RESUMEN
Merozoites utilize sialic acids on the red blood cell (RBC) cell surface to rapidly adhere to and invade the RBCs. Newcastle disease virus (NDV) displays a strong affinity toward membrane-bound sialic acids. Incubation of NDV with the malaria parasites dose-dependently reduces its cellular viability. The antiplasmodial activity of NDV is specific, as incubation with Japanese encephalitis virus, duck enteritis virus, infectious bronchitis virus, and influenza virus did not affect the parasite propagation. Interestingly, NDV is reducing more than 80% invasion when RBCs are pretreated with the virus. Removal of the RBC surface proteins or the NDV coat proteins results in disruption of the virus binding to RBC. It suggests the involvement of specific protein: ligand interaction in virus binding. We established that the virus engages with the parasitized RBCs (PRBCs) through its hemagglutinin neuraminidase (HN) protein by recognizing sialic acid-containing glycoproteins on the cell surface. Blocking of the HN protein with free sialic acid or anti-HN antibodies abolished the virus binding as well as its ability to reduce parasite growth. Interestingly, the purified HN from the virus alone could inhibit the parasite's growth in a dose-dependent manner. NDV binds strongly to knobless murine parasite strain Plasmodium yoelii and restricted the parasite growth in mice. Furthermore, the virus was found to preferentially target the PRBCs compared to normal erythrocytes. Immunolocalization studies reveal that NDV is localized on the plasma membrane as well as weakly inside the PRBC. NDV causes neither any infection nor aggregation of the human RBCs. Our findings suggest that NDV is a potential candidate for developing targeted drug delivery platforms for the Plasmodium-infected RBCs.
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Eritrocitos , Ácido N-Acetilneuramínico , Virus de la Enfermedad de Newcastle , Virus de la Enfermedad de Newcastle/fisiología , Virus de la Enfermedad de Newcastle/metabolismo , Eritrocitos/parasitología , Eritrocitos/metabolismo , Animales , Ácido N-Acetilneuramínico/metabolismo , Humanos , Plasmodium yoelii/metabolismo , Ratones , Proteína HN/metabolismo , Malaria/parasitología , Malaria/metabolismoRESUMEN
BACKGROUND: Indoor residual spraying (IRS) is a cornerstone malaria control intervention in Burkina Faso. From 2018 to 2021, non-pyrethroid IRS was implemented annually in two regions of Burkina Faso with distinct malaria transmission patterns, concurrently with annual seasonal malaria chemoprevention (SMC), and a mass insecticide-treated net (ITN) distribution in 2019. METHODS: A retrospective quasi-experimental approach was used to evaluate the impact of the 2018, 2020, and 2021 IRS campaigns on routinely reported confirmed malaria case incidence at health facilities. The 2019 campaign was excluded due to lack of data reporting during a health sector strike. Controlled interrupted time series models were fit to detect changes in level and trend in malaria case incidence rates following each IRS campaign when compared to the baseline period 24-months before IRS. IRS districts Solenzo (Sudano-Sahelien climate), and Kampti (tropical climate) were compared with neighbouring control districts and the analyses were stratified by region. Modelled health facility catchment population estimates based on travel time to health facilities and weighted by non-malaria outpatient visits were used as an offset. The study period encompassed July 2016 through June 2022, excluding July 2018 to June 2019. RESULTS: District-level population and structure coverage achieved by IRS campaigns was greater than 85% in 2018, 2020, and 2021 in Solenzo and Kampti. In Solenzo a significant difference in malaria case incidence rates was detected after the 2018 campaign (IRR = 0.683; 95% CI 0.564-0.827) when compared to the control district. The effect was not detected following the 2020 or 2021 IRS campaigns. In Kampti, estimated malaria incidence rates were between 36 and 38% lower than in the control district following all three IRS campaigns compared to the baseline period. CONCLUSIONS: Implementation of IRS in Kampti, a tropical region of Burkina Faso, appeared to have a consistent significant beneficial impact on malaria case rates. An initial positive impact in Solenzo after the first IRS campaign was not sustained in the successive evaluated IRS campaigns. This study points to a differential effect of IRS in different malaria transmission settings and in combination with ITN and SMC implementation.
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Insecticidas , Malaria , Control de Mosquitos , Burkina Faso/epidemiología , Control de Mosquitos/estadística & datos numéricos , Malaria/prevención & control , Malaria/epidemiología , Estudios Retrospectivos , Humanos , Incidencia , Mosquiteros Tratados con Insecticida/estadística & datos numéricosRESUMEN
ABSTRACT: Accurate diagnosis is a key strategy for controlling and preventing malaria. Regular evaluation of the performance of malaria microscopy diagnosis is essential to ensure its high quality. This study aims to assess the accuracy of malaria microscopy at selected public health facilities on the border of Indonesia and Timor-Leste. The design of this research is observational with a cross-sectional approach, conducted at five public health centers located on the Indonesia Timor-Leste border from July to September 2022. Stained slides were collected from patients with a fever (≥37°C). These stained slides were then examined for malaria diagnosis. The results revealed that all five public health centers showed perfect or nearly perfect agreement with the reference microscopist regarding malaria detection by microscopy (κ =0.9-1). To maintain the high quality of malaria microscopy diagnosis, it is imperative to conduct regular training, monitoring, and evaluation.
