Anopheles gambiae Re-Emergence and Resurgent Malaria Transmission in Eastern Rwanda, 2010-2020.

Rwanda achieved unprecedented malaria control gains from 2000 to 2010, but cases increased 20-fold between 2011 and 2017. Vector control challenges and environmental changes were noted as potential explanations, but no studies have investigated causes of the resurgence or identified which vector species drove transmission. We conducted a retrospective study in four sites in eastern Rwanda that conducted monthly entomological surveillance and outpatient malaria care. We compared sporozoite rates, human blood index (HBI), and relative abundance of the primary vectors, Anopheles gambiae and Anopheles arabiensis, from 2017 to 2020. We then modeled the effects of vector control interventions, insecticide resistance, and temperature changes on species composition and reported malaria incidence. Sporozoite rates were 28 times higher and HBI was four times higher in An. gambiae compared with An. arabiensis. Insecticide-treated bed nets, first distributed nationally in 2010, were associated with decreased An. gambiae relative abundance. However, increased pyrethroid resistance was associated with increased An. gambiae relative abundance and malaria incidence. Epidemic malaria peaks corresponded to periods of model-predicted An. gambiae re-emergence, and increased regional air temperatures during the period were further associated with increased malaria incidence. Indoor residual spraying (IRS), implemented with non-pyrethroid insecticides later in the period, was associated with 86% reductions in An. gambiae relative abundance and 75% reductions in malaria incidence. These findings suggest that increased pyrethroid resistance and the re-emergence of An. gambiae were closely linked to the malaria resurgence in eastern Rwanda. Non-pyrethroid IRS or other control measures that effectively target An. gambiae may help prevent future resurgences.

The impact of Bacillus thuringiensis var. israelensis (Vectobac® WDG) larvicide sprayed with drones on the bio-control of malaria vectors in rice fields of sub-urban Kigali, Rwanda.

BACKGROUND: The core vector control tools used to reduce malaria prevalence are currently long-lasting insecticidal nets (LLINs), and indoor residual spraying (IRS). These interventions are hindered by insecticide resistance and behavioural adaptation by malaria vectors. Thus, for effective interruption of malaria transmission, there is a need to develop novel vector control interventions and technologies to address the above challenges. Larviciding using drones was experimented as an innovative tool that could complement existing indoor interventions to control malaria. METHODS: A non-randomized larviciding trial was carried out in irrigated rice fields in sub-urban Kigali, Rwanda. Potential mosquito larval habitats in study sites were mapped and subsequently sprayed using multirotor drones. Application of Bacillus thuringiensis var. israelensis (Bti) (Vectobac® WDG) was followed by entomological surveys that were performed every two weeks over a ten-month period. Sampling of mosquito larvae was done with dippers while adult mosquitoes were collected using CDC miniature light traps (CDC-LT) and pyrethrum spraying collection (PSC) methods. Malaria cases were routinely monitored through community health workers in villages surrounding the study sites. RESULTS: The abundance of all-species mosquito larvae, Anopheles larvae and all-species pupae declined by 68.1%, 74.6% and 99.6%, respectively. Larval density was reduced by 93.3% for total larvae, 95.3% for the Anopheles larvae and 61.9% for pupae. The total adult mosquitoes and Anopheles gambiae sensu lato collected using CDC-Light trap declined by 60.6% and 80% respectively. Malaria incidence also declined significantly between intervention and control sites (U = 20, z = - 2.268, p = 0.023). CONCLUSIONS: The larviciding using drone technology implemented in Rwanda demonstrated a substantial reduction in abundance and density of mosquito larvae and, concomitant decline in adult mosquito populations and malaria incidences in villages contingent to the treatment sites. The scaling up of larval source management (LSM) has to be integrated in malaria programmes in targeted areas of malaria transmission in order to enhance the gains in malaria control.

A qualitative look at bed net access and use in Burkina Faso, Mozambique, Nigeria, and Rwanda following piloted distributions of dual-active ingredient insecticide-treated nets.

