Overview
This lecture explains the difference between infection and disease, emphasizing that infection does not always lead to disease and clearing up common misconceptions.
Infection vs. Disease
- Infection occurs when a pathogen (organism causing disease) invades or colonizes the body.
- A disease is an abnormal state where homeostasis is disrupted, causing signs and symptoms.
- Not all infections result in disease; you can be infected and never become ill.
Examples & Clarifications
- During the incubation period after infection, you may not have symptoms, so you’re infected but not diseased.
- Some pathogens can remain in the body for years before causing disease (e.g., shingles, HIV, C. diff).
- The presence of a pathogen alone does not mean disease is present; disease requires disruption of normal bodily functions.
Key Terms & Definitions
- Infection — invasion or colonization of the body by a pathogen, possibly without symptoms.
- Pathogen — an organism capable of causing disease.
- Disease — a condition with abnormal bodily function, symptoms, and loss of homeostasis.
- Homeostasis — stable internal environment in the body.
Action Items / Next Steps
- Review the definitions of infection and disease.
- Reflect on examples where infection does not immediately result in disease.