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Malaria , Microscopía , Humanos , Microscopía/métodos , Estudios Transversales , Indonesia/epidemiología , Timor Oriental/epidemiología , Malaria/diagnóstico , Malaria/epidemiología , Femenino , Masculino , Salud PúblicaRESUMEN
As we strive towards the ambitious goal of malaria elimination, we must embrace integrated strategies and interventions. Like many diseases, malaria is heterogeneously distributed. This inherent spatial component means that geography and geospatial data is likely to have an important role in malaria control strategies. For instance, focussing interventions in areas where malaria risk is highest is likely to provide more cost-effective malaria control programmes. Equally, many malaria vector control strategies, particularly interventions like larval source management, would benefit from accurate maps of malaria vector habitats - sources of water that are used for malarial mosquito oviposition and larval development. In many landscapes, particularly in rural areas, the formation and persistence of these habitats is controlled by geographical factors, notably those related to hydrology. This is especially true for malaria vector species like Anopheles funestsus that show a preference for more permanent, often naturally occurring water sources like small rivers and spring-fed ponds. Previous work has embraced geographical concepts, techniques, and geospatial data for studying malaria risk and vector habitats. But there is much to be learnt if we are to fully exploit what the broader geographical discipline can offer in terms of operational malaria control, particularly in the face of a changing climate. This chapter outlines potential new directions related to several geographical concepts, data sources and analytical approaches, including terrain analysis, satellite imagery, drone technology and field-based observations. These directions are discussed within the context of designing new protocols and procedures that could be readily deployed within malaria control programmes, particularly those within sub-Saharan Africa, with a particular focus on experiences in the Kilombero Valley and the Zanzibar Archipelago, United Republic of Tanzania.
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Anopheles , Malaria , Control de Mosquitos , Mosquitos Vectores , Malaria/prevención & control , Malaria/epidemiología , Malaria/transmisión , Animales , Mosquitos Vectores/fisiología , Control de Mosquitos/métodos , Humanos , Anopheles/fisiología , Anopheles/parasitología , Ecosistema , GeografíaRESUMEN
Acute febrile illness (AFI) is a common reason for healthcare seeking and hospitalization in Sub-Saharan Africa and is often presumed to be malaria. However, a broad range of pathogens cause fever, and more comprehensive data on AFI etiology can improve clinical management, prevent unnecessary prescriptions, and guide public health interventions. We conducted surveillance for AFI (temperature ≥38.0°C <14 days duration) among hospitalized patients of all ages at four sites in Kenya (Nairobi, Mombasa, Kakamega, and Kakuma). For cases of undifferentiated fever (UF), defined as AFI without diarrhea (≥3 loose stools in 24 hours) or lower respiratory tract symptoms (cough/difficulty breathing plus oxygen saturation <90% or [in children <5 years] chest indrawing), we tested venous blood with real-time PCR-based TaqMan array cards (TAC) for 17 viral, 8 bacterial, and 3 protozoal fever-causing pathogens. From June 2017 to March 2019, we enrolled 3,232 AFI cases; 2,529 (78.2%) were aged <5 years. Among 3,021 with outcome data, 131 (4.3%) cases died while in hospital, including 106/2,369 (4.5%) among those <5 years. Among 1,735 (53.7%) UF cases, blood was collected from 1,340 (77.2%) of which 1,314 (98.1%) were tested by TAC; 715 (54.4%) had no pathogens detected, including 147/196 (75.0%) of those aged <12 months. The most common pathogen detected was Plasmodium, as a single pathogen in 471 (35.8%) cases and in combination with other pathogens in 38 (2.9%). HIV was detected in 51 (3.8%) UF cases tested by TAC and was most common in adults (25/236 [10.6%] ages 18-49, 4/40 [10.0%] ages ≥50 years). Chikungunya virus was found in 30 (2.3%) UF cases, detected only in the Mombasa site. Malaria prevention and control efforts are critical for reducing the burden of AFI, and improved diagnostic testing is needed to provide better insight into non-malarial causes of fever. The high case fatality of AFI underscores the need to optimize diagnosis and appropriate management of AFI to the local epidemiology.
