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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 -
Parasitology Nov 2023Of the 5 human malarial parasites, and are the most prevalent species globally, while and are less prevalent and typically occur as mixed-infections. , previously... (Review)
Review
Of the 5 human malarial parasites, and are the most prevalent species globally, while and are less prevalent and typically occur as mixed-infections. , previously considered a non-human primate (NHP) infecting species, is now a cause of human malaria in Malaysia. The other NHP species, , , , , and cause malaria in primates, which are mainly reported in southeast Asia and South America. The non- NHP species also emerged and were found to cross-transmit from their natural hosts (NHP) – to human hosts in natural settings. Here we have reviewed and collated data from the literature on the NHPs-to-human-transmitting species. It was observed that the natural transmission of these NHP parasites to humans had been reported from 2010 onwards. This study shows that: (1) the majority of the non- NHP mixed species infecting human cases were from Yala province of Thailand; (2) mono/mixed infections with other human-infecting species were prevalent in Malaysia and Thailand and (3) and were found in Central and South America.
Topics: Animals; Humans; Malaria; Plasmodium knowlesi; Primates; Asia, Southeastern; Plasmodium vivax
PubMed: 37929579
DOI: 10.1017/S003118202300077X -
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 -
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 -
The Cochrane Database of Systematic... Jul 2007Four types of malaria vaccine, SPf66 and MSP/RESA vaccines (against the asexual stages of the Plasmodium parasite) and CS-NANP and RTS,S vaccines (against the sporozoite... (Review)
Review
BACKGROUND
Four types of malaria vaccine, SPf66 and MSP/RESA vaccines (against the asexual stages of the Plasmodium parasite) and CS-NANP and RTS,S vaccines (against the sporozoite stages), have been tested in randomized controlled trials in endemic areas.
OBJECTIVES
To assess malaria vaccines against Plasmodium falciparum, P. vivax, P. malariae and P ovale in preventing infection, disease and death.
SEARCH STRATEGY
We searched the Cochrane Infectious Diseases Group Specialized Register (April 2004), CENTRAL (The Cochrane Library Issue 2, 2004), MEDLINE (1966 to April 2004), EMBASE (1980 to April 2004), Science Citation Index (1981 to April 2004), and reference lists of articles. We also contacted organizations and researchers in the field.
SELECTION CRITERIA
Randomized controlled trials comparing vaccines against Plasmodium falciparum, P. vivax, P. malariae or P. ovale with placebo or routine antimalarial control measures in people of any age receiving a challenge malaria infection.
DATA COLLECTION AND ANALYSIS
Two reviewers independently assessed trial quality and extracted data.
MAIN RESULTS
Eighteen efficacy trials involving 10,971 participants were included. There were ten trials of SPf66 vaccine, four trials of CS-NANP vaccines, two trials of RTS,S vaccine, and two of MSP/RESA vaccine. Results with SPf66 in reducing new malaria infections (P. falciparum) were heterogeneous: it was not effective in four African trials (Peto odds ratio (OR) 0.96, 95% confidence interval (CI) 0.81 to 1.14), but in five trials outside Africa the number of first attacks was reduced (Peto OR 0.77, 95% CI 0.67 to 0.88). Trials to date have not indicated any serious adverse events with SPf66 vaccine. In three trials of CS-NANP vaccines, there was no evidence for protection by these vaccines against P. falciparum malaria (Peto OR 1.12, 95% CI 0.64 to 1.93). In a small trial in non-immune adults in the USA, RTS,S gave strong protection against experimental infection with P. falciparum. In a trial in an endemic area of the Gambia in semi-immune people, there was a reduction in clinical malaria episodes in the second year of follow up, corresponding to a vaccine efficacy of 66% (CI 14% to 85%). In a trial in Papua New Guinea, MSP/RESA had no protective effect against episodes of clinical malaria. There was evidence of an effect on parasite density, but this differed according to whether the participants had been pretreated with sulfadoxine/pyrimethamine or not. The prevalence of infections with the parasite subtype of MSP2 in the vaccine was reduced compared with the other subtype (Peto OR 0.35, CI 0.23 to 0.53).
AUTHORS' CONCLUSIONS
There is no evidence for protection by SPf66 vaccines against P. falciparum in Africa. There is a modest reduction in attacks of P. falciparum malaria following vaccination with SPf66 in other regions. Further research with SPf66 vaccines in South America or with new formulations of SPf66 may be justified. There was not enough evidence to evaluate the use of CS-NANP vaccines. The RTS,S vaccine showed promising result, as did the MSP/RESA vaccine, but it should include the other main allelic form of MSP2. The MSP/RESA trial demonstrated that chemotherapy during a vaccine trial may reduce vaccine efficacy, and trials should consider very carefully whether this practice is justified.
Topics: Adult; Antigens, Protozoan; Humans; Malaria; Malaria Vaccines; Malaria, Falciparum; Protozoan Proteins; Randomized Controlled Trials as Topic; Recombinant Proteins; Vaccines, Synthetic
PubMed: 17636596
DOI: 10.1002/14651858.CD000129.pub2 -
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 -
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 -
The Cochrane Database of Systematic... Jan 2007Plasmodium vivax infections contribute to a significant proportion of the malaria infections in many countries. Primaquine is the most widely used drug for treating the... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Plasmodium vivax infections contribute to a significant proportion of the malaria infections in many countries. Primaquine is the most widely used drug for treating the dormant liver stage. Different primaquine dosing regimens are in use.
