Implementation of reactive case detection strategy recommendations towards malaria elimination in the Shai Osudoku district of Ghana

Ghana has refocused its national malaria programme to align with an agenda of malaria elimination. The key interventions in the strategic plan include enhancing epidemiological surveillance for reactive case detection (RACD). Identifying asymptomatic infections using index cases can help understand the epidemiology of malaria and guide its elimination. The study determined asymptomatic carriage in index cases household members and neighbours living near index cases and the suitability of diagnostic accuracy to inform RACD. A cross-sectional health centre and community-based studies were conducted in the Shai Osudoku district. Passive surveillance involved 19 index cases that triggered RACD in 67 index cases household members and 414 neighbours. Malaria was diagnosed using rapid diagnostic test (RDT) kits, microscopy and quantitative polymerase chain reaction (qPCR). Overall malaria prevalence was 8.00% [CI₉₅: 5.78–10.73] by RDT, 10.00% [CI₉₅: 7.51–12.97] by microscopy and 12.60% [CI₉₅: 9.82–15.83] by qPCR. Index cases household members were 2 times more likely of having malaria compared to their neighbours. Across cohorts, significant difference [p = 0.012] was observed between index cases household members and neighbours by qPCR. The mean distribution of Plasmodium spp. parasite densities among positive outcomes of the RDT test in study participants was 162 [IQR: 77.75–3919] parasite/µL of blood, and 96.00 [IQR: 48.00–181.30] parasite/µL of blood in RDT negative outcomes. The mean parasite densities associated with RDT positive results differed significantly from that of the RDT negative results [p = 0.026]. Index cases household members were more likely of having malaria compared to their neighbours. RACD is needed to identify asymptomatic malaria infections and complement efforts that target individuals in low transmission and elimination areas.