High Zoonotic Disease Risk Looms Over 9% of Global Land Due to Climate Change: Study

29 Jul 2025

High Zoonotic Disease Risk Looms Over 9% of Global Land Due to Climate Change: Study

A new study published in Science Advances reveals that over 9% of the world’s land area is at high or very high risk of zoonotic disease outbreaks, driven significantly by climate-related factors.

About Zoonotic Diseases / Zoonoses

  • Zoonoses are infectious diseases transmitted from animals to humans.
  • Pathogens Involved: May be bacterial, viral, parasitic, or involve unconventional agents (e.g. prions).
  • Modes of Transmission: Spread through direct contact, contaminated food, water, or the environment.
  • Over 60% of emerging infectious diseases are zoonotic in origin.
  • Examples: 
    • Recurring Outbreaks: Ebola, salmonellosis
    • Pandemics: COVID-19 (caused by a novel coronavirus)
    • Mutated Human Strains: HIV (originated as a zoonosis)

Zoonotic Risk – Global Overview

  • High-Risk Land Areas Identified: 9.3% of the global land surface is at high (6.3%) or very high (3%) risk of zoonotic outbreaks — infections transferred between animals and humans.
  • Population at Risk: 3% of the global population lives in extremely high-risk areas; around 20% live in medium-risk zones.
  • Key Infections of Concern: COVID-19, Ebola, MERS, SARS, and Nipah are among the most prioritised zoonotic infections as per WHO.

Drivers of Zoonotic Spillovers

  • Climate Change as Key Risk Factor: Higher temperatures, increased rainfall, and water scarcity are identified as major contributors to increased zoonotic risks.
  • Environmental Vulnerabilities: These climate-related changes significantly increase a region’s vulnerability to spillover events, as per the study.

Risk Mapping and Methodology

  • Global Data Sources Used: The study relied on the ‘Global Infectious Diseases and Epidemiology Network’ dataset and WHO’s prioritised disease list.
  • Risk Index Developed: Researchers created an “epidemic risk index” combining region-specific disease risk with countries’ preparedness and response capacities (excluding SARS-CoV-2).

Regional Risk Distribution

  • Latin America: 27% of its land area falls in the high/very high-risk category.
  • Oceania: 18.6% of its land also falls into these categories.
  • Asia: 7% and Africa: 5% of land areas are at elevated risk.

Zoonotic Trends in India

  • ICMR Study Insights (2018–2023): A study by the Indian Council of Medical Research (ICMR), published in The Lancet Regional Southeast Asia, found that 8.3% of reported disease outbreaks in India were zoonotic.
    • Out of 6,948 outbreaks analysed, 583 involved animal-to-human transmission.
  • Seasonal Peak: Outbreaks consistently peaked during the months of June, July, and August.

Policy Relevance and Recommendations

  • Need for Public Health Integration: The study emphasizes integrating climate mitigation and adaptation strategies into public health planning.
  • Use of Epidemic Risk Index: This tool can help identify high-risk zones, guide policymaker interventions, strengthen response systems, and encourage international cooperation.

WHO Bacterial Priority Pathogens List

  • A global tool to prioritize research, development (R&D), and public health interventions against antimicrobial resistance (AMR).
  • Objective: To guide AMR response strategies, foster region-specific planning, and stimulate development of new antimicrobials.
  • Classification: Pathogens are categorized into:
    • Critical Priority
    • High Priority
    • Medium Priority
  • Coverage: Includes 24 bacterial pathogens across 15 families, with focus on:
    • Gram-negative bacteria resistant to last-resort antibiotics
    • Drug-resistant Mycobacterium tuberculosis
    • Other key pathogens: Salmonella, Shigella, Neisseria gonorrhoeae, Pseudomonas aeruginosa, Staphylococcus aureus

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Quick Revise Now !
UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
हिंदी में भी उपलब्ध

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