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1.
Parasit Vectors ; 17(1): 280, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38951912

ABSTRACT

BACKGROUND: Application of numerous malaria control interventions has led to reduction in clinical malaria cases and deaths but also the realisation that asymptomatic parasite carriers play a key role in sustaining transmission. This study assessed the effectiveness of using the Ultra-sensitive NxTek eliminate RDT (uRDT) and conventional SD Bioline HRP2 RDT (cRDT) in diagnosing asymptomatic parasitaemia while measuring the impact of mass testing, treatment and tracking (MTTT) on the prevalence of asymptomatic malaria over a 1-year period in Ghana. METHODS: A total of 4000 targeted participants from two towns, Obom and Kofi Kwei, with their surrounding villages, were tested for asymptomatic malaria four times over the study period using uRDT (intervention) and the cRDT (control) respectively. Participants carrying malaria parasites were followed by home visit and phone calls for compliance to treatment, and filter paper blood blots collected from participants were used to determine true parasite carriage by PET-PCR. A mathematical model of the study site was developed and used to test the impact of test sensitivity and mass migration on the effect of MTTT. RESULTS: The start and end point sensitivities of the cRDT were 48.8% and 41.7% and those for the uRDT were 52.9% and 59.9% respectively. After a year of MTTTs, asymptomatic parasite prevalence, as determined by PCR, did not differ statistically in the control site (40.6% to 40.1%, P = 0.730) but decreased at the intervention site (55.9% to 46.4%, P < 0.0001). Parasite prevalence by RDT, however, indicated statistical reduction in the control site (25.3% to 22.3%, P = 0.017) and no change in the intervention site (35.1% to 36.0%, P = 0.614). The model predicted a mild effect of both diagnostic sensitivity and human movement in diminishing the impact of MTTT in the study sites. CONCLUSIONS: Asymptomatic parasite prevalence at the molecular level reduced significantly in the site where the uRDT was used but not where the cRDT was used. Overall, the uRDT exhibited higher sensitivity relative to the cRDT. Highly sensitive molecular techniques such as PET-PCR should be included in parasite prevalence estimation during MTTT exercises.


Subject(s)
Sensitivity and Specificity , Ghana/epidemiology , Humans , Female , Male , Adult , Adolescent , Child, Preschool , Young Adult , Child , Diagnostic Tests, Routine/methods , Parasitemia/epidemiology , Parasitemia/diagnosis , Malaria, Falciparum/diagnosis , Malaria, Falciparum/epidemiology , Middle Aged , Malaria/diagnosis , Malaria/epidemiology , Malaria/drug therapy , Plasmodium falciparum/isolation & purification , Plasmodium falciparum/genetics , Prevalence , Mass Screening/methods , Infant
2.
Ethiop J Health Sci ; 34(1): 39-46, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38957335

ABSTRACT

Background: Globally, there were 241 million cases of malaria in 2020, with an estimated 627,000 deaths with Nigeria accounting for 27% of the global malaria cases. In sub-Saharan Africa, testing is low with only 28% of children with a fever receiving medical advice or a rapid diagnostic test in 2021. In Nigeria, there are documented reports of over-diagnosis and over-treatment of malaria in children. Therefore, this study examined the diagnosis of malaria at the Benue State University Teaching Hospital, Makurdi. Methods: A 5-year (2018-2022) retrospective study was carried out at the Emergency Pediatric Unit (EPU). Records of all children presenting to the EPU with an assessment of malaria were retrieved and reviewed. Data was analyzed using SPSS 23. Results: Out of 206 children reviewed, 128 (62.1%) were tested using either malaria RDT or microscopy while 78(37.9%) were not tested. Out of the number tested, 59(46.1%) were negative while 69(53.9%) tested positive, of which 14(20.3%) had uncomplicated malaria while 55(79.7%) had severe malaria. However, while 97.1% (n=67) of the positive cases were treated with IV artesunate, 69.5% (n=41) of those who tested negative and 88.5% (69) of those who were not tested also received IV artesunate. Moreover, while 85.5% (n=59) of those who tested positive received oral artemisinin-based combination therapy (ACT), 72.9% (n=43) of those who tested negative and 67.9% (53) of those who were not tested also received oral ACT. Conclusion: There was over-diagnosis of malaria, and subsequently, over-treatment. Hence continued emphasis on parasitological confirmation of malaria before treatment is recommended.


