1. Definition

Emerging Infectious Diseases (EIDs) are infections that have newly appeared in a population or have existed but are rapidly increasing in incidence or geographic range. EIDs can be caused by bacteria, viruses, fungi, or parasites.

2. Key Characteristics

  • Novelty: Previously unknown or newly recognized pathogens.
  • Incidence: Sudden increase in case numbers.
  • Geographic Spread: Expansion to new regions or populations.
  • Adaptation: Ability to evolve rapidly, sometimes crossing species barriers.

3. Causes of Emergence

Cause Explanation
Zoonosis Transmission from animals to humans (e.g., SARS-CoV-2, Ebola)
Environmental Change Deforestation, climate change, urbanization
Globalization Increased travel and trade, facilitating spread
Microbial Adaptation Mutation, recombination, antibiotic resistance
Breakdown of Public Health Reduced vaccination, poor sanitation, conflict zones

4. Examples of EIDs

  • COVID-19 (SARS-CoV-2): Coronavirus pandemic starting in 2019.
  • Zika Virus: Spread in the Americas, causing birth defects.
  • Ebola Virus: Outbreaks in West Africa (2014-2016).
  • Candida auris: Drug-resistant fungal infections.
  • Antibiotic-resistant Tuberculosis: Increasing globally.

5. Transmission Dynamics

Transmission Pathways Image: Common transmission pathways for infectious diseases

  • Direct Contact: Person-to-person, animal-to-person.
  • Indirect Contact: Contaminated surfaces, vectors (mosquitoes, ticks).
  • Airborne: Droplets, aerosols.
  • Food/Waterborne: Contaminated food or water.

6. Surprising Facts

  1. Extreme Survivors: Some bacteria, like Deinococcus radiodurans, can survive in radioactive waste and deep-sea vents, showing the potential for pathogens to emerge from unexpected environments.
  2. Silent Spreaders: Asymptomatic carriers can transmit diseases (e.g., COVID-19), making detection and control challenging.
  3. Rapid Evolution: Viruses like influenza can undergo antigenic shift, creating new strains in a single season.

7. Practical Applications

  • Surveillance Systems: Real-time monitoring (e.g., WHOโ€™s Global Outbreak Alert and Response Network).
  • Rapid Diagnostics: PCR, CRISPR-based tests for early detection.
  • Vaccination Programs: mRNA vaccines (e.g., COVID-19) developed in record time.
  • Antimicrobial Stewardship: Strategies to combat antibiotic resistance.
  • Public Health Education: Promoting hygiene, vaccination, and responsible antibiotic use.

8. Relation to Current Events

  • COVID-19 Pandemic: Ongoing global impact, highlighting the need for preparedness and rapid response.
  • Mpox (Monkeypox) Outbreaks (2022): Spread outside Africa, demonstrating zoonotic potential and global vulnerability.
  • Climate Change: Expansion of vector-borne diseases (e.g., dengue, malaria) into new regions due to warming temperatures.

9. Future Trends

  • Genomic Surveillance: Use of AI and big data to predict outbreaks (e.g., Nextstrain platform).
  • One Health Approach: Integrating human, animal, and environmental health to prevent zoonotic spillovers.
  • Universal Vaccines: Research into broad-spectrum vaccines for influenza and coronaviruses.
  • Antimicrobial Innovation: Development of new antibiotics and alternative therapies (e.g., phage therapy).
  • Global Collaboration: Enhanced international cooperation for rapid response and resource sharing.

10. Recent Research

A 2022 study published in Nature Microbiology (โ€œGlobal patterns and drivers of emerging zoonotic diseasesโ€) found that land-use change and biodiversity loss are major drivers of EIDs, with hotspots in tropical regions. The authors highlight the importance of surveillance and ecosystem management to prevent future pandemics.
Read the study

11. Concept Map

Emerging Infectious Diseases Concept Map Image: Concept map showing relationships between EID drivers, transmission, and control strategies

12. Summary Table

Aspect Details
Definition New or increasing infectious diseases
Causes Zoonosis, environment, globalization, adaptation, health breakdown
Examples COVID-19, Zika, Ebola, Candida auris, drug-resistant TB
Transmission Direct, indirect, airborne, food/water
Applications Surveillance, diagnostics, vaccines, stewardship, education
Current Events COVID-19, Mpox, climate-driven outbreaks
Future Trends Genomics, One Health, universal vaccines, innovation, collaboration
Recent Study Nature Microbiology (2022): land-use and biodiversity as EID drivers

13. Self-Test Questions

  1. What are the main drivers of emerging infectious diseases?
  2. How do environmental changes contribute to EIDs?
  3. Name two practical applications for controlling EIDs.
  4. What is the One Health approach?
  5. Cite a recent example of an EID and its global impact.

14. References

  • Nature Microbiology (2022). Global patterns and drivers of emerging zoonotic diseases. Link
  • World Health Organization. Emerging diseases. Link

End of Study Notes