RESUMEN
BACKGROUND: Community acceptance is an important criterion to assess in community trials, particularly for new tools that require high coverage and use by a target population. Installed on exterior walls of household structures, the attractive targeted sugar bait (ATSB) is a new vector control tool designed to attract and kill mosquitoes. ATSBs were evaluated in Western Zambia during a two-year cluster randomized controlled trial to assess the efficacy of ATSBs in reducing malaria transmission. Community acceptance of ATSBs was critical for successful trial implementation. METHODS: A community engagement strategy outlined activities and key messages to promote acceptance. Annual cross-sectional surveys, conducted during the peak transmission period, assessed households for presence of ATSBs as well as perceived benefits, concerns, and willingness to use ATSBs. Sixteen focus group discussions and 16 in-depth interviews, conducted at the end of each ATSB station deployment period, obtained a range of perceptions and household experiences with ATSB stations, as well as ITN use in the context of ATSB deployment. RESULTS: Methods used during the study to promote acceptance and continued use of ATSBs were effective in achieving greater than 90% coverage, a high (greater than 70%) level of perceived benefits, and fewer than 10% of households reporting safety concerns. Common facilitators of acceptance included the desire for protection against malaria and reduction of mosquitoes, trust in health initiatives, and understanding of the product. Common barriers to acceptance included misconceptions of product impact on mosquitoes, continued cases of malaria, association with satanism, and damage to household structures. DISCUSSION: Future use of the ATSB intervention will likely require activities that foster community acceptance before, during, and after the intervention is introduced. Additional research may be needed to understand the impact of different levels of community engagement on ATSB station coverage, ATSB station perception, and ITN use. CONCLUSION: There was high acceptance of ATSB stations during the trial in Western Zambia. Continuous and intense community engagement efforts contributed to sustained ATSB coverage and trust in the product. Acceptance of ATSBs during programmatic delivery requires further research.
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Malaria , Control de Mosquitos , Zambia , Control de Mosquitos/métodos , Humanos , Malaria/prevención & control , Estudios Transversales , Femenino , Masculino , Adulto , Animales , Persona de Mediana Edad , Azúcares/administración & dosificación , Adulto Joven , Insecticidas , AdolescenteRESUMEN
BACKGROUND: Attractive Targeted Sugar Baits (ATSBs) offer a complementary vector control strategy to interventions targeting blood feeding or larval control by attacking the sugar feeding behaviour of adult mosquitoes using an attract-and-kill approach. Western Zambia was the first location to receive and deploy ATSB Sarabi version 1.2 stations in a Phase III cluster randomized controlled trial. This paper describes ATSB station installation, monitoring, removal, and disposal, quantifies ATSB station coverage, and reports major reasons for ATSB station replacement. METHODS: ATSB stations were deployed during two annual transmission seasons, through scheduled installation and removal campaigns. During deployment, monitoring was conducted per protocol to maintain high coverage of the ATSB stations in good condition. Routine monitoring visits during the trial captured details on ATSB station damage necessitating replacement following pre-defined replacement criteria. Annual cross-sectional household surveys measured ATSB station coverage during peak malaria transmission. RESULTS: A total of 67,945 ATSB stations were installed in Year 1 (41,695 initially installed+ 26,250 installed during monitoring) and 69,494 ATSB stations were installed in Year 2 (41,982 initially installed+ 27,512 installed during monitoring) across 35 intervention clusters to maintain high coverage of two ATSB stations in good condition per eligible household structure. The primary reasons for ATSB station replacement due to damage were holes/tears and presence of mold. Cross-sectional household surveys documented high coverage of ATSB stations across Year 1 and Year 2 with 93.1% of eligible structures having ≥ 2 ATSB stations in any condition. DISCUSSION: ATSB station deployment and monitoring efforts were conducted in the context of a controlled cRCT to assess potential product efficacy. Damage to ATSB stations during deployment required replacement of a subset of stations. High coverage of eligible structures was maintained over the two-year study despite replacement requirements. Additional research is needed to better understand the impact of damage on ATSB station effectiveness under programmatic conditions, including thresholds of threats to physical integrity and biological deterioration on product efficacy. CONCLUSIONS: Optimizing ATSB stations to address causes of damage and conducting implementation research to inform optimal delivery and cost-effective deployment will be important to facilitate scale-up of ATSB interventions.
