Epidemiology

Definition

The scientific study of disease distribution, patterns, and determinants in defined populations, and the application of this knowledge to disease prevention and control. In medical and veterinary entomology, epidemiology specifically addresses how arthropod vectors, reservoirs, and environmental factors shape the transmission dynamics of vector-borne pathogens.

Etymology

From Greek epi- (upon, among) + dēmos (people) + -logia (study of); originally the study of what befalls populations

Example

Epidemiological investigation of Lyme disease emergence in the northeastern United States revealed that forest fragmentation increases encounter rates between blacklegged ticks (Ixodes scapularis), white-footed mice, and human hosts, informing targeted acaricide application and landscape management interventions.

Related Terms

• vector-borne disease
• disease ecology
• basic reproduction number
• herd immunity
• entomological inoculation rate
• force of infection
• pathogen transmission
• Zoonosis

Usage Notes

Distinguish from epizootiology, which is the animal disease equivalent. Medical entomologists often focus on 'field epidemiology' linking entomological surveillance (vector abundance, infection rates) to human case data. The term carries no implication of epidemic scale—endemic disease patterns are equally within scope. Contrast with etiology (causal mechanisms of disease) and clinical medicine (individual patient care).