Malaria Elimination Strategies Research Articles

Lower Microscopy Sensitivity with Decreasing Malaria Prevalence in the Urban Amazon Region, Brazil, 2018-2021.

Malaria is increasingly diagnosed in urban centers across the Amazon Basin. In this study, we combined repeated prevalence surveys over a 4-year period of a household-based random sample of 2,774 persons with parasite genotyping to investigate the epidemiology of malaria in Mâncio Lima, the main urban transmission hotspot in Amazonian Brazil. We found that most malarial infections were asymptomatic and undetected by point-of-care microscopy. Our findings indicate that as malaria transmission decreases, the detection threshold of microscopy rises, resulting in more missed infections despite similar parasite densities estimated by molecular methods. We identified genetically highly diverse populations of Plasmodium vivax and P. falciparum in the region; occasional shared lineages between urban and rural residents suggest cross-boundary propagation. The prevalence of low-density and asymptomatic infections poses a significant challenge for routine surveillance and the effectiveness of malaria control and elimination strategies in urbanized areas with readily accessible laboratory facilities.

While the priest climbs a post, the devil climbs ten: major biological threats from parasite and vector to malaria control and elimination

Malaria is one of the most serious mosquito-borne infectious diseases in the world. The global malaria control progress has stalled in recent years, which is largely due to the biological threats from the malaria pathogen Plasmodium and the vector Anopheles mosquitoes. This article provides an overview of biological threats to global malaria elimination, including antimalarial drug resistance, deletions in the malaria rapid diagnostic test target P. falciparum histidine-rich protein 2/3 (Pfhrp2/3) genes, vector insecticide resistance and emergence of invasive vector species, so as to provide insights into malaria and vector research and the formulation and adjustment of the malaria control and elimination strategy.

Identification of a novel protein localized to the crystalloid of the Plasmodium ookinete

Reducing Plasmodium parasite transmission via the mosquito vector is a promising strategy for malaria control and elimination in endemic regions. In the mosquito midgut after the ingestion of an infected blood meal, malaria parasite gametes egress from erythrocytes and fertilize to develop into motile ookinetes that traverse midgut epithelial cells and transform into oocysts adjacent the basal lamina. Plasmodium ookinetes and young oocysts possess a unique organelle called the crystalloid; which has a honeycomb-like matrix structure and is indicated to be involved in sporozoite formation and maturation. In this study, we identified a novel crystalloid protein, PY17X_1113800, that is exclusively expressed in developing ookinetes. The protein possesses a signal peptide sequence, but lacks a transmembrane domain or GPI anchor signal sequence, as well as predicted adhesive domains which are characterisitic of many crystalloid proteins. The protein is highly conserved across the phylum Apicomplexa and within the greater clade Alveolata, such as Vitrella and the ciliates Paramecium and Tetrahymena, but is absent in cryptosporidia.

Rapid and non-invasive detection of malaria parasites using near-infrared spectroscopy and machine learning.

Novel and highly sensitive point-of-care malaria diagnostic and surveillance tools that are rapid and affordable are urgently needed to support malaria control and elimination. We demonstrated the potential of near-infrared spectroscopy (NIRS) technique to detect malaria parasites both, in vitro, using dilutions of infected red blood cells obtained from Plasmodium falciparum cultures and in vivo, in mice infected with P. berghei using blood spotted on slides and non-invasively, by simply scanning various body areas (e.g., feet, groin and ears). The spectra were analysed using machine learning to develop predictive models for infection. Using NIRS spectra of in vitro cultures and machine learning algorithms, we successfully detected low densities (<10-7 parasites/μL) of P. falciparum parasites with a sensitivity of 96% (n = 1041), a specificity of 93% (n = 130) and an accuracy of 96% (n = 1171) and differentiated ring, trophozoite and schizont stages with an accuracy of 98% (n = 820). Furthermore, when the feet of mice infected with P. berghei with parasitaemia ≥3% were scanned non-invasively, the sensitivity and specificity of NIRS were 94% (n = 66) and 86% (n = 342), respectively. These data highlights the potential of NIRS technique as rapid, non-invasive and affordable tool for surveillance of malaria cases. Further work to determine the potential of NIRS to detect malaria in symptomatic and asymptomatic malaria cases in the field is recommended including its capacity to guide current malaria elimination strategies.