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Control de Mosquitos , Zambia , Control de Mosquitos/métodos , Humanos , Animales , Femenino , Malaria/prevención & control , Azúcares , Estudios Transversales , Mosquitos Vectores/fisiología , Anopheles/fisiología , MasculinoRESUMEN
BACKGROUND: The attractive targeted sugar bait (ATSB) is a novel malaria vector control tool designed to attract and kill mosquitoes using a sugar-based bait, laced with oral toxicant. Western Province, Zambia, was one of three countries selected for a series of phase III cluster randomized controlled trials of the Westham ATSB Sarabi version 1.2. The trial sites in Kenya, Mali, and Zambia were selected to represent a range of different ecologies and malaria transmission settings across sub-Saharan Africa. This case study describes the key characteristics of the ATSB Zambia trial site to allow for interpretation of the results relative to the Kenya and Mali sites. METHODS: This study site characterization incorporates data from the trial baseline epidemiological and mosquito sugar feeding surveys conducted in 2021, as well as relevant literature on the study area. RESULTS: CHARACTERIZATION OF THE TRIAL SITE: The trial site in Zambia was comprised of 70 trial-designed clusters in Kaoma, Nkeyema, and Luampa districts. Population settlements in the trial site were dispersed across a large geographic area with sparsely populated villages. The overall population density in the 70 study clusters was 65.7 people per square kilometre with a total site population of 122,023 people living in a geographic area that covered 1858 square kilometres. However, the study clusters were distributed over a total area of approximately 11,728 square kilometres. The region was tropical with intense and seasonal malaria transmission. An abundance of trees and other plants in the trial site were potential sources of sugar meals for malaria vectors. Fourteen Anopheles species were endemic in the site and Anopheles funestus was the dominant vector, likely accounting for around 95% of all Plasmodium falciparum malaria infections. Despite high coverage of indoor residual spraying and insecticide-treated nets, the baseline malaria prevalence during the peak malaria transmission season was 50% among people ages six months and older. CONCLUSION: Malaria transmission remains high in Western Province, Zambia, despite coverage with vector control tools. New strategies are needed to address the drivers of malaria transmission in this region and other malaria-endemic areas in sub-Saharan Africa.
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Anopheles , Malaria , Control de Mosquitos , Mosquitos Vectores , Azúcares , Zambia , Control de Mosquitos/métodos , Control de Mosquitos/estadística & datos numéricos , Mosquitos Vectores/efectos de los fármacos , Animales , Anopheles/efectos de los fármacos , Anopheles/fisiología , Humanos , Malaria/prevención & control , Malaria/transmisión , Femenino , Insecticidas/farmacologíaRESUMEN
BACKGROUND: Attractive targeted sugar bait (ATSB) stations are a novel tool with potential to complement current approaches to malaria vector control. To assess the public health value of ATSB station deployment in areas of high coverage with standard vector control, a two-arm cluster-randomized controlled trial (cRCT) of Sarabi ATSB® stations (Westham Ltd., Hod-Hasharon, Israel) was conducted in Western Province, Zambia, a high-burden location were Anopheles funestus is the dominant vector. The trial included 70 clusters and was designed to measure the effect of ATSBs on case incidence and infection prevalence over two 7-month deployments. Reported here are results of the vector surveillance component of the study, conducted in a subset of 20 clusters and designed to provide entomological context to guide overall interpretation of trial findings. METHODS: Each month, 200 paired indoor-outdoor human landing catch (HLC) and 200 paired light trap (LT) collections were conducted to monitor An. funestus parity, abundance, biting rates, sporozoite prevalence, and entomological inoculation rates (EIR). RESULTS: During the study 20,337 female An. funestus were collected, 11,229 from control and 9,108 from intervention clusters. A subset of 3,131 HLC specimens were assessed for parity: The mean non-parous proportion was 23.0% (95% CI 18.2-28.7%, total n = 1477) in the control and 21.2% (95% CI 18.8-23.9%, total n = 1654) in the intervention arm, an OR = 1.05 (95% CI 0.82-1.34; p = 0.688). A non-significant reduction in LT abundance (RR = 0.65 [95% CI 0.30-1.40, p = 0.267]) was associated with ATSB deployment. HLC rates were highly variable, but model results indicate a similar non-significant trend with a RR = 0.68 (95%CI 0.22-2.00; p = 0.479). There were no effects on sporozoite prevalence or EIR. CONCLUSIONS: Anopheles funestus parity did not differ across study arms, but ATSB deployment was associated with a non-significant 35% reduction in vector LT density, results that are consistent with the epidemiological impact reported elsewhere. Additional research is needed to better understand how to maximize the potential impact of ATSB approaches in Zambia and other contexts. TRIAL REGISTRATION NUMBER: This trial was registered with Clinicaltrials.gov (NCT04800055, 16 March 2021).
