Definition: An Emerging Infectious Disease (EID) is a disease that has newly appeared in a population, or has existed previously but is rapidly increasing in incidence or geographic range, or threatens to increase in the near future.
Emerging Infectious Diseases represent a significant and dynamic threat to global public health. These diseases can arise from newly identified pathogens, such as novel viruses or bacteria, or from known pathogens that acquire new characteristics enabling them to spread more easily, cause more severe illness, or affect new host populations. Factors driving their emergence are multifaceted, including ecological changes, increased human-animal interaction (leading to zoonotic spillover), rapid global travel and trade, climate change, urbanization, and antimicrobial resistance. Historically, diseases like HIV/AIDS, SARS, MERS, Ebola, Zika, and most recently COVID-19 exemplify the devastating potential of EIDs to cause widespread morbidity and mortality.
The importance of EIDs in public health cannot be overstated due to their potential to trigger epidemics and pandemics, overwhelm healthcare systems, disrupt economies, and destabilize societies. Public health responses to EIDs demand robust surveillance systems for early detection, rapid diagnostic capabilities, swift outbreak investigation and contact tracing, and the accelerated development of vaccines and therapeutics. Effective management also relies on strong international collaboration, transparent risk communication, and the implementation of proactive preparedness strategies. Understanding the complex interplay of factors contributing to EID emergence is crucial for developing resilient public health infrastructures capable of preventing, detecting, and responding to future threats.
Key Context:
- Re-emerging Infectious Diseases: Diseases that were once a major health problem globally or in a particular country, and then declined significantly, but are now increasing in incidence again.
- Zoonotic Diseases: Infections naturally transmissible from vertebrate animals to humans; the vast majority of EIDs are zoonotic in origin.
- One Health Approach: A collaborative, multi-sectoral, and trans-disciplinary approach — working at the local, regional, national, and global levels — with the goal of achieving optimal health outcomes recognizing the interconnections between people, animals, plants, and their shared environment.