morbidity rate; infection rate; disease rate
Technical term used in epidemiology and public health to indicate the proportion of a population that contracts a disease over a specific period.
This year's influenza morbidity rate is higher than usual.
The tuberculosis infection rate in this region is on a downward trend.
死亡率 (mortality rate) measures deaths, whereas 罹患率 measures disease occurrence regardless of outcome.
Compound of 罹患 (りかん, 'contracting a disease') and 率 (りつ, 'rate'). The exact historical derivation is uncertain, but the term is a modern technical coinage.