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Anopheles , Control de Mosquitos , Mosquitos Vectores , Zambia , Anopheles/fisiología , Animales , Mosquitos Vectores/fisiología , Control de Mosquitos/métodos , Femenino , Humanos , Azúcares , Malaria/prevención & controlRESUMEN
BACKGROUND: Malaria is endemic throughout Mozambique, contributing significantly to the country's burden of disease. Prompt and effective treatment for fevers in children can limit the mortality and morbidity impacts of the disease but many children in the country are not taken for formal care when ill. Using an ideational model of behaviour, this study assesses the magnitude of the relationships for potential drivers of care-seeking, including interpersonal communication, malaria messaging, and knowledge and attitudes about malaria, with actual care-seeking behaviours for under-five children with fever in Magoé district, Mozambique. METHODS: Data on the care-seeking behaviours for fever come from a 2019 household malaria survey in Magoé district. Households were randomly selected for interview from among those with at least one child under age five and one net for every two household members. From 1621 mother-child dyads, the analytical sample consists of 300 children under age five with a fever in the 2 weeks prior to the survey. Multilevel random effects logistic regression models are estimated to test for associations between care-seeking behaviours and hypothesized behavioural determinants, including interpersonal communication (IPC), malaria messaging, ideational factors (e.g., norms, attitudes, beliefs, risk perceptions), and community characteristics. RESULTS: Overall, 18.5% of children under age five (N = 300) were reported to have fever in the previous 2 weeks and, of these, 68.5% were taken to a formal sector health care provider. Multivariate models highlight significant roles for interpersonal communication; care-seeking was highest among mothers who spoke only with friends/community members about malaria (94.0%, p < 0.001), followed by those who spoke only with their husband (78.6%, p = 0.015), relative to 63.3% who spoke with no one. Care-seeking decisions made by a child's grandmother were associated with a 25.0% point (p = 0.001) greater likelihood of seeking care relative to decisions made by the mother alone. Exposure to any malaria messaging was also positively associated with care-seeking (90.5% versus 62.7%, p < 0.001). In contrast, among all individual- and community-level ideational factors, only perceptions of self-efficacy to seek care were related to care-seeking behaviours. CONCLUSIONS: These results suggest that social and behaviour change interventions that focus on encouraging families and community members to talk about malaria and the need to promptly seek treatment for fevers in children may be particularly effective at increasing this behaviour in this and similar settings. Such messaging and IPC should consider grandmothers as a target audience, as they appear to be perceived as highly influential in care-seeking decision-making in this community.
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Comunicación , Fiebre , Humanos , Lactante , Mozambique/epidemiología , Fiebre/terapia , Personal de Salud , ConocimientoRESUMEN
BACKGROUND: Community case management of malaria (CCM) has been expanded in many settings, but there are limited data describing the impact of these services in routine implementation settings or at large scale. Zambia has intensively expanded CCM since 2013, whereby trained volunteer community health workers (CHW) use rapid diagnostic tests and artemether-lumefantrine to diagnose and treat uncomplicated malaria. METHODS: This retrospective, observational study explored associations between changing malaria service point (health facility or CHW) density per 1000 people and severe malaria admissions or malaria inpatient deaths by district and month in a dose-response approach, using existing routine and programmatic data. Negative binomial generalized linear mixed-effect models were used to assess the impact of increasing one additional malaria service point per 1000 population, and of achieving Zambia's interim target of 1 service point per 750 population. Access to insecticide-treated nets, indoor-residual spraying, and rainfall anomaly were included in models to reduce potential confounding. RESULTS: The study captured 310,855 malaria admissions and 7158 inpatient malaria deaths over 83 districts (seven provinces) from January 2015 to May 2020. Total CHWs increased from 43 to 4503 during the study period, while health facilities increased from 1263 to 1765. After accounting for covariates, an increase of one malaria service point per 1000 was associated with a 19% reduction in severe malaria admissions among children under five (incidence rate ratio [IRR] 0.81, 95% confidence interval [CI] 0.75-0.87, p < 0.001) and 23% reduction in malaria deaths among under-fives (IRR 0.77, 95% CI 0.66-0.91). After categorizing the exposure of population per malaria service point, there was evidence for an effect on malaria admissions and inpatient malaria deaths among children under five only when reaching the target of one malaria service point per 750 population. CONCLUSIONS: CCM is an effective strategy for preventing severe malaria and deaths in areas such as Zambia where malaria diagnosis and treatment access remains challenging. These results support the continued investment in CCM scale-up in similar settings, to improve access to malaria diagnosis and treatment.
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Antimaláricos , Sistemas de Información en Salud , Malaria , Niño , Humanos , Antimaláricos/uso terapéutico , Zambia/epidemiología , Manejo de Caso , Estudios Retrospectivos , Pacientes Internos , Arteméter/uso terapéutico , Combinación Arteméter y Lumefantrina/uso terapéutico , Malaria/tratamiento farmacológico , Malaria/prevención & control , Malaria/epidemiología , Agentes Comunitarios de SaludRESUMEN
BACKGROUND: In 2020, the Zambia National Malaria Elimination Centre targeted the distribution of long-lasting insecticidal nets (LLINs) and indoor-residual spraying (IRS) campaigns based on sub-district micro-planning, where specified geographical areas at the health facility catchment level were assigned to receive either LLINs or IRS. Using data from the 2021 Malaria Indicator Survey (MIS), the objectives of this analysis were to (1) assess how well the micro-planning was followed in distributing LLINs and IRS, (2) investigate factors that contributed to whether households received what was planned, and (3) investigate how overall coverage observed in the 2021 MIS compared to the 2018 MIS conducted prior to micro-planning. METHODS: Households' receipt of ≥ 1 LLIN, and/or IRS within the past 12 months in the 2021 MIS, was compared against the micro-planning area under which the households fell. GPS points for 3,550 households were overlayed onto digitized micro-planning maps in order to determine what micro-plan the households fell under, and thus whether they received their planned intervention. Mixed-effects regression models were conducted to investigate what factors affected whether these households: (1) received their planned intervention, and (2) received any intervention. Finally, coverage indicators between the 2021 and 2018 MIS were compared. RESULTS: Overall, 60.0% (95%CI 55.4, 64.4) of households under a micro-plan received their assigned intervention, with significantly higher coverage of the planned intervention in LLIN-assigned areas (75.7% [95%CI 69.5, 80.9]) compared to IRS-assigned areas (49.4% [95%CI: 44.4, 54.4]). Regression analysis indicated that households falling under the IRS micro-plan had significantly reduced odds of receiving their planned intervention (OR: 0.34 [95%CI 0.24, 0.48]), and significantly reduced odds of receiving any intervention (OR: 0.51 [95%CI 0.37, 0.72] ), compared to households under the LLIN micro-plan. Comparison between the 2021 and 2018 MIS indicated a 27% reduction in LLIN coverage nationally in 2021, while IRS coverage was similar. Additionally, between 2018 and 2021, there was a 13% increase in households that received neither intervention. CONCLUSIONS: This analysis shows that although the micro-planning strategy adopted in 2020 worked much better for LLIN-assigned areas compared to IRS-assigned areas, there was reduced overall vector control coverage in 2021 compared to 2018 before micro-planning.
