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Travel Medicine and Infectious Disease 2017With increased international travel over the world the need for safe and effective chemoprophylaxis for malaria is as great as ever. The choice of regimen is difficult,... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
With increased international travel over the world the need for safe and effective chemoprophylaxis for malaria is as great as ever. The choice of regimen is difficult, as effectiveness should be weighted against potential adverse effects. Although, some studies have reported high prophylactic efficacy of primaquine, there is no comprehensive evidence comparing its prophylactic effectiveness as well as toxicity. To fill the gap, this systematic review and meta-analysis study was carried out.
METHODS
Using MeSH terms, 756 records were detected through searching "Pubmed", "Embase","Web of Science"and "Cochrane" databases. From these,7 relevant full-text articles with 14 comparisons for final quantitative meta-analysis were included in our review. In order to make a comparison between the studies, Risk Ratios(RRs) and their 95% confidence intervals(CIs) were estimated.
RESULTS
Overall,74% reduction in the incidence of parasitaemia by primaquine versus other prophylactic regimens was estimated(RRoverall = 0.26, CI 95%:0.16-0.41--RRvivax = 0.16, CI 95%:0.07-0.36--RRfalciparum = 0.31, CI 95%:0.18-0.55). The incidence rate ratios for adverse effects showed no statistically significant difference between primaquine and control groups (p > 0.05).
CONCLUSIONS
For persons without G6PD deficiency, who are not pregnant, primaquine is the most effective presently available prophylactic for P. vivax malaria and comparable to such regimens as doxycycline, mefloquine and atovaquone-proguanil for the prevention of P. falciparum malaria.
Topics: Antibiotic Prophylaxis; Antimalarials; Humans; Malaria, Falciparum; Malaria, Vivax; Parasitemia; Plasmodium falciparum; Plasmodium vivax; Primaquine; Travel
PubMed: 28450185
DOI: 10.1016/j.tmaid.2017.04.005 -
Malaria Journal Dec 2021Ethiopia is one of the few countries in Africa where Plasmodium vivax commonly co-exists with Plasmodium falciparum, and which accounts for ~ 40% of the total number... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Ethiopia is one of the few countries in Africa where Plasmodium vivax commonly co-exists with Plasmodium falciparum, and which accounts for ~ 40% of the total number of malaria infections in the country. Regardless of the growing evidence over many decades of decreasing sensitivity of this parasite to different anti-malarial drugs, there has been no comprehensive attempt made to systematically review and meta-analyse the efficacy of different anti-malarial drugs against P. vivax in the country. However, outlining the efficacy of available anti-malarial drugs against this parasite is essential to guide recommendations for the optimal therapeutic strategy to use in clinical practice. The aim of this study was to synthesize evidence on the efficacy of anti-malarial drugs against clinical P. vivax malaria in Ethiopia.
METHODS
All potentially relevant, peer-reviewed articles accessible in PubMed, Scopus, Web of Science, and Clinical Trial.gov electronic databases were retrieved using a search strategy combining keywords and related database-specific subject terms. Randomized controlled trials (RCTs) and non-randomized trials aiming to investigate the efficacy of anti-malarial drugs against P. vivax were included in the review. Data were analysed using Review Manager Software. Cochrane Q (χ) and the I tests were used to assess heterogeneity. The funnel plot and Egger's test were used to examine risk of publication bias.
RESULTS
Out of 1294 identified citations, 14 articles that presented data on 29 treatment options were included in the analysis. These studies enrolled 2144 clinical vivax malaria patients. The pooled estimate of in vivo efficacy of anti-malarial drugs against vivax malaria in Ethiopia was 97.91% (95% CI: 97.29-98.52%), with significant heterogeneity (I = 86%, p < 0.0001) and publication bias (Egger's test = -12.86, p < 0.001). Different anti-malarial drugs showed varied efficacies against vivax malaria. The duration of follow-up significantly affected the calculated efficacy of any given anti-malarial drug, with longer duration of the follow-up (42 days) associated with significantly lower efficacy than efficacy reported on day 28. Also, pooled PCR-corrected efficacy and efficacy estimated from altitudinally lower transmission settings were significantly higher than PCR-uncorrected efficacy that estimated for moderate transmission settings, respectively.
