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Malaria Journal May 2023Understanding malaria epidemiology is a critical step toward efficient malaria control and elimination. The objective of this meta-analysis was to derive robust... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Understanding malaria epidemiology is a critical step toward efficient malaria control and elimination. The objective of this meta-analysis was to derive robust estimates of malaria prevalence and Plasmodium species from studies conducted in Mauritania and published since 2000.
METHODS
The present review followed the PRISMA guidelines. Searches were conducted in various electronic databases such as PubMed, Web of Science, and Scopus. To obtain pooled prevalence of malaria, meta-analysis was performed using the DerSimonian-Laird random-effects model. Methodological quality of eligible prevalence studies was assessed using Joanna Briggs Institute tool. Inconsistency and heterogeneity between studies were quantified by the I index and Cochran's Q test. Publication bias was assessed with funnel plots and Egger's regression tests.
RESULTS
A total of 16 studies with a good individual methodological quality were included and analysed in this study. The overall random effects pooled prevalence of malaria infection (symptomatic and asymptomatic) across all included studies was 14.9% (95% confidence interval [95% CI]: 6.64, 25.80, I = 99.8%, P < 0.0001) by microscopy, 25.6% (95% CI: 8.74, 47.62, I = 99.6%, P < 0.0001) by PCR and 24.3% (95% CI: 12.05 to 39.14, I = 99.7%, P < 0.0001) by rapid diagnostic test. Using microscopy, the prevalence of asymptomatic malaria was 1.0% (95% CI: 0.00, 3.48) against 21.46% (95% CI: 11.03, 34.21) in symptomatic malaria. The overall prevalence of Plasmodium falciparum and Plasmodium vivax was 51.14% and 37.55%, respectively. Subgroup analysis showed significant variation (P = 0.039) in the prevalence of malaria between asymptomatic and symptomatic cases.
CONCLUSION
Plasmodium falciparum and P. vivax are widespread in Mauritania. Results of this meta-analysis implies that distinct intervention measures including accurate parasite-based diagnosis and appropriate treatment of confirmed malaria cases are critical for a successful malaria control and elimination programme in Mauritania.
Topics: Humans; Prevalence; Mauritania; Malaria; Malaria, Vivax; Plasmodium; Plasmodium vivax; Plasmodium falciparum; Malaria, Falciparum
PubMed: 37131226
DOI: 10.1186/s12936-023-04569-4 -
Heliyon Apr 2023Malaria is one of the major public health issues globally. Malaria infection spreads through mosquito bites from infected female Anopheles mosquitoes. This study aims to...
Malaria is one of the major public health issues globally. Malaria infection spreads through mosquito bites from infected female Anopheles mosquitoes. This study aims to conduct a systematic review and meta-analysis on malaria prevalence in Pakistan from 2006 to 2021. We searched PubMed, Science Direct, EMBASE, EMCare, and Google Scholar to acquire data on the prevalence of malaria infections. We performed a meta-analysis with a random-effects model to obtain the pooled prevalence of malaria, Plasmodium vivax, and Plasmodium falciparum. Meta-analysis was computed using R 4.1.2 Version statistical software. I and time series analysis were performed to identify a possible source of heterogeneity across studies. A funnel plot and the Freeman-Tukey Double Arcsine Transformed Proportion were used to evaluate the presence of publication bias. Out of the 315 studies collected, only 45 full-text articles were screened and included in the final measurable meta-analysis. Pooled malaria prevalence in Pakistan was 23.3%, with , , and mixed infection rates of 79.13%, 16.29%, and 3.98%, respectively. Similarly, the analysis revealed that the maximum malaria prevalence was 99.79% in Karachi and the minimum was 1.68% in the Larkana district. Amazingly, this systematic review and meta-analysis detected a wide variation in malaria prevalence in Pakistan. Pakistan's public health department and other competent authorities should pay close attention to the large decrease in mosquito populations to curb the infection rate.
PubMed: 37123939
DOI: 10.1016/j.heliyon.2023.e15373 -
The Lancet. Global Health Apr 2023Humanitarian emergencies can lead to population displacement, food insecurity, severe health system disruptions, and malaria epidemics among individuals who are... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Humanitarian emergencies can lead to population displacement, food insecurity, severe health system disruptions, and malaria epidemics among individuals who are immunologically naive. We aimed to assess the impact of different vector control interventions on malaria disease burden during humanitarian emergencies.