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Mosquiteros Tratados con Insecticida , Insecticidas , Malaria , Humanos , Control de Mosquitos , Zambia/epidemiología , Malaria/prevención & controlRESUMEN
BACKGROUND: In 2016, the Zambian National Malaria Elimination Centre started programmatic mass drug administration (pMDA) campaigns with dihydroartemisinin-piperaquine as a malaria elimination tool in Southern Province. Two rounds were administered, 2 months apart (coverage 70% and 57%, respectively). We evaluated the impact of 1 year of pMDA on malaria incidence using routine data. METHODS: We conducted an interrupted time series with comparison group analysis on monthly incidence data collected at the health facility catchment area (HFCA) level, with a negative binomial model using generalized estimating equations. Programmatic mass drug administration was conducted in HFCAs with greater than 50 cases/1000 people per year. Ten HFCAs with incidence rates marginally above this threshold (pMDA group) were compared with 20 HFCAs marginally below (comparison group). RESULTS: The pMDA HFCAs saw a 46% greater decrease in incidence at the time of intervention than the comparison areas (incidence rate ratio = 0.536; confidence interval = 0.337-0.852); however, incidence increased toward the end of the season. No HFCAs saw a transmission interruption. CONCLUSIONS: Programmatic mass drug administration, implemented during 1 year with imperfect coverage in low transmission areas with suboptimal vector control coverage, significantly reduced incidence. However, elimination will require additional tools. Routine data are important resources for programmatic impact evaluations and should be considered for future analyses.
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Antimaláricos , Malaria , Antimaláricos/uso terapéutico , Humanos , Incidencia , Malaria/tratamiento farmacológico , Malaria/epidemiología , Malaria/prevención & control , Administración Masiva de Medicamentos , Zambia/epidemiologíaRESUMEN
BACKGROUND: Haiti is planning targeted interventions to accelerate progress toward malaria elimination. In the most affected department (Grande-Anse), a combined mass drug administration (MDA) and indoor residual spraying (IRS) campaign was launched in October 2018. This study assessed the intervention's effectiveness in reducing Plasmodium falciparum prevalence. METHODS: An ecological quasi-experimental study was designed, using a pretest and posttest with a nonrandomized control group. Surveys were conducted in November 2017 in a panel of easy access groups (25 schools and 16 clinics) and were repeated 2-6 weeks after the campaign, in November 2018. Single-dose sulfadoxine-pyrimethamine and primaquine was used for MDA, and pirimiphos-methyl as insecticide for IRS. RESULTS: A total of 10 006 participants were recruited. Fifty-two percent of the population in the intervention area reported having received MDA. Prevalence diminished between 2017 and 2018 in both areas, but the reduction was significantly larger in the intervention area (ratio of adjusted risk ratios, 0.32 [95% confidence interval, .104-.998]). CONCLUSIONS: Despite a moderate coverage, the campaign was effective in reducing P. falciparum prevalence immediately after 1 round. Targeted MDA plus IRS is useful in preelimination settings to rapidly decrease the parasite reservoir, an encouraging step to accelerate progress toward malaria elimination.
