Entering the host body, evading the immune system, adhering to specific host cells, invading and colonizing host tissues, and inflicting damage on those tissues

What is the term for an organism that causes disease?

Pathogen

When does disease occur?

If and when the invasion and growth of a pathogen impair bodily functions

What must a pathogen do to infect a host?

Enter the host body, evade the immune system, adhere to specific host cells, invade and colonize host tissues, and inflict damage on those tissues

What happens when a pathogen invades and grows within a host?

The host's bodily functions may be impaired

Study Notes

Disease Frequency

Epidemiologists use specific terms to describe the frequency or number of cases of a disease in a population to understand the disease's spread and identify at-risk individuals.

Disease Classification

Sporadic disease: occurs infrequently and irregularly.
Epidemic: a sudden increase in the number of cases of a disease in a population.

Infection and Disease

Infection occurs when a disease-causing organism invades and grows within a host organism
Disease occurs when the invasion and growth of a pathogen impairs bodily functions

Pathogens

Pathogens are organisms that are infectious and cause disease
To cause disease, pathogens must:
- Enter the host body
- Evade the immune system
- Adhere to specific host cells
- Invade and colonize host tissues
- Inflict damage on host tissues

Learn key terms used in epidemiology to describe disease frequency, including sporadic diseases and epidemics. Understand how to measure disease occurrence in a population.