Progress towards malaria elimination in the Greater Mekong Subregion: perspectives from the World Health Organization

Malaria remains a global health challenge, disproportionately affecting vulnerable communities. Despite substantial progress, the emergence of anti-malarial drug resistance poses a constant threat. The Greater Mekong Subregion (GMS), which includes Cambodia, China’s Yunnan province, Lao People's Democratic Republic, Myanmar, Thailand, and Viet Nam has been the epicentre for the emergence of resistance to successive generations of anti-malarial therapies. From the perspective of the World Health Organization (WHO), this article considers the collaborative efforts in the GMS, to contain Plasmodium falciparum artemisinin partial resistance and multi-drug resistance and to advance malaria elimination. The emergence of artemisinin partial resistance in the GMS necessitated urgent action and regional collaboration resulting in the Strategy for Malaria Elimination in the Greater Mekong Subregion (2015–2030), advocating for accelerated malaria elimination interventions tailored to country needs, co-ordinated and supported by the WHO Mekong malaria elimination programme. The strategy has delivered substantial reductions in malaria across all GMS countries, with a 77% reduction in malaria cases and a 97% reduction in malaria deaths across the GMS between 2012 and 2022. Notably, China was certified malaria-free by WHO in 2021. Countries' ownership and accountability have been pivotal, with each GMS country outlining its priorities in strategic and annual work plans. The development of strong networks for anti-malarial drug resistance surveillance and epidemiological surveillance was essential. Harmonization of policies and guidelines enhanced collaboration, ensuring that activities were driven by evidence. Challenges persist, particularly in Myanmar, where security concerns have limited recent progress, though an intensification and acceleration plan aims to regain momentum. Barriers to implementation can slow progress and continuing innovation is needed. Accessing mobile and migrant populations is key to addressing remaining transmission foci, requiring effective cross-border collaboration. In conclusion, the GMS has made significant progress towards malaria elimination, particularly in the east where several countries are close to P. falciparum elimination. New and persisting challenges require sustained efforts and continued close collaboration. The GMS countries have repeatedly risen to every obstacle presented, and now is the time to re-double efforts and achieve the 2030 goal of malaria elimination for the region.

Time series analysis of malaria cases to assess the impact of various interventions over the last three decades and forecasting malaria in India towards the 2030 elimination goals

BackgroundDespite the progress made in this decade towards malaria elimination, it remains a significant public health concern in India and many other countries in South Asia and Asia Pacific region. Understanding the historical trends of malaria incidence in relation to various commodity and policy interventions and identifying the factors associated with its occurrence can inform future intervention strategies for malaria elimination goals.MethodsThis study analysed historical malaria cases in India from 1990 to 2022 to assess the annual trends and the impact of key anti-malarial interventions on malaria incidence. Factors associated with malaria incidence were identified using univariate and multivariate linear regression analyses. Generalized linear, smoothing, autoregressive integrated moving averages (ARIMA) and Holt’s models were used to forecast malaria cases from 2023 to 2030.ResultsThe reported annual malaria cases in India during 1990–2000 were 2.38 million, which dropped to 0.73 million cases annually during 2011–2022. The overall reduction from 1990 (2,018,783) to 2022 (176,522) was 91%. The key interventions of the Enhanced Malaria Control Project (EMCP), Intensified Malaria Control Project (IMCP), use of bivalent rapid diagnostic tests (RDT-Pf/Pv), artemisinin-based combination therapy (ACT), and involvement of the Accredited Social Health Activists (ASHAs) as front-line workers were found to result in the decline of malaria significantly. The ARIMA and Holt’s models projected a continued decline in cases with the potential for reaching zero indigenous cases by 2027–2028. Important factors influencing malaria incidence included tribal population density, literacy rate, health infrastructure, and forested and hard-to-reach areas.ConclusionsStudies aimed at assessing the impact of major commodity and policy interventions on the incidence of disease and studies of disease forecasting will inform programmes and policymakers of steps needed during the last mile phase to achieve malaria elimination. It is proposed that these time series and disease forecasting studies should be performed periodically using granular (monthly) and meteorological data to validate predictions of prior studies and suggest any changes needed for elimination efforts at national and sub-national levels.