BACKGROUND: Universal coverage with insecticide-treated nets (ITNs) is important for malaria control and elimination. The emergence and intensification of insecticide resistance threatens progress made through the deployment of these interventions and has required the development of newer, more expensive ITN types. Understanding malaria prevention behaviour, including barriers and facilitators to net access and use, can support effective decision-making for the promotion and distribution of ITNs. METHODS: In-depth interviews and focus group discussions were conducted in 3 to 4 villages per district, in 13 districts across Burkina Faso, Mozambique, Nigeria and Rwanda from 2019 to 2022. Interviews were conducted in the local language, translated and transcribed in English, French or Portuguese. Transcripts were coded and analysed using Nvivo and ATLAS.ti. RESULTS: ITNs were obtained from mass distribution campaigns, antenatal care and immunization visits, and purchased on the private market in some locations. While there were divergent perspectives in whether the number of distributed nets were adequate, participants consistently expressed concerns of bias, discrimination, and a lack of transparency with the distribution process. ITNs were frequently used alongside other malaria prevention methods. The primary motivation for use was malaria prevention. While some participants reported using nets nightly throughout the year, other participants reported seasonal use, both due to the perceived higher density of mosquitoes and discomfort of sleeping under a net in the increased heat. Other barriers to consistent net use included activities that take place away from the home, sleeping patterns and arrangements, and sensitivity to the insecticides on the nets. CONCLUSIONS: ITNs remain an important malaria control intervention. To ensure adequate and increased net access, distribution campaigns should consider family structures, available sleeping spaces, and other bed sharing preferences when identifying the number of nets needed for distribution. In addition, campaigns should allow for multiple options for net distribution points and timing to accommodate households remote to health services. Continuous distribution channels and complimentary distribution through the private sector could help fill gaps in coverage. Solutions are needed for outdoor malaria transmission, including alternative designs for ITNs, and improving access to complementary personal protective measures.

Impact of Pyrethroid Plus Piperonyl Butoxide Synergist-Treated Nets on Malaria Incidence 24 Months after a National Distribution Campaign in Rwanda.

Malaria remains a public health priority in Rwanda. The use of insecticide-treated nets (ITNs) is a key malaria prevention tool. However, expanding pyrethroid resistance threatens the gains made in malaria control. In 2018, the Rwandan malaria program strategic approach included the use of newer types of ITNs such as pyrethroid plus piperonyl butoxide (PBO) synergist-treated nets to counter pyrethroid resistance. In February 2020, 5,892,280 ITNs were distributed countrywide; 1,085,517 of these were PBO nets distributed in five districts. This study was a pragmatic observational study that leveraged the 2020 net distribution and routinely collected confirmed malaria cases to determine the impact of PBO nets 1 and 2 years after ITN distribution. No differences were observed in the average net coverage between the PBO and standard net districts. A significant reduction in malaria incidence was reported in both the PBO (P = 0.019) and two control districts that received standard nets (P = 0.008) 1 year after ITN distribution. However, 2 years after, this reduction was sustained only in the PBO (P = 0.013) and not in the standard net districts (P = 0.685). One year after net distribution, all districts had a significant reduction in malaria incidence rate (incidence rate ratio < 1). In the second year, incidence in districts with PBO nets continued to decrease, whereas in districts with standard nets, incidences were similar to predistribution levels. The results indicate that PBO nets are a promising tool to combat pyrethroid resistance in Rwanda, with protective effects of up to 2 years post distribution.

Peripheral and Placental Prevalence of Sulfadoxine-Pyrimethamine Resistance Markers in Plasmodium falciparum among Pregnant Women in Southern Province, Rwanda.

Intermittent preventive therapy during pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended in areas of moderate to high malaria transmission intensity. As a result of the increasing prevalence of SP resistance markers, IPTp-SP was withdrawn from Rwanda in 2008. Nonetheless, more recent findings suggest that SP may improve birthweight even in the face of parasite resistance, through alternative mechanisms that are independent of antimalarial effects. The prevalence of single nucleotide polymorphisms in Plasmodium falciparum dihydropteroate synthase (pfdhps) and dihydrofolate reductase (pfdhfr) genes associated with SP resistance among 148 pregnant women from 2016 to 2018 within Rwanda's Southern Province (Huye and Kamonyi districts) was measured using a ligase detection reaction-fluorescent microsphere assay. The frequency of pfdhps K540E, A581G, and the quintuple (pfdhfr N51I + C59R + S108N/pfdhps A437G + K540E) and sextuple (pfdhfr N51I + C59R + S108N/pfdhps A437G + K540E + A581G) mutant genotypes was 90%, 38%, 75%, and 28%, respectively. No significant genotype difference was seen between the two districts, which are approximately 50 km apart. Observed agreements for matched peripheral to placental blood were reported and found to be 207 of 208 (99%) for pfdhfr and 239 of 260 (92%) for pfdhps. The peripheral blood sample did not miss any pfdhfr drug-resistant mutants or pfdhps except at the S436 loci. At this level of the sextuple mutant, the antimalarial efficacy of SP for preventing low birthweight is reduced, although overall SP still exerts a nonmalarial benefit during pregnancy. This study further reveals the need to intensify preventive measures to sustain malaria control in Rwanda to keep the overall incidence of malaria during pregnancy low.

