Infectious disease dynamics: What characterizes a successful invader?

Area of Science:

• Epidemiology
• Infectious Disease Dynamics
• Public Health

Background:

• Emerging and re-emerging infectious diseases pose significant public health challenges.
• Understanding pathogen establishment in new host populations is crucial for disease control.
• Human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) serve as key examples.

Purpose of the Study:

• To review the properties enabling infectious agents to establish and persist in host populations.
• To analyze the critical threshold for pathogen transmission using the basic reproductive number (R0).
• To explore the interplay between pathogen biology, host behavior, and disease dynamics.

Main Methods:

• Literature review focusing on infectious disease transmission.
• Analysis of epidemiological principles, including the basic reproductive number (R0).
• Examination of factors influencing pathogen spread and persistence.

Main Results:

• A pathogen must achieve a basic reproductive number (R0) greater than 1 to maintain itself in a new host population.
• Pathogen transmission is influenced by the interaction between biological transmission stages and host behavioral factors.
• Secular changes can affect the magnitude of R0 over time.

Conclusions:

• The R0 is a fundamental metric for assessing the potential for infectious disease establishment and spread.
• Behavioral and biological factors are critical determinants of R0 and disease persistence.
• Insights gained from HIV/AIDS dynamics are applicable to other emerging and re-emerging infectious diseases.