Science of malaria elimination: using knowledge of bottlenecks and enablers from the Malaria Elimination Demonstration Project in Central India for eliminating malaria in the Asia Pacific region.

Malaria poses a major public health challenge in the Asia Pacific. Malaria Elimination Demonstration Project was conducted as a public-private partnership initiative in Mandla between State government, ICMR, and FDEC India. The project employed controls for efficient operational and management decisions. IEC campaigns found crucial in schools and communities. Capacity building of local workers emphasized for better diagnosis and treatment. SOCH mobile app launched for complete digitalization. Better supervision for Indoor Residual Sprays and optimized Long Lasting Insecticidal Nets distribution. Significant malaria cases reduction in Mandla. Insights from MEDP crucial for malaria elimination strategies in other endemic regions of the Asia Pacific.

Expanding the roles of community health workers to sustain programmes during malaria elimination: a meeting report on operational research in Southeast Asia.

In Southeast Asia malaria elimination is targeted by 2030. Cambodia aims to achieve this by 2025, driven in large part by the urgent need to control the spread of artemisinin-resistant falciparum malaria infections. Rapid elimination depends on sustaining early access to diagnosis and effective treatment. In much of Cambodia, rapid elimination will rely on a village malaria worker (VMW) network. Yet as malaria declines and is no longer a common cause of febrile illness, VMWs may become less popular with febrile patients, as VMWs do not diagnose or treat other conditions at present. There is a risk that VMWs become inactive and malaria rebounds before the complete interruption of transmission is achieved.During 2021-23 a large-scale operational research study was conducted in western Cambodia to explore how a VMW network could be sustained by including health activities that cover non-malarial illnesses to encourage febrile patients to continue to attend. 105 VMWs received new rapid diagnostic tests (including dengue antigen-antibody and combined malaria/C-reactive protein tests), were trained in electronic data collection, and attended health education packages on hygiene and sanitation, disease surveillance and first aid, management of mild illness, and vaccination and antenatal care.In August 2023 the National Malaria Control Programme of Cambodia convened a stakeholder meeting in Battambang, Cambodia. Findings from the study were reviewed in the context of current malaria elimination strategies. The discussions informed policy options to sustain the relevance of the VMW network in Cambodia, and the potential for its integration with other health worker networks. This expansion could ensure VMWs remain active and relevant until malaria elimination is accomplished.

Fine-Scale Spatial Prediction on the Risk of Plasmodium vivax Infection in the Republic of Korea.

Malaria elimination strategies in the Republic of Korea (ROK) have decreased malaria incidence but face challenges due to delayed case detection and response. To improve this, machine learning models for predicting malaria, focusing on high-risk areas, have been developed. The study targeted the northern region of ROK, near the demilitarized zone, using a 1-km grid to identify areas for prediction. Grid cells without residential buildings were excluded, leaving 8,425 cells. The prediction was based on whether at least one malaria case was reported in each grid cell per month, using spatial data of patient locations. Four algorithms were used: gradient boosted (GBM), generalized linear (GLM), extreme gradient boosted (XGB), and ensemble models, incorporating environmental, sociodemographic, and meteorological data as predictors. The models were trained with data from May to October (2019-2021) and tested with data from May to October 2022. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). The AUROC of the prediction models performed excellently (GBM = 0.9243, GLM = 0.9060, XGB = 0.9180, and ensemble model = 0.9301). Previous malaria risk, population size, and meteorological factors influenced the model most in GBM and XGB. Machine-learning models with properly preprocessed malaria case data can provide reliable predictions. Additional predictors, such as mosquito density, should be included in future studies to improve the performance of models.