Effectiveness of Intermittent Screening and Treatment of Malaria in Pregnancy on Maternal and Birth Outcomes in Selected Districts in Rwanda: A Cluster Randomized Controlled Trial.

BACKGROUND: Malaria during pregnancy can cause serious consequences including maternal anemia and low birthweight (LBW). Routine antenatal care (ANC) in Rwanda includes malaria symptom screening at each ANC visit. This cluster randomized controlled trial investigated whether adding intermittent screening with a malaria rapid diagnostic test at each routine ANC visit and treatment of positives during pregnancy (ISTp) is more effective than routine ANC for reducing malaria prevalence at delivery. METHODS: Between September 2016 and June 2018, pregnant women initiating ANC at 14 health centers in Rwanda were enrolled into ISTp or control arms. All women received an insecticide-treated bed net at enrollment. Hemoglobin concentration, placental and peripheral parasitemia, newborn outcome, birthweight, and prematurity were assessed at delivery. RESULTS: Nine hundred seventy-five women were enrolled in ISTp and 811 in the control group. Routine ANC plus ISTp did not significantly reduce polymerase chain reaction-confirmed placental malaria compared to control (adjusted relative risk [aRR], 0.94 [95% confidence interval {CI}, .59-1.50]; P = .799). ISTp had no impact on anemia (aRR, 1.08 [95% CI, .57-2.04]; P = .821). The mean birthweight of singleton newborns was not significantly different between arms (3054 g vs 3096 g, P = .395); however, women in the ISTp arm had a higher proportion of LBW (aRR, 1.59 [95% CI, 1.02-2.49]; P = .042). CONCLUSIONS: This is the only study to compare ISTp to symptomatic screening at ANC in a setting where intermittent preventive treatment is not routinely provided. ISTp did not reduce the prevalence of malaria or anemia at delivery and was associated with an increased risk of LBW. CLINICAL TRIALS REGISTRATION: NCT03508349.

The impact of Covid-19 on malaria services in three high endemic districts in Rwanda: a mixed-method study.

BACKGROUND: Rwanda has achieved impressive reductions in malaria morbidity and mortality over the past two decades. However, the disruption of essential services due to the current Covid-19 pandemic can lead to a reversal of these gains in malaria control unless targeted, evidence-based interventions are implemented to mitigate the impact of the pandemic. The extent to which malaria services have been disrupted has not been fully characterized. This study was conducted to assess the impact of Covid-19 on malaria services in Rwanda. METHODS: A mixed-methods study was conducted in three purposively selected districts in Rwanda. The quantitative data included malaria aggregated data reported at the health facility level and the community level. The data included the number of malaria tests, uncomplicated malaria cases, severe malaria cases, and malaria deaths. The qualitative data were collected using focus group discussions with community members and community health workers, as well as in-depth interviews with health care providers and staff working in the malaria programme. Interrupted time series analysis was conducted to compare changes in malaria presentations between the pre-Covid-19 period (January 2019 to February 2020) and Covid-19 period (from March 2020 to November 2020). The constant comparative method was used in qualitative thematic analysis. RESULTS: Compared to the pre-Covid-19 period, there was a monthly reduction in patients tested in health facilities of 4.32 per 1000 population and a monthly increase in patients tested in the community of 2.38 per 1000 population during the Covid-19 period. There was no change in the overall presentation rate for uncomplicated malaria. The was a monthly reduction in the proportion of severe malaria of 5.47 per 100,000 malaria cases. Additionally, although healthcare providers continued to provide malaria services, they were fearful that this would expose them and their families to Covid-19. Covid-19 mitigation measures limited the availability of transportation options for the community to seek care in health facilities and delayed the implementation of some key malaria interventions. The focus on Covid-19-related communication also reduced the amount of health information for other diseases provided to community members. CONCLUSION: The Covid-19 pandemic resulted in patients increasingly seeking care in the community and poses challenges to maintaining delivery of malaria services in Rwanda. Interventions to mitigate these challenges should focus on strengthening programming for the community and home-based care models and integrating malaria messages into Covid-19-related communication. Additionally, implementation of the interrupted interventions should be timed and overlap with the malaria transmission season to mitigate Covid-19 consequences on malaria.

Design and methods for a quasi-experimental pilot study to evaluate the impact of dual active ingredient insecticide-treated nets on malaria burden in five regions in sub-Saharan Africa.

