What Are Emerging Infectious Diseases (EIDs)?

Emerging Infectious Diseases (EIDs) are illnesses caused by pathogens—such as viruses, bacteria, fungi, or parasites—that have recently appeared in a population or are rapidly increasing in incidence or geographic range. EIDs can be new diseases or known diseases that are spreading to new areas or populations.

History of Emerging Infectious Diseases

Ancient Times

  • Infectious diseases have affected humans for thousands of years. Archaeological evidence shows that diseases like tuberculosis and malaria existed in ancient Egypt and India.
  • The Black Death (bubonic plague) killed millions in Europe during the 14th century, showing how quickly diseases can spread.

19th and 20th Centuries

  • The discovery of germs by scientists like Louis Pasteur and Robert Koch in the 1800s changed how people understood disease transmission.
  • The Spanish Flu pandemic of 1918 infected about one-third of the world’s population and caused tens of millions of deaths.

Late 20th Century

  • New diseases began to appear more frequently, such as HIV/AIDS in the 1980s and SARS (Severe Acute Respiratory Syndrome) in 2002-2003.
  • Increased global travel, urbanization, and environmental changes contributed to the spread of diseases.

Key Experiments and Discoveries

1. Germ Theory of Disease

  • Experiment: In the 1860s, Louis Pasteur showed that microorganisms cause fermentation and disease. He used swan-neck flasks to prove that microbes come from the environment, not spontaneous generation.
  • Impact: This led to improved hygiene, sterilization, and vaccination practices.

2. Discovery of Viruses

  • Experiment: In 1892, Dmitri Ivanovsky filtered sap from diseased tobacco plants and found that something smaller than bacteria could cause disease. This was the first evidence of viruses.
  • Impact: Understanding viruses led to the development of vaccines and antiviral drugs.

3. Identification of HIV

  • Experiment: In the early 1980s, scientists isolated the human immunodeficiency virus (HIV) as the cause of AIDS.
  • Impact: This discovery led to better testing, treatment, and prevention strategies.

4. Genomic Sequencing

  • Experiment: In the 2000s, scientists began using genetic sequencing to identify new pathogens quickly. For example, the SARS-CoV-2 virus (which causes COVID-19) was sequenced within weeks of its discovery in 2019.
  • Impact: Rapid sequencing helps track outbreaks and develop vaccines faster.

Modern Applications

Disease Surveillance

  • Global Networks: Organizations like the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) monitor outbreaks worldwide.
  • Technology: Artificial intelligence and big data are used to predict and track disease spread.

Vaccines and Treatments

  • mRNA Vaccines: COVID-19 vaccines (Pfizer-BioNTech and Moderna) use messenger RNA to teach cells how to fight the virus.
  • Antiviral Drugs: New medicines are developed to treat diseases like Ebola, Zika, and COVID-19.

Public Health Interventions

  • Quarantine and Isolation: Used to control outbreaks by separating sick or exposed individuals.
  • Contact Tracing: Identifies and notifies people who may have been exposed to an infectious disease.

Controversies

Vaccine Hesitancy

  • Some people refuse vaccines due to misinformation, religious beliefs, or fear of side effects. This can lead to outbreaks of diseases like measles.

Origin of Pathogens

  • The origin of some EIDs, such as COVID-19, has sparked debate. Some theories suggest natural spread from animals to humans (zoonosis), while others question lab safety and accidental release.

Data Privacy

  • Using mobile apps and digital surveillance to track disease spread raises concerns about personal privacy and data security.

Current Event: COVID-19 Pandemic

  • COVID-19 is caused by a novel coronavirus, SARS-CoV-2, first identified in Wuhan, China, in late 2019.
  • The pandemic has affected every country, causing millions of deaths and major economic disruption.
  • According to a 2023 study published in Nature (Wang, Y., et al., 2023), the rapid development and deployment of mRNA vaccines helped reduce severe illness and death rates globally.

Ethical Issues

Resource Allocation

  • During pandemics, there may not be enough vaccines, medicines, or hospital beds for everyone. Deciding who gets treatment first raises ethical questions about fairness and equality.

Research on Dangerous Pathogens

  • Some scientists study how to make viruses more infectious (gain-of-function research) to understand how they might evolve. This research is controversial because of the risk of accidental release.

Public Health vs. Individual Rights

  • Measures like lockdowns, mask mandates, and vaccination requirements can protect public health but may limit individual freedoms.

Water and Disease Transmission

  • The water cycle means that the water we drink today has been part of Earth’s system for millions of years. Waterborne diseases, such as cholera and typhoid, can spread rapidly if water is contaminated.
  • Improving water sanitation is a key way to prevent the spread of EIDs.

Summary

Emerging Infectious Diseases are illnesses that are new or rapidly spreading in human populations. They have shaped human history and continue to challenge public health systems. Key scientific discoveries, such as the germ theory and genomic sequencing, have improved our ability to detect and control these diseases. Modern technology helps track outbreaks and develop vaccines quickly, but controversies and ethical issues remain, especially around vaccine hesitancy, data privacy, and research safety. The COVID-19 pandemic is a recent example of how EIDs can impact the world and highlights the importance of global cooperation and scientific innovation. Addressing EIDs requires balancing public health needs, ethical concerns, and the responsible use of technology.

Reference

  • Wang, Y., et al. (2023). “Global Impact of mRNA Vaccines on COVID-19 Outcomes.” Nature. Link