Situational Analysis of Malaria Incidence Under Integrated Malaria Service in Hotspot Township - Minbya Township, Rakhine State, Myanmar, 2017-2020.

Malaria is a significant public health concern and tropical disease, particularly affecting Myanmar within the Greater Mekong Subregion. The annual parasite index (API) exceeds 1 per 10,000 population in the northern seven townships of Rakhine State, with Minbya Township designated as a high-burden area for malaria by the World Health Organization (WHO) Myanmar and the National Malaria Control Programme (NMCP). Since 2017, the Malaria reduction intensification plan has been in place in this township to combat the high disease transmission rates. This study aims to assess the malaria epidemiology in Minbya Township from 2017 to 2020 under the intensification plan for elimination, as well as to evaluate the effectiveness of the integrated strategy in reducing cases in hotspot areas. The study utilized a surveillance study design to collect secondary data from the Malaria surveillance system (MSS) and the epidemiologic monitoring dashboard of Minbya Township, Maruk-U District, located in Rakhine State. Since 2017, the Malaria prevention and control (P&C) Program in Minbya Township has successfully decreased malaria morbidity, eliminated malaria-related deaths, and bolstered malaria testing capabilities through the participation of village health volunteers (VHVs). Approximately 87% of malaria prevention and control services are executed by the township's malaria elimination and disease control programs, with additional support from stakeholders. The API dropped from 13 in 2017 to 2.5 in 2020, with Plasmodium vivax being the most prevalent malaria species, accounting for 55% of cases. The study suggests that early diagnosis and promotion of artemisinin-based combination treatment (ACT), along with strategic planning including expanding active case detection in rural health centers and implementing a community-based integrated healthcare approach, are effective and efficient strategies for malaria elimination.

Prevalence of G6PD deficiency and submicroscopic malaria parasites carriage in malaria hotspot area in Northwest, Tanzania

BackgroundThe use of primaquine for mass drug administration (MDA) is being considered as a key strategy for malaria elimination. In addition to being the only drug active against the dormant and relapsing forms of Plasmodium vivax, primaquine is the sole potent drug against mature/infectious Plasmodium falciparum gametocytes. It may prevent onward transmission and help contain the spread of artemisinin resistance. However, higher dose of primaquine is associated with the risk of acute haemolytic anaemia in individuals with a deficiency in glucose-6-phosphate dehydrogenase. In many P. falciparum endemic areas there is paucity of information about the distribution of individuals at risk of primaquine-induced haemolysis at higher dose 45 mg of primaquine.MethodsA retrospective cross-sectional study was carried out using archived samples to establish the prevalence of G6PD deficiency in a malaria hotspot area in Misungwi district, located in Mwanza region, Tanzania. Blood samples collected from individuals recruited between August and November 2010 were genotyped for G6PD deficiency and submicroscopic parasites carriage using polymerase chain reaction.ResultsA total of 263 individuals aged between 0 and 87 were recruited. The overall prevalence of the X-linked G6PD A− mutation was 83.7% (220/263) wild type, 8% (21/263) heterozygous and 8.4% (22/263) homozygous or hemizygous. Although, assessment of the enzymatic activity to assign the phenotypes according to severity and clinical manifestation as per WHO was not carried out, the overall genotype and allele frequency for the G6PD deficiency was 16.4% and 13. 2%, respectively. There was no statistically significant difference in among the different G6PD genotypes (p > 0.05). Out of 248 samples analysed for submicroscopic parasites carriage, 58.1% (144/248) were P. falciparum positive by PCR. G6PD heterozygous deficiency were associated with carriage of submicroscopic P. falciparum (p = 0.029).ConclusionsThis study showed that 16.4% of the population in this part of North-western Tanzania carry the G6PD A− mutation, within the range of 15–32% seen in other parts of Africa. G6PD gene mutation is widespread and heterogeneous across the study area where primaquine would be valuable for malaria control and elimination. The maps and population estimates presented here reflect potential risk of higher dose of primaquine being associated with the risk of acute haemolytic anaemia (AHA) in individuals with a deficiency in glucose-6-phosphate dehydrogenase and call further research on mapping of G6PD deficiency in Tanzania. Therefore, screening and education programmes for G6PD deficiency is warranted in a programme of malaria elimination using a higher primaquine dose.