BACKGROUND: Vector control tools have contributed significantly to a reduction in malaria burden since 2000, primarily through insecticidal-treated bed nets (ITNs) and indoor residual spraying. In the face of increasing insecticide resistance in key malaria vector species, global progress in malaria control has stalled. Innovative tools, such as dual active ingredient (dual-AI) ITNs that are effective at killing insecticide-resistant mosquitoes have recently been introduced. However, large-scale uptake has been slow for several reasons, including higher costs and limited evidence on their incremental effectiveness and cost-effectiveness. The present report describes the design of several observational studies aimed to determine the effectiveness and cost-effectiveness of dual-AI ITNs, compared to standard pyrethroid-only ITNs, at reducing malaria transmission across a variety of transmission settings. METHODS: Observational pilot studies are ongoing in Burkina Faso, Mozambique, Nigeria, and Rwanda, leveraging dual-AI ITN rollouts nested within the 2019 and 2020 mass distribution campaigns in each country. Enhanced surveillance occurring in select study districts include annual cross-sectional surveys during peak transmission seasons, monthly entomological surveillance, passive case detection using routine health facility surveillance systems, and studies on human behaviour and ITN use patterns. Data will compare changes in malaria transmission and disease burden in districts receiving dual-AI ITNs to similar districts receiving standard pyrethroid-only ITNs over three years. The costs of net distribution will be calculated using the provider perspective including financial and economic costs, and a cost-effectiveness analysis will assess incremental cost-effectiveness ratios for Interceptor® G2, Royal Guard®, and piperonyl butoxide ITNs in comparison to standard pyrethroid-only ITNs, based on incidence rate ratios calculated from routine data. CONCLUSIONS: Evidence of the effectiveness and cost-effectiveness of the dual-AI ITNs from these pilot studies will complement evidence from two contemporary cluster randomized control trials, one in Benin and one in Tanzania, to provide key information to malaria control programmes, policymakers, and donors to help guide decision-making and planning for local malaria control and elimination strategies. Understanding the breadth of contexts where these dual-AI ITNs are most effective and collecting robust information on factors influencing comparative effectiveness could improve uptake and availability and help maximize their impact.

Association of Plasmodium falciparum kelch13 R561H genotypes with delayed parasite clearance in Rwanda: an open-label, single-arm, multicentre, therapeutic efficacy study.

BACKGROUND: Partial artemisinin resistance is suspected if delayed parasite clearance (ie, persistence of parasitaemia on day 3 after treatment initiation) is observed. Validated markers of artemisinin partial resistance in southeast Asia, Plasmodium falciparum kelch13 (Pfkelch13) R561H and P574L, have been reported in Rwanda but no association with parasite clearance has been observed. We aimed to establish the efficacy of artemether-lumefantrine and genetic characterisation of Pfkelch13 alleles and their association with treatment outcomes. METHODS: This open-label, single-arm, multicentre, therapeutic efficacy study was done in 2018 in three Rwandan sites: Masaka, Rukara, and Bugarama. Children aged 6-59 months with P falciparum monoinfection and fever were eligible and treated with a 3-day course of artemether-lumefantrine. Treatment response was monitored for 28 days using weekly microscopy screenings of blood samples for P falciparum. Mutations in Pfkelch13 and P falciparum multidrug resistance-1 (Pfmdr1) genes were characterised in parasites collected from enrolled participants. Analysis of flanking microsatellites surrounding Pfkelch13 was done to define the origins of the R561H mutations. The primary endpoint was PCR-corrected parasitological cure on day 28, as per WHO protocol. FINDINGS: 228 participants were enrolled and 224 (98·2%) reached the study endpoint. PCR-corrected efficacies were 97·0% (95% CI 88-100) in Masaka, 93·8% (85-98) in Rukara, and 97·2% (91-100) in Bugarama. Pfkelch13 R561H mutations were present in 28 (13%) of 218 pre-treatment samples and P574L mutations were present in two (1%) pre-treatment samples. 217 (90%) of the 240 Pfmdr1 haplotypes observed in the pretreatment samples, had either the NFD (N86Y, Y184F, D1246Y) or NYD haplotype. Eight (16%) of 51 participants in Masaka and 12 (15%) of 82 participants in Rukara were microscopically positive 3 days after treatment initiation, which was associated with pre-treatment presence of Pfkelch13 R561H in Masaka (p=0·0005). Genetic analysis of Pfkelch13 R561H mutations suggest their common ancestry and local origin in Rwanda. INTERPRETATION: We confirm evidence of emerging artemisinin partial resistance in Rwanda. Although artemether-lumefantrine remains efficacious, vigilance for decreasing efficacy, further characterisation of artemisinin partial resistance, and evaluation of additional antimalarials in Rwanda should be considered. FUNDING: The US President's Malaria Initiative. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Emergence and clonal expansion of in vitro artemisinin-resistant Plasmodium falciparum kelch13 R561H mutant parasites in Rwanda.