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Fiebre , Hospitalización , Humanos , Kenia/epidemiología , Fiebre/epidemiología , Masculino , Femenino , Preescolar , Adulto , Adolescente , Niño , Lactante , Adulto Joven , Persona de Mediana Edad , Enfermedad Aguda , Malaria/epidemiología , Malaria/diagnóstico , Anciano , Recién NacidoRESUMEN
BACKGROUND: Ghana is a malaria-endemic country with the entire population at risk. The Northern region of the country recorded the highest malaria case fatality rate (CFR) for two consecutive years: 1.11% in 2013 and 1.07% in 2014. Even though the National Malaria Elimination Programme (NMEP) has achieved a reduction in malaria mortality, the existence of high case fatality in the Northern region was alarming. This study, therefore, aimed to determine the factors associated with malaria mortality in the northern region of Ghana to institute control measures. METHODS: An unmatched case control study was conducted from July 2015 to August 2015. The study population consisted of patients admitted to health facilities for severe malaria in the Northern region of Ghana. A case was defined as a patient diagnosed with severe malaria at an eligible health facility who died as a result of malaria. A control was a patient diagnosed with severe malaria admitted to an eligible health facility who did not die. Health facilities that recorded CFRs of 1.0% and above were randomly sampled for this study, after which, 10 cases and 20 controls were recruited from each health facility. Information on cases and controls was then abstracted from hospital records using an electronically deployed abstraction tool. Continuous variables were expressed as means and medians, and categorical variables as frequencies and proportions. Multivariable logistic regression was used to assess the strength of the association between malaria mortality and factors predictive of malaria mortality. A p-value of < 0.05 was considered statistically significant. RESULTS: In all, a total of 95 cases and 190 controls participated in this study. The median ages of cases and controls were 4.1 years (IQR = 21.6) and 5.7 years (IQR = 18.2), respectively. Fifty-four (56.8%) cases were females, while 93 (49.0%) of the controls were females. Factors associated with malaria mortality included: duration of hospital stay less than 24 h [aOR: 12.0, 95% CI (5.9-24.6)], severe pallor [aOR: 2.3, 95% CI (1.1-4.6)], children under 5 years [aOR: 2.8, 95% CI (1.4-5.6)], oral Artesunate/Amodiaquine administration [aOR: 0.4, 95% CI (0.2-0.9)] and sepsis as an additional diagnosis [aOR: 4.1, 95% CI (1.8-9.5)]. CONCLUSION: Predictors of malaria mortality in the Northern region include children under 5 years, severe pallor, sepsis as an additional diagnosis, and use of oral anti-malarial. Patients with severe pallor and sepsis as co-morbidities should receive proactive management. The NMEP and its partners should implement measures to strengthen the referral system, anaemia prevention and management, and retrain health workers on malaria case management. Malaria control interventions targeted at under five children in the region should be reviewed and enhanced.
Asunto(s)
Malaria , Humanos , Ghana/epidemiología , Estudios de Casos y Controles , Femenino , Masculino , Malaria/mortalidad , Adulto , Adolescente , Adulto Joven , Persona de Mediana Edad , Preescolar , Niño , Lactante , Anciano , Factores Sociodemográficos , Factores de Riesgo , Factores SocioeconómicosRESUMEN
BACKGROUND: More than 95% of malaria transmission in Brazil occurs in the Legal Amazon Region, which in 2010 recorded around 333,429 cases reported in the Epidemiological Surveillance Information System-Malaria (Sivep_malaria), presenting an annual parasitic incidence (IPA) of 13.1 cases/1000 inhabitants. METHODS: This was a descriptive study that measured the community prevalence of Plasmodium infection and its relationship with land use in Três Fronteiras District, Colniza Municipality, Mato Grosso State. Data were collected during household visits in July 2011, with blood collection from finger pricks for the preparation of thick smear slides, and completion of a standardized case notification form. A georeferenced database was analysed, with land use evaluated as categorical variables. A kernel density map was built to show the density of cases and their location. RESULTS: Of the 621 respondents, 68(11%) had Plasmodium infection: 39 (57.4%) with Plasmodium vivax, 27(39.7%) with Plasmodium falciparum and two (2.9%) with mixed infections. Among infected individuals, 49 (72.1%) were men. Cases of malaria were distributed over the district, with greater occurrence of cases per household in open areas close to the mining company and artisanal mining sites. The was a greater density of cases located in the gold mining region. CONCLUSION: Transmission of malaria in Três Fronteiras District has a heterogeneous distribution. Individuals residing in mining and timber extraction sites have increased occurrence of Plasmodium infection.
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Malaria Falciparum , Malaria Vivax , Población Rural , Brasil/epidemiología , Humanos , Femenino , Masculino , Adolescente , Adulto , Población Rural/estadística & datos numéricos , Persona de Mediana Edad , Adulto Joven , Niño , Preescolar , Malaria Vivax/epidemiología , Malaria Vivax/parasitología , Malaria Falciparum/epidemiología , Malaria Falciparum/parasitología , Prevalencia , Lactante , Anciano , Incidencia , Anciano de 80 o más Años , Plasmodium vivax , Malaria/epidemiología , Malaria/transmisiónRESUMEN
Traditional manual blood smear diagnosis methods are time-consuming and prone to errors, often relying heavily on the experience of clinical laboratory analysts for accuracy. As breakthroughs in key technologies such as neural networks and deep learning continue to drive digital transformation in the medical field, image recognition technology is increasingly being leveraged to enhance existing medical processes. In recent years, advancements in computer technology have led to improved efficiency in the identification of blood cells in blood smears through the use of image recognition technology. This paper provides a comprehensive summary of the methods and steps involved in utilizing image recognition algorithms for diagnosing diseases in blood smears, with a focus on malaria and leukemia. Furthermore, it offers a forward-looking research direction for the development of a comprehensive blood cell pathological detection system.