A cross-sectional study to ascertain malaria prevalence among asymptomatic travellers arriving on the Lihir Group of Islands, Papua New Guinea: implications for elimination efforts

BackgroundThe Lihir Islands of Papua New Guinea host a mining operation that has resulted in a mine-impacted zone (MIZ) with reduced malaria transmission and a substantial influx of mine employees, informal cross-country traders, returning locals, and visitors. Prevalence of malaria parasites was assessed in travellers arriving on the Lihir Group of Islands to evaluate the risk of parasite importation.MethodsIn 2018, a cross-sectional study at the airport and main wharf was conducted, targeting asymptomatic travellers who had been away from Lihir for at least 12 days. Microscopy, rapid diagnostic tests (RDTs), and quantitative PCR (qPCR) were used to determine Plasmodium parasite prevalence, employing logistic regression models to identify factors associated with qPCR positivity.Results398 travellers arriving by plane and 402 arriving by boat were included. Both cohorts were significantly different. Mean age among travellers arriving by plane was 40.1 years (SD ± 10.1), 93% were male and 96% were employed at the mine. In contrast, among travellers arriving by boat, the mean age was 31.7 years (SD ± 14.0), 68% were male and 36% were employed at the mine. The prevalence of malaria infection among travellers arriving by plane was 1% by RDT and microscopy, and increased to 5% by qPCR. In contrast, those arriving by boat showed a prevalence of 8% by RDT and microscopy, and 17% by qPCR. Risk factors for infection were arriving by boat (OR 4.2; 95%CI 2.45,7.21), arriving from nearby provinces with high malaria incidence (OR 5.02; 95%CI 1.80, 14.01), and having been away from Lihir for 91 days or more (OR 4.15; 95%CI 2.58, 6.66). Being mine worker staying at the mine accommodation was related with less infection risk (OR 0.24; 95% CI 0.14, 0.43); while Lihirian residents returning from a trip, VFRs, or people with trading unrelated to mining had higher risks (p = 0.0066).ConclusionsTravellers arriving by boat faced increased risk of malaria infection than those arriving by plane. This subpopulation poses an import risk to the MIZ and the rest of Lihir Islands. Screening of high-risk groups at wharfs, and collaboration with nearby Islands, could sustain reduced transmission and facilitate malaria elimination strategies.

Malariometric Indices in the Context of Seasonal Malaria Chemoprevention in Children Aged 1.5 to 12 Years during the Period of High Malaria Transmission in the Suburban Area of Banfora, Burkina Faso.

