Number of occurrences of illness commencing, or of persons falling ill, during a given period in a specific population: usually expressed as a rate.
Source:
PAC, 2004, 76, 1033. 'Glossary of terms used in toxicokinetics (IUPAC Recommendations 2003)' on page 1054 (https://doi.org/10.1351/pac200476051033)