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Insecticidas , Malaria , Haití/epidemiología , Humanos , Insecticidas/farmacología , Malaria/tratamiento farmacológico , Malaria/epidemiología , Malaria/prevención & control , Administración Masiva de Medicamentos , Control de MosquitosRESUMEN
BACKGROUND: Insecticide treated bed nets (ITN) are considered a core malaria vector control tool by the WHO and are the main contributor to the large decline in malaria burden in sub-Saharan Africa over the past 20 years, but they are less effective if they are not broadly and regularly used. ITN use may depend on factors including temperature, relative humidity, mosquito density, seasonality, as well as ideational or psychosocial factors including perceptions of nets and perceptions of net use behaviours. METHODS: A cross-sectional household survey was conducted as part of a planned randomized controlled trial in Magoe District, Mozambique. Interviewers captured data on general malaria and ITN perceptions including ideational factors related to perceived ITN response efficacy, self-efficacy to use an ITN, and community norms around ITN using a standardized questionnaire. Only households with sufficient ITNs present for all children to sleep under (at least one ITN for every two children under the age of five years) were eligible for inclusion in the study. Additional questions were added about seasonality and frequency of ITN use. RESULTS: One-thousand six hundred sixteen mother-child dyads were interviewed. Responses indicated gaps in use of existing nets and net use was largely independent of ideational factors related to ITNs. Self-reported ITN use varied little by season nor meaningfully when different methods were used to solicit responses on net use behaviour. Mothers' perceived response efficacy of ITNS was negatively associated with net use (high perceived response efficacy reduced the log-odds of net use by 0.27 (95% CI - 0.04 to - 0.51), implying that stronger beliefs in the effectiveness of ITNs might result in reduced net use among their children. CONCLUSIONS: In this context, ITN use among children was not clearly related to mothers' ideational factors measured in the study. Scales used in solicitation of ideation around ITN use and beliefs need careful design and testing across a broader range of populations in order to identify ideational factors related to ITN use among those with access.
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Anopheles , Mosquiteros Tratados con Insecticida , Insecticidas , Malaria , Femenino , Animales , Humanos , Preescolar , Malaria/prevención & control , Estudios Transversales , Mozambique , Mosquitos Vectores , Control de Mosquitos/métodosRESUMEN
BACKGROUND: Widespread insecticide resistance to pyrethroids could thwart progress towards elimination. Recently, the World Health Organization has encouraged the use of non-pyrethroid insecticides to reduce the spread of insecticide resistance. An electronic tool for implementing and tracking coverage of IRS campaigns has recently been tested (mSpray), using satellite imagery to improve the accuracy and efficiency of the enumeration process. The purpose of this paper is to retrospectively analyse cross-sectional observational data to provide evidence of the epidemiological effectiveness of having introduced Actellic 300CS and the mSpray platform into IRS programmes across Zambia. METHODS: Health facility catchment areas in 40 high burden districts in 5 selected provinces were initially targeted for spraying. The mSpray platform was used in 7 districts in Luapula Province. An observational study design was used to assess the relationship between IRS exposure and confirmed malaria case incidence. A random effects Poisson model was used to quantify the effect of IRS (with and without use of the mSpray platform) on confirmed malaria case incidence over the period 2013-2017; analysis was restricted to the 4 provinces where IRS was conducted in each year 2014-2016. RESULTS: IRS was conducted in 283 health facility catchment areas from 2014 to 2016; 198 health facilities from the same provinces, that received no IRS during this period, served as a comparison. IRS appears to be associated with reduced confirmed malaria incidence; the incidence rate ratio (IRR) was lower in areas with IRS but without mSpray, compared to areas with no IRS (IRR = 0.91, 95% CI 0.84-0.98). Receiving IRS with mSpray significantly lowered confirmed case incidence (IRR = 0.75, 95% CI 0.66-0.86) compared to no IRS. IRS with mSpray resulted in lower incidence compared to IRS without mSpray (IRR = 0.83, 95% CI 0.72-0.95). CONCLUSIONS: IRS using Actellic-CS appears to substantially reduce malaria incidence in Zambia. The use of the mSpray tool appears to improve the effectiveness of the IRS programme, possibly through improved population level coverage. The results of this study lend credence to the anecdotal evidence of the effectiveness of 3GIRS using Actellic, and the importance of exploring new platforms for improving effective population coverage of areas targeted for spraying.
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Insecticidas/administración & dosificación , Malaria/transmisión , Control de Mosquitos/estadística & datos numéricos , Compuestos Organotiofosforados/administración & dosificación , Estudios Transversales , Incidencia , Malaria/epidemiología , Estudios Retrospectivos , Zambia/epidemiologíaRESUMEN
Accurate malaria diagnosis is foundational for control and elimination, and Haiti relies on histidine-rich protein 2 (HRP2)-based rapid diagnostic tests (RDTs) identifying Plasmodium falciparum in clinical and community settings. In 2017, 1 household and 2 easy-access group surveys tested all participants (N = 32 506) by conventional and high-sensitivity RDTs. A subset of blood samples (n = 1154) was laboratory tested for HRP2 by bead-based immunoassay and for P. falciparum 18S rDNA by photo-induced electron transfer polymerase chain reaction. Both RDT types detected low concentrations of HRP2 with sensitivity estimates between 2.6 ng/mL and 14.6 ng/mL. Compared to the predicate HRP2 laboratory assay, RDT sensitivity ranged from 86.3% to 96.0% between tests and settings, and specificity from 90.0% to 99.6%. In the household survey, the high-sensitivity RDT provided a significantly higher number of positive tests, but this represented a very small proportion (<0.2%) of all participants. These data show that a high-sensitivity RDT may have limited utility in a malaria elimination setting like Haiti.
