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Clin Infect Dis. 2019 May 16. pii: ciz403. doi: 10.1093/cid/ciz403. [Epub ahead of print]

Active case-finding for malaria: A three-year national evaluation of optimal approaches to detect infections and hotspots through reactive case detection in the low transmission setting of Eswatini.

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Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, USA.
Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), USA.
Department of Pediatrics, UCSF, USA.
Clinton Health Access Initiative, Eswatini Office, Mbabane, Eswatini.
Division of Prevention Science, Department of Medicine, UCSF, USA.
Eswatini National Malaria Programme, Manzini, Eswatini.
Eswatini National Reference Laboratory, Mbabane, Eswatini.
Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF, USA.



Reactive case detection (RACD) is a widely practiced malaria elimination intervention whereby close contacts of index cases receive malaria testing to inform treatment and other interventions. However, the optimal diagnostic and operational approaches for this resource-intensive strategy are not clear.


We conducted a three-year prospective national evaluation of RACD in Eswatini, a malaria elimination setting. Loop-mediated isothermal amplification (LAMP) was compared to traditional rapid diagnostic test (RDT) for the improved detection of infections, and hotspots (RACD events yielding ≥1 additional infection). The potential for index case-, RACD-, and individual-level factors to improve efficiencies was also evaluated.


Among 377 RACD events, 10,890 participants residing within 500 meters of index cases were tested. Compared to RDT, LAMP provided a 3- and 2.3-fold higher yield to detect infections (1.7% vs. 0.6%) and hotspots (29.7% vs. 12.7%), respectively. Hotspot detection improved with ≥80% target population coverage and response times within 7 days. Proximity to the index case was associated with a dose-dependent increased infection risk (up to 4-fold). Individual-, index case-, and other RACD-level factors were considered but the simple approach of restricting RACD to a 200-meter radius maximized yield and efficiency.


We present the first large-scale national evaluation of optimal RACD approaches from a malaria elimination setting. To inform delivery of antimalarial drugs or other interventions, RACD when conducted should utilize more sensitive diagnostics and clear context-specific operational parameters. Future studies of RACD's impact on transmission may still be needed.


Eswatini; efficiency; loop-mediated isothermal amplification; malaria elimination; reactive case detection


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