Definition

Emerging Infectious Diseases (EIDs):
Diseases caused by pathogens newly recognized in a population, or those increasing in incidence or geographic range.

Historical Overview

  • Pre-20th Century:

    • Infectious diseases like plague, smallpox, and cholera shaped human history.
    • Germ theory (Louis Pasteur, Robert Koch, late 1800s) revolutionized understanding of disease causation.

  • 20th Century:

    • Discovery of antibiotics (penicillin, 1928).
    • Vaccination campaigns reduced diseases like polio and measles.
    • Emergence of HIV/AIDS (1981), Ebola (1976), and Legionnaires’ disease (1976).

  • 21st Century:

    • SARS (2002-2003), H1N1 influenza (2009), MERS (2012), Zika virus (2015-2016), COVID-19 (2019-present).
    • Increased global travel, urbanization, and climate change contribute to emergence.

Key Experiments and Discoveries

1. Koch’s Postulates (1880s)

  • Set of criteria to link specific pathogens to diseases.
  • Foundation for identifying causative agents of EIDs.

2. Discovery of HIV (1983)

  • Luc Montagnier and Robert Gallo isolated the virus from patients.
  • Techniques: electron microscopy, reverse transcriptase assays.

3. SARS-CoV Identification (2003)

  • Rapid sequencing of viral genome.
  • Use of PCR and phylogenetic analysis to trace origins.

4. CRISPR-Based Diagnostics (2017+)

  • SHERLOCK and DETECTR platforms for rapid detection of viral RNA.
  • Application in field testing for Zika and COVID-19.

5. mRNA Vaccine Development (2020)

  • Pfizer-BioNTech and Moderna vaccines for COVID-19.
  • First widespread use of mRNA technology for infectious disease prevention.

Modern Applications

Surveillance and Monitoring

  • Genomic Epidemiology:
    • Real-time sequencing (e.g., GISAID database for SARS-CoV-2 variants).
  • Digital Health Tools:
    • Mobile apps for contact tracing, symptom tracking.
  • Environmental Monitoring:
    • Wastewater surveillance for poliovirus, SARS-CoV-2.

Rapid Diagnostics

  • Point-of-care tests using CRISPR, lateral flow assays.
  • AI-driven image analysis for malaria and tuberculosis.

Therapeutics

  • Antiviral drugs (remdesivir, molnupiravir).
  • Monoclonal antibodies for Ebola, COVID-19.
  • Phage therapy for antibiotic-resistant bacteria.

Vaccines

  • mRNA, viral vector, and protein subunit vaccines.
  • Universal influenza vaccine candidates under trial.

One Health Approach

  • Integrates human, animal, and environmental health.
  • Used to monitor zoonotic spillover (e.g., Nipah virus, avian influenza).

Practical Applications

  • Hospital Infection Control:
    • Implementation of isolation protocols, PPE usage.
  • Outbreak Response:
    • Rapid deployment of field teams, mobile labs.
  • Public Health Campaigns:
    • Education on hand hygiene, vaccination drives.
  • Policy Making:
    • Travel advisories, quarantine laws, funding for research.
  • Biotechnology:
    • Development of diagnostic kits, vaccines, and therapeutics.

Teaching in Schools

  • Curriculum Integration:
    • Biology: Microbiology, immunology, disease transmission.
    • Geography: Impact of globalization on disease spread.
    • Social Studies: Historical pandemics, public health policies.
  • Practical Activities:
    • Simulated outbreak investigations.
    • Laboratory work: Culturing bacteria, PCR demonstrations.
  • Interdisciplinary Projects:
    • Case studies on recent outbreaks.
    • Debates on ethical issues (vaccination, quarantine).

Recent Research Example

  • Citation:
    Gibb, R. et al. (2020). “Zoonotic host diversity increases in human-dominated ecosystems.” Nature, 584, 398–402.

    • Findings: Human-driven changes to ecosystems increase the diversity of zoonotic hosts, raising the risk of EIDs.
    • Implications: Urbanization and deforestation may accelerate emergence of new pathogens.

  • News Article:
    “Wastewater surveillance for COVID-19 expands globally.” Nature News, 2021.

    • Summary: Wastewater monitoring is now a key tool for early detection of outbreaks, even before clinical cases rise.

Further Reading

  • Books:

    • “Spillover: Animal Infections and the Next Human Pandemic” by David Quammen
    • “The Next Pandemic” by Ali S. Khan

  • Journals:

    • Emerging Infectious Diseases (CDC)
    • The Lancet Infectious Diseases

  • Web Resources:

Summary

Emerging Infectious Diseases are a major global health challenge, driven by ecological, social, and technological changes. Key discoveries have shaped our ability to detect, prevent, and treat these diseases, with modern applications ranging from genomic surveillance to mRNA vaccines. Practical responses involve coordinated public health efforts, technological innovation, and education. Recent research highlights the impact of human activity on the emergence of new pathogens. Understanding EIDs is essential for science club members interested in microbiology, epidemiology, and global health.