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Células Sanguíneas , Procesamiento de Imagen Asistido por Computador , Patología Clínica , Patología Clínica/métodos , Patología Clínica/tendencias , Células Sanguíneas/microbiología , Células Sanguíneas/parasitología , Células Sanguíneas/patología , Malaria/diagnóstico por imagen , Leucemia/diagnóstico por imagen , Algoritmos , Aprendizaje Automático , Recuento de Células Sanguíneas , HumanosRESUMEN
Introduction: Plasmodium malariae is the most common non-falciparum species in sub-Saharan Africa. Despite this, data on its genetic diversity is scarce. Therefore, we aimed to establish a P. malariae genotyping approach based on size polymorphic regions that can be easily applied in molecular epidemiological studies. Methods: Four potential genotyping markers, Pm02, Pm09, P. malariae thrombospondin-related anonymous protein (pmtrap), and P. malariae merozoite surface protein fragment 2 (pmmsp1 F2) were amplified via nested PCR and analysed using automated capillary gel electrophoresis. Results: We observed the highest allelic diversity for pmtrap (MOI = 1.61) and pmmsp1 F2 (He = 0.81). Further applying the two markers pmtrap and pmmsp1 F2 on a different sample set of 21 P. malariae positive individuals followed up over one week, we saw a high consistency in their performance. The results show a large complexity and high dynamics of P. malariae infections in the asymptomatic Gabonese study population. Discussion: We successfully implemented a new genotyping panel for P. malariae consisting of only two markers: pmtrap and pmmsp1 F2. It can be easily applied in other settings to investigate the genotype diversity of P. malariae populations, providing further important data on the molecular epidemiology of this parasite species.
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Variación Genética , Genotipo , Malaria , Epidemiología Molecular , Plasmodium malariae , Proteínas Protozoarias , Plasmodium malariae/genética , Plasmodium malariae/aislamiento & purificación , Humanos , Malaria/epidemiología , Malaria/parasitología , Epidemiología Molecular/métodos , África del Sur del Sahara/epidemiología , Proteínas Protozoarias/genética , Técnicas de Genotipaje/métodos , Reacción en Cadena de la Polimerasa/métodos , ADN Protozoario/genética , Alelos , Gabón/epidemiología , Marcadores GenéticosRESUMEN
BACKGROUND: Biological control is a promising alternative or complementary approach for controlling vector populations in response to the spread of insecticide resistance in malaria vectors. This study evaluated the efficacy of three selected potential predators on the density and fitness parameters of Anopheles funestus larvae in rural Tanzania. METHODS: Common predator families Aeshnidae (dragonflies), Coenagrionidae (damselflies), and Notonectidae (backswimmers) and An. funestus group larvae were collected from natural aquatic habitats in rural south-eastern Tanzania. Predators were starved for 12-h while An. funestus larvae were given fish food before starting the experiment. Anopheles funestus larvae were placed into artificial habitats containing predators, exposing them to potential predation. The number of surviving An. funestus larvae were counted every 24-h. An emergence traps were placed at the top of artificial habitats to capture emerging mosquitoes. Emerged mosquitoes were monitored until they died. Female wings were measured and used as a proxy for body size. Generalized linear mixed models (GLMM) with binomial variates at 95% CI and Cox proportional hazard models were used to assess the proportion of dead mosquitoes and the daily survival determined. RESULTS: There were significant differences in the number of emerged mosquitoes between the treatment and control groups (P < 0.001). Thus, all predator species played a significant role in reducing the density of An. funestus mosquitoes (P < 0.001). Furthermore, these predators had notable effects on the fitness parameters and survival of emerged mosquitoes (P < 0.001). Among the three predators studied, Coenagrionidae (damselflies) were most efficient followed by Notonectidae (backswimmers), with Aeshnidae (dragonflies) being the least efficient. CONCLUSION: Selected aquatic predators have the potential to reduce the survival and density of An. funestus larvae. They might eventually be included within an integrated malaria vector control strategy, ultimately leading to a reduction in malaria transmission.
