Chapter 16: Understanding Epidemiology and Disease Transmission

Epidemiology

Study of disease frequency and spread factors.

Etiologic agent

Cause of a disease identified by epidemiologists.

Morbidity rate

Percentage of cases in a population.

Mortality rate

Measure of deaths in a population.

Prevalence rate

Number of infected individuals at a time.

Incidence rate

New cases per population per time period.

Sporadic diseases

Occasionally seen diseases in populations.

Endemic diseases

Diseases constantly present in a population.

Epidemic diseases

Unexpected increase in disease cases over time.

Pandemic diseases

Epidemic diseases spread worldwide.

Common source outbreak

Single source infects multiple individuals.

Point source outbreak

Infection from a source for a short time.

Continuous common source

Infection occurs over an extended time.

Intermittent common source

Infections stop and start periodically.

Propagated spread

Infection spread through person-to-person contact.

Observational studies

Data collected from participants without manipulation.

Descriptive epidemiology

Describes characteristics of disease in populations.

Analytical epidemiology

Analyzes relationships between risk factors and disease.

Retrospective studies

Looks back at data from past events.

Prospective studies

Follows participants into the future.

Case Control studies

Compares individuals with and without a disease.

Cross sectional studies

Analyzes data from a population at one time.

Experimental studies

Investigates causal relationships through manipulation.

Zoonotic diseases

Diseases transmitted between animals and humans.

R0 (Basic reproduction number)

Indicates contagiousness of an infectious disease.

Herd immunity

Resistance to disease in a population.

Nosocomial infections

Infections acquired in healthcare settings.

Universal precautions

Infection control practices in healthcare settings.

Notifiable diseases

Infectious diseases that must be reported.

Quarantine

Isolation of healthy individuals exposed to disease.

Isolation

Separation of sick individuals from healthy ones.

Disease eradication challenges

Factors hindering complete elimination of diseases.