METHODS
In this systematic review and meta-analysis, we searched ten electronic databases and two clinical trial registries from database inception to Oct 19, 2020, with no restrictions on language or study design. We also searched grey literature from 59 stakeholders. Studies were eligible if the population was affected by a humanitarian emergency in a malaria endemic region. We included studies assessing any vector control intervention and in which the primary outcome of interest was malaria infection risk. Reviewers (LAM, JF-A, KC, BP, and LP) independently extracted information from eligible studies, without masking of author or publication, into a database. We did random-effects meta-analyses to calculate pooled risk ratios (RRs) for randomised controlled trials, odds ratios (ORs) for dichotomous outcomes, and incidence rate ratios (IRR) for clinical malaria in non-randomised studies. Certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. This study is registered with PROSPERO, CRD42020214961.
FINDINGS
Of 12 475 studies screened, 22 studies were eligible for inclusion in our meta-analysis. All studies were conducted between Sept 1, 1989, and Dec 31, 2018, in chronic emergencies, with 616 611 participants from nine countries, evaluating seven different vector control interventions. Insecticide-treated nets significantly decreased Plasmodium falciparum incidence (RR 0·55 [95% CI 0·37-0·79]; high certainty) and Plasmodium vivax incidence (RR 0·69 [0·51-0·94]; high certainty). Evidence for an effect of indoor residual spraying on P falciparum (IRR 0·57 [95% CI 0·53-0·61]) and P vivax (IRR 0·51 [0·49-0·52]) incidence was of very low certainty. Topical repellents were associated with reductions in malaria infection (RR 0·58 [0·35-0·97]; moderate certainty). Moderate-to-high certainty evidence for an effect of insecticide-treated chaddars (equivalent to shawls or blankets) and insecticide-treated cattle on malaria outcomes was evident in some emergency settings. There was very low certainty evidence for the effect of insecticide-treated clothing.
INTERPRETATION
Study findings strengthen and support WHO policy recommendations to deploy insecticide-treated nets during chronic humanitarian emergencies. There is an urgent need to evaluate and adopt novel interventions for malaria control in the acute phase of humanitarian emergencies.
FUNDING
WHO Global Malaria Programme.
Topics: Humans; Animals; Cattle; Insecticides; Emergencies; Malaria; Malaria, Falciparum; Plasmodium falciparum
PubMed: 36925174
DOI: 10.1016/S2214-109X(23)00044-X -
Parasites & Vectors Dec 2022The production of Plasmodium gametocytes in vitro is a real challenge. Many protocols have been described, but few have resulted in the production of viable and... (Review)
Review
BACKGROUND
The production of Plasmodium gametocytes in vitro is a real challenge. Many protocols have been described, but few have resulted in the production of viable and infectious gametocytes in sufficient quantities to conduct research on-but not limited to-transmission-blocking drug and vaccine development. The aim of this review was to identify and discuss gametocyte production protocols that have been developed over the last two decades.
METHODS
We analyzed the original gametocyte production protocols published from 2000 onwards based on a literature search and a thorough review. A systematic review was performed of relevant articles identified in the PubMed, Web of Sciences and ScienceDirect databases.
RESULTS
A total 23 studies on the production of Plasmodium gametocytes were identified, 19 involving in vitro Plasmodium falciparum, one involving Plasmodium knowlesi and three involving ex vivo Plasmodium vivax. Of the in vitro studies, 90% used environmental stressors to trigger gametocytogenesis. Mature gametocytemia of up to 4% was reported.
CONCLUSIONS
Several biological parameters contribute to an optimal production in vitro of viable and infectious mature gametocytes. The knowledge gained from this systematic review on the molecular mechanisms involved in gametocytogenesis enables reproducible gametocyte protocols with transgenic parasite lines to be set up. This review highlights the need for additional gametocyte production protocols for Plasmodium species other than P. falciparum.