Subject(s)
Antimalarials , Emergency Service, Hospital , Hospitals, Teaching , Malaria , Humans , Nigeria/epidemiology , Retrospective Studies , Child, Preschool , Hospitals, Teaching/statistics & numerical data , Female , Male , Child , Antimalarials/therapeutic use , Emergency Service, Hospital/statistics & numerical data , Malaria/diagnosis , Malaria/drug therapy , Malaria/epidemiology , Infant , Artemisinins/therapeutic use , Adolescent
3.
Int Marit Health ; 75(2): 103-108, 2024.
Article in English | MEDLINE | ID: mdl-38949218

ABSTRACT

BACKGROUND: The World Health Organization (WHO) reported an estimated 249 million malaria cases globally in 2023, of which 94% were reported from Africa. Tanzania, a Sub-Saharan African country, has an exceptionally high malaria prevalence (3.6 million in 2023). The aim of the present study was to assess malaria prevalence rates in the Arusha Region, northern Tanzania. This region is famous for its national parks and wildlife reserves, and it is visited by thousands of tourists from all over the world each year. The assessment of malaria prevalence in the region is important in the context of the necessity to administer antimalarial chemoprophylaxis to international travellers. MATERIAL AND METHODS: The study group consisted of 101 people, residents of the Karatu District in the Arusha Region, aged between 1 and 73 years, who volunteered to participate in the screening. Phase I of the study was conducted in July 2022 in the Karatu Lutheran Hospital in Karatu Town (located close to the Ngorongoro Conservation Area and the Serengeti National Park). During this phase a venous blood sample was collected from each patient. The samples were tested for malaria using a rapid diagnostic test (mRDT); the same samples were also used to measure haemoglobin concentration and next they were applied onto the Whatman FTA micro cards for further molecular diagnostics in Poland (phase II). RESULTS: mRDT detected two (2.0%) infections caused by Plasmodium (the etiological factor of malaria), the molecular tests (RT-PCR) confirmed the two positive results by mRDT but also detected infections in six other samples (7.9% in total). The study found that six patients were infected with the Plasmodium falciparum species, while two other subjects had co-infections (P. falciparum + P. ovale, P. falciparum + P. vivax + P. malariae). CONCLUSIONS: The study findings confirm the prevalence of malaria in areas located close to national parks in northern Tanzania and support the use of antimalarial chemoprophylaxis in international travellers visiting the area. The present study found co-infections caused by four different species of Plasmodium species which supports the prevalence of different parasitic species in Sub-Saharan Africa and is in line with CDC reports but contrary to WHO reports which estimate that 100% of malaria cases in Sub-Saharan Africa are caused by P. falciparum.


Subject(s)
Malaria , Humans , Tanzania/epidemiology , Prevalence , Adult , Middle Aged , Adolescent , Male , Female , Child , Aged , Young Adult , Child, Preschool , Malaria/epidemiology , Infant , Antimalarials/therapeutic use
4.
BMC Infect Dis ; 24(1): 664, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38961345

ABSTRACT

This paper introduces a novel approach to modeling malaria incidence in Nigeria by integrating clustering strategies with regression modeling and leveraging meteorological data. By decomposing the datasets into multiple subsets using clustering techniques, we increase the number of explanatory variables and elucidate the role of weather in predicting different ranges of incidence data. Our clustering-integrated regression models, accompanied by optimal barriers, provide insights into the complex relationship between malaria incidence and well-established influencing weather factors such as rainfall and temperature.We explore two models. The first model incorporates lagged incidence and individual-specific effects. The second model focuses solely on weather components. Selection of a model depends on decision-makers priorities. The model one is recommended for higher predictive accuracy. Moreover, our findings reveal significant variability in malaria incidence, specific to certain geographic clusters and beyond what can be explained by observed weather variables alone.Notably, rainfall and temperature exhibit varying marginal effects across incidence clusters, indicating their differential impact on malaria transmission. High rainfall correlates with lower incidence, possibly due to its role in flushing mosquito breeding sites. On the other hand, temperature could not predict high-incidence cases, suggesting that other factors other than temperature contribute to high cases.Our study addresses the demand for comprehensive modeling of malaria incidence, particularly in regions like Nigeria where the disease remains prevalent. By integrating clustering techniques with regression analysis, we offer a nuanced understanding of how predetermined weather factors influence malaria transmission. This approach aids public health authorities in implementing targeted interventions. Our research underscores the importance of considering local contextual factors in malaria control efforts and highlights the potential of weather-based forecasting for proactive disease management.


Subject(s)
Malaria , Weather , Humans , Malaria/epidemiology , Malaria/transmission , Incidence , Nigeria/epidemiology , Cluster Analysis , Regression Analysis , Temperature , Models, Statistical , Meteorological Concepts
5.
Sci Rep ; 14(1): 15399, 2024 07 04.
Article in English | MEDLINE | ID: mdl-38965406

ABSTRACT

If a mutated gene with heterozygous advantage against malaria, e.g., hemoglobin S (HbS) gene, is introduced in a small tribe, the gene (allele) frequency (fgene) increases until it reaches a steady state value (feq) where the total mortality from malaria and sickle cell disease is a minimum. This is a classic example of balanced-polymorphism named malaria hypothesis. In a previous in silico study, assuming realistic initial conditions, it has been shown that the feq is around 14%, far less than the fgene observed in certain parts of Africa, 24%. It seems that the malaria hypothesis, per se, could not explain such a high fgene, unless it is assumed that malaria and HbS gene can provide protection against other diseases. Using Monte-Carlo simulation, the current study was conducted to examine the effect on feq of five scenarios was examined. The studied scenarios consisted of different combinations of mortality of other diseases and the possible amounts of protections conferred by malaria and HbS gene against the diseases. Taking into account other diseases causing mortality in the population makes the fgene rate of change steeper over generations. feq is an increasing function of the amount of protection conferred by HbS gene against other diseases. The effect of protection provided by malaria against other diseases on feq, is however, variable-depending on the amount of protection conferred by HbS gene against other diseases, it may increase or decrease feq. If malaria and HbS gene provide protections of 1.5-fold and threefold against other diseases, respectively, the feq is around 24%, the amount reported in certain tribes of Africa. Under certain scenarios, the feq attained is even higher.