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Anopheles , Larva , Control de Mosquitos , Animales , Anopheles/fisiología , Tanzanía , Control de Mosquitos/métodos , Larva/fisiología , Larva/crecimiento & desarrollo , Femenino , Mosquitos Vectores/fisiología , Odonata/fisiología , Conducta Predatoria , Control Biológico de Vectores/métodos , Población Rural , Malaria/prevención & control , Malaria/transmisiónRESUMEN
BACKGROUND: Malaria is a serious, fatal disease, and a high-risk determinant for human health globally. Children, pregnant women, and migrants are vulnerable groups for malaria infection in African regions. Recently, malaria is an endemic disease in Ethiopia. OBJECTIVES: This study aimed to determine the pooled prevalence of malaria and its determinant factors among the most vulnerable populations in Ethiopia. METHODS: Electronic databases, including PubMed, Google Scholar, Web of Science, Semantic Scholar, and Scopus were used for searching articles published since the 2020 Gregorian calendar and onwards. All peer-reviewed Ethiopian journals, health institutions, and Universities were considered for article searching. A PRISMA flow chart and Endnote software were used for article screening, and to remove duplications, respectively. The modified version of the Newcastle-Ottawa Scale was used for potential risk of bias assessments. The heterogeneity among the included studies was evaluated using the indicator of heterogeneity (I2). Egger's test and funnel plot were used to examine the possible publication bias. A random-effects analysis was used to assess the pooled prevalence of malaria, and its determinant factors with a 95% CI. The screening process, data extraction, and quality assessment were done independently, and any disagreements were resolved through discussions. RESULTS: A total of twelve studies were included in this study. The pooled malaria prevalence was 11.10% (95% CI: 6.10, 16.11). Stagnant water (AOR: 4.19, 95% CI: 2.47, 7.11), no insecticide-treated net utilization (AOR: 3.15, 95% CI: 1.73, 5.73), and staying outdoors at night (AOR: 5.19, 95% CI: 2.08, 12.94) were the pooled estimated statistically risk factors for malaria prevalence. Whereas, insecticide-treated bed net utilization (AOR: 1.59, 95% CI: 0.23, 10.95) reduces the risk of malaria infection. CONCLUSIONS: The pooled prevalence of malaria is high among vulnerable populations. Creating awareness regarding utilization of insecticide-treated bed nets, and draining stagnant water from the environment are possible interventions to reduce the prevalence of malaria.
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Malaria , Poblaciones Vulnerables , Humanos , Etiopía/epidemiología , Prevalencia , Malaria/epidemiología , Poblaciones Vulnerables/estadística & datos numéricos , Factores de Riesgo , Femenino , Embarazo , NiñoRESUMEN
BACKGROUND: Malaria is the leading cause of hospitalizations and death in Uganda, particularly in children under the age of five. Studies have shown that adherence to the World Health Organization (WHO) guidelines for the management of severe malaria reduces mortality in hospitalized children. This study aimed to determine the impact of targeted interventions on adherence to the WHO severe malaria treatment guidelines in children at a Ugandan hospital as part of a quality improvement initiative. METHODS: Interventions included workflow changes, such as obtaining patient blood samples for diagnostic testing by the admitting healthcare provider as well as utilizing patient caregivers to assist nursing staff in timing medications. An additional intervention was the use of an admission checklist sticker. The post-intervention sample was compared to the baseline assessment. The primary outcome was the proportion of patients receiving care consistent with all aspects of the WHO guidelines. Secondary outcomes included the proportion of patients receiving malaria diagnostic testing, those receiving at least 3 doses of artesunate, the timely administration of artesunate, and adherence to other guideline components. Statistical analyses were conducted using GraphPad PRISM 9.0. Comparisons between groups were analysed using Chi-square or Fisher's exact test for categorical variables and Mann-Whitney test for continuous variables. RESULTS: The post-intervention group included 230 patients with a median age of 5 years [4-8], and 58% of patients were male. Adherence to all aspects of the WHO guidelines was achieved in 10% of patients in the post-intervention group compared to 3% of patients in the baseline (P = 0.007). Appropriate malaria diagnostic testing was performed in 85% of patients post-intervention compared to 66% of patients in the baseline (P < 0.0001). Patients in the post-intervention group were more likely to receive the minimum 3 doses of artesunate (86%) than in the baseline (74%) (P = 0.008). Patients in the post-intervention group were more likely to receive artesunate doses on time than in the baseline (dose 2 P = 0.02, dose 3 P = 0.003). CONCLUSIONS: Targeted, low-cost interventions led to improvement in adherence to severe malaria treatment guidelines. The most notable changes were in malaria diagnostic testing and antimalarial administration.
