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The Lancet. Global Health Dec 2020The burden of malaria infection in sub-Saharan Africa among school-aged children aged 5-15 years is underappreciated and represents an important source of... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The burden of malaria infection in sub-Saharan Africa among school-aged children aged 5-15 years is underappreciated and represents an important source of human-to-mosquito transmission of Plasmodium falciparum. Additional interventions are needed to control and eliminate malaria. We aimed to assess whether preventive treatment of malaria might be an effective means of reducing P falciparum infection and anaemia in school-aged children and lowering parasite transmission.
METHODS
In this systematic review and two meta-analyses, we searched the online databases PubMed, Embase, Cochrane CENTRAL, and Clinicaltrials.gov for intervention studies published between Jan 1, 1990, and Dec 14, 2018. We included randomised studies that assessed the effect of antimalarial treatment among asymptomatic school-aged children aged 5-15 years in sub-Saharan Africa on prevalence of P falciparum infection and anaemia, clinical malaria, and cognitive function. We first extracted data for a study-level meta-analysis, then contacted research groups to request data for an individual participant data meta-analysis. Outcomes of interest included prevalence of P falciparum infection detected by microscopy, anaemia (study defined values or haemoglobin less than age-adjusted and sex-adjusted values), clinical malaria (infection and symptoms on the basis of study-specific definitions) during follow-up, and code transmission test scores. We assessed effects by treatment type and duration of time protected, and explored effect modification by transmission setting. For study-level meta-analysis, we calculated risk ratios for binary outcomes and standardised mean differences for continuous outcomes and pooled outcomes using fixed-effect and random-effects models. We used a hierarchical generalised linear model for meta-analysis of individual participant data. This study is registered with PROSPERO, CRD42016030197.
FINDINGS
Of 628 studies identified, 13 were eligible for the study-level meta-analysis (n=16 309). Researchers from 11 studies contributed data on at least one outcome (n=15 658) for an individual participant data meta-analysis. Interventions and study designs were highly heterogeneous; overall risk of bias was low. In the study-level meta-analysis, treatment was associated with reductions in P falciparum prevalence (risk ratio [RR] 0·27, 95% CI 0·17-0·44), anaemia (0·77, 0·65-0·91), and clinical malaria (0·40, 0·28-0·56); results for cognitive outcomes are not presented because data were only available for three trials. In our individual participant data meta-analysis, we found treatment significantly decreased P falciparum prevalence (adjusted RR [ARR] 0·46, 95% CI 0·40-0·53; p<0·0001; 15 648 individuals; 11 studies), anaemia (ARR 0·85, 0·77-0·92; p<0·0001; 15 026 individuals; 11 studies), and subsequent clinical malaria (ARR 0·50, 0·39-0·60; p<0·0001; 1815 individuals; four studies) across transmission settings. We detected a marginal effect on cognitive function in children older than 10 years (adjusted mean difference in standardised test scores 0·36, 0·01-0·71; p=0·044; 3962 individuals; five studies) although we found no significant effect when combined across all ages.
INTERPRETATION
Preventive treatment of malaria among school-aged children significantly decreases P falciparum prevalence, anaemia, and risk of subsequent clinical malaria across transmission settings. Policy makers and programme managers should consider preventive treatment of malaria to protect this age group and advance the goal of malaria elimination, while weighing these benefits against potential risks of chemoprevention.
FUNDING
US National Institutes of Health and Burroughs Wellcome Fund/ASTMH Fellowship.
Topics: Adolescent; Africa South of the Sahara; Antimalarials; Child; Child, Preschