Over 9% of Global Land at High Risk for Animal-to-Human Disease Spread, Study Finds

New Delhi: A new study published in the journal Science Advances has found that over 9% of the world's land area is at high or very high risk of zoonotic outbreaks diseases that spread between animals and humans. These “spillover events” can lead to widespread health crises, such as the Covid-19 pandemic.

The research, conducted by a team including scientists from the European Commission's Joint Research Centre (JRC) Scientific Development Programmes Unit in Italy, used data from the Global Infectious Diseases and Epidemiology Network and the World Health Organization’s (WHO) list of priority diseases. These include Covid, Ebola, MERS, SARS, and Nipah virus, which are known for their potential to cause epidemics or pandemics.

According to the study, 9.3% of global land is at elevated risk, with 6.3% classified as high risk and 3% as very high risk. These zones are also home to around 3% of the world’s population, while about 20% live in areas considered medium-risk.

The analysis showed that climate change-related factors such as increasing temperatures, changing rainfall patterns, and water scarcity contribute significantly to the growing vulnerability of certain regions. “Our results indicate that 9.3 per cent of the global land surface is at high (6.3 per cent) or very high (three per cent) risk,” the authors stated.

The research also mapped the risk across continents. Latin America had the highest proportion of land at high or very high risk (27%), followed by Oceania (18.6%), Asia (7%), and Africa (5%).

The authors highlighted the need for integrated public health strategies that consider environmental changes: “This underscores the need for continued monitoring and the integration of climate adaptation and mitigation efforts into public health planning.”

They also proposed an “epidemic risk index” that combines regional zoonotic risk with the capacity of countries to prepare for and respond to such threats. “Translating these risk estimates into an epidemic risk index allows for the identification of high-risk areas and supports policymakers in improving response capacities, allocating resources effectively, and fostering international collaboration to address global health threats,” the team said.

Separately, a study published in The Lancet Regional Southeast Asia by the Indian Council of Medical Research (ICMR) in May 2025 found that 8.3% of outbreaks in India between 2018 and 2023 were zoonotic. Of the 6,948 outbreaks recorded, 583 were linked to animal-to-human transmission. The study also noted a consistent seasonal trend, with most outbreaks peaking between June and August.

(With inputs from PTI)