Subject(s)
Anemia, Sickle Cell , Gene Frequency , Hemoglobin, Sickle , Malaria , Humans , Malaria/prevention & control , Hemoglobin, Sickle/genetics , Anemia, Sickle Cell/genetics , Monte Carlo Method , Computer Simulation , Genetic Predisposition to Disease
6.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 36(3): 228-232, 2024 Apr 29.
Article in Chinese | MEDLINE | ID: mdl-38952306

ABSTRACT

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


Subject(s)
Malaria , Mosquito Vectors , Animals , Malaria/prevention & control , Malaria/transmission , Malaria/parasitology , Humans , Mosquito Vectors/parasitology , Anopheles/parasitology , Anopheles/genetics , Drug Resistance/genetics
7.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 36(3): 233-238, 2024 May 23.
Article in Chinese | MEDLINE | ID: mdl-38952307

ABSTRACT

Malaria is an infectious disease that seriously threatens human health. Currently, malaria control mainly depends on antimalarial chemotherapy. However, antimalarial drug resistance is becoming increasingly severe, which poses a great challenge to malaria control, notably treatment of Plasmodium falciparum malaria. To address this challenge, there is a need to facilitate development of novel antimalarial drugs and innovation of treatment strategies, as well as reinforce surveillance and research on antimalarial drug resistance. This article reviews the main categories and use guidelines of current antimalarial agents, summarizes the current status and monitoring methods of antimalarial drug resistance, and proposes the response to antimalarial drug resistance, so as to provide insights into the use of antimalarial drugs and response to antimalarial drug resistance, and contribute to global malaria elimination.


Subject(s)
Antimalarials , Drug Resistance , Malaria , Antimalarials/therapeutic use , Antimalarials/pharmacology , Humans , Malaria/drug therapy , Malaria/prevention & control , Disease Eradication/methods
8.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 36(3): 247-250, 2024 Apr 26.
Article in Chinese | MEDLINE | ID: mdl-38952310

ABSTRACT

Driven by international exchanges and climate changes, the invasion and spread of vector Anopheles mosquitoes posed a new challenge to achieving global malaria elimination. Taking the invasion of An. stephensi to exacerbate the malaria epidemic in Africa as an example, this article summarizes the current situation of global Anopheles invasion, and estimates the potential risk of vector Anopheles mosquitoes to unravel the difficulties and challenges in the global malaria elimination program, so as to provide insights into improved early earning and precision control of vector Anopheles mosquito invasion across the world.


Subject(s)
Anopheles , Introduced Species , Malaria , Mosquito Vectors , Malaria/prevention & control , Malaria/transmission , Animals , Anopheles/parasitology , Anopheles/physiology , Humans , Mosquito Vectors/parasitology , Mosquito Vectors/physiology , Disease Eradication/methods
9.
PLoS One ; 19(7): e0306289, 2024.
Article in English | MEDLINE | ID: mdl-38950022

ABSTRACT

Although the overall burden of malaria is decreasing in Ethiopia, a recent report of an unpredictable increased incidence may be related to the presence of community-wide gametocyte-carrier individuals and a high proportion of infected vectors. This study aimed to reveal the current prevalence of gametocyte-carriage and the sporozoite infectivity rate of Anopheles vectors for Plasmodium parasites. A community-based cross-sectional study was conducted from May 01 to June 30/2019. A total of 53 households were selected using systematic random sampling and a 242 study participants were recruited. Additionally,515 adult female Anopheles mosquitoes were collected using Center for Diseases Control and Prevention (CDC) light traps and mouth aspirators. Parasite gametocytemia was determined using giemsa stain microscopy, while sporozoite infection was determined by giemsa staining microscopy and enzyme linked immunosorbent assay (ELISA). Among the total 242 study participants, 5.4% (95%, CI = 2.9-8.3) of them were positive for any of the Plasmodium species gametocyte. Furthermore, being female [AOR = 15.5(95%, CI = 1.71-140.39)], age group between 15-29 years old [AOR = 16.914 (95%, CI = 1.781-160.63)], no ITNs utilization [AOR = 16.7(95%, CI = 1.902 -146.727)], and high asexual parasite density [(95%, CI = 0.057-0.176, P = 0.001, F = 18.402)] were identified as statistically significant factors for gametocyte carriage. Whereas sporozoite infection rate was 11.6% (95%, CI = 8.2-15.5) and 12.7% (95%, CI = 9.6-16.3) by microscopy and ELISA, respectively. Overall, this study indicated that malaria remains to be an important public health problem in Gondar Zuria district where high gametocyte carriage rate and sporozoite infection rate could sustain its transmission and burden. Therefore, in Ethiopia, where malaria elimination program is underway, frequent, and active community-based surveillance of gametocytemia and sporozoite infection rate is important.


