One Health Approach

One Health is a way of thinking about health that treats the health of humans, animals, plants and the environment as one connected system. It says that we cannot keep people healthy if animals are sick or nature is damaged. So doctors, vets, farm experts and environment experts must work together, not separately. The idea is most often used to fight diseases that pass between animals and humans.

Why do we need One Health?

Many of the diseases that harm people start in animals. About 60% of known human infectious diseases are zoonotic (they come from animals), and nearly 75% of new or emerging human infectious diseases come from domestic or wild animals. COVID-19, Nipah, bird flu (H5N1) and rabies are examples. If a health department only watches hospitals, it sees an outbreak late, after people are already sick.

If vets, forest officers and doctors share information, the warning can come early, when the virus is still in birds, bats or pigs. Think of it like a joint family: if one member falls ill with something infectious, the whole house is at risk, so everyone must look out for each other.

What problems does it try to solve?

One Health mainly targets four linked problems:

• Zoonotic diseases: diseases that jump from animals to people, such as rabies, Nipah and avian influenza.
• Antimicrobial resistance (AMR): germs that no longer respond to medicines, partly because antibiotics are overused in people, poultry, fish and cattle.
• Food safety: germs and chemicals that reach us through meat, milk, eggs and crops.
• Environmental damage: cutting forests, wildlife trade and pollution, which push wild animals and people into closer contact and help diseases spill over.

Where did the idea come from?

The idea is old, but the name is new.

• In the 1800s, doctors noticed that the same germs cause disease in animals and people. The German doctor Rudolf Virchow is often credited with coining the word "zoonosis".
• In 1964, the American vet Calvin Schwabe used the term "One Medicine" in his textbook Veterinary Medicine and Human Health. He argued that human and animal medicine are one science.
• In 2004, the Wildlife Conservation Society held a meeting in New York that produced the "Manhattan Principles" under the banner "One World, One Health". These added the environment and wildlife to the picture.
• Outbreaks of SARS (2003) and bird flu pushed global bodies to act together.
• In 2010, the Tripartite was formed: the Food and Agriculture Organization (FAO), the World Organisation for Animal Health (WOAH, earlier called OIE) and the World Health Organization (WHO).
• In 2021, a panel of experts called the One Health High-Level Expert Panel (OHHLEP) gave a common definition. On 1 December 2021, the Tripartite and the UN Environment Programme (UNEP) backed it.
• In March 2022, UNEP formally joined, and the group became the Quadripartite.
• In October 2022, the Quadripartite released the One Health Joint Plan of Action (2022–2026).

What is the official definition?

The OHHLEP definition calls One Health "an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems". In simple words: look at all three together, and improve all three together, in a way that lasts. The definition also stresses that the health of plants and the wider environment is part of this system.

How does it work in practice?

One Health is not a single law or a single agency. It is a way of working. In practice, it means:

1. Joint surveillance: human health, animal health and wildlife departments watch for unusual illness and share data in one system.
2. Joint response: when a disease appears, for example bird flu on a poultry farm, vets cull or vaccinate birds while doctors test and treat workers.
3. Joint planning: ministries of health, agriculture, animal husbandry and environment make one plan, with clear roles.
4. Prevention at the source: reduce risky wildlife trade, improve farm hygiene and animal welfare, and use fewer antibiotics on animals.

Where does animal welfare fit?

Animals kept in crowded, dirty or stressful conditions get sick more easily. Sick animals get more antibiotics, which feeds AMR. Packed farms and live wildlife markets also give viruses more chances to mix and jump to humans. So better animal welfare is not only about kindness; it is also a public health tool. This is why newer One Health plans, and frameworks in countries such as Bangladesh and Cameroon, now name animal welfare directly.

How is it linked to biodiversity treaties?

The Convention on Biological Diversity has treated biodiversity and health as linked for years. At COP14 in 2018, the parties asked for a global plan on this link. At COP16 in Cali, Colombia, on 1 November 2024, they adopted the Global Action Plan on Biodiversity and Health (Decision 16/19). It is voluntary. It encourages countries to use One Health thinking to reduce the rise of zoonotic diseases, prevent non-communicable diseases and keep ecosystems healthy, in support of the Kunming-Montreal Global Biodiversity Framework.

India's position and Indian examples

India faces a heavy load of zoonotic diseases, such as rabies, Nipah in Kerala, Kyasanur Forest Disease (monkey fever) in Karnataka, and bird flu outbreaks in poultry.

• National One Health Mission: In July 2022, the Prime Minister's Science, Technology and Innovation Advisory Council (PM-STIAC) endorsed a National One Health Mission. It brings many ministries together for disease control and pandemic preparedness.
• National Institute of One Health, Nagpur: Its foundation stone was laid in December 2022. On 29 February 2024, the Union Cabinet approved the post of its Director, who will also act as the Mission Director of the National One Health Mission.
• National Action Plan on AMR: India's first plan ran from 2017 to 2021. The second plan, NAP-AMR 2.0 (2025–2029), was launched on 18 November 2025. It involves more than 20 ministries and covers human health, animal health, agriculture and the environment.
• Disease control programmes: The National Centre for Disease Control (NCDC) runs programmes on zoonoses, including the national plan to end dog-mediated rabies.

Commonly confused concepts

• One Health vs Planetary Health vs EcoHealth: All three link human health to nature. One Health grew from vets and doctors working together on shared diseases. Planetary Health looks at how big human-made changes to Earth's systems (climate, land use) affect human health. EcoHealth focuses on how ecosystems and local communities shape health.
• Tripartite vs Quadripartite: The Tripartite (2010) was FAO, WOAH and WHO. The Quadripartite (from March 2022) adds UNEP.
• WOAH vs WHO: WOAH (World Organisation for Animal Health, set up in 1924 as OIE) deals with animal diseases. WHO deals with human health.
• Zoonosis vs pandemic: A zoonosis is any disease that passes from animals to humans. A pandemic is a disease spreading widely across many countries. Some zoonoses become pandemics (COVID-19); most do not.

Issues, criticism and the way forward

• Silo working: In most countries, including India, health, animal husbandry and forest departments have separate budgets, data systems and bosses. Joint working often stays on paper.
• Animal and environment health get less money: Most funding goes to human hospitals. Veterinary services and wildlife surveillance remain weak.
• AMR from farms: Antibiotics are still used in poultry and fish farming to make animals grow faster. Rules exist but are hard to enforce.
• Data sharing: Laboratories for humans and animals often do not share results in real time.
• Way forward: Experts suggest one shared surveillance platform, joint training of doctors and vets, more funding for veterinary and wildlife health, curbs on risky wildlife trade, better farm animal welfare, and making One Health part of national pandemic laws and budgets.

Concepts to Know

• Zoonotic disease (zoonosis): A disease that spreads from animals to humans, for example rabies from dogs or Nipah from fruit bats.
• Antimicrobial resistance (AMR): When bacteria, viruses, fungi or parasites change so that medicines no longer kill them. Common infections then become hard or impossible to treat.
• Spillover: The moment a germ jumps from an animal species into humans for the first time.
• Surveillance: Regular watching and recording of disease cases so that outbreaks are spotted early.
• Quadripartite: The four global bodies that lead One Health work together: FAO, UNEP, WHO and WOAH.
• Non-communicable disease: A disease that does not spread from person to person, such as diabetes or heart disease.