Active Surveillance: implies the collection of data on specific VPDs, through the review of records during regular visits to selected health facilities, reporting sites or the
community. This method is used
ƒ During outbreaks to determine the extent of the outbreak and keep mortality rates low by initiating early treatment.
ƒ When a disease is targeted for eradication or elimination (e.g. polio eradication) every possible case must be found and investigated.
Active Surveillance does not replace passive surveillance, but if conducted regularly and frequently it has the following advantages over passive surveillance, as it:
ƒ helps to improve the timeliness and accuracy of case detection and notification
ƒ enables rapid case investigation, including collection of laboratory specimens
ƒ helps to link cases epidemiologically.
ƒ enables timely action to be taken in response to the detected case
ƒ identifies areas where passive surveillance needs to be strengthened.