CONCLUSION
The overall efficacy of anti-malarial drugs evaluated for the treatment of vivax malaria in Ethiopia was generally high, although there was wide-ranging degree of efficacy, which was affected by the treatment options, duration of follow-up, transmission intensity, and the confirmation procedures for recurrent parasitaemia. Regardless of evidence of sporadic efficacy reduction reported in the country, chloroquine (CQ), the first-line regimen in Ethiopia, remained highly efficacious, supporting its continuous utilization for confirmed P. vivax mono-infections. The addition of primaquine (PQ) to CQ is recommended, as this is the only approved way to provide radical cure, and thus ensure sustained efficacy and longer protection against P. vivax. Continuous surveillance of the efficacy of anti-malarial drugs and clinical trials to allow robust conclusions remains necessary to proactively act against possible emergence and spread of drug-resistant P. vivax in Ethiopia.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antimalarials; Child; Child, Preschool; Ethiopia; Female; Humans; Infant; Malaria, Vivax; Male; Middle Aged; Non-Randomized Controlled Trials as Topic; Plasmodium vivax; Randomized Controlled Trials as Topic; Young Adult
PubMed: 34952581
DOI: 10.1186/s12936-021-04016-2 -
PloS One 2021Knowledge about malaria associated with pregnancy is scarce in Latin America, and in Colombia, little is known about the magnitude of this infection. A systematic review... (Meta-Analysis)
Meta-Analysis
Knowledge about malaria associated with pregnancy is scarce in Latin America, and in Colombia, little is known about the magnitude of this infection. A systematic review was conducted to determine the prevalence of malaria associated with pregnancy (MAP) and each of its three forms: gestational (GM), placental (PM), and congenital (CM) tested using thick blood smear (TBS) and PCR. Also to compare the proportion of cases due to Plasmodium falciparum and Plasmodium vivax in Colombia from the year 2000-2020. We searched in Pubmed, Science Direct, EMBASE, EMCare, Cochrane Library, Scielo, Lilacs, Google Scholar, libraries, and repositories of Colombian universities, to obtain data on prevalence of GM, PM and CM with their respective testing method. We performed a meta-analysis with a random-effects model to obtain pooled prevalence of MAP and its three forms categorized by testing methods (TBS and PCR). We used data from 14 studies (out of 258 screened) contributing 7932, 2506 women for GM and PM respectively, also data on 1143 umbilical cord blood samples, and 899 peripheral blood of neonates. We found prevalence by TBS as, MAP 4.5% (95%CI = 2.9-6.9), GM 5.8% (95%CI = 3.8-8.7), PM 3.4% (95%CI = 1.7-6.7) and CM 1.3% (95%CI = 0.6-3.0). With PCR the prevalence was, MAP 14.4% (95%CI = 7.6-25.5), GM 16.7% (95%CI = 9.0-28.8), PM 11.0% (95%CI = 4.1-26.3) and CM 16.2% (95%CI = 8.2-29.5). The prevalence of submicroscopic infection was 8.5% (95%CI = 3.4-19.7) in GM, 10.1% (95%CI = 3.5-25.5) in PM and 22.0% (95%CI = 13.2-34.3) in CM. Infections by P. vivax was dominant over P. falciparum when tested with TBS, the PCR test gave similar proportions of P. falciparum and P. vivax. This meta-analysis has demonstrated high prevalence of MAP in Colombia, and highlights the urgent need to increase attention of researchers, research funding institutions, government agencies, and health authorities to study and intervene MAP, that has currently been under investigated.
Topics: Colombia; Female; Humans; Malaria, Falciparum; Malaria, Vivax; Plasmodium falciparum; Plasmodium vivax; Pregnancy; Pregnancy Complications, Parasitic
PubMed: 34329329
DOI: 10.1371/journal.pone.0255028 -
Value in Health Regional Issues Dec 2015The objective of this study was to evaluate the burden of malaria in Latin America and the Caribbean countries through a systematic review and meta-analysis of published... (Review)
Review
OBJECTIVE
The objective of this study was to evaluate the burden of malaria in Latin America and the Caribbean countries through a systematic review and meta-analysis of published literature, gray literature, and information from countries' public health authorities for the period 1990 to 2009.
METHODS
The random-effects meta-analysis of the prospective studies, carried out in very highly endemic areas, showed an annual incidence rate of 409.0 malaria episodes/1000 person-years (95% confidence interval [CI] 263.1-554.9), considering all ages, which was 40-fold the one estimated from areas with passive surveillance only.
RESULTS
Overall, the most prevalent species was Plasmodium vivax (77.5%; 95% CI 75.6-79.4) followed by Plasmodium falciparum (20.8%; 95% CI 19.0-22.6) and Plasmodium malariae (0.08%; 95% CI 0.07-0.010). Data from regional ministries of health yielded an estimated pooled crude annual mortality rate of 6 deaths/100,000 people, mainly associated with P. falciparum.
