The Microbe, the Infection Enigma, and the Host

Area of Science:

• Infectious Disease Epidemiology
• Host-Pathogen Interactions
• Genetics of Infectious Disease

Background:

• The germ theory of disease led to effective treatments for infectious diseases.
• However, understanding why most infected individuals remain asymptomatic is lacking.
• This highlights the 'infection enigma' and the need for host-centric research.

Purpose of the Study:

• To investigate the underlying causes of disease severity in infectious diseases.
• To explore host factors, particularly genetic and immunological determinants, in disease outcomes.
• To shift focus from solely microbial triggers to host susceptibility.

Main Methods:

• Review of canonical approaches (in vitro, in vivo, clinical studies) focusing on microbial impact.
• Analysis of alternative approaches examining pre-existing host factors in diverse populations.
• Investigating human genetic and immunological variations in individuals exposed to infectious agents.

Main Results:

• Canonical methods adequately addressed microbial roles but overlooked host variability.
• Infection outcomes vary significantly among individuals despite exposure to the same microbe.
• Pre-existing host factors, including genetics and immunity, are crucial in determining disease.
• Most infected individuals do not develop severe disease, indicating a host-driven component.

Conclusions:

• Understanding infectious disease requires a deeper investigation into host determinants beyond the microbe.
• Human genetic and immunological factors play a critical role in disease manifestation.
• Future research should prioritize host-based solutions to the infection enigma.