From Nipah and Ebola to COVID-19, the most severe global crises of our time share a volatile origin: they begin in animals before crossing into human populations. These zoonotic diseases now account for more than 60 per cent of all infectious diseases and 75 per cent of newly emerging infections.
In countries like India, the threat is escalating within a strained public health landscape characterised by a deep rural-urban divide, chronic underfunding, and severe medical shortages. This fragile system is currently battling a ‘triple burden’: lingering infectious diseases, rising non-communicable diseases, and the highly unpredictable, dynamic threat of emerging zoonoses. Because spillovers can trigger sudden, large-scale crises, even a single outbreak can completely overwhelm the healthcare infrastructure.
But while the pathogen itself is biological, the reasons it spills over, and the reasons it devastates certain communities over others are deeply social.
Zoonotic spillovers are rarely random accidents. They happen in landscapes that humans have actively reshaped. In fact, since the 1960s, environmental modification has driven over 30 per cent of new infectious diseases.
When natural habitats are fragmented, biodiversity plummets. This creates ‘edge habitats’ that force wildlife, domestic animals, and humans into close contact. Healthy, intact ecosystems possess a natural defense where a wide variety of species acts as a buffer, preventing any single pathogen-carrying species from dominating, called the ‘dilution effect’. You can think of it as the immunity of landscape. When it is degraded, that immunity breaks down. For instance, the Nipah outbreak that occurred in Malaysia connects to the deforestation and climate stress which pushed fruit bats out of their natural homes and into commercial orchards and pig farms, forging a deadly new transmission route from wildlife to livestock to humans.
However, we often blame these outbreaks on a generic ‘broken relationship with nature,’ assuming nature should remain a pristine, untouched wilderness. This narrative is flawed and often reinforces exclusionary conservation policies. Indigenous communities have long proven that human interaction can coexist with, and even enhance, biodiversity. While the real issue is often industrial and capitalist expansion, specific modes of land transformation oversimplify ecological systems and intensify high-risk contacts.
Crucially, the fallout from this environmental degradation is not shared equally. Marginalised populations are often pushed into high risk scenarios due to limited livelihood options, unequal access to resources, and weak governance. In tropical regions, for example, high biodiversity and humid climates naturally allow diseases to persist. However, diseases emerge because these ecological factors overlap with poverty, rapid population growth, and limited healthcare. The zoonotic risk is therefore not caused by environmental change alone, but by the devastating interplay between ecological disruption and social inequality.
To address this escalating threat, scientists and policymakers have turned to ‘One Health’, a framework recognising that human, animal, and environmental health are inseparable. In India, this has taken the form of the National One Health Mission (NOHM) and the National One Health Programme for Prevention and Control of Zoonoses (NOHP-PCZ), which aim to move from reactive responses to anticipatory surveillance. But in practice, these initiatives reveal critical gaps, as their efforts are heavily technocratic, focusing almost entirely on biological surveillance, pathogen detection, and laboratory networks. Most initiatives are led by veterinary and public health experts, with very little engagement from ecologists or social scientists.
Thereby treating zoonoses as a technical issue, the framework ignores the everyday realities of how people live, work, and depend on animals. It looks at the pathogen but misses the wider circumstances creating the vulnerability, ultimately focusing on symptomatic treatment rather than the root causes of the disease.
The challenge ahead is not a lack of scientific capability, but the failure to integrate science with complex social, cultural, and ecological realities. If we want to understand why diseases emerge, we need an interdisciplinary approach that considers how development decisions are made and how institutions function. Building on this, Wallace et al. (2015) proposed ‘Structural One Health.’ This approach strengthens the original framework by linking the political and economic drivers of environmental change to the disease itself. It asks why environments are being altered and how social systems force interactions between vulnerable people and displaced wildlife.
Addressing the threat of zoonoses requires moving beyond biological lenses. It needs deepening the perspective of One Health to include social and political analysis, as we can finally treat these outbreaks for what they truly are: socio-ecological crises that demand structural solutions.
Chaithra Bhagavathi Parambu is a Doctoral Researcher with Ashoka Trust for Research in Ecology and Environment (ATREE) in Bengaluru
Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth