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

Abstract 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.

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Adding proactive and reactive case detection into the integrated community case management system to optimise diagnosis and treatment of malaria in a high transmission setting of Cameroon: an observational quality improvement study

BMJ Open ◽

10.1136/bmjopen-2018-026678 ◽

2019 ◽

Vol 9 (6) ◽

pp. e026678 ◽

Cited By ~ 2

Author(s):

Cavin Epie Bekolo ◽

Thomas D’Arcy Williams

Keyword(s):

Quality Improvement ◽

Case Management ◽

Diagnostic Testing ◽

Sub Saharan Africa ◽

Secondary Outcome ◽

Case Detection ◽

Community Case Management ◽

Reactive Case Detection ◽

Integrated Community Case Management ◽

Index Cases

ObjectiveIntegrated community case management (iCCM) of childhood illness is a powerful intervention to reduce mortality. Yet, only 29% and 59% of children with fever in sub-Saharan Africa had access to malaria testing and treatment between 2015 and 2017. We report how iCCM+ based on incorporating active case detection of malaria into iCCM could help improve testing and treatment.DesignA community-led observational quality improvement study.SettingThe rural community of Bare-Bakem in Cameroon.ParticipantsChildren and adults with fever between April and June 2018.InterventionA modified iCCM programme (iCCM+) comprising a proactive screening of febrile children <5 years old for malaria using rapid diagnostic testing to identify index cases and a reactive screening triggered by these index cases to detect secondary cases in the community.Primary and secondary outcome measuresThe proportion of additional malaria cases detected by iCCM+ over iCCM.ResultsWe screened 501 febrile patients of whomPlasmodiuminfection was confirmed in 425 (84.8%) cases. Of these cases, 102 (24.0%) were index cases identified in the community during routine iCCM activity and 36 (8.5%) cases detected passively in health facilities; 38 (8.9%) were index cases identified proactively in schools and 249 (58.6%) were additional cases detected by reactive case detection—computing to a total of 287 (67.5%) additional cases found by iCCM+ over iCCM. The likelihood of finding additional cases increased with increasing family size (adjusted odd ratio (aOR)=1.2, 95% CI: 1.1 to 1.3) and with increasing age (aOR=1.7, 95% CI: 1.5 to 1.9).ConclusionMost symptomatic cases of malaria remain undetected in the community despite the introduction of CCM of malaria. iCCM+ can be adopted to diagnose and treat more of these undiagnosed cases especially when targeted to schools, older children and larger households.

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Case investigation and reactive case detection for malaria elimination in northern Senegal

Malaria Journal ◽

10.1186/1475-2875-12-331 ◽

2013 ◽

Vol 12 (1) ◽

Cited By ~ 46

Author(s):

Megan Littrell ◽

Gnagna Dieng Sow ◽

Algaye Ngom ◽

Mady Ba ◽

Balla Mbacke Mboup ◽

...

Keyword(s):

Malaria Elimination ◽

Case Detection ◽

Reactive Case Detection ◽

Case Investigation

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Effectiveness of reactive case detection for malaria elimination in three archetypical transmission settings: a modelling study

Malaria Journal ◽

10.1186/s12936-017-1903-z ◽

2017 ◽

Vol 16 (1) ◽

Cited By ~ 25

Author(s):

Jaline Gerardin ◽

Caitlin A. Bever ◽

Daniel Bridenbecker ◽

Busiku Hamainza ◽

Kafula Silumbe ◽

...

Keyword(s):

Malaria Elimination ◽

Case Detection ◽

Reactive Case Detection ◽

Modelling Study

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A framework for evaluating the costs of malaria elimination interventions: an application to reactive case detection in Southern Province of Zambia, 2014

Malaria Journal ◽

10.1186/s12936-016-1457-5 ◽

2016 ◽

Vol 15 (1) ◽

Cited By ~ 6

Author(s):

Bruce A. Larson ◽

Thandiwe Ngoma ◽

Kafula Silumbe ◽

Marie-Reine I. Rutagwera ◽

Busiku Hamainza ◽

...