Artemisinin resistance (delayed P. falciparum clearance following artemisinin-based combination therapy), is widespread across Southeast Asia but to date has not been reported in Africa1-4. Here we genotyped the P. falciparum K13 (Pfkelch13) propeller domain, mutations in which can mediate artemisinin resistance5,6, in pretreatment samples collected from recent dihydroarteminisin-piperaquine and artemether-lumefantrine efficacy trials in Rwanda7. While cure rates were >95% in both treatment arms, the Pfkelch13 R561H mutation was identified in 19 of 257 (7.4%) patients at Masaka. Phylogenetic analysis revealed the expansion of an indigenous R561H lineage. Gene editing confirmed that this mutation can drive artemisinin resistance in vitro. This study provides evidence for the de novo emergence of Pfkelch13-mediated artemisinin resistance in Rwanda, potentially compromising the continued success of antimalarial chemotherapy in Africa.

Nationwide Remapping of Schistosoma mansoni Infection in Rwanda Using Circulating Cathodic Antigen Rapid Test: Taking Steps toward Elimination.

The field standard for the detection of Schistosoma mansoni infection is Kato-Katz (KK), although it misses many active infections, especially light infections. In 2014, a reassessment of S. mansoni prevalence was conducted in Rwanda using the more sensitive point-of-care circulating cathodic antigen (POC-CCA) rapid assay. A total of 19,371 children from 399 schools were selected for testing for single urine CCA. Of these, 8,697 children from 175 schools were also tested with single stool double-slide KK. Samples from eight of these 175 schools were tested again with CCA and additionally with the highly specific and sensitive up-converting phosphor-lateral flow circulating anodic antigen (UCP-LF CAA) assay. Latent class analysis was applied to all four test results to assess sensitivity and specificity of POC-CCA and estimate the proportion of trace results from Rwanda likely to be true infections. The overall prevalence of S. mansoni infection in Rwanda when CCA trace results were considered negative was 7.4% (school interquartile range [IQR] 0-8%) and 36.1% (school IQR 20-47%) when trace was considered positive. Prevalence by KK was 2.0% with a mean intensity of infection of 1.66 eggs per gram. The proportion of active infections among children diagnosed with CCA trace was estimated by statistical analysis at 61% (Bayesian credibility interval: 50-72%). These results indicate that S. mansoni infection is still widespread in Rwanda and prevalence is much underestimated by KK testing. Circulating cathodic antigen is an affordable alternative to KK and more suitable for measuring S. mansoni prevalence in low-intensity regions.

Safety and Efficacy of Limited Laboratory Monitoring for Hepatitis C Treatment: A Blinded Clinical Trial in Rwanda.

Direct-acting antivirals for hepatitis C virus (HCV) are highly effective and well-tolerated. However, only a small percentage of HCV-infected individuals globally have received therapy. Reducing the complexity of monitoring during HCV therapy, if shown to be safe, could facilitate greater access to HCV services, particularly in resource-limited settings such as sub-Saharan Africa. We enrolled a total of 300 patients who were chronically infected with genotype 4 HCV in Rwanda and treated them with fixed-dose ledispasvir/sofosbuvir for 12 weeks. For 60 consecutive participants enrolled, we blinded the study clinician to on-treatment laboratory results. We compared the efficacy, safety, and tolerability in those with blinded laboratory results to those with standard laboratory monitoring. Baseline characteristics among those with blinded laboratory values were comparable to those with standard monitoring. Among both groups, the median age was 63 years, and the median HCV viral load was 5.9 log (versus 64 years and 6.0 log, respectively). Sustained virologic response rates at 12 weeks after treatment completion were similar in those with blinded laboratories (87%) compared to those with standard laboratory monitoring (87%). There was no increase in adverse events in those with blinded laboratory results, and no participants discontinued the study medication because of an adverse event. Conclusion: On-treatment laboratory monitoring did not improve patient outcomes in those treated with ledispasvir/sofosbuvir. Eliminating this monitoring in treatment programs in resource-limited settings may facilitate and accelerate scale-up of HCV therapy.

Parasite associations predict infection risk: incorporating co-infections in predictive models for neglected tropical diseases.