CONCLUSION
This study represents the first systematic review of the burden of malaria in Latin America and the Caribbean, with data from 21 countries.
PubMed: 29698174
DOI: 10.1016/j.vhri.2015.05.002 -
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 -
Scientific Reports Dec 2020Plasmodium ovale is a benign tertian malaria parasite that morphologically resembles Plasmodium vivax. P. ovale also shares similar tertian periodicity and can cause... (Meta-Analysis)
Meta-Analysis
Plasmodium ovale is a benign tertian malaria parasite that morphologically resembles Plasmodium vivax. P. ovale also shares similar tertian periodicity and can cause relapse in patients without a radical cure, making it easily misidentified as P. vivax in routine diagnosis. Therefore, its prevalence might be underreported worldwide. The present study aimed to quantify the prevalence of P. ovale misidentified as P. vivax malaria using data from studies reporting confirmed P. ovale cases by molecular methods. Studies reporting the misidentification of P. ovale as P. vivax malaria were identified from three databases, MEDLINE, Web of Science, and Scopus, without language restrictions, but the publication date was restricted to 1993 and 2020. The quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). The random-effects model was used to estimate the pooled prevalence of the misidentification of P. ovale as P. vivax malaria by the microscopic method when compared to those with the reference polymerase chain reaction method. Subgroup analysis of participants was also performed to demonstrate the difference between imported and indigenous P. ovale cases. The heterogeneity of the included studies was assessed using Cochran's Q and I statistics. Publication bias across the included studies was assessed using the funnel plot and Egger's test, and if required, contour-enhanced funnel plots were used to identify the source(s) of funnel plot asymmetry. Of 641 articles retrieved from databases, 22 articles met the eligibility criteria and were included in the present study. Of the 8,297 malaria-positive cases identified by the PCR method, 453 P. ovale cases were confirmed. The pooled prevalence of misidentification of P. ovale as P. vivax malaria by the microscopic method was 11% (95% CI: 7-14%, I: 25.46%). Subgroup analysis of the participants demonstrated a higher prevalence of misidentification in indigenous cases (13%, 95% CI: 6-21%, I: 27.8%) than in imported cases (10%, 95% CI: 6-14%, I: 24.1%). The pooled prevalence of misidentification of P. vivax as P. ovale malaria by the microscopic method was 1%, without heterogeneity (95% CI: 0-3%, I: 16.8%). PCR was more sensitive in identifying P. ovale cases than the microscopic method (p < 0.00001, OR: 2.76, 95% CI: 1.83-4.15, I: 65%). Subgroup analysis of participants demonstrated the better performance of PCR in detecting P. ovale malaria in indigenous cases (p: 0.0009, OR: 6.92, 95% CI: 2.21-21.7%, I: 68%) than in imported cases (p: 0.0004, OR: 2.15, 95% CI: 1.41-3.29%, I: 63%). P. ovale infections misidentified as P. vivax malaria by the microscopic method were frequent and led to underreported P. ovale cases. The molecular identification of P. ovale malaria in endemic areas is needed because a higher rate of P. ovale misidentification was found in endemic or indigenous cases than in imported cases. In addition, updated courses, enhanced training, and refreshers for microscopic examinations, particularly for P. ovale identification, are necessary to improve the microscopic identification of Plasmodium species in rural health centres where PCR is unavailable.
Topics: Diagnostic Errors; Humans; Malaria, Vivax; Microscopy; Plasmodium ovale; Plasmodium vivax
PubMed: 33311528
DOI: 10.1038/s41598-020-78691-7 -
Malaria Journal Nov 2014Recommended vector control tools against malaria, such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), mainly target mosquitoes that rest... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Recommended vector control tools against malaria, such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), mainly target mosquitoes that rest and feed on human hosts indoors. However, in some malaria-endemic areas, such as Southeast Asia and South America, malaria vectors primarily bite outdoors meaning that LLINs and IRS may be less effective. In these situations the use of topical insect repellents may reduce outdoor biting and morbidity from malaria. A systematic review and meta-analysis was conducted to assess the efficacy of topical insect repellents against malaria.
