Introduction

One Health is a transdisciplinary approach recognizing that the health of humans, animals, and ecosystems are interconnected. This paradigm addresses complex health challenges at the interface of these domains, including emerging infectious diseases, antimicrobial resistance, and environmental hazards. One Health integrates expertise from medicine, veterinary science, ecology, epidemiology, and public health, aiming for collaborative solutions to global health threats.

Main Concepts

1. Interconnectedness of Human, Animal, and Environmental Health

  • Zoonoses: Over 60% of emerging infectious diseases are zoonotic, originating from animals and crossing into humans. Examples include Ebola, SARS-CoV-2, and avian influenza.
  • Environmental Drivers: Deforestation, climate change, and biodiversity loss alter habitats, increasing contact between wildlife, livestock, and humans, facilitating pathogen spillover.
  • Food Systems: Intensive agriculture and livestock production can contribute to antimicrobial resistance and contamination of food chains.

2. Surveillance and Early Detection

  • Integrated Surveillance: One Health promotes joint monitoring of disease in humans, animals, and the environment. Data sharing across sectors enables early warning and coordinated response.
  • Genomic Epidemiology: Advanced sequencing technologies track pathogen evolution and transmission routes, informing outbreak control strategies.

3. Antimicrobial Resistance (AMR)

  • Cross-sectoral Spread: Use of antibiotics in veterinary and human medicine leads to resistant bacteria that can transfer between species and persist in the environment.
  • Mitigation Strategies: Stewardship programs, alternative therapies, and improved sanitation are essential to slow AMR emergence.

4. Mathematical Modeling and Key Equations

Mathematical models are central to understanding disease dynamics in One Health.

SIR Model (Susceptible-Infectious-Recovered)

The classic SIR model is extended in One Health to include multiple host species and environmental reservoirs.

Equation:

  • For each population (human, animal, environmental reservoir):

    dS/dt = -βSI
dI/dt = βSI - γI
dR/dt = γI

    Where:

    • S = Susceptible individuals
    • I = Infectious individuals
    • R = Recovered individuals
    • β = Transmission rate (can include cross-species terms)
    • γ = Recovery rate

  • Multi-host models incorporate transmission coefficients between humans, animals, and the environment.

Basic Reproduction Number (R₀)

  • R₀ quantifies the average number of secondary infections produced by one case in a fully susceptible population.
  • In One Health, R₀ can be calculated for each host and environmental reservoir, with composite values reflecting cross-species transmission.

5. Ethical Considerations

  • Data Sharing and Privacy: Integrating health data from humans, animals, and environments raises privacy and consent issues, especially in resource-limited settings.
  • Equity: One Health interventions must address disparities in access to healthcare, veterinary services, and environmental resources.
  • Animal Welfare: Disease control measures (e.g., culling) must balance public health benefits with ethical treatment of animals.
  • Community Engagement: Local knowledge and participation are vital for sustainable interventions, respecting cultural practices and indigenous rights.

6. Recent Research and Case Studies

A 2022 study published in Nature Communications (“A One Health approach to SARS-CoV-2 surveillance in wildlife”) demonstrated the value of integrated surveillance. Researchers tracked SARS-CoV-2 in wild deer populations, revealing spillover and potential reservoirs for future outbreaks (Pickering et al., 2022). This highlights the necessity of cross-sectoral data and response strategies.

7. Future Trends

  • Digital Integration: Artificial intelligence and big data analytics will enhance real-time surveillance, predictive modeling, and rapid response.
  • Climate Change Adaptation: One Health frameworks will be critical for addressing health impacts of climate-driven shifts in disease vectors and ecosystem services.
  • Global Policy: International organizations (WHO, FAO, OIE) are formalizing One Health strategies in pandemic preparedness and AMR action plans.
  • Education and Workforce Development: Cross-disciplinary training programs are expanding to build One Health competencies in STEM fields.

Conclusion

One Health is a transformative approach to safeguarding global health by integrating human, animal, and environmental perspectives. It leverages collaborative science, ethical practice, and advanced modeling to address complex challenges such as zoonoses, AMR, and environmental change. Ongoing research, technological innovation, and policy development will shape its evolution, making One Health a cornerstone of future STEM education and practice.

Reference:
Pickering, B., Smith, G., et al. (2022). A One Health approach to SARS-CoV-2 surveillance in wildlife. Nature Communications, 13, 1371. Link