Topics: Humans; Malaria, Falciparum; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Systematic Reviews as Topic
PubMed: 36471426
DOI: 10.1186/s13071-022-05566-3 -
Malaria Journal Nov 2022This review article aims to investigate the genotypic profiles of Plasmodium falciparum and Plasmodium vivax isolates collected across a wide geographic region and their... (Review)
Review
This review article aims to investigate the genotypic profiles of Plasmodium falciparum and Plasmodium vivax isolates collected across a wide geographic region and their association with resistance to anti-malarial drugs used in Indonesia. A systematic review was conducted between 1991 and date. Search engines, such as PubMed, Science Direct, and Google Scholar, were used for articles published in English and Indonesian to search the literature. Of the 471 initially identified studies, 61 were selected for 4316 P. falciparum and 1950 P. vivax individual infections. The studies included 23 molecular studies and 38 therapeutic efficacy studies. K76T was the most common pfcrt mutation. K76N (2.1%) was associated with the haplotype CVMNN. By following dihydroartemisinin-piperaquine (DHA-PPQ) therapy, the mutant pfmdr1 alleles 86Y and 1034C were selected. Low prevalence of haplotype N86Y/Y184/D1246Y pfmdr1 reduces susceptibility to AS-AQ. SNP mutation pvmdr1 Y976F reached 96.1% in Papua and East Nusa Tenggara. Polymorphism analysis in the pfdhfr gene revealed 94/111 (84.7%) double mutants S108N/C59R or S108T/A16V in Central Java. The predominant pfdhfr haplotypes (based on alleles 16, 51, 59,108, 164) found in Indonesia were ANCNI, ANCSI, ANRNI, and ANRNL. Some isolates carried A437G (35.3%) or A437G/K540E SNPs (26.5%) in pfdhps. Two novel pfdhps mutant alleles, I588F/G and K540T, were associated with six pfdhps haplotypes. The highest prevalence of pvdhfr quadruple mutation (F57L/S58R/T61M/S117T) (61.8%) was detected in Papua. In pvdhps, the only polymorphism before and after 2008 was 383G mutation with 19% prevalence. There were no mutations in the pfk13 gene reported with validated and candidate or associated k13 mutation. An increased copy number of pfpm2, associated with piperaquine resistance, was found only in cases of reinfection. Meanwhile, mutation of pvk12 and pvpm4 I165V is unlikely associated with ART and PPQ drug resistance. DHA-PPQ is still effective in treating uncomplicated falciparum and vivax malaria. Serious consideration should be given to interrupt local malaria transmission and dynamic patterns of resistance to anti-malarial drugs to modify chemotherapeutic policy treatment strategies. The presence of several changes in pfk13 in the parasite population is of concern and highlights the importance of further evaluation of parasitic ART susceptibility in Indonesia.
Topics: Plasmodium vivax; Plasmodium falciparum; Indonesia; Antimalarials; Artemisinins; Polymorphism, Single Nucleotide; Drug Resistance
PubMed: 36443817
DOI: 10.1186/s12936-022-04385-2 -
Biomedica : Revista Del Instituto... Jun 2022Introduction: Tafenoquine was approved in 2018 by the Food and Drug Administration in the United States and in 2019 by the Therapeutic Goods Administration in Australia.... (Meta-Analysis)
Meta-Analysis
Introduction: Tafenoquine was approved in 2018 by the Food and Drug Administration in the United States and in 2019 by the Therapeutic Goods Administration in Australia. Its administration in a single dose and its mechanism of action in the acute and latent phases of the disease have been studied to change the treatment regimen for Plasmodium vivax malaria. Objective: To evaluate the available scientific evidence of the efficacy of tafenoquine in prophylaxis and treatment between 2009 and 2019. Materials and methods: We established the MeSH and DeCS descriptors and we used the syntax ((Malaria Vivax) AND (tafenoquine) AND (prophylaxis)) OR [(Malaria Vivax) AND (tafenoquine) AND (relapse)] in the following databases: Pubmed, The Cochrane Central Register of Controlled Clinical Trials (CENTRAL), ISIS Web of Science, Lilacs, and Scopus. The results obtained were subjected to critical analysis (CASPE matrix). The quantitative analysis was performed with risk differences in survival analysis (Kaplan Meier) in the final three articles. Results: Three studies underwent meta-analysis (Llanos-Cuentas, 2014; Llanos-Cuentas, 2019, and Lacerda, 2019) to evaluate the efficacy of the treatment with tafenoquine compared to primaquine. A global risk difference of 0.04 was obtained (95% CI: 0.00-0.08; p=0.07). Tafenoquine did not show inferiority in the efficacy of treatment compared to the primaquine scheme. Conclusion: Tafenoquine is a therapeutic alternative to primaquine that improves adherence, which could bring Colombia closer to the goals of the World Technical Strategy against Malaria 2016-2030.
