Active Case Finding for Malaria: A 3-Year National Evaluation of Optimal Approaches to Detect Infections and Hotspots Through Reactive Case Detection in the Low-transmission Setting of Eswatini

Clin Infect Dis. 2020 Mar 17;70(7):1316-1325. doi: 10.1093/cid/ciz403.


Background: 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.

Methods: We conducted a 3-year prospective national evaluation of RACD in Eswatini, a malaria elimination setting. Loop-mediated isothermal amplification (LAMP) was compared to traditional rapid diagnostic testing (RDT) for the improved detection of infections and for hotspots (RACD events yielding ≥1 additional infection). The potential for index case-, RACD-, and individual-level factors to improve efficiencies was also evaluated.

Results: Among 377 RACD events, 10 890 participants residing within 500 m of index cases were tested. Compared to RDT, LAMP provided a 3-fold 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-m radius maximized yield and efficiency.

Conclusions: 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.

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

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Eswatini
  • Humans
  • Malaria* / diagnosis
  • Malaria* / epidemiology
  • Molecular Diagnostic Techniques
  • Nucleic Acid Amplification Techniques*
  • Prospective Studies

Supplementary concepts

  • LAMP assay