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Pruebas Diagnósticas de Rutina/métodos , Malaria Falciparum/diagnóstico , Malaria Falciparum/transmisión , Plasmodium falciparum/genética , Plasmodium falciparum/inmunología , Adolescente , Antígenos de Protozoos/sangre , Antígenos de Protozoos/inmunología , Niño , Preescolar , ADN Protozoario/sangre , ADN Protozoario/genética , ADN Ribosómico/sangre , ADN Ribosómico/genética , Ensayo de Inmunoadsorción Enzimática/métodos , Femenino , Haití/epidemiología , Humanos , Lactante , Malaria Falciparum/epidemiología , Malaria Falciparum/parasitología , Masculino , Reacción en Cadena de la Polimerasa/métodos , Proteínas Protozoarias/sangre , Proteínas Protozoarias/inmunología , Sensibilidad y EspecificidadRESUMEN
Haiti is striving for zero local malaria transmission by the year 2025. Chloroquine remains the first-line treatment, and sulfadoxine/pyrimethamine (SP) has been used for mass drug-administration pilot programs. In March 2016, nationwide molecular surveillance was initiated to assess molecular resistance signatures for chloroquine and SP. For 778 samples collected through December 2017, we used Sanger sequencing to investigate putative resistance markers to chloroquine (Pfcrt codons 72, 74, 75, and 76), sulfadoxine (Pfdhps codons 436, 437, 540, 581, 613), and pyrimethamine (Pfdhfr codons 50, 51, 59, 108, 164). No parasites harbored Pfcrt point mutations. Prevalence of the Pfdhfr S108N single mutation was 47%, and we found the triple mutant Pfdhfr haplotype (108N, 51I, and 59R) in a single isolate. We observed no Pfdhps variants except in 1 isolate (A437G mutation). These data confirm the lack of highly resistant chloroquine and SP alleles in Haiti and support the continued use of chloroquine and SP.
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Antimaláricos , Malaria Falciparum , Alelos , Antimaláricos/farmacología , Antimaláricos/uso terapéutico , Cloroquina/farmacología , Cloroquina/uso terapéutico , Resistencia a Medicamentos/genética , Haití/epidemiología , Humanos , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/epidemiología , Mutación , Plasmodium falciparum/genética , Pirimetamina/farmacología , Pirimetamina/uso terapéutico , Sulfadoxina/farmacología , Sulfadoxina/uso terapéuticoRESUMEN
BACKGROUND: As in most eliminating countries, malaria transmission is highly focal in Haiti. More granular information, including identifying asymptomatic infections, is needed to inform programmatic efforts, monitor intervention effectiveness, and identify remaining foci. Easy access group (EAG) surveys can supplement routine surveillance with more granular information on malaria in a programmatically tractable way. This study assessed how and which type of venue for EAG surveys can improve understanding malaria epidemiology in two regions with different transmission profiles. METHODS: EAG surveys were conducted within the departments of Artibonite and Grand'Anse (Haiti), in regions with different levels of transmission intensity. Surveys were conducted in three venue types: primary schools, health facilities, and churches. The sampling approach varied accordingly. Individuals present at the venues at the time of the survey were eligible whether they presented malaria symptoms or not. The participants completed a questionnaire and were tested for Plasmodium falciparum by a highly sensitive rapid diagnostic test (hsRDT). Factors associated with hsRDT positivity were assessed by negative binomial random-effects regression models. RESULTS: Overall, 11,029 individuals were sampled across 39 venues in Artibonite and 41 in Grand'Anse. The targeted sample size per venue type (2100 in Artibonite and 2500 in Grand'Anse) was reached except for the churches in Artibonite, where some attendees left the venue before they could be approached or enrolled. Refusal rate and drop-out rate were < 1%. In total, 50/6003 (0.8%) and 355/5026 (7.1%) sampled individuals were hsRDT positive in Artibonite and Grand'Anse, respectively. Over half of all infections in both regions were identified at health facilities. Being male and having a current or reported fever in the previous 2 weeks were consistently identified with increased odds of being hsRDT positive. CONCLUSIONS: Surveys in churches were problematic because of logistical and recruitment issues. However, EAG surveys in health facilities and primary schools provided granular information about malaria burden within two departments in Haiti. The EAG surveys were able to identify residual foci of transmission that were missed by recent national surveys. Non-care seeking and/or asymptomatic malaria infections can be identified in this alternative surveillance tool, facilitating data-driven decision-making for improved targeting of interventions.