OBJECTIVES
To compare primaquine regimens for preventing relapses in people with P. vivax malaria.
SEARCH STRATEGY
In 2006, we searched the Cochrane Infectious Diseases Group's Specialized Register (January), CENTRAL (The Cochrane Library 2006, Issue 3), MEDLINE (October), EMBASE (January), LILACS (January). We also checked conference proceedings and reference lists, and contacted researchers, the World Health Organization (WHO), malaria mailing lists, and pharmaceutical companies.
SELECTION CRITERIA
Randomized and quasi-randomized controlled trials comparing primaquine plus chloroquine with chloroquine alone, and the standard primaquine regimen (15 mg/day for 14 days) with other primaquine-containing regimens in people with vivax malaria.
DATA COLLECTION AND ANALYSIS
All authors independently assessed trial eligibility and quality, and extracted data. We calculated odds ratios (OR) with 95% confidence intervals (CI) for dichotomous data, and used the random-effects model if there was significant heterogeneity.
MAIN RESULTS
Nine trials (3423 participants) met the inclusion criteria. Compared with chloroquine alone, five-day primaquine plus chloroquine was no better at preventing relapses (OR 1.04, 95% CI 0.64 to 1.69, random-effects model; 2104 participants; 3 trials), while 14-day primaquine plus chloroquine was significantly better (OR 0.24, 95% CI 0.12 to 0.45, random-effects model; 1071 participants, 6 trials). Limited data suggest the advantage for the 14-day primaquine regimen persisted for over six months (OR 0.41, 95% CI 0.29 to 0.60; 585 participants, 2 trials). Direct comparisons of the 14-day and five-day primaquine plus chloroquine regimens also confirm the superiority of the longer course (OR 13.33, 95% CI 3.45 to 51.44; 186 participants, 2 trials). Adverse effects were poorly reported, with three trials reporting skin rash, vertigo, headache, abdominal pain and/or nausea, and two trials reporting that primaquine was well tolerated.
AUTHORS' CONCLUSIONS
Primaquine (15 mg/kg/day for 14 days) plus chloroquine is more effective than chloroquine alone or primaquine (15 mg/kg for 5 days) plus chloroquine in preventing relapses of vivax malaria. Primaquine (five days) plus chloroquine appears no better than chloroquine. Countries should follow the WHO's recommendation for 14-day primaquine plus chloroquine regimen. Alternative regimens need to be evaluated in randomized controlled trials, which should also consider variations in regional P. vivax strains and the possibility of primaquine resistance, reinfection, and adherence in those who relapse.
Topics: Adult; Antimalarials; Child; Chloroquine; Humans; Malaria, Vivax; Primaquine; Randomized Controlled Trials as Topic; Secondary Prevention
PubMed: 17253504
DOI: 10.1002/14651858.CD004389.pub2 -
International Journal of Environmental... Jan 2021Coinfection of malaria and intestinal helminths affects one third of the global population, largely among communities with severe poverty. The spread of these parasitic... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Coinfection of malaria and intestinal helminths affects one third of the global population, largely among communities with severe poverty. The spread of these parasitic infections overlays in several epidemiological locations and the host shows different outcomes. This systematic review and meta-analysis determine the pooled prevalence of malaria and intestinal helminthiases coinfections among malaria suspected patients in Ethiopia.
METHODS
Primary studies published in English language were retrieved using appropriate search terms on Google Scholar, PubMed/MEDLINE, CINHAL, Scopus, and Embase. The Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) was used for critical appraisal of studies. A pooled statistical meta-analysis was conducted using STATA Version 14.0 software. The heterogeneity and publication bias were assessed using the I2 statistics and Egger's test, respectively. Duval and Tweedie's nonparametric trim and fill analysis using the random-effect analysis. The Random effects model was used to estimate the summary prevalence of comorbidity of malaria and soil transmitted helminthiases and the corresponding 95% confidence intervals (CI). The review protocol has registered in PROSPERO number CRD42019144803.
RESULTS
We identified ten studies ( = 6633 participants) in this study. The overall pooled result showed 13% of the ambulatory patients infected by malaria and intestinal helminths concurrently in Ethiopia. The pooled prevalence of and , and mixed infections were 12, 30, and 6%, respectively. The most common intestinal helminth parasites detected were , , and .
CONCLUSIONS
The comorbidity of malaria and intestinal helminths causes lower hemoglobin level leading to maternal anemia, preterm delivery, and still birth in pregnant women and lactating mother. School-aged children and neonates coinfected by plasmodium species and soil transmitted helminths develop cognitive impairment, protein energy malnutrition, low birth weight, small for gestational age, and gross motor delay. The Ministry of Health of Ethiopia and its international partners working on malaria elimination programs should give more emphasis to the effect of the interface of malaria and soil transmitted helminths, which calls for an integrated disease control and prevention.
Topics: Animals; Child; Comorbidity; Ethiopia; Female; Health Facilities; Helminths; Humans; Infant, Newborn; Lactation; Malaria; Outpatients; Pregnancy; Prevalence
PubMed: 33498343
DOI: 10.3390/ijerph18030862 -
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