BACKGROUND: Schistosomiasis and infection by soil-transmitted helminths are some of the world's most prevalent neglected tropical diseases. Infection by more than one parasite (co-infection) is common and can contribute to clinical morbidity in children. Geostatistical analyses of parasite infection data are key for developing mass drug administration strategies, yet most methods ignore co-infections when estimating risk. Infection status for multiple parasites can act as a useful proxy for data-poor individual-level or environmental risk factors while avoiding regression dilution bias. Conditional random fields (CRF) is a multivariate graphical network method that opens new doors in parasite risk mapping by (i) predicting co-infections with high accuracy; (ii) isolating associations among parasites; and (iii) quantifying how these associations change across landscapes. METHODS: We built a spatial CRF to estimate infection risks for Ascaris lumbricoides, Trichuris trichiura, hookworms (Ancylostoma duodenale and Necator americanus) and Schistosoma mansoni using data from a national survey of Rwandan schoolchildren. We used an ensemble learning approach to generate spatial predictions by simulating from the CRF's posterior distribution with a multivariate boosted regression tree that captured non-linear relationships between predictors and covariance in infection risks. This CRF ensemble was compared against single parasite gradient boosted machines to assess each model's performance and prediction uncertainty. RESULTS: Parasite co-infections were common, with 19.57% of children infected with at least two parasites. The CRF ensemble achieved higher predictive power than single-parasite models by improving estimates of co-infection prevalence at the individual level and classifying schools into World Health Organization treatment categories with greater accuracy. The CRF uncovered important environmental and demographic predictors of parasite infection probabilities. Yet even after capturing demographic and environmental risk factors, the presences or absences of other parasites were strong predictors of individual-level infection risk. Spatial predictions delineated high-risk regions in need of anthelminthic treatment interventions, including areas with higher than expected co-infection prevalence. CONCLUSIONS: Monitoring studies routinely screen for multiple parasites, yet statistical models generally ignore this multivariate data when assessing risk factors and designing treatment guidelines. Multivariate approaches can be instrumental in the global effort to reduce and eventually eliminate neglected helminth infections in developing countries.

Mapping Schistosoma mansoni endemicity in Rwanda: a critical assessment of geographical disparities arising from circulating cathodic antigen versus Kato-Katz diagnostics.

BACKGROUND: Schistosomiasis is a neglected tropical disease caused by Schistosoma parasites. Intervention relies on identifying high-risk regions, yet rapid Schistosoma diagnostics (Kato-Katz stool assays (KK) and circulating cathodic antigen urine assays (CCA)) yield different prevalence estimates. We mapped S. mansoni prevalence and delineated at-risk regions using a survey of schoolchildren in Rwanda, where S. mansoni is an endemic parasite. We asked if different diagnostics resulted in disparities in projected infection risk. METHODS: Infection data was obtained from a 2014 Rwandan school-based survey that used KK and CCA diagnostics. Across 386 schools screened by CCA (N = 19,217). To allow for uncertainty when interpreting ambiguous CCA trace readings, which accounted for 28.8% of total test results, we generated two presence-absence datasets: CCA trace as positive and CCA trace as negative. Samples (N = 9,175) from 185 schools were also screened by KK. We included land surface temperature (LST) and the Normalized Difference Vegetation and Normalized Difference Water Indices (NDVI, NDWI) as predictors in geostatistical regressions. FINDINGS: Across 8,647 children tested by both methods, prevalence was 35.93% for CCA trace as positive, 7.21% for CCA trace as negative and 1.95% for KK. LST was identified as a risk factor using KK, whereas NDVI was a risk factor for CCA models. Models predicted high endemicity in Northern and Western regions of Rwanda, though the CCA trace as positive model identified additional high-risk areas that were overlooked by the other methods. Estimates of current burden for children at highest risk (boys aged 5-9 years) varied by an order of magnitude, with 671,856 boys projected to be infected by CCA trace as positive and only 60,453 projected by CCA trace as negative results. CONCLUSIONS: Our findings show that people in Rwanda's Northern, Western and capital regions are at high risk of S. mansoni infection. However, variation in identification of environmental risk factors and delineation of at-risk regions using different diagnostics likely provides confusing messages to disease intervention managers. Further research and statistical analyses, such as latent class analysis, can be used to improve CCA result classification and assess its use in guiding treatment regimes.

Mapping Soil-Transmitted Helminth Parasite Infection in Rwanda: Estimating Endemicity and Identifying At-Risk Populations.

Soil-transmitted helminth (STH) infections are globally distributed intestinal parasite infections caused by Ascaris lumbricoides, Trichuris trichiura, and hookworms (Ancylostoma duodenale and Necator americanus). STH infection constitutes a major public health threat, with heavy burdens observed in many of the world's tropical and subtropical regions. Mass drug administration and sanitation improvements can drastically reduce STH prevalence and associated morbidity. However, identifying targeted areas in need of treatment is hampered by a lack of knowledge on geographical and population-level risk factors. In this study, we applied Bayesian geostatistical modelling to data from a national school-based STH infection survey in Rwanda to (1) identify ecological and population-level risk factors and (2) provide comprehensive precision maps of infection burdens. Our results indicated that STH infections were heterogeneously distributed across the country and showed signatures of spatial clustering, though the magnitude of clustering varied among parasites. The highest rates of endemic clustering were attributed to A. lumbricoides infection. Concordant infection patterns among the three parasite groups highlighted populations currently most at-risk of morbidity. Population-dense areas in the Western and North-Western regions of Rwanda represent areas that have continued to exhibit high STH burden across two surveys and are likely in need of targeted interventions. Our maps support the need for an updated evaluation of STH endemicity in western Rwanda to evaluate progress in MDA efforts and identify communities that need further local interventions to further reduce morbidity caused by STH infections.

