Epidemiology

Epidemiology is the study of how disease spreads and is controlled in populations.

• It examines the distribution and determinants of health conditions.
• The epidemiologic triangle links agent, host, and environment.
• Key measures include incidence (new cases) and prevalence (total cases).
• Terms: endemic (constant presence), epidemic (sudden rise), and pandemic (worldwide).

Governments and global agencies work to detect and contain disease.

• The WHO coordinates global health; the CDC leads U.S. disease control.
• Surveillance tracks outbreaks so responders can act quickly.
• Tools include quarantine, isolation, vaccination, and contact tracing.
• Herd immunity protects a population when enough people are immune.

The MMWR is the CDC's key channel for public health data.

• Morbidity is the rate of disease; mortality is the rate of death.
• The MMWR publishes timely reports on outbreaks, trends, and recommendations.
• It guides public health action and informs clinicians.
• Data comes from reportable diseases that providers must report to health departments.