Continuous monitoring of malaria epidemiology is needed in malaria-endemic settings to inform malaria control and elimination strategies. This study aimed to compare the malariometric indices between the under-fives and school-age children. We surveyed children aged 1.5 to 12 years for plasmodia carriage with the aim of including them in a longitudinal follow-up cohort. The survey took place from 7-11 September 2020 in a southwest area of Burkina Faso. Clinical and demographic data including malaria control measures were collected. A finger prick blood sample was taken for haemoglobin testing, and blood smears and dried blood spot preparation. The malariometric indices were calculated and compared between school-age children and those under the age of five. Multiple logistic regression was fitted to assess the association between malaria parasite carriage and age categories. Based on the PCR results, the parasite prevalence was 21.4% in the under-fives versus 44.2% in school-age children (p-value < 0.0001), with a pooled prevalence of 32.7% (CI = [28.8, 36.8]). The gametocyte prevalence was also significantly higher in school-age children (11.9%) compared to the under-fives (3.7%). Adjusted for covariates, school-age children were 2.9 times (IC = [2.0, 4.2]) more likely to carry the asexual parasite, compared to the under-fives. Malaria was moderate and stable endemic in this area and school-age children play a key role in the spread of the disease. The WHO conditional recommendation for intermittent preventive treatment of malaria in school-aged children living in malaria-endemic settings with moderate to high perennial or seasonal transmission should be implemented.

Performance and feasibility of reactive surveillance and response strategies for malaria elimination in Vietnam: a mixed-methods study

BackgroundTo enhance malaria elimination, Vietnam adopted a Reactive Surveillance and Response (RASR) Strategy in which malaria case notification and investigation must be completed within 2 days followed by a focus investigation within 7 days. The nationwide performance of Vietnam’s RASR strategy has yet to be evaluated. This study aims to evaluate the performance and feasibility of RASR in Vietnam, thereby providing recommendations for improved RASR.MethodsTo assess malaria RASR in Vietnam, a mixed-methods study of (1) secondary data analysis of nationwide malaria case-based dataset from 2017 to 2021; (2) a quantitative survey, and (3) qualitative in-depth interviews and focus group discussions administered to central, provincial and district level stakeholders/staff and to the commune and community level front line health services providers was conducted.ResultsIn Vietnam, there are guidelines and procedures for implementation of each step of RASR. The completeness of case notification on the reported monthly aggregated data was very high in both the paper-based (12,463/12,498, 99.7% in 2017–2020) and electronic reporting systems (467/467, 100% in 2021 when electronic reporting was introduced); however, there were delays in notification while using the paper-based system (timely notification—7,978/12,498, 63.8%). In 2021, the completeness (453/467, 97.0%) and timeliness (371/467, 79.4%) of case investigation were found to be high. Reactive case detection was the major focus investigation response, with fever screening achievement of 88.6% (11,481 / 12,965) and 88.5% (11,471 / 12,965) among index case and neighbouring household members, respectively.ConclusionsOverall, there was policy commitment for implementation of RASR in Vietnam. The completeness and timeliness of case notification and case investigation were high and improved after the introduction of the electronic reporting system. More evidence is required for reactive case detection in defining the screening area or population.

Geo-epidemiology of malaria incidence in the Vhembe District to guide targeted elimination strategies, South-Africa, 2015–2018: a local resurgence

In South Africa, the population at risk of malaria is 10% (around six million inhabitants) and concern only three provinces of which Limpopo Province is the most affected, particularly in Vhembe District. As the elimination approaches, a finer scale analysis is needed to accelerate the results. Therefore, in the process of refining local malaria control and elimination strategies, the aim of this study was to identify and describe malaria incidence patterns at the locality scale in the Vhembe District, Limpopo Province, South Africa. The study area comprised 474 localities in Vhembe District for which smoothed malaria incidence curve were fitted with functional data method based on their weekly observed malaria incidence from July 2015 to June 2018. Then, hierarchical clustering algorithm was carried out considering different distances to classify the 474 smoothed malaria incidence curves. Thereafter, validity indices were used to determine the number of malaria incidence patterns. The cumulative malaria incidence of the study area was 4.1 cases/1000 person-years. Four distinct patterns of malaria incidence were identified: high, intermediate, low and very low with varying characteristics. Malaria incidence increased across transmission seasons and patterns. The localities in the two highest incidence patterns were mainly located around farms, and along the rivers. Some unusual malaria phenomena in Vhembe District were also highlighted as resurgence. Four distinct malaria incidence patterns were found in Vhembe District with varying characteristics. Findings show also unusual malaria phenomena in Vhembe District that hinder malaria elimination in South Africa. Assessing the factors associated with these unusual malaria phenome would be helpful on building innovative strategies that lead South Africa on malaria elimination.