METHODS
Studies were identified using database searches (MEDLINE, EMBASE, Web of Science and clinical trials registers), as well as reference list searches and contact with researchers. Randomized and non-randomized controlled trials were included that assessed the effect of topical repellents (all active ingredients and concentrations) on Plasmodium falciparum or Plasmodium vivax malaria or infection in malaria-endemic populations. Meta-analysis of clinical data was conducted in order to generate summary risk ratios.
RESULTS
Ten trials met the inclusion criteria. Studies varied in terms of repellent active ingredient and formulation, co-interventions, study population, compliance, and follow-up period. Topical repellents showed an 18% protective efficacy against P. falciparum malaria, although this was not significant (95% CI: -8%, 38%). Similarly, the average protective efficacy of topical repellents against P. vivax malaria did not reach significance (protective efficacy: 20%, 95% CI: -37%, 53%). Exclusion of non-randomized trials from the meta-analysis did not alter the findings.
CONCLUSIONS
Although topical repellents can provide individual protection against mosquitoes, the results of this meta-analysis indicate that topical repellents are unlikely to provide effective protection against malaria. However, there was substantial heterogeneity between studies included and the relatively small number of studies meant that this heterogeneity could not be fully explored in the analysis. Further well-designed trials of topical repellents at appropriate doses and alternative modes of repellent delivery, such as spatial repellents and long-lasting insecticide-treated clothing, are required.
Topics: Endemic Diseases; Humans; Insect Repellents; Malaria, Falciparum; Malaria, Vivax; Randomized Controlled Trials as Topic; Treatment Outcome
PubMed: 25413142
DOI: 10.1186/1475-2875-13-446 -
Malaria Journal Sep 2015Multiple studies in various parts of the world have analysed the association of nutritional status on malaria using anthropometric measures, but results differ due to... (Review)
Review
BACKGROUND
Multiple studies in various parts of the world have analysed the association of nutritional status on malaria using anthropometric measures, but results differ due to the heterogeneity of the study population, species of the parasite, and other factors involved in the host and parasite relationship. The aim of this study was to perform a systematic review on the inter-relationship of nutritional status based on anthropometry and malarial infection.
METHODS
Two independent reviewers accessed the MEDLINE and LILACS databases using the same search terms related to malaria and anthropometry. Prospective studies associating anthropometry and malaria (incidence or severity) were selected. References from the included studies and reviews were used to increase the review sensitivity. Data were extracted using a standardized form and the quality of the prospective studies was assessed. Selected articles were grouped based on exposures and outcomes.
RESULTS
The search identified a total of 1688 studies: 1629 from MEDLINE and 59 from LILACS. A total of 23 met the inclusion criteria. Five additional studies were detected by reading the references of the 23 included studies and reviews, totaling 28 studies included. The mean sample size was 662.1 people, ranging from 57 to 5620. The mean follow-up was 365.8 days, ranging from 14 days to 1 year and 9 months, and nine studies did not report the follow-up period. Prospective studies assessing the relationship between malaria and malnutrition were mostly carried out in Africa. Of the 20 studies with malarial outcomes, fifteen had high and five had average quality, with an average score of 80.5 %. Most anthropometric parameters had no association with malaria incidence (47/52; 90.4 %) or parasite density (20/25; 80 %). However, the impact of malnutrition was noted in malaria mortality and severity (7/17; 41.2 %). Regarding the effects of malaria on malnutrition, malaria was associated with very few anthropometric parameters (8/39; 20.6 %).
CONCLUSIONS
This systematic review found that most of the evidence associating malaria and malnutrition comes from P. falciparum endemic areas, with a significant heterogeneity in studies' design. Apparently malnutrition has not a great impact on malaria morbidity, but could have a negative impact on malaria mortality and severity. Most studies show no association between malaria and subsequent malnutrition in P. falciparum areas. In Plasmodium vivax endemic areas, malaria was associated with malnutrition in children. A discussion among experts in the field is needed to standardize future studies to increase external validity and accuracy.
Topics: Adolescent; Adult; Anthropometry; Child; Child, Preschool; Humans; Infant; Infant, Newborn; Malaria, Falciparum; Malaria, Vivax; Nutritional Status; Observational Studies as Topic; Plasmodium falciparum; Plasmodium vivax; Young Adult
PubMed: 26377094
DOI: 10.1186/s12936-015-0870-5 -
Malaria Journal Feb 2017Transfusion-transmitted (TT) malaria is an alternative infection route that has gained little attention from authorities, despite representing a life-threatening... (Review)
Review
BACKGROUND
Transfusion-transmitted (TT) malaria is an alternative infection route that has gained little attention from authorities, despite representing a life-threatening condition. There has been no systematic review of this health problem in American countries. The aim of this study was to describe the clinical and epidemiological characteristics of TT malaria in the Americas and identify factors associated with lethality based on the studies published in the literature.
