitment, the world risks repeating the same cycle of delayed detection, escalating outbreaks, and costly emergency responses.
Conclusion
If the world continues to wait until diseases reach people, it will remain trapped in a cycle of reaction—always trying to catch up.
But by investing in surveillance where diseases first emerge—at the wildlife–livestock–human interface—it can finally begin to get ahead.
The next pandemic will not begin in a hospital.
It will begin quietly, at the intersection of ecosystems, animals, and people.
The choice is clear: invest upstream today, or pay a far greater price downstream tomorrow.
Ezana Kassa is the FAO Representative in Uganda. This opinion piece was written to mark World Zoonoses Day, observed on 6 July 2026.