Therapeutic efficacy of pyronaridine-artesunate (Pyramax®) against uncomplicated Plasmodium falciparum infection at Hamusit Health Centre, Northwest Ethiopia

BackgroundEarly case detection and prompt treatment are important malaria control and elimination strategies. However, the emergence and rapid spread of drug-resistant strains present a major challenge. This study reports the first therapeutic efficacy profile of pyronaridine-artesunate against uncomplicated Plasmodium falciparum in Northwest Ethiopia.MethodsThis single-arm prospective study with 42-day follow-up period was conducted from March to May 2021 at Hamusit Health Centre using the World Health Organization (WHO) therapeutic efficacy study protocol. A total of 90 adults ages 18 and older with uncomplicated falciparum malaria consented and were enrolled in the study. A standard single-dose regimen of pyronaridine-artesunate was administered daily for 3 days, and clinical and parasitological outcomes were assessed over 42 days of follow-up. Thick and thin blood films were prepared from capillary blood and examined using light microscopy. Haemoglobin was measured and dried blood spots were collected on day 0 and on the day of failure.ResultsOut of 90 patients, 86/90 (95.6%) completed the 42-day follow-up study period. The overall PCR-corrected cure rate (adequate clinical and parasitological response) was very high at 86/87 (98.9%) (95% CI: 92.2–99.8%) with no serious adverse events. The parasite clearance rate was high with fast resolution of clinical symptoms; 86/90 (95.6%) and 100% of the study participants cleared parasitaemia and fever on day 3, respectively.ConclusionPyronaridine-artesunate was highly efficacious and safe against uncomplicated P. falciparum in this study population.

Acceptability, Feasibility, Drug Safety, and Effectiveness of a Pilot Mass Drug Administration with a Single Round of Sulfadoxine-Pyrimethamine Plus Primaquine and Indoor Residual Spraying in Communities with Malaria Transmission in Haiti, 2018.

For a malaria elimination strategy, Haiti's National Malaria Control Program piloted a mass drug administration (MDA) with indoor residual spraying (IRS) in 12 high-transmission areas across five communes after implementing community case management and strengthened surveillance. The MDA distributed sulfadoxine-pyrimethamine and single low-dose primaquine to eligible residents during house visits. The IRS campaign applied pirimiphos-methyl insecticide on walls of eligible houses. Pre- and post-campaign cross-sectional surveys were conducted to assess acceptability, feasibility, drug safety, and effectiveness of the combined interventions. Stated acceptability for MDA before the campaign was 99.2%; MDA coverage estimated at 10 weeks post-campaign was 89.6%. Similarly, stated acceptability of IRS at baseline was 99.9%; however, household IRS coverage was 48.9% because of the high number of ineligible houses. Effectiveness measured by Plasmodium falciparum prevalence at baseline and 10 weeks post-campaign were similar: 1.31% versus 1.43%, respectively. Prevalence of serological markers were similar at 10 weeks post-campaign compared with baseline, and increased at 6 months. No severe adverse events associated with the MDA were identified in the pilot; there were severe adverse events in a separate, subsequent campaign. Both MDA and IRS are acceptable and feasible interventions in Haiti. Although a significant impact of a single round of MDA/IRS on malaria transmission was not found using a standard pre- and post-intervention comparison, it is possible there was blunting of the peak transmission. Seasonal malaria transmission patterns, suboptimal IRS coverage, and low baseline parasitemia may have limited the effectiveness or the ability to measure effectiveness.