Subject(s)
Anopheles , Mosquito Vectors , Sporozoites , Animals , Ethiopia/epidemiology , Humans , Anopheles/parasitology , Female , Adult , Sporozoites/physiology , Adolescent , Young Adult , Male , Cross-Sectional Studies , Mosquito Vectors/parasitology , Child , Child, Preschool , Malaria/epidemiology , Malaria/parasitology , Malaria/transmission , Middle Aged , Plasmodium/isolation & purification , Infant , Plasmodium falciparum/isolation & purification , Plasmodium falciparum/physiology , Prevalence
10.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 36(3): 243-246, 2024 May 22.
Article in Chinese | MEDLINE | ID: mdl-38952309

ABSTRACT

The insecticide resistance is becoming increasingly severe in malaria vectors and has become one of the most important threats to global malaria elimination. Currently, malaria vectors not only have developed high resistance to conventional insecticides, including organochlorine, organophosphates, carbamates, and pyrethroids, but also have been resistant to recently used neonicotinoids and pyrrole insecticides. This article describes the current status of global insecticide resistance in malaria vectors and global insecticide resistance management strategies, analyzes the possible major challenges in the insecticide resistance management, and proposes the response actions, so as to provide insights into global insecticide resistance management and contributions to global malaria elimination.


Subject(s)
Insecticide Resistance , Insecticides , Malaria , Animals , Humans , Insect Vectors/drug effects , Insect Vectors/parasitology , Insecticides/pharmacology , Malaria/prevention & control , Malaria/transmission , Mosquito Vectors/drug effects , Mosquito Vectors/parasitology
11.
F1000Res ; 13: 226, 2024.
Article in English | MEDLINE | ID: mdl-38948349

ABSTRACT

Objective: This scoping review will identify existing literature regarding contextual factors relevant to vector-control interventions to prevent malaria. We will use the findings of the scoping review to produce an interactive evidence and gap map. The map will assist in the priority setting, development, and conduct of targeted systematic reviews. These systematic reviews seek to assist the Vector Control and Insecticide Resistance Unit of the World Health Organization's Global Malaria Programme by informing recommendation development by their Guidelines Development Group. Introduction: Malaria contributes substantially to the global burden of disease, with an estimated 247 million cases and 619,000 deaths in 2021. Vector-control is key in reducing malaria transmission. Vector-control interventions directly target the mosquito, reducing the potential for parasite infections. These interventions commonly include insecticides used in indoor residual spraying or insecticide-treated nets and larval source management. Several new vector-control interventions are under evaluation to complement these. In addition to estimating the effects of interventions on health outcomes, it is critical to understand how populations at risk of malaria consider them in terms of their feasibility, acceptability, and values. Inclusion Criteria: Eligible studies will have assessed the contextual factors of feasibility or acceptability of the interventions of interest, or the valuation of the outcomes of interests. These assessments will be from the perspective of people who receive (residents) or deliver (workers or technicians) the vector-control intervention for the purpose of preventing malaria. Methods: We will conduct this scoping review in accordance with the JBI methodology for scoping reviews and report in line with the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews (PRISMA-ScR). We will construct the evidence and gap map following guidance from the Campbell Collaboration.


Subject(s)
Malaria , Mosquito Control , Malaria/prevention & control , Malaria/transmission , Humans , Mosquito Control/methods , Animals , Insecticides , Mosquito Vectors
12.
PLoS One ; 19(7): e0298512, 2024.
Article in English | MEDLINE | ID: mdl-38995958

ABSTRACT

Pyrethroids are the most widely used insecticides to control vector borne diseases including malaria. Physiological resistance mechanisms to these insecticides have been well described, whereas those for behavioral resistance remain overlooked. Field data suggest the presence of spatial sensory detection by Anopheles mosquitoes of the pyrethroid molecules used in insecticide-based control tools, such as long-lasting insecticide nets or insecticide residual spraying. This opens the way to the emergence of a wide range of behavioral adaptations among malaria vectors. However, the spatial sensory detection of these molecules is controversial and needs to be demonstrated. The goal of this study was to behaviorally characterize the non-contact detection of three of the most common pyrethroids used for malaria vector control: permethrin, deltamethrin an ⍺-cypermethrin. To reach this goal, we recorded the behavior (takeoff response) of Anopheles gambiae pyrethroid-sensitive and resistant laboratory strains, as well as field collected mosquitoes from the Gambiae Complex, when exposed to the headspace of bottles containing different doses of the insecticides at 25 and 35°C, in order to represent a range of laboratory and field temperatures. We found the proportion of laboratory susceptible and resistant female mosquitoes that took off was, in all treatments, dose and the temperature dependent. Sensitive mosquitoes were significantly more prone to take off only in the presence of ⍺-cypermethrin, whereas sensitive and resistant mosquitoes showed similar responses to permethrin and deltamethrin. Field-collected mosquitoes of the Gambiae Complex were also responsive to permethrin, independently of the species identity (An. gambiae, An. coluzzii and An. arabiensis) or their genotypes for the kdr mutation, known to confer resistance to pyrethroids. The observed ability of Anopheles spp. mosquitoes to detect insecticides without contact could favor the evolution of behavioral modifications that may allow them to avoid or reduce the adverse effect of insecticides and thus, the development of behavioral resistance.