Efficacy of artemether-lumefantrine versus dihydroartemisinin-piperaquine for the treatment of uncomplicated malaria among children in Rwanda: an open-label, randomized controlled trial.

BACKGROUND: Artemisinin-based combination therapies (ACTs) have proven highly effective in reducing malaria morbidity in sub-Saharan Africa. Artemether-lumefantrine (AL) was introduced in 2005 as a first-line ACT for the treatment of uncomplicated malaria in Rwanda. Monitoring the therapeutic efficacy of ACTs is necessary to ensure effective malaria case management. METHODS: A comparative study on the efficacy of AL and dihydroartemisinin-piperaquine (DHP) was conducted in two sites, Masaka and Ruhuha, between September 2013 and December 2015. Clinical and parasitological responses were assessed at days 28 and 42. RESULTS: A total of 534 children were treated with AL (n=267) or DHP (n=267). After polymerase chain reaction (PCR) adjustment, 98.3% and 98.9% of children in the AL and DHP arms, respectively, achieved an adequate clinical and parasitological response (ACPR) at day 28. At day 42, PCR-adjusted ACPR proportions were 97.3% and 98.4% for AL and DHP, respectively. PCR-adjusted ACPR was 99% for both drugs at days 28 and 42 in Ruhuha. The PCR-adjusted ACPR proportions in Masaka were 97.3% for AL and 98.5% for DHP at day 28 and 95.2% for AL and 97.5% for DHP at day 42. CONCLUSIONS: AL remains efficacious in Rwanda 10 y after its adoption. The probability of new infections occurring among patients in the DHP arm was significantly lower than those in the AL arm. DHP also demonstrated a greater post-treatment prophylactic effect against new infections compared with AL.

Geographical distribution and prevalence of podoconiosis in Rwanda: a cross-sectional country-wide survey.

BACKGROUND: Podoconiosis is a type of tropical lymphoedema that causes massive swelling of the lower limbs. The disease is associated with both economic insecurity, due to long-term morbidity-related loss of productivity, and intense social stigma. Reliable and detailed data on the prevalence and distribution of podoconiosis are scarce. We aimed to fill this data gap by doing a nationwide community-based study to estimate the number of cases throughout Rwanda. METHODS: We did a population-based cross-sectional survey to determine the national prevalence of podoconiosis. A podoconiosis case was defined as a person with bilateral, asymmetrical lymphoedema of the lower limb present for more than 1 year, who tested negative for Wuchereria bancrofti antigen (determined by Filariasis Test Strip) and specific IgG4 (determined by Wb123 test), and had a history of any of the associated clinical signs and symptoms. All adults (aged ≥15 years) who resided in any of the 30 districts of Rwanda for 10 or more years were invited at the household level to participate. Participants were interviewed and given a physical examination before Filariasis Test Strip and Wb123 testing. We fitted a binomial mixed model combining the site-level podoconiosis prevalence with continuous environmental covariates to estimate prevalence at unsampled locations. We report estimates of cases by district combining our mean predicted prevalence and a contemporary gridded map of estimated population density. FINDINGS: Between June 12, and July 28, 2017, 1 360 612 individuals-719 730 (53%) women and 640 882 (47%) men-were screened from 80 clusters in 30 districts across Rwanda. 1143 individuals with lymphoedema were identified, of whom 914 (80%) had confirmed podoconiosis, based on the standardised diagnostic algorithm. The overall prevalence of podoconiosis was 68·5 per 100 000 people (95% CI 41·0-109·7). Podoconiosis was found to be widespread in Rwanda. District-level prevalence ranged from 28·3 per 100 000 people (16·8-45·5, Nyarugenge, Kigali province) to 119·2 per 100 000 people (59·9-216·2, Nyamasheke, West province). Prevalence was highest in districts in the North and West provinces: Nyamasheke, Rusizi, Musanze, Nyabihu, Nyaruguru, Burera, and Rubavu. We estimate that 6429 (95% CI 3938-10 088) people live with podoconiosis across Rwanda. INTERPRETATION: Despite relatively low prevalence, podoconiosis is widely distributed geographically throughout Rwanda. Many patients are likely to be undiagnosed and morbidity management is scarce. Targeted interventions through a well coordinated health system response are needed to manage those affected. Our findings should inform national level planning, monitoring, and implementation of interventions. FUNDING: Wellcome Trust.

