How Real-Time Case-Based Malaria Surveillance Helps Zanzibar Get a Step Closer to Malaria Elimination: Description of Operational Platform and Resources

Abstract

Testing and treating asymptomatic populations have the potential to reduce the population's parasite reservoir and reduce malaria transmission. Zanzibar's malaria case notification (MCN) platform collects detailed sociodemographic and epidemiological data from all confirmed malaria cases to inform programmatic decision-making. We describe the design and operationalization process of the platform and other malaria surveillance resources that are enabling Zanzibar's progress toward malaria elimination.The MCN platform consists of an interactive short message service (SMS) system for case notification, a software application for Android mobile devices, a visual question set and workflow manager, a back-end database server, and a web browser-based application for data analytics, configuration, and management. Malaria case data were collected from August 2012 to December 2021 and reported via SMS from all public and private health facilities to a central database and then to district malaria surveillance officers' mobile devices. Data included patient names, shehia (administrative area), and date of diagnosis, enabling officers to track patients, ideally within 24 hours of reporting. Patients' household members were tested for malaria using conventional rapid diagnostic tests (RDTs). Treatment using artemisinin-based combination therapy was provided for persons testing positive.Between 2012 and 2021, a total of 48,899 index malaria cases were confirmed at health facilities, 22,152 (45.3%) within 24 hours of reporting; 41,886 (85.7%) cases were fully investigated and followed up to the household level. A total of 111,811 additional household members were tested with RDTs, of whom 10,602 (9.5%) were malaria positive.The MCN platform reports malaria case data in near real time, enabling prompt follow-up of index cases and prompt testing and treatment of members in index case households. Along with routine testing and treatment and other preventive interventions, the MCN platform is foundational to the programmatic efforts in further reducing malaria and ultimately eliminating autochthonous malaria transmission in Zanzibar.

FIGURE 1

Information Technology Infrastructure of Zanzibar's Malaria Case Notification Platform Abbreviations: rACD, reactive case detection; SMS, short message service; USSD, unstructured supplementary service data.

FIGURE 2

Schematic Framework of Index Case Notification and Household Level Follow-Up and Reactive Case Detection Abbreviations: DMSO, district malaria surveillance officer; rACD, reactive case detection.

FIGURE 3

Number and Proportion of Malaria Index Cases Notified Within 24 Hours of Diagnosis, 2012–2021, Zanzibar

FIGURE 4

Number and Proportion of Malaria Index Cases Investigated After Notification, 2012–2021, Zanzibar

FIGURE 5

Number and Proportion of Malaria Index Case Households Investigated After Notification, 2012–2021, Zanzibar

FIGURE 6

Number of Malaria Cases Notified, Household Members Tested, and Positivity Rate, 2012–2021, Zanzibar Abbreviations: HF, health facility; HH, household.

FIGURE 7

Number and Proportion of Malaria Cases With Self-Reported Travel History in 30 Days Before Diagnosis, 2012–2021, Zanzibar

FIGURE 8

Number and Proportion of Malaria Cases and Their Household Members With Self-Reported LLIN Use, 2012–2021, Zanzibar Abbreviation: LLIN, long-lasting insecticidal net.