1 Never use a microwave or conventional oven to pre-heat your flask. 2  If your flask has not been used for some time, rinse with warm water to remove any residual odours.  DO NOT overfill your flask. Leave sufficient space in the neck to fit the stopper.
Prevalence is a measure of disease that allows us to determine a person's likelihood of having a disease. Therefore, the number of prevalent cases is the total number of cases of disease existing in a population.
Both incidence and prevalence are words used in the field of epidemiology. Epidemiology is a branch of medicine that looks at (you probably guessed it) how many people have a particular disease, what the risks are of contracting a disease, what happens to people who get that disease, and ultimately, how to prevent disease from occurring.