🤒intro to epidemiology review

Stage 5: Age of Emergent and Re-emergent Infections

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

Stage 5 refers to a phase in the epidemiologic transition model where infectious diseases that were previously controlled or considered eradicated begin to reappear, and new infectious diseases emerge. This stage highlights the challenges of globalization, urbanization, and climate change, which can facilitate the spread of infections that affect populations in both developing and developed countries.

5 Must Know Facts For Your Next Test

  1. Stage 5 signifies an increase in outbreaks of diseases such as tuberculosis, measles, and newly identified viruses like SARS-CoV-2.
  2. Factors like climate change can alter disease patterns by expanding habitats for disease vectors, such as mosquitoes that transmit malaria and dengue fever.
  3. Emerging infections can often be traced back to human behaviors, including land use changes and increased contact with wildlife.
  4. Vaccination coverage gaps can lead to outbreaks of previously controlled diseases, showcasing the importance of public health initiatives.
  5. This stage emphasizes the interconnectedness of global health, as travel and trade facilitate rapid transmission of infections across borders.

Review Questions

  • What are the key characteristics of Stage 5 in the epidemiologic transition model, and how do they impact public health?
    • Stage 5 is characterized by the emergence of new infectious diseases and the resurgence of previously controlled infections. This impacts public health by creating new challenges in disease prevention and control. Factors such as globalization, urbanization, and changing human behaviors contribute to these dynamics, making it crucial for public health systems to adapt their strategies for surveillance and response.
  • Discuss the role of antimicrobial resistance in the context of Stage 5 and its implications for treating infectious diseases.
    • Antimicrobial resistance plays a significant role in Stage 5 by complicating the treatment of infections that are becoming harder to manage with existing medications. This resistance can lead to longer hospital stays, higher medical costs, and increased mortality. It underscores the need for ongoing research into new therapies and better stewardship practices in prescribing antibiotics to mitigate this growing problem.
  • Evaluate how globalization contributes to the emergence and re-emergence of infectious diseases during Stage 5.
    • Globalization contributes significantly to the emergence and re-emergence of infectious diseases by facilitating human movement across borders and increasing interconnectedness among populations. This rapid exchange can lead to quick spread of pathogens, as seen with diseases like COVID-19. Additionally, global trade can introduce new vectors and reservoirs for infections in areas previously unaffected, emphasizing the importance of coordinated global health responses to effectively manage these threats.
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