<prompt> Which of the following increases the prevalence of the disease-Immigration of healthy peopleIncrease in cure ratesDecrease in the number of new casesIncrease in duration of disease  <response>: Ans. is d i.e. Increase in duration of disease Prevalence refers to all current cases old new existing at a given point in time point prevalence or over a period of time period prevalence in a given populationIt thus includes all the new cases, as well as those old persisting cases. 