METHODS
Potentially relevant papers in all languages were retrieved from MEDLINE and LILACS. Additional articles were obtained from reviews and original papers. Publications on screening of candidate blood donors and on surveillance of TT malaria cases were included. Odds ratios with respective 95% confidence intervals (95% CI) were calculated. Epidemiological characteristics of blood donors of TT malaria cases, including a pooled positivity of different tests for malaria diagnosis, were retrieved.
RESULTS
A total of 63 publications regarding TT malaria from seven countries were included, from 1971 to 2016. A total of 422 cases of TT malaria were recorded. Most TT malaria cases were in females (62.0%) and 39.5% were in the ≥61 years-old age group. About half of all cases were from Mexico (50.7%), 40.3% from the United States of America (USA) and 6.6% from Brazil. Gyneco-obstetrical conditions (67.3%), surgical procedures (20.6%) and complications from neoplasias (6.1%) were the most common indications of transfusion. Packed red blood cells (RBCs) (50.7%) and whole blood (43.3%) were the blood products mostly associated with TT malaria. Cases were mostly caused by Plasmodium malariae (58.4%), followed by Plasmodium vivax (20.7%) and Plasmodium falciparum (17.9%). A total of 66.6% of cases were diagnosed by microscopy. Incubation period of 2-3 weeks was the most commonly observed (28.6%). Lethality was seen in 5.3% of cases and was associated with living in non-endemic countries, P. falciparum infection and concomitant neoplastic diseases.
CONCLUSION
There is an important research and knowledge gap regarding the TT malaria burden in Latin American countries where malaria remains endemic. No screening method that is practical, affordable and suitably sensitive is available at blood banks in Latin American countries, where infections with low parasitaemia contribute greatly to transmission. Lethality from TT malaria was not negligible. TT malaria needs to be acknowledged and addressed in areas moving toward elimination.
Topics: Brazil; Disease Transmission, Infectious; Humans; Malaria; Mexico; Plasmodium falciparum; Plasmodium malariae; Plasmodium vivax; Survival Analysis; Transfusion Reaction; United States
PubMed: 28202065
DOI: 10.1186/s12936-017-1726-y -
Nutrients Aug 2023Vitamin E has an antioxidant property and is associated with protection against malaria. The current study used systematic review and meta-analysis approaches examining... (Meta-Analysis)
Meta-Analysis Review
Vitamin E has an antioxidant property and is associated with protection against malaria. The current study used systematic review and meta-analysis approaches examining the variance in blood levels of vitamin E in malaria patients as compared with uninfected individuals. The protocol for the systematic review was registered with PROSPERO (CRD4202341481). Searches for pertinent studies were carried out on Embase, MEDLINE, Ovid, PubMed, Scopus, ProQuest, and Google Scholar. The combined effect estimate (Cohen's d) of the difference in vitamin E levels in malaria patients as compared with uninfected individuals was estimated using the random effects model. The searches yielded 2009 records, and 23 studies were included in the systematic review. The majority of the studies (80%) found that vitamin E levels were significantly lower in malaria patients than those who were not infected. Overall, the results revealed a significant reduction in blood levels of vitamin E in malaria patients when compared with uninfected individuals ( < 0.01, Cohen's d: -2.74, 95% CI: -3.72-(-1.76), I: 98.69%, 21 studies). There was a significant reduction in blood levels of vitamin E in patients suffering from severe malaria, in comparison with those experiencing less severe forms of the disease ( < 0.01, Cohen's d: -0.56, 95% CI: -0.85-(-0.26), I: 0%, 2 studies), but no variation in blood levels of vitamin E among patients suffering from either or malaria ( = 0.13, Cohen's d: -1.15, 95% CI: -2.62-0.33, I: 93.22%, 3 studies). In summary, the present study strongly suggests that vitamin E levels are significantly reduced in malaria patients, with a more pronounced decrease observed in cases of severe malaria. However, the type of malaria parasite, specifically or , did not appear to influence the levels of vitamin E. This study highlights the potential role of vitamin E in the pathogenesis of malaria and suggests that improved vitamin E status might be beneficial for improving disease outcomes.
Topics: Humans; Vitamin E; Malaria; Malaria, Vivax; Antioxidants
PubMed: 37571409
DOI: 10.3390/nu15153472