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Antimaláricos , Adhesión a Directriz , Malaria , Mejoramiento de la Calidad , Humanos , Uganda , Preescolar , Adhesión a Directriz/estadística & datos numéricos , Masculino , Femenino , Malaria/tratamiento farmacológico , Malaria/diagnóstico , Mejoramiento de la Calidad/estadística & datos numéricos , Antimaláricos/uso terapéutico , Antimaláricos/administración & dosificación , Lactante , Organización Mundial de la Salud , Niño , Hospitales/estadística & datos numéricosRESUMEN
The malaria-causing parasites have to complete a complex infection cycle in the mosquito vector that also involves attack by the insect's innate immune system, especially at the early stages of midgut infection. However, Anopheles immunity to the late Plasmodium sporogonic stages, such as oocysts, has received little attention as they are considered to be concealed from immune factors due to their location under the midgut basal lamina and for harboring an elaborate cell wall comprising an external layer derived from the basal lamina that confers self-properties to an otherwise foreign structure. Here, we investigated whether Plasmodium berghei oocysts and sporozoites are susceptible to melanization-based immunity in Anopheles gambiae. Silencing of the negative regulator of melanization response, CLIPA14, increased melanization prevalence without significantly increasing the numbers of melanized oocysts, while co-silencing CLIPA14 with CLIPA2, a second negative regulator of melanization, resulted in a significant increase in melanized oocysts and melanization prevalence. Only late-stage oocysts were found to be melanized, suggesting that oocyst rupture was a prerequisite for melanization-based immune attack, presumably due to the loss of the immune-evasive features of their wall. We also found melanized sporozoites inside oocysts and in the hemocoel, suggesting that sporozoites at different maturation stages are susceptible to melanization. Silencing the melanization promoting factors TEP1 and CLIPA28 rescued oocyst melanization in CLIPA2/CLIPA14 co-silenced mosquitoes. Interestingly, silencing of CTL4, that protects early stage ookinetes from melanization, had no effect on oocysts and sporozoites, indicating differential regulation of immunity to early and late sporogonic stages. Similar to previous studies addressing ookinete stage melanization, the melanization of Plasmodium falciparum oocysts was significantly lower than that observed for P. berghei. In summary, our results provide conclusive evidence that late sporogonic malaria parasite stages are susceptible to melanization, and we reveal distinct regulatory mechanisms for ookinete and oocyst melanization.
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Anopheles , Melaninas , Oocistos , Plasmodium berghei , Esporozoítos , Animales , Anopheles/parasitología , Anopheles/inmunología , Plasmodium berghei/inmunología , Oocistos/metabolismo , Melaninas/metabolismo , Esporozoítos/inmunología , Esporozoítos/metabolismo , Mosquitos Vectores/parasitología , Mosquitos Vectores/inmunología , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/inmunología , Malaria/inmunología , Malaria/parasitología , Silenciador del Gen , Inmunidad Innata , FemeninoRESUMEN
BACKGROUND: Insecticide-treated nets (ITNs) are pivotal tools for malaria prevention in endemic regions like Ghana. Understanding the protective factors and barriers influencing ITN ownership and usage is crucial for designing effective interventions. A scoping review was conducted to identify studies exploring protective factors and barriers related to ITN ownership and usage. METHODS: This review followed the guidelines by Askey and O'Malley. Search was done in four major databases including PubMed, Science Direct, PubMed CENTRAL, and JSTOR. Additional searches were done in Google Scholar and Google. Peer-reviewed and grey literature were included. RESULTS: A total of 24 papers met the eligibility criteria and were included in the review. Included studies found regional disparities in ITN ownership and usage. Furthermore, included studies reported ownership rates between 97.8 and 28% and usage rates between 94 and 20%. Protective factors facilitating ITN ownership were marital status, higher educational attainment, higher income levels, and being aged 25 years or older. In contrast, the factors for its use included community-level campaigns advocating for ITN use and awareness, individuals with secondary education or higher and those residing in urban areas. Missed opportunities in free distribution exercises and the unavailability of subsidized ITNs at health facilities were barriers to ownership. CONCLUSION: Understanding and addressing protective factors and barriers influencing ITN ownership and usage are crucial for enhancing malaria prevention strategies and achieving sustainable progress in combating malaria in endemic areas. Collaborative and evidence-based interventions are essential for addressing these challenges effectively.
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Mosquiteros Tratados con Insecticida , Malaria , Control de Mosquitos , Propiedad , Ghana , Mosquiteros Tratados con Insecticida/estadística & datos numéricos , Propiedad/estadística & datos numéricos , Malaria/prevención & control , Control de Mosquitos/estadística & datos numéricos , Control de Mosquitos/métodos , HumanosRESUMEN
Plasmodium falciparum malaria remains a dominant infectious disease that affects Africa than the rest of the world, considering its associated cases and death rates. It's a febrile illness that produces several reliable biomarkers, for example, P. falciparum lactate dehydrogenase (PfLDH), P. falciparum Plasmodium glutamate dehydrogenase (PfGDH), and P. falciparum histidine-rich proteins (HRP-II) in blood circulatory system that can easily be employed as targets in rapid diagnostic tests (RDTs). In recent times, several DNA aptamers have been developed via SELEX technology to detect some specific malaria biomarkers (PfLDH, PvLDH, HRP-II, PfGDH) in a biosensor mode with good binding affinity properties to overcome the trend of cross-reactivity, limited sensitivity and stability problems that have been observed with immunodiagnostics. In this review, we summarized existing diagnostic methods and relevant biomarkers to suggest promising approaches to develop sensitive and species-specific multiplexed diagnostic devices enabling effective detection of malaria in complex biological matrices and surveillance in the endemic region.