Treatment of chronic hepatitis C virus infection in Rwanda with ledipasvir-sofosbuvir (SHARED): a single-arm trial.

BACKGROUND: Limited treatment data are available for hepatitis C virus (HCV) in sub-Saharan Africa, especially for genotype 4. Our objective was to establish the safety and efficacy of ledipasvir-sofosbuvir for chronic HCV genotype 1 or 4 infection in adults in Rwanda. METHODS: We did a single-arm trial to evaluate the safety and efficacy of ledipasvir-sofosbuvir in Rwandan adults with chronic HCV infection at a single study site (Rwanda Military Hospital, Kigali, Rwanda). We enrolled individuals aged 18 years or older with HCV genotype 1 or 4 infection and a plasma HCV RNA concentration of more than 1000 IU/mL at screening. All participants were given ledipasvir (90 mg) and sofosbuvir (400 mg) in a single combination tablet once daily for 12 weeks. We established HCV genotype using an Abbott platform, and HCV subtype with PCR amplification. The primary endpoint was the proportion of participants with a sustained virological response 12 weeks after therapy (SVR12). All patients enrolled in the study were included in the primary endpoint analyses. This study is registered with ClinicalTrials.gov, number NCT02964091. FINDINGS: 300 participants were enrolled between Feb 6, 2017, and Sept 18, 2017, and the follow-up period was completed on March 1, 2018. On genotyping, 248 (83%) participants were reported as having genotype 4, four (1%) genotype 1, and 48 (16%) both genotype 1 and genotype 4. Subsequent viral sequencing showed all participants actually had genotype 4 infection with subtype 4k (134 [45%]), subtype 4r (48 [16%]), subtype 4q (42 [14%]), and subtype 4v (24 [8%]) predominating. Overall, 261 (87%, 95% CI 83-91) participants achieved SVR12. In participants with genotype 4r, SVR12 was observed in 27 (56%, 95% CI 41-71) participants versus 234 (93%, 90-96) individuals with other subtypes. There were no drug-related treatment discontinuations due to ledipasvir-sofosbuvir. The most common adverse events were hypertension (97 [32%]), headache (78 [26%]), dizziness (61 [20%]), and fatigue (56 [19%]). There were six serious adverse events; none were assessed to be due to the study drug. 296 participants had data for pill counts at week 4 and 8; 271 (92%) had 100% adherence and only one (<1%) had an adherence of less than 90%. INTERPRETATION: This is the first large-scale prospective study reporting direct-acting antiviral outcomes in sub-Saharan Africa. The high adherence and treatment success without intensive support measures or highly specialised clinical providers, and lack of treatment discontinuations due to adverse events support the feasibility of HCV treatment decentralisation and scale-up in sub-Saharan Africa. Genotype 4r is uniquely expressed in this region and associated with high rates of treatment failure, suggesting a need for rigorous test-of-cure in clinical practice and consideration of the use of newer pangenotypic direct-acting antiviral regimens in this region. FUNDING: Gilead Sciences.

Expanding home-based management of malaria to all age groups in Rwanda: analysis of acceptability and facility-level time-series data.

Background: In response to a resurgence of malaria in Rwanda, home-based management (HBM) was expanded to enable community-health workers (CHWs) to provide malaria treatment to patients of all ages. We assessed the effect of the expanded HBM program on malaria case presentations at health facilities. Methods: Services provided by CHWs and health facility presentations among individuals >5 y of age were considered. Presentations to CHWs were analyzed descriptively to assess acceptability and segmented regression modeling using facility-level data was employed to compare changes between the pre- and postintervention periods for intervention and control districts. Results: Individuals >5 y of age readily accessed malaria diagnosis and treatment services from CHWs. Severe and uncomplicated malaria increased in the postintervention period for both the intervention and control districts. Presentations for uncomplicated malaria increased in the intervention and control districts to a similar degree. Severe cases increased to a greater degree in the intervention districts immediately after HBM was expanded compared with controls, but the monthly rate of increase was lower in the intervention districts. Conclusions: Services were shifted to CHWs, as demonstrated by the number of individuals treated through the expanded program. The rate of severe malaria increased immediately after implementation within intervention districts relative to controls, potentially because of enhanced case-finding. The rate of increase in severe cases was lower in the intervention districts comparatively, likely due to expedited treatment.