Estimate true prevalence from apparent prevalence

Theory

True prevalence is the proportion of animals that present the event of interest in the population at a given point in time. Its true value is practically impossible to determine, but it can be estimated from the apparent prevalence. Apparent prevalence is the proportion of animals from a representative sample of the population that are positive to the diagnostic method used.

Where:

AP	The apparent prevalence.
Se	The sensitivity of the diagnostic procedure.
Sp	The specificity of the diagnostic procedure.