Keyword(s):

Malaria Elimination ◽

Case Detection ◽

Reactive Case Detection ◽

Southern Province

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Improving the efficiency of reactive case detection for malaria elimination in southern Zambia: A cross-sectional study

10.21203/rs.2.21595/v1 ◽

2020 ◽

Author(s):

Fiona R.P. Bhondoekhan ◽

Kelly M. Searle ◽

Harry Hamapumba ◽

Mukuma Lubinda ◽

Japhet Matoba ◽

...

Keyword(s):

Risk Factors ◽

Environmental Risk ◽

Catchment Area ◽

Health Workers ◽

Index Case ◽

Satellite Image ◽

Environmental Risk Factors ◽

Local Health ◽

Case Detection ◽

Reactive Case Detection

Abstract Background: Reactive case detection (RCD) seeks to enhance malaria surveillance and control by identifying and treating parasitemic individuals residing near index cases. In Zambia, this strategy starts with passive detection of symptomatic incident malaria cases at local health facilities or by community health workers, with subsequent home visits to screen-and-treat residents in the index case and neighboring (secondary) households within a 140-meter radius using rapid diagnostic tests (RDTs). However, a small circular radius may not be the most efficient strategy to identify parasitemic individuals in low-endemic areas with hotspots of malaria transmission. To evaluate if RCD efficiency could be improved by increasing the probability of identifying parasitemic residents while screening fewer houses, we incorporated environmental risk factors and a larger screening radius (250 meters) in a region of low malaria endemicity. Methods: Between January 12, 2015 and July 26, 2017, 4,170 individuals (residing in 158 index and 531 secondary households) were enrolled and completed a baseline questionnaire in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia. Plasmodium falciparum prevalence was measured using PfHRP2 RDTs and qPCR. A Quickbird™ high-resolution satellite image of the catchment area was used to create environmental risk factors in ArcGIS, and generalized estimating equations were used to evaluate associations between risk factors and secondary households with parasitemic individuals. Results: The overall parasite prevalence in secondary (non-index case) households was 0.7% by RDT and 1.8% by qPCR. 8.5% (45) of secondary households had at least one resident with parasitemia by qPCR or RDT. The risk of a secondary household having a parasitemic resident was significantly increased in proximity to higher order streams and marginally with increasing distance from index households. The adjusted OR for proximity to third- and fifth-order streams were 2.97(95% CI: 1.04 – 8.42) and 2.30 (95% CI: 1.04 – 5.09), respectively, and that for distance to index households for each 50 meters was 1.24 (95% CI: 0.98– 1.58). Conclusion: Applying proximity to streams as a screening tool, 16% (3) more malaria-positive secondary households were identified than using a 140 m circular screening radius. This analysis highlights the potential use of environmental risk factors as a screening strategy to increase RCD efficiency.

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Risk factors associated with malaria infection identified through reactive case detection in Zanzibar, 2012–2019

Malaria Journal ◽

10.1186/s12936-021-04025-1 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Humphrey R. Mkali ◽

Erik J. Reaves ◽

Shabbir M. Lalji ◽

Abdul-Wahid Al-mafazy ◽

Joseph J. Joseph ◽

...

Keyword(s):

