ziekterperioden

Ziekterperioden, sometimes written ziekteperioden, is a term found in Dutch-language medical literature used to describe the time span of a single illness episode, from the onset of symptoms to recovery or death. It is used to analyze how long patients are affected and to compare disease burden across populations. The term is related to, but distinct from, the incubation period (incubatieperiode) when a disease is asymptomatic, and the infectious period when contagion can occur.

Illness periods vary by disease and by individual factors such as age, comorbidity, and access to care. Clinically, an illness period may include prodromal symptoms, the acute phase of illness, and convalescence, though many diseases do not show all phases. In chronic conditions, illness periods may recur or persist over long durations, creating patterns of relapses and remissions.

In epidemiology and health services research, the duration of illness is used to estimate disease burden, plan hospital capacity, and assess economic impact through lost work or school days. Data come from medical records, patient interviews, and surveys, but recall bias and inconsistent definitions can affect comparability. International usage may favor terms such as “duration of illness” rather than the Dutch form.

See also: incubation period, prodromal period, convalescence, infectious period. The concept has historical roots in natural-history descriptions of disease and remains a component of discussions about disease burden in public health.