Topics: Colombia; Plasmodium vivax; Retrospective Studies
PubMed: 35867928
DOI: 10.7705/biomedica.5988 -
PLoS Neglected Tropical Diseases Jun 2022In areas with both Plasmodium vivax and Plasmodium falciparum malaria, interventions can reduce the burden of both species but the impact may vary due to their different...
BACKGROUND
In areas with both Plasmodium vivax and Plasmodium falciparum malaria, interventions can reduce the burden of both species but the impact may vary due to their different biology. Knowing the expected relative impact on the two species over time for vector- and drug-based interventions, and the factors affecting this, could help plan and evaluate intervention strategies.
METHODS
For three interventions (treated bed nets (ITN), mass drug administration (MDA) and indoor residual spraying (IRS)), we identified studies providing information on the proportion of clinical illness and patent infections attributed to P. vivax over time using a literature search. The change in the proportion of malaria attributed to P. vivax up to two years since implementation was estimated using logistic regression accounting for clustering with random effects. Potential factors (intervention type, coverage, relapse pattern, transmission intensity, seasonality, initial proportion of P. vivax and round of intervention) were assessed.
RESULTS
In total there were 55 studies found that led to 72 series of time-points for clinical case data and 69 series for patent infection data. The main reason of study exclusion was insufficient information on interventions. There was considerable variation in the proportion of malaria attributed to P. vivax over time by study and location for all of the interventions. Overall, there was an increase apart from MDA in the short-term. The potential factors could not be ruled in or out. Although not consistently significant, coverage, transmission intensity and relapse pattern are possible factors that explain some of the variation found.
CONCLUSION
While there are reports of an increase in the proportion of malaria due to P. vivax following interventions in the long-term, there was substantial variation for the shorter time-scales considered in this study (up to 24 months for IRS and ITN, and up to six months for MDA). The large variability points to the need for the monitoring of both species after an intervention. Studies should report intervention timing and characteristics to allow inclusion in systematic reviews.
Topics: Humans; Malaria; Malaria, Falciparum; Malaria, Vivax; Plasmodium falciparum; Plasmodium vivax; Recurrence
PubMed: 35767578
DOI: 10.1371/journal.pntd.0010541 -
The Lancet Regional Health. Southeast... Jul 2022The long-term maintenance of parasite biomass below the detection threshold of microscopy may stymie malaria elimination. Variation in microscopists' competencies to...
BACKGROUND
The long-term maintenance of parasite biomass below the detection threshold of microscopy may stymie malaria elimination. Variation in microscopists' competencies to detect and correctly identify parasite species reflect in microscopy sensitivity, resulting in incorrect species-specific burden.
METHODS
The study estimated SMI pooled burden from published reports using a random effect model & identifies their hotspots in India. The study applied a prediction model for the first time on Indian data, emphasizing the importance of such models that can predict PCR-prevalence from slide- prevalence.
FINDINGS
A total of 17,449 samples from 39 districts were examined for by microscopy and PCR. The overall heterogeneity in clinic-based and community-based studies was 91% and 96%, respectively, with the pooled prevalence of 3.63%. The SMI prevalence in individual studies ranged from 38.4% to 0.4%. Sensitivity of microscopy for mono- (91%) was found to be better than mono- (82 %). But surprisingly, it was much lower for mixed PfPv (45%).
INTERPRETATION
Primary regional data in the form of SMIs hot spots should be generated from countries on the verge of malaria elimination, and genetic monitoring should be integrated into national programs, particularly in key areas for successful malaria elimination.
FUNDING
Not applicable.
