Key Notes

  • Human, animal, and environmental health are deeply interconnected.
  • Many diseases pass between animals and humans.
  • Environmental change drives new health threats.
  • One Health tackles these challenges across disciplines.
  • Collaboration is essential to protect health.

Health Is One Connected System

We often think of human health as a world unto itself, separate from the health of animals and the environment. The reality is that these are deeply, inseparably connected. The health of people depends on the health of the animals we live alongside and the ecosystems we inhabit. This insight is the foundation of One Health — an approach that recognizes human, animal, and environmental health as a single interconnected system, and tackles health challenges across all three together. As the world faces threats that span these boundaries, One Health has become an essential framework in public health, studied at AIRCST as part of protecting populations.

The Connections That Matter

The links between human, animal, and environmental health are profound and increasingly consequential.

Diseases that cross between species

A large share of infectious diseases that affect humans originate in animals — so-called zoonotic diseases that pass from animals to people. Many of the most serious disease threats in history, and the pandemics that most worry experts, arise at the interface between humans and animals. You cannot fully understand or prevent these human diseases without understanding their animal origins. To protect human health from such threats, we must look beyond humans to the animals and environments where these diseases emerge.

The environment as a driver of health

The health of the environment profoundly shapes human health. Environmental change — habitat destruction, climate change, pollution, and the disruption of ecosystems — can create new health threats, bringing humans into closer contact with disease-carrying wildlife, spreading disease-carrying organisms into new areas, and degrading the clean air, water, and food that health depends on. A damaged environment is, ultimately, a threat to human health.

Shared threats

Some of the gravest health challenges span all three domains at once. Antibiotic resistance, for instance — the rise of bacteria that resist our medicines — is driven by the use of antibiotics in both human medicine and animal agriculture, and spreads through the environment. It cannot be solved by human medicine alone. Such shared threats demand a shared, connected response.

What One Health Does

One Health responds to these connections by breaking down the walls between disciplines that traditionally worked separately — human medicine and public health, veterinary science, and environmental science. It brings together experts across these fields to understand and address health challenges as the interconnected problems they truly are.

In practice, this means monitoring diseases in animals and the environment, not just in humans, to detect emerging threats early — often before they reach people. It means designing solutions that account for all three domains, recognizing that an intervention in one affects the others. And it means fostering collaboration across professions that have too often operated in isolation. One Health succeeds through collaboration, bringing together those who study human, animal, and environmental health to protect them all together.

A Concrete Example

Consider the emergence of a new infectious disease that spreads from animals to humans — a pattern behind many of history's most serious outbreaks. A narrow approach that watches only for illness in people would detect the threat only after it had already spread to humans, when it may be too late to contain easily. A One Health approach instead monitors disease in animal populations and watches the environmental conditions that bring humans and wildlife into contact. It can detect a dangerous disease circulating in animals before it reaches people, giving the chance to intervene early — the most precious advantage in preventing an outbreak. Veterinarians, doctors, public health experts, and environmental scientists work together, each seeing part of a picture that none could see alone. This connected vigilance can stop a threat that a siloed approach would miss.

Why This Matters

Many of the most serious health threats facing the world — pandemics, antibiotic resistance, the health impacts of environmental change — arise from the connections between human, animal, and environmental health. Addressing them requires seeing and acting on those connections, which is exactly what One Health does. As these interconnected threats grow, the One Health approach becomes ever more essential to protecting the health of people everywhere. It needs professionals who can work across disciplines and understand health as the connected system it truly is.

Looking Ahead

Recognition of the deep connections between human, animal, and environmental health continues to grow, driven by the hard lessons of recent global health events. One Health is increasingly central to how the world prepares for and responds to health threats. The future of protecting human health lies in understanding that it can never be separated from the health of the animals and the planet we share.

Protect Health as One System — Research Public Health at AIRCST

At the Aleta International Research Center for Science and Technology (AIRCST), our public health researchers study health as a connected system spanning people, animals, and the environment. If you want to help protect health across these boundaries, explore our research programs and join us, or get in touch to learn more.