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Aptámeros de Nucleótidos , Biomarcadores , Técnicas Biosensibles , Dispositivos Laboratorio en un Chip , Plasmodium falciparum , Biomarcadores/análisis , Biomarcadores/metabolismo , Aptámeros de Nucleótidos/química , Humanos , Malaria Falciparum/diagnóstico , Proteínas Protozoarias/análisis , Proteínas Protozoarias/metabolismo , L-Lactato Deshidrogenasa/metabolismo , L-Lactato Deshidrogenasa/análisis , Malaria/diagnóstico , Glutamato Deshidrogenasa/análisis , Glutamato Deshidrogenasa/metabolismo , Técnica SELEX de Producción de AptámerosRESUMEN
BACKGROUND: The Republic of Guinea, where malaria represents the leading cause of morbidity and mortality among children, the seasonal malaria chemoprevention (SMC) is deployed only in areas with very seasonal modes of transmission. It should target children at the highest risk of serious illness. The objective of the study was to prevent uncomplicated and serious cases of malaria in the target population. This study aimed to analyse the monthly trends in malaria-related morbidity among children under the age of 5 in Guinea. METHODS: This was a quasi-experimental study with routine data from the National Health Information System (SNIS). The two districts Mamou (the SMC intervention site) and Kindia (the control site) were selected to compare the monthly trends in malaria cases among children under the age of 5, from July to October, covering the years from 2015 to 2020. The statistical analysis used interrupted time series to estimate the effects of the SMC. RESULTS: The SMC programme contributed to a significant average reduction in the number of malaria cases of 225 cases per month in the intervention district (95% CI - 362 to - 88; p = 0.002), compared to the control district. However, the study also revealed that the effect of SMC varied between cycles, presenting different monthly malaria cases. CONCLUSION: The SMC contributed to a significant reduction in malaria cases among children under the age of 5 in the health district of Mamou from 2018 to 2020. However, this reduction varied by monthly SMC cycle. This study suggests extending the SMC in other areas with high perennial seasonal transmission respecting the World Health Organization SMC eligibility criteria, as a strategy in the dynamic of reducing malaria cases in children under the age of 5 in Guinea.
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Antimaláricos , Quimioprevención , Malaria , Estaciones del Año , Humanos , Preescolar , Quimioprevención/estadística & datos numéricos , Quimioprevención/métodos , Lactante , Guinea/epidemiología , Malaria/prevención & control , Malaria/epidemiología , Antimaláricos/uso terapéutico , Antimaláricos/administración & dosificación , Recién Nacido , Masculino , Femenino , IncidenciaRESUMEN
BACKGROUND: Typically mobile and vulnerable, migrants face significant barriers to access to routine malaria prevention, diagnostics and treatment, which leads to unchecked malaria transmission, particularly in border regions with a high population displacement. This study aimed to investigate the demographic and socioeconomic obstacles to access to malaria services among Myanmar migrants residing in the Thailand-Myanmar border areas. METHODS: A cross-sectional study was conducted in early 2024 across three districts near the Thailand-Myanmar border. Quantitative data were collected from Myanmar migrants using standardized questionnaires through structured surveys. Data analysis included descriptive statistics and simple and multiple logistic regression models. RESULTS: Out of 300 participants, approximately a quarter (27.3%) reported adequate access to comprehensive malaria services, including prevention, diagnostics, treatment and malaria-related health information. In multiple logistic regression models, factors associated with inadequate access included Myanmar migrants aged over 60 years (aOR: 7.63, 95% CI 1.74-20.58), accompanied by one to three family members (aOR: 3.33, 95% CI 1.06-8.45), earning monthly incomes below 3000 THB (aOR: 5.13, 95% CI 1.38-19.09) and 3000 to 6000 THB (aOR: 3.64, 95% CI 1.06-12.51), belonging to the Karen ethnicity (aOR: 2.13, 95% CI 1.02-3.84), with poor perception toward malaria (aOR: 2.03, 95% CI 1.03-4.01) and with poor preventive and health-seeking practices (aOR: 5.83, 95% CI 2.71-9.55). CONCLUSIONS: A significant proportion of Myanmar migrants encounter demographic and socioeconomic barriers to access to routine malaria services in Thailand. Tailored interventions are required to expand such access, including the recruitment of worksite health volunteers, strengthening the role of ethnic health organizations across the border and collaboration with private sector stakeholders (e.g. farm/company owners) to distribute preventive tools and ensure timely referral of suspected malaria cases to health facilities.
