"(epidemiology) the ratio (for a given time period) of the number of occurrences of a disease or event to the number of units at risk in the population"@en-us . . "prevalence"^^ . . "13824114-n"^^ . "0"^^ . "113042144"@en-us . . . . "0"^^ . "prevalence"@en-us . . . "113824114"^^ . . .