title: Under-notification of giardiasis in Auckland, New Zealand: a capture-recapture estimation.
abstract: Estimation of the degree of undercount is important for disease surveillance. Capture-recapture techniques are now being used to evaluate the completeness of disease ascertainment. This study estimated the level of under-notification of giardiasis in the Auckland adult population using a capture-recapture method. Two independent datasets of giardiasis cases > or = 15 years were generated from the 1998-1999 Auckland Giardiasis Study (AGS) case database and cases notified to Auckland Regional Public Health Services (ARPHS) for the same period of time. Cases were matched and under-notification was estimated using a two-sample capture-recapture method. During the 12-month period, 199 cases participated in the AGS and 413 cases were notified to ARPHS. The capture-recapture calculation indicated that only 49% of cases were notified. Under-notification by a factor of 2 obscures the true burden of giardiasis. Socio-economic conditions and water quality may influence disease notification inversely. Capture-recapture techniques are useful in evaluating the completeness of surveillance.
authors.affiliation: Section of Epidemiology and Biostatistics, School of Population Health, The University of Auckland, New Zealand. e.hoque@auckland.ac.nz
authors.forename: M E
authors.initials: ME
authors.lastname: Hoque
authors.forename: V T
authors.initials: VT
authors.lastname: Hope
authors.forename: R
authors.initials: R
authors.lastname: Scragg
authors.forename: J
authors.initials: J
authors.lastname: Graham
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D018563:Disease Notification / Q000592:standards*; D004812:Epidemiologic Methods; D005260:Female; D005873:Giardiasis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D011159:Population Surveillance