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Brotes de Enfermedades/estadística & datos numéricos , Monitoreo Epidemiológico , Malaria Falciparum/epidemiología , Plasmodium falciparum/patogenicidad , Adolescente , Adulto , Niño , Femenino , Haití/epidemiología , Humanos , Masculino , Adulto JovenRESUMEN
BACKGROUND: Prompt and effective malaria diagnosis and treatment is a cornerstone of malaria control. Case management guidelines recommend confirmatory testing of suspected malaria cases, then prescription of specific drugs for uncomplicated malaria and for severe malaria. This study aims to describe case management practices for children aged 1-59 months seeking treatment with current or recent fever from public and private, rural and urban health providers in Mali. METHODS: Data were collected at sites in Sikasso Region and Bamako. Health workers recorded key information from the consultation including malaria diagnostic testing and result, their final diagnosis, and all drugs prescribed. Children with signs of severe diseases were ineligible. Consultations were not independently observed. Appropriate case management was defined as both 1) tested for malaria using rapid diagnostic test or microscopy, and 2) receiving artemisinin combination therapy (ACT) and no other antimalarials if test-positive, or receiving no antimalarials if test-negative. RESULTS: Of 1602 participating children, 23.7% were appropriately managed, ranging from 5.3% at public rural facilities to 48.4% at community health worker sites. The most common reason for 'inappropriate' management was lack of malaria diagnostic testing (50.4% of children). Among children with confirmed malaria, 50.8% received a non-ACT antimalarial (commonly artesunate injection or artemether), either alone or in combination with ACT. Of 215 test-negative children, 44.2% received an antimalarial drug, most commonly ACT. Prescription of multiple drugs was common: 21.7% of all children received more than one type of antimalarial, while 51.9% received an antibiotic and antimalarial. Inappropriate case management increased in children with increasing axillary temperatures and those seeking care over weekends. CONCLUSIONS: Multiple limitations in management of febrile children under five were identified, including inconsistent use of confirmatory testing and apparent use of severe malaria drugs for uncomplicated malaria. While we cannot confirm the reasons for these shortcomings, there is a need to address the high use of non-ACT antimalarials in this context; to minimize potential for drug resistance, reduce unnecessary expense, and preserve life-saving treatment for severe malaria cases. These findings highlight the challenge of managing febrile illness in young children in a high transmission setting.
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Antimaláricos , Artemisininas , Malaria , Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , Preescolar , Humanos , Lactante , Recién Nacido , Malaria/diagnóstico , Malaria/tratamiento farmacológico , Malaria/epidemiología , Malí/epidemiología , Sector PrivadoRESUMEN
The Global Technical Strategy 2016-2030 of the World Health Organization (WHO) has the ambitious goal of malaria being eliminated from at least 35 countries by 2030. However, in areas with once-stable malaria transmission, the reservoir of human infection may be intermittently symptomatic or fully silent yet still lead to transmission, posing a serious challenge to elimination. Mass drug administration (MDA), defined as the provision of a therapeutic dose of an effective anti-malarial drug to the entire target population, irrespective of infection status or symptoms, is one strategy to combat the silent human reservoir of infection. MDA is currently recommended by the WHO as a potential strategy for the elimination of Plasmodium falciparum malaria in areas approaching interruption of transmission, given the prerequisites of good access to case management, effective vector control and surveillance, and limited potential for reintroduction. Recent community randomized controlled trials of MDA with dihydroartemisinin-piperaquine, implemented as part of a comprehensive package of interventions, have shown this strategy to be safe and effective in significantly lowering the malaria burden in pre-elimination settings. Here it is argued that effectively implemented MDA should be kept in the elimination toolbox as a potential strategy for P. falciparum elimination in a variety of settings, including islands, appropriate low transmission settings, and in epidemics and complex emergencies. Effectively implemented MDA using an ACT has been shown to be safe, unrelated to the emergence of drug resistance, and may play an important role in sufficiently lowering the malaria burden to allow malaria transmission foci to be more easily identified, and to allow elimination programmes to more feasibly implement case-based surveillance and follow-up activities. To be most impactful and guard against drug resistance, MDA should use an ACT, achieve high programmatic coverage and adherence, be implemented when transmission is lowest in areas of limited risk of immediate parasite reintroduction, and must always be implemented only once good access to case management, high coverage of effective vector control, and strong surveillance have been achieved. If these considerations are taken into account, MDA should prove to be a valuable tool for the malaria elimination toolbox.
Asunto(s)
Antimaláricos/uso terapéutico , Erradicación de la Enfermedad/métodos , Malaria/prevención & control , Administración Masiva de Medicamentos/métodos , Erradicación de la Enfermedad/estadística & datos numéricos , Combinación de Medicamentos , Resistencia a Medicamentos , Humanos , Administración Masiva de Medicamentos/ética , Administración Masiva de Medicamentos/estadística & datos numéricosRESUMEN
BACKGROUND: Reactive case detection (RCD) is an integral part of many malaria control and elimination programmes and can be conceived of as a way of gradually decreasing transmission. However, it is unclear under what circumstances RCD may have a substantial impact on prevalence, how likely it is to lead to local elimination, or how effective it needs to be to prevent reintroduction after transmission has been interrupted. METHODS: Analyses and simulations of a discrete time compartmental susceptible-infectious-susceptible (SIS) model were used to understand the mechanisms of how RCD changes transmission dynamics and estimate the impact of RCD programmes in a range of settings with varying patterns of transmission potential and programme characteristics. Prevalence survey data from recent studies in Zambia were used to capture the effects of spatial clustering of patent infections. RESULTS: RCD proved most effective at low prevalence. Increasing the number of index cases followed was more important than increasing the number of neighbours tested per index case. Elimination was achieved only in simulations of situations with very low transmission intensity and following many index cases. However, RCD appears to be helpful in maintaining the disease-free state after achieving malaria elimination (through other interventions). CONCLUSION: RCD alone can eliminate malaria in only a very limited range of settings, where transmission potential is very low, and improving the coverage of RCD has little effect on this range. In other settings, it is likely to reduce disease burden. RCD may also help maintain the disease-free state in the face of imported infections. Prevalence survey data can be used to estimate a targeting ratio (the ratio of prevalence found through RCD to that in the general population) which is an important determinant of the effect of RCD.