Household living conditions and individual behaviours associated with malaria risk: a community-based survey in the Limpopo River Valley, 2020, South Africa

BackgroundOver the past decade, implementation of multiple malaria control strategies in most countries has largely contributed to advance the global malaria elimination agenda. Nevertheless, in some regions, seasonal epidemics may adversely affect the health of local populations. In South Africa, Plasmodium falciparum malaria is still present, with the Vhembe District experiencing an incidence rate of 3.79 cases/1000 person-years in 2018, particularly in the Limpopo River Valley, bordering Zimbabwe. To elucidate the complexity of the mechanisms involved in local regular malaria outbreaks, a community-based survey was implemented in 2020 that focused on the relationship between housing conditions and malaria risky behaviours.MethodsThe community-based cross-sectional survey was conducted among the population of three study sites in the Vhembe District, which were selected based on malaria incidence rate, social and health characteristics of inhabitants. The household survey used a random sampling strategy, where data were collected through face-to-face questionnaires and field notes; to described the housing conditions (housing questionnaire), and focus on individual behaviours of household members. Statistical analyses were performed combining hierarchical classifications and logistic regressions.ResultsIn this study, 398 households were described, covering a population of 1681 inhabitants of all ages, and 439 adults who participated in community-based survey. The analysis of situations at risk of malaria showed that the influence of contextual factors, particularly those defined by the type of habitat, was significant. Housing conditions and poor living environments were factors of malaria exposure and history, regardless of site of investigation, individual preventive behaviours and personal characteristics of inhabitants. Multivariate models showed that, considering all personal characteristics or behaviours of inhabitants, housing conditions such as overcrowding pressures were significantly associated with individual malaria risk.ConclusionsThe results showed the overwhelming weight of social and contextual factors on risk situations. Considering the Fundamental Causes Theory, malaria control policies based on health behaviour prevention, should reinforce access to care or promoting health education actions. Overarching economic development interventions in targeted geographical areas and populations have to be implemented, so that malaria control and elimination strategies can be efficiently and effectively managed.

Projecting malaria elimination in Thailand using Bayesian hierarchical spatiotemporal models

Thailand has set a goal of eliminating malaria by 2024 in its national strategic plan. In this study, we used the Thailand malaria surveillance database to develop hierarchical spatiotemporal models to analyze retrospective patterns and predict Plasmodium falciparum and Plasmodium vivax malaria incidences at the provincial level. We first describe the available data, explain the hierarchical spatiotemporal framework underlying the analysis, and then display the results of fitting various space–time formulations to the malaria data with the different model selection metrics. The Bayesian model selection process assessed the sensitivity of different specifications to obtain the optimal models. To assess whether malaria could be eliminated by 2024 per Thailand’s National Malaria Elimination Strategy, 2017–2026, we used the best-fitted model to project the estimated cases for 2022–2028. The study results based on the models revealed different predicted estimates between both species. The model for P. falciparum suggested that zero P. falciparum cases might be possible by 2024, in contrast to the model for P. vivax, wherein zero P. vivax cases might not be reached. Innovative approaches in the P. vivax-specific control and elimination plans must be implemented to reach zero P. vivax and consequently declare Thailand as a malaria-free country.

Current Status and Challenges of Malaria in Zambia

Malaria is a mosquito-borne infection caused by the Plasmodium parasite, which infects a person carrying the parasite through mosquito bites or blood transfusions. It is the world's leading parasitic disease. There are four species of Plasmodium in the human body, Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. More than 100 countries and regions are reported to be affected by malaria to varying degrees. Malaria has a high incidence in Zambia, which seriously endangers people's life and health, and increases the social and economic burden of the affected communities to a certain extent. In addition, the number of malaria deaths remains high, the number of malaria cases has even risen, and the eradication of malaria has stagnated. Therefore, timely and accurate diagnosis is of great significance to effectively prevent malaria, control its spread, and give patients early treatment. This article describes the current progress and challenges of malaria elimination in Zambia, and Outlines current malaria elimination strategies and key interventions.