Subject(s)
Anopheles , Insecticide Resistance , Insecticides , Mosquito Control , Mosquito Vectors , Pyrethrins , Animals , Anopheles/drug effects , Anopheles/physiology , Pyrethrins/pharmacology , Pyrethrins/toxicity , Insecticides/pharmacology , Insecticides/toxicity , Mosquito Vectors/drug effects , Mosquito Control/methods , Female , Nitriles/pharmacology , Permethrin/pharmacology , Malaria/transmission , Malaria/prevention & control
13.
BMC Complement Med Ther ; 24(1): 267, 2024 Jul 12.
Article in English | MEDLINE | ID: mdl-38997693

ABSTRACT

BACKGROUND: Malaria continues to wreak havoc on the well-being of the community. Resistant parasites are jeopardizing the treatment. This is a wake-up call for better medications. Folk plants are the key starting point for antimalarial drug discovery. After crushing and mixing the leaves of Coriandrum sativum with water, one cup of tea is drunk daily for a duration of three to five days as a remedy for malaria by local folks in Ethiopia. Additionally, in vitro experiments conducted on the plant leaf extract elsewhere have also demonstrated the plant's malaria parasite inhibitory effect. There has been no pharmacologic research to assert this endowment in animals, though. This experiment was aimed at evaluating the antimalarial efficacy of C. sativum in Plasmodium berghei infected mice. METHODS: The plant's leaf was extracted using maceration with distilled water. The extract was examined for potential acute toxicity. An evaluation of secondary phytoconstituents was done. Standard antimalarial screening models (prophylactic, chemosuppressive, curative tests) were utilized to assess the antiplasmodial effect. In each test, thirty mice were organized into groups of five. To the three categories, the test substance was given at doses of 100, 200 and 400 mg/kg/day before or after the commencement of P. berghei infection. Positive and negative control mice were provided Chloroquine and distilled water, respectively. Rectal temperature, parasitemia, body weight, survival time and packed cell volume were ultimately assessed. Analysis of the data was performed using Statistical Package for Social Sciences. RESULTS: No toxicity was manifested in mice. The extract demonstrated a significant inhibition of parasitemia (p < 0.05) in all the models. The inhibition of parasite load was highest with the upper dose in the suppressive test (82.74%) followed by the curative procedure (78.49%). Likewise, inhibition of hypothermia, weight loss hampering, improved survival and protection against hemolysis were elicited by the extract. CONCLUSIONS: The results of our experimental study revealed that the aqueous crude leaf extract of C. sativum exhibits significant antimalarial efficacy in multiple in vivo models involving mice infected with P. berghei. Given this promising therapeutic attribute, in depth investigation on the plant is recommended.


Subject(s)
Antimalarials , Coriandrum , Disease Models, Animal , Malaria , Plant Extracts , Plant Leaves , Plasmodium berghei , Animals , Plant Extracts/pharmacology , Antimalarials/pharmacology , Antimalarials/therapeutic use , Mice , Plasmodium berghei/drug effects , Malaria/drug therapy , Coriandrum/chemistry , Ethiopia , Male , Female
14.
PLoS One ; 19(7): e0305167, 2024.
Article in English | MEDLINE | ID: mdl-38968228

ABSTRACT

Malaria elimination in Southeast Asia remains a challenge, underscoring the importance of accurately identifying malaria mosquitoes to understand transmission dynamics and improve vector control. Traditional methods such as morphological identification require extensive training and cannot distinguish between sibling species, while molecular approaches are costly for extensive screening. Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as a rapid and cost-effective tool for Anopheles species identification, yet its current use is limited to few specialized laboratories. This study aimed to develop and validate an online reference database for MALDI-TOF MS identification of Southeast Asian Anopheles species. The database, constructed using the in-house data analysis pipeline MSI2 (Sorbonne University), comprised 2046 head mass spectra from 209 specimens collected at the Thailand-Myanmar border. Molecular identification via COI and ITS2 DNA barcodes enabled the identification of 20 sensu stricto species and 5 sibling species complexes. The high quality of the mass spectra was demonstrated by a MSI2 median score (min-max) of 61.62 (15.94-77.55) for correct answers, using the best result of four technical replicates of a test panel. Applying an identification threshold of 45, 93.9% (201/214) of the specimens were identified, with 98.5% (198/201) consistency with the molecular taxonomic assignment. In conclusion, MALDI-TOF MS holds promise for malaria mosquito identification and can be scaled up for entomological surveillance in Southeast Asia. The free online sharing of our database on the MSI2 platform (https://msi.happy-dev.fr/) represents an important step towards the broader use of MALDI-TOF MS in malaria vector surveillance.