Asunto(s)
Control de Enfermedades Transmisibles/métodos , Erradicación de la Enfermedad/métodos , Malaria/prevención & control , Humanos , Malaria/epidemiología , Modelos Teóricos , Prevalencia , Análisis Espacial , Zambia/epidemiologíaRESUMEN
BACKGROUND: Zambia continues to make strides in reducing malaria burden through the use of proven malaria interventions and has recently pledged to eliminate malaria by 2021. Case management services have been scaled up at community level with rapid diagnostic tests (RDTs) providing antigen-based detection of falciparum malaria only. Key to national malaria elimination goals is the ability to identify, treat and eliminate all Plasmodium species. This study sought to determine the distribution of non-falciparum malaria and assess the performance of diagnostic tests for Plasmodium falciparum in Western and Southern Provinces of Zambia, two provinces planned for early malaria elimination. METHODS: A sub-set of individuals' data and samples from a cross-sectional household survey, conducted during peak malaria transmission season in April and May 2017, was used. The survey collected socio-demographic information on household members and coverage of malaria interventions. Malaria testing was done on respondents of all ages using blood smears and RDTs while dried blood spots were collected on filter papers for analysis using photo-induced electron transfer polymerase chain reaction (PET-PCR). Slides were stained using Giemsa stain and examined by microscopy for malaria parasites. RESULTS: From the 1567 individuals included, the overall prevalence of malaria was 19.4% (CI 17.5-21.4) by PCR, 19.3% (CI 17.4-21.4) by RDT and 12.9% (CI 11.3-14.7) by microscopy. Using PET-PCR as the gold standard, RDTs showed a sensitivity of 75.7% (CI 70.4-80.4) and specificity of 94.2% (CI 92.8-95.4). The positive predictive value (PPV) was 75.9% (CI 70.7-80.6) and negative predictive value (NPV) was 94.1% (CI 92.1-95.4). In contrast, microscopy for sensitivity, specificity, PPV, and NPV values were 56.9% (CI 51.1-62.5), 97.7% (CI 96.7-98.5), 85.6% (CI 80.0-90.2), 90.4% (CI 88.7-91.9), respectively. Non-falciparum infections were found only in Western Province, where 11.6% of P. falciparum infections were co-infections with Plasmodium ovale or Plasmodium malariae. CONCLUSION: From the sub-set of survey data analysed, non-falciparum species are present and occurred as mixed infections. As expected, PET-PCR was slightly more sensitive than both malaria RDTs and microscopy to detecting malaria infections.
Asunto(s)
Pruebas Diagnósticas de Rutina/métodos , Malaria Falciparum/epidemiología , Plasmodium falciparum/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Lactante , Recién Nacido , Malaria Falciparum/diagnóstico , Malaria Falciparum/parasitología , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Adulto Joven , Zambia/epidemiologíaRESUMEN
BACKGROUND: Nationally-representative household surveys are the standard approach to monitor access to and treatment with artemisinin-based combination therapy (ACT) among children under 5 years (U5), however these indicators are dependent on caregivers' recall of the treatment received. METHODS: A prospective case-control study was performed in Mali to validate caregivers' recall of treatment received by U5s when seeking care for fever from rural and urban public health facilities, community health workers and urban private facilities. Clinician-recorded consultation details were the gold standard. Consenting caregivers were followed-up for interview at home within 2 weeks using standard questions from Demographic and Health Surveys and Malaria Indicator Surveys. RESULTS: Among 1602 caregivers, sensitivity of recalling that the child received a finger/heel prick was 91.5%, with specificity 85.7%. Caregivers' recall of a positive malaria test result had sensitivity 96.2% with specificity 59.7%. Irrespective of diagnostic test result, the sensitivity and specificity of caregivers' recalling a malaria diagnosis made by the health worker were 74.3% and 74.9%, respectively. Caregivers' recall of ACT being given had sensitivity of 43.2% and specificity 90.2%, while recall that any anti-malarial was given had sensitivity 59.0% and specificity 82.7%. Correcting caregivers' response of treatment received using a combination of a visual aid with photographs of common drugs for fever, prescription documents and retained packaging changed ACT recall sensitivity and specificity to 91.5% and 71.1%, respectively. CONCLUSIONS: These findings indicate that caregivers' responses during household surveys are valid when assessing if a child received a finger/heel prick during a consultation in the previous 2 weeks, and if the malaria test result was positive. Recall of ACT treatment received by U5s was poor when based on interview response only, but was substantially improved when incorporating visual aids, prescriptions and drug packaging review.