Risk Factors ◽

Malaria Infection ◽

Universal Access ◽

Behavioural Change ◽

P Value ◽

Case Detection ◽

Reactive Case Detection ◽

Factors Associated ◽

Household Members ◽

Index Cases

Abstract Background Over the past two decades, Zanzibar substantially reduced malaria burden. As malaria decreases, sustainable improvements in control interventions may increasingly depend on accurate knowledge of malaria risk factors to further target interventions. This study aimed to investigate the risk factors associated with malaria infection in Zanzibar. Methods Surveillance data from Zanzibar’s Malaria Case Notification system from August 2012 and December 2019 were analyzed. This system collects data on malaria cases passively detected and reported by all health facilities (index cases), and household-based reactive case detection (RCD) activities linked to those primary cases. All members of households of the index cases were screened for malaria using a malaria rapid diagnostic test (RDT). Individuals with a positive RDT were treated with artemisinin-based combination therapy. Univariate and multivariate logistic regression analyses were done to investigate the association between RDT positivity among the household members and explanatory factors with adjustment for seasonality and clustering at Shehia level. Results A total of 30,647 cases were reported of whom household RCD was completed for 21,443 (63%) index case households and 85,318 household members tested for malaria. The findings show that younger age (p-value for trend [Ptrend] < 0.001), history of fever in the last 2 weeks (odds ratio [OR] = 35.7; 95% CI 32.3–39.5), travel outside Zanzibar in the last 30 days (OR = 2.5; 95% CI 2.3–2.8) and living in Unguja (OR = 1.2; 95% CI 1.0–1.5) were independently associated with increased odds of RDT positivity. In contrast, male gender (OR=0.8; 95% CI 0.7–0.9), sleeping under an LLIN the previous night (OR = 0.9; 95% CI 0.7–0.9), having higher household net access (Ptrend < 0.001), and living in a household that received IRS in the last 12 months (OR = 0.8; 95% CI 0.7–0.9) were independently associated with reduced odds of RDT positivity. A significant effect modification of combining IRS and LLIN was also noted (OR = 0.7; 95% CI 0.6–0.8). Conclusions The findings suggest that vector control remains an important malaria prevention intervention: they underscore the need to maintain universal access to LLINs, the persistent promotion of LLIN use, and application of IRS. Additionally, enhanced behavioural change and preventive strategies targeting children aged 5–14 years and travellers are needed.

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Improving the efficiency of reactive case detection for malaria elimination in southern Zambia: A cross-sectional study

10.21203/rs.2.21595/v2 ◽

2020 ◽

Author(s):

Fiona R.P. Bhondoekhan ◽

Kelly M. Searle ◽

Harry Hamapumba ◽

Mukuma Lubinda ◽

Japhet Matoba ◽

...

Keyword(s):

Risk Factors ◽

Environmental Risk ◽

Catchment Area ◽

Health Workers ◽

Index Case ◽

Satellite Image ◽

Environmental Risk Factors ◽

Local Health ◽

Case Detection ◽

Reactive Case Detection

Abstract Background : Reactive case detection (RCD) seeks to enhance malaria surveillance and control by identifying and treating parasitemic individuals residing near index cases. In Zambia, this strategy starts with passive detection of symptomatic incident malaria cases at local health facilities or by community health workers, with subsequent home visits to screen-and-treat residents in the index case and neighboring (secondary) households within a 140-meter radius using rapid diagnostic tests (RDTs). However, a small circular radius may not be the most efficient strategy to identify parasitemic individuals in low-endemic areas with hotspots of malaria transmission. To evaluate if RCD efficiency could be improved by increasing the probability of identifying parasitemic residents, we incorporated environmental risk factors and a larger screening radius (250 meters) in a region of low malaria endemicity. Methods: Between January 12, 2015 and July 26, 2017, 4,170 individuals residing in 158 index and 531 secondary households were enrolled and completed a baseline questionnaire in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia. Plasmodium falciparum prevalence was measured using Pf HRP2 RDTs and qPCR. A Quickbird™ high-resolution satellite image of the catchment area was used to create environmental risk factors in ArcGIS, and generalized estimating equations were used to evaluate associations between risk factors and secondary households with parasitemic individuals. Results: The parasite prevalence in secondary (non-index case) households was 0.7% by RDT and 1.8% by qPCR. Overall, 8.5% (n = 45) of secondary households had at least one resident with parasitemia by qPCR or RDT. The risk of a secondary household having a parasitemic resident was significantly increased in proximity to higher order streams and marginally with increasing distance from index households. The adjusted OR for proximity to third- and fifth-order streams were 2.97 (95% CI: 1.04 – 8.42) and 2.30 (95% CI: 1.04 – 5.09), respectively, and that for distance to index households for each 50 meters was 1.24 (95% CI: 0.98– 1.58). Conclusion: Applying proximity to streams as a screening tool, 16% (n = 3) more malaria-positive secondary households were identified compared to using a 140-meter circular screening radius. This analysis highlights the potential use of environmental risk factors as a screening strategy to increase RCD efficiency.

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