Subject(s)
Anopheles , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Anopheles/genetics , Anopheles/classification , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Animals , Mosquito Vectors/genetics , Mosquito Vectors/classification , Malaria/transmission , Asia, Southeastern , Species Specificity , DNA Barcoding, Taxonomic/methods , Thailand , Southeast Asian People
15.
PLoS One ; 19(7): e0306664, 2024.
Article in English | MEDLINE | ID: mdl-38968270

ABSTRACT

BACKGROUNDS: Malaria, a preventive and treatable disease, is still responsible for annual deaths reported in most tropical regions, principally in sub-Saharan Africa. Subunit recombinant transmission-blocking vaccines (TBVs) have been proposed as promising vaccines to succeed in malaria elimination and eradication. Here, a provisional study was designed to assess the immunogenicity and functional activity of alanyl aminopeptidase N (APN1) of Anopheles stephensi, as a TBV candidate, administered with MPL, CpG, and QS21 adjuvants in the murine model. METHODOLOGY/PRINCIPAL FINDINGS: The mouse groups were immunized with recombinant APN1 (rAPN1) alone or formulated with CpG, MPL, QS-21, or a combination of adjuvants (CMQ), and the elicited immune responses were evaluated after the third immunization. The standard membrane feeding assay (SMFA) measured the functional activity of antibodies against bacterial-expressed APN1 protein in adjuvanted vaccine groups on transmission of P. falciparum (NF54) to An. stephensi mosquitoes. Evaluation of mice vaccinated with rAPN1 formulated with distinct adjuvants manifested a significant increase in the high-avidity level of anti-APN1 IgG and IgG subclasses; however, rAPN1 induced the highest level of high-avidity anti-APN1 IgG1, IgG2a, and IgG2b antibodies in the immunized vaccine group 5 (APN1/CMQ). In addition, vaccine group 5 (receiving APN1/CMQ), had still the highest level of anti-APN1 IgG antibodies relative to other immunized groups after six months, on day 180. The SMFA data indicates a trend towards higher transmission-reducing activity in groups 2 and 5, which received the antigen formulated with CpG or a combination of three adjuvants. CONCLUSIONS/SIGNIFICANCE: The results have shown the capability of admixture to stimulate high-affinity and long-lasting antibodies against the target antigen to hinder Plasmodium parasite development in the mid-gut of An. stephensi. The attained results authenticated APN1/CMQ and APN1/CpG as a potent APN1-based TBV formulation which will be helpful in designing a vaccine in the future.


Subject(s)
Adjuvants, Immunologic , Anopheles , CD13 Antigens , Malaria Vaccines , Saponins , Animals , Anopheles/parasitology , Anopheles/immunology , Adjuvants, Immunologic/pharmacology , Adjuvants, Immunologic/administration & dosage , Mice , Malaria Vaccines/immunology , Malaria Vaccines/administration & dosage , Saponins/pharmacology , Saponins/administration & dosage , CD13 Antigens/immunology , CD13 Antigens/metabolism , Female , Plasmodium falciparum/immunology , Malaria/prevention & control , Malaria/transmission , Malaria/immunology , Malaria/parasitology , Oligodeoxyribonucleotides/pharmacology , Oligodeoxyribonucleotides/administration & dosage , Oligodeoxyribonucleotides/immunology , Mice, Inbred BALB C , Malaria, Falciparum/prevention & control , Malaria, Falciparum/transmission , Malaria, Falciparum/immunology , Malaria, Falciparum/parasitology
16.
PLoS One ; 19(7): e0305207, 2024.
Article in English | MEDLINE | ID: mdl-38968330

ABSTRACT

Increasing reports of insecticide resistance continue to hamper the gains of vector control strategies in curbing malaria transmission. This makes identifying new insecticide targets or alternative vector control strategies necessary. CLassifier of Essentiality AcRoss EukaRyote (CLEARER), a leave-one-organism-out cross-validation machine learning classifier for essential genes, was used to predict essential genes in Anopheles gambiae and selected predicted genes experimentally validated. The CLEARER algorithm was trained on six model organisms: Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens, Mus musculus, Saccharomyces cerevisiae and Schizosaccharomyces pombe, and employed to identify essential genes in An. gambiae. Of the 10,426 genes in An. gambiae, 1,946 genes (18.7%) were predicted to be Cellular Essential Genes (CEGs), 1716 (16.5%) to be Organism Essential Genes (OEGs), and 852 genes (8.2%) to be essential as both OEGs and CEGs. RNA interference (RNAi) was used to validate the top three highly expressed non-ribosomal predictions as probable vector control targets, by determining the effect of these genes on the survival of An. gambiae G3 mosquitoes. In addition, the effect of knockdown of arginase (AGAP008783) on Plasmodium berghei infection in mosquitoes was evaluated, an enzyme we computationally inferred earlier to be essential based on chokepoint analysis. Arginase and the top three genes, AGAP007406 (Elongation factor 1-alpha, Elf1), AGAP002076 (Heat shock 70kDa protein 1/8, HSP), AGAP009441 (Elongation factor 2, Elf2), had knockdown efficiencies of 91%, 75%, 63%, and 61%, respectively. While knockdown of HSP or Elf2 significantly reduced longevity of the mosquitoes (p<0.0001) compared to control groups, Elf1 or arginase knockdown had no effect on survival. However, arginase knockdown significantly reduced P. berghei oocytes counts in the midgut of mosquitoes when compared to LacZ-injected controls. The study reveals HSP and Elf2 as important contributors to mosquito survival and arginase as important for parasite development, hence placing them as possible targets for vector control.


