Healthcare utilization surveys (HUS), one method of determining the healthcare utilization practices for specific diseases in defined populations, have been conducted in several countries. [5] [6] [7] [8] [9] [10] [11] [12] In HUS, random samples of the catchment population are interviewed with respect to their healthcare seeking and treatment behaviors during recent episodes of disease. These data can be used in a number of ways to support the interpretation of information from sentinel surveillance sites: first, to establish correction factors for estimates of incidence in the community based on numbers of cases presenting at the sentinel surveillance site, including the incidence in particular population sub-groups; second, to describe the actual catchment population accessing healthcare at the sentinel site to determine generalizability; and third, to identify other healthcare providers who may be recruited to participate in the surveillance system.