PubMed: 37383294
DOI: 10.1016/j.lansea.2022.05.001 -
SAGE Open Medicine 2022Active detection of asymptomatic malaria cases and resolution of associated factors are essential for malaria elimination. There are no nationwide estimates for... (Review)
Review
Active detection of asymptomatic malaria cases and resolution of associated factors are essential for malaria elimination. There are no nationwide estimates for asymptomatic malaria and associated factors in Ethiopia. Therefore, this study aims to generate comprehensive and conclusive evidence from various studies conducted in Ethiopia. Published articles from various electronic databases such as PubMed, Google Scholar, CINAHL, Scopes, Cochrane Library, the Web of Science, and African Journals Online were accessed. Also, unpublished studies from Addis Ababa digital library were identified. All observational study designs were included in the search. Data were extracted on the Microsoft Excel spreadsheet and analyzed using STATA version 14.1. A random-effects model was fitted to estimate the pooled prevalence of asymptomatic malaria. A meta-regression and subgroup analysis was computed to see heterogeneity. The publication bias was assessed by the funnel plots and Egger's statistical tests. The analysis found that the pooled burden of asymptomatic malaria was 6.7 (95% confidence interval = 4.60, 8.79). The pooled prevalence of Plasmodium falciparum was 3.75 (95% confidence interval = 2.25, 5.18), and that of Plasmodium vivax was 2.22 (95% confidence interval = 1.46, 2.99). Factors such indoor residual spray service (odds ratio = 0.46; 95% confidence interval = 0.26, 0.81), never used insecticide-treated nets (odds ratio = 6.36; 95% confidence interval = 4.01, 10.09), and presence of stagnant water in the vicinity (odds ratio = 3.24; 95% confidence interval = 1.20, 8.71) were found to have a significant association with asymptomatic malaria. This study highlighted that pooled prevalence of asymptomatic malaria is high and varied by population groups. Prevalence of asymptomatic malaria was increased among those who never used insecticide-treated nets and were living near stagnant water by six and three times, respectively. The use of more sensitive diagnostic methods could yield a higher burden of the disease. Furthermore, active case detection is recommended for effective intervention toward elimination.
PubMed: 35433001
DOI: 10.1177/20503121221088085 -
Scientific Reports Mar 2022A better understanding of the occurrence and risk of Plasmodium vivax infection among Duffy-negative individuals is required to guide further research on these... (Meta-Analysis)
Meta-Analysis
A better understanding of the occurrence and risk of Plasmodium vivax infection among Duffy-negative individuals is required to guide further research on these infections across Africa. To address this, we used a meta-analysis approach to investigate the prevalence of P. vivax infection among Duffy-negative individuals and assessed the risk of infection in these individuals when compared with Duffy-positive individuals. This study was registered with The International Prospective Register of Systematic Reviews website (ID: CRD42021240202) and followed Preferred Reporting Items for Systematic review and Meta-Analyses guidelines. Literature searches were conducted using medical subject headings to retrieve relevant studies in Medline, Web of Science, and Scopus, from February 22, 2021 to January 31, 2022. Selected studies were methodologically evaluated using the Joanna Briggs Institute (JBI) Critical Appraisal Tools to assess the quality of cross-sectional, case-control, and cohort studies. The pooled prevalence of P. vivax infection among Duffy-negative individuals and the odds ratio (OR) of infection among these individuals when compared with Duffy-positive individuals was estimated using a random-effects model. Results from individual studies were represented in forest plots. Heterogeneity among studies was assessed using Cochrane Q and I statistics. We also performed subgroup analysis of patient demographics and other relevant variables. Publication bias among studies was assessed using funnel plot asymmetry and the Egger's test. Of 1593 retrieved articles, 27 met eligibility criteria and were included for analysis. Of these, 24 (88.9%) reported P. vivax infection among Duffy-negative individuals in Africa, including Cameroon, Ethiopia, Sudan, Botswana, Nigeria, Madagascar, Angola, Benin, Kenya, Mali, Mauritania, Democratic Republic of the Congo, and Senegal; while three reported occurrences in South America (Brazil) and Asia (Iran). Among studies, 11 reported that all P. vivax infection cases occurred in Duffy-negative individuals (100%). Also, a meta-analysis on 14 studies showed that the pooled prevalence of P. vivax infection among Duffy-negative individuals was 25% (95% confidence interval (CI) - 3%-53%, I = 99.96%). A meta-analysis of 11 studies demonstrated a decreased odds of P. vivax infection among Duffy-negative individuals (p = 0.009, pooled OR 0.46, 95% CI 0.26-0.82, I = 80.8%). We confirmed that P. vivax infected Duffy-negative individuals over a wide prevalence range from 0 to 100% depending on geographical area. Future investigations on P. vivax infection in these individuals must determine if Duffy-negativity remains a protective factor for P. vivax infection.
Topics: Brazil; Cross-Sectional Studies; Humans; Kenya; Malaria, Vivax; Plasmodium vivax; Prevalence
PubMed: 35256675
DOI: 10.1038/s41598-022-07711-5