Subject(s)
Anopheles , Malaria , Mosquito Vectors , RNA Interference , Animals , Anopheles/genetics , Anopheles/parasitology , Malaria/prevention & control , Malaria/transmission , Malaria/parasitology , Mosquito Vectors/genetics , Mosquito Vectors/parasitology , Computational Biology/methods , Mice , Humans , Mosquito Control/methods , Genes, Essential , Female , Plasmodium berghei/genetics
17.
Malar J ; 23(1): 201, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38970076

ABSTRACT

BACKGROUND: Intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) reduces malaria-attributable adverse pregnancy outcomes and may also prevent low birth weight (< 2,500 g) through mechanisms independent of malaria. Malaria transmission in Papua New Guinea (PNG) is highly heterogeneous. The impact of IPTp-SP on adverse birth outcomes in settings with little or no malaria transmission, such as PNG's capital city Port Moresby, is unknown. METHODS: A retrospective cohort study was conducted amongst HIV-negative women with a singleton pregnancy who delivered at Port Moresby General Hospital between 18 July and 21 August 2022. The impact of IPTp-SP doses on adverse birth outcomes and anaemia was assessed using logistic and linear regression models, as appropriate. RESULTS: Of 1,140 eligible women amongst 1,228 consecutive births, 1,110 had a live birth with a documented birth weight. A total of 156 women (13.7%) did not receive any IPTp-SP, 347 women (30.4%) received one, 333 (29.2%) received two, and 304 (26.7%) received the recommended ≥ 3 doses of IPTp-SP. A total of 65 of 1,110 liveborn babies (5.9%) had low birth weight and there were 34 perinatal deaths (3.0%). Anaemia (haemoglobin < 100 g/L) was observed in 30.6% (243/793) of women, and 14 (1.2%) had clinical malaria in pregnancy. Compared to women receiving 0-1 dose of IPTp-SP, women receiving ≥ 2 doses had lower odds of LBW (adjusted odds ratio [aOR] 0.50; 95% confidence interval [CI] 0.26, 0.96), preterm birth (aOR 0.58; 95% CI 0.32, 1.04), perinatal death (aOR 0.49; 95% CI 0.18, 1.38), LBW/perinatal death (aOR 0.55; 95% CI 0.27, 1.12), and anaemia (OR 0.50; 95% CI 0.36, 0.69). Women who received 2 doses versus 0-1 had 45% lower odds of LBW (aOR 0.55, 95% CI 0.27, 1.10), and a 16% further (total 61%) reduction with ≥ 3 doses (aOR 0.39, 95% CI 0.14, 1.05). Birth weights for women who received 2 or ≥ 3 doses versus 0-1 were 81 g (95% CI -3, 166) higher, and 151 g (58, 246) higher, respectively. CONCLUSIONS: Provision of IPTp-SP in a low malaria-transmission setting in PNG appears to translate into substantial health benefits, in a dose-response manner, supporting the strengthening IPTp-SP uptake across all transmission settings in PNG.


Subject(s)
Antimalarials , Drug Combinations , Malaria , Pregnancy Outcome , Pyrimethamine , Sulfadoxine , Humans , Female , Pregnancy , Sulfadoxine/therapeutic use , Sulfadoxine/administration & dosage , Pyrimethamine/therapeutic use , Pyrimethamine/administration & dosage , Retrospective Studies , Papua New Guinea/epidemiology , Antimalarials/therapeutic use , Antimalarials/administration & dosage , Adult , Young Adult , Malaria/prevention & control , Pregnancy Complications, Parasitic/prevention & control , Infant, Low Birth Weight , Infant, Newborn , Adolescent , Cohort Studies
18.
BMJ Open ; 14(7): e081856, 2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38964800