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Accesibilidad a los Servicios de Salud , Malaria , Migrantes , Mianmar , Tailandia , Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Estudios Transversales , Malaria/prevención & control , Migrantes/estadística & datos numéricos , Masculino , Femenino , Adulto , Humanos , Persona de Mediana Edad , Adulto Joven , Factores Socioeconómicos , Adolescente , AncianoRESUMEN
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
INTRODUCTION: Hyperreactive malarial splenomegaly (HMS) is one of the main causes of massive splenomegaly in malaria-endemic zones. Diagnosis is often challenging in Bobo-Dioulasso. This study aimed to describe the clinical and socio-demographic profile, and the reasons for delay in the diagnosis of HMS cases recorded in the Medicine and Medical Specialties wards of Souro Sanou Teaching hospital. METHODS: A retrospective descriptive study was conducted from August 2022 by focusing on HMS cases diagnosed in the Infectious Diseases and Clinical Hematology wards of Souro Sanou Teaching Hospital. RESULTS: Overall, 65 patients met our inclusion criteria over the 12-year period. Burkinabe nationals and have been residing in Burkina Faso since their birth. 79% (79%) of the patients were seen for medical consultation with the reason for consultation being a voluminous mass in the left hypochondrium. Indigence, self-medication, and lack of information were essential elements in late diagnosis of HMS in Bobo-Dioulasso. All patients were treated with a single tablet of Artemether (80 mg) and Lumefantrine (480 mg) in the morning and evening for 3 days, followed by sulfadoxine-pyrimethamine per week. Nine months later, patients were clinically asymptomatic. CONCLUSION: This study provides a database on hyperreactive malarial splenomegaly (HMS) in the south-west region of Burkina Faso. Rapid and accurate diagnosis of the disease and appropriate use of effective antimalarial drugs would significantly reduce the burden of HMS in Sub-Saharan African countries.
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Antimaláricos , Malaria , Esplenomegalia , Humanos , Esplenomegalia/etiología , Esplenomegalia/parasitología , Burkina Faso/epidemiología , Masculino , Femenino , Estudios Retrospectivos , Adulto , Antimaláricos/uso terapéutico , Adolescente , Persona de Mediana Edad , Malaria/complicaciones , Malaria/epidemiología , Malaria/tratamiento farmacológico , Adulto Joven , Pirimetamina/uso terapéutico , Combinación Arteméter y Lumefantrina/uso terapéutico , Sulfadoxina/uso terapéutico , Niño , Enfermedades Endémicas , Combinación de MedicamentosRESUMEN
BACKGROUND: In endemic locations, asymptomatic malaria is a major contribution to the rise in clinical malaria. In order to achieve the goal of interrupting malaria transmission, control programmes should take into consideration carriers of asymptomatic malaria parasite. Hence, the purpose of this study was to look at the prevalence and risk factors of asymptomatic malaria in children in Nkwen village. METHODS: Using a cross-sectional and community-based design, conducted between June and December 2022, a total of 246 children were enrolled after obtaining informed and signed consent from parents and/ or guardians. To collect data, pre-tested, closed-ended, structured questionnaires were used, ensuring the accuracy and reliability of the information gathered. A digital thermometer with infrared forehead capability was used to take participants' body temperature, providing precise measurements and respondents with temperature < 37.5 °C, and not presenting any symptoms or indicators of malaria were included in the study, ensuring the focus on asymptomatic cases. Blood samples were collected by venipuncture and screened for the presence of asymptomatic parasitaemia using blood smear microscopy and nested polymerase chain reaction (PCR). Data was entered into Microsoft Excel worksheet and analysed using SPSS version 23 software. Logistic regression models were carried out to explore the risk factors associated with asymptomatic malaria at household and individual levels and statistically significant association was considered at a p-value < 0.05. RESULTS: A total of 246 healthy children were examined for asymptomatic malaria infection using microscopy and PCR. Of the examined children, 65.9% (162/246) were malaria positive by PCR while 59.3% (146/246) were malaria positive by microscopy. Considering both diagnostic methods, females had a greater prevalence of asymptomatic malaria than males. In logistic analysis, the risk of developing asymptomatic malaria was associated several factors: previous malaria episode (OR = 5.14; CI 2.94-9.01), family history of malaria (OR = 3.86; CI 2.21-6.74), homestead near swampy areas (OR = 3.56; CI 2.10-10.61), non-utilization of insecticide treated nets (OR = 4.36; CI 2.53-7.5), non-usage of indoor residual spray (IRS) (OR = 6.67; CI 3.75-11.86) and opened eaves (OR = 3.86; CI 2.21-6.74). No associations were established between asymptomatic malaria and the following factors: age group (p > 0.05), gender (p > 0.05) and type of wall construction (p > 0.05). CONCLUSION: The high rate of asymptomatic malaria in this study is a significant problem and may jeopardize the current malaria control effort. Personal and house-level risk factors were linked with asymptomatic malaria. Therefore, it should be considered when evaluating and restructuring more successful malaria elimination tactics to accomplish the intended goals of malaria control.