ABSTRACT

INTRODUCTION: India's contribution to the malaria burden was highest in South-East Asia Region in 2021, accounting for 79% of the estimated malaria cases and 83% of malaria-related deaths. Intensified Malaria Control Programme supported by Global Funds to Fight against AIDS, Tuberculosis and Malaria has deployed crucial interventions to reduce the overall burden of malaria in India. Evaluation of utilisation of malaria elimination interventions by the community and assessment of the healthcare system is underway in eleven high malaria endemic states in India. Health system preparedness for malaria elimination, logistics, and supply chain management of diagnostic kits and anti-malarial drugs in addition to the knowledge, attitude and practice of the healthcare workers is also being assessed. METHODS AND ANALYSIS: The study is being undertaken in 11 malaria endemic states with a variable annual parasite incidence of malaria. In total, 47 districts (administrative unit of malaria control operations) covering 37 976 households are to be interviewed and assessed. We present here the protocol following which the study is being undertaken at the behest and approval of Ministry of Health and Family Welfare in India. ETHICS AND DISSEMINATION: No patients were involved in the study. Study findings will be shared with Institutional ethics board of National Institute for Malaria Research New Delhi (NIMR) in a timely, comprehensive, accurate, unbiased, unambiguous and transparent manner and to the National Vector-borne Disease (Malaria) Control Programme officers and the Community public who participated. Important findings will be communicated through community outreach meetings which are existing in the Health system. Results will be informed to study participants via local fieldwork supervised by District Malaria Officers. Also findings will be published in reputed journals based on Indian Council of Medical Research (ICMR) publication policy.The ICMR-NIMR ethics committee approved the study via letter No. NIMR/ECM/2023/Feb/14 dated 24 April 2023 for version 5. All standard ethical practices will be followed.


Subject(s)
Endemic Diseases , Malaria , Humans , India/epidemiology , Malaria/epidemiology , Malaria/prevention & control , Cross-Sectional Studies , Research Design , Antimalarials/therapeutic use , Health Knowledge, Attitudes, Practice , Delivery of Health Care
19.
PLoS One ; 19(7): e0306776, 2024.
Article in English | MEDLINE | ID: mdl-38968218

ABSTRACT

BACKGROUND: Despite significant reductions in recent malaria cases and deaths globally, the persistence of this health concern necessitates a shift from traditional top-down approaches. Consequently, malaria control initiatives increasingly focus on empowering local communities through community-centred strategies. Therefore, this scoping review protocol systematically explores diverse community knowledge approaches adopted in malaria programmes worldwide and their associated outcomes. METHODS: Adhering rigorously to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines, a comprehensive scoping review protocol was developed. Collaborating with a research librarian, a systematic search strategy targeted peer-reviewed literature from databases such as PubMed, Embase, Scopus, and Web of Science, complemented by a thorough grey literature search. Titles and abstracts will be screened, followed by extracting bibliographic details and outcome information using a standardized framework. Subsequently, the results will be systematically summarized and presented in a structured tabular format (S1 Checklist). DISCUSSION: This scoping review promises an in-depth understanding of current research regarding the impact of community knowledge in malaria programmes. The identification of knowledge gaps and intervention needs serves as a valuable resource for malaria-affected countries. The profound implications of community knowledge underscore its pivotal role in enhancing the effectiveness of prevention, control, and elimination efforts. Insights from this review will assist policymakers, empowering implementers and community leaders in designing effective interventions. This concerted effort aims to adeptly leverage community knowledge, thereby propelling progress toward the achievement of malaria elimination goals.


Subject(s)
Malaria , Humans , Health Knowledge, Attitudes, Practice , Malaria/prevention & control , Review Literature as Topic
20.
Parasitol Res ; 123(7): 262, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38970660

ABSTRACT

Malaria poses a significant threat to global health, with particular severity in Nigeria. Understanding key factors influencing health outcomes is crucial for addressing health disparities. Disease mapping plays a vital role in assessing the geographical distribution of diseases and has been instrumental in epidemiological research. By delving into the spatiotemporal dynamics of malaria trends, valuable insights can be gained into population dynamics, leading to more informed spatial management decisions. This study focused on examining the evolution of malaria in Nigeria over twenty years (2000-2020) and exploring the impact of environmental factors on this variation. A 5-year-period raster map was developed using malaria indicator survey data for Nigeria's six geopolitical zones. Various spatial analysis techniques, such as point density, spatial autocorrelation, and hotspot analysis, were employed to analyze spatial patterns. Additionally, statistical methods, including Principal Component Analysis, Spearman correlation, and Ordinary Least Squares (OLS) regression, were used to investigate relationships between indicators and develop a predictive model. The study revealed regional variations in malaria prevalence over time, with the highest number of cases concentrated in northern Nigeria. The raster map illustrated a shift in the distribution of malaria cases over the five years. Environmental factors such as the Enhanced Vegetation Index, annual land surface temperature, and precipitation exhibited a strong positive association with malaria cases in the OLS model. Conversely, insecticide-treated bed net coverage and mean temperature negatively correlated with malaria cases in the same model. The findings from this research provide valuable insights into the spatiotemporal patterns of malaria in Nigeria and highlight the significant role of environmental drivers in influencing disease transmission. This scientific knowledge can inform policymakers and aid in developing targeted interventions to combat malaria effectively.


Subject(s)
Geographic Information Systems , Malaria , Spatio-Temporal Analysis , Nigeria/epidemiology , Malaria/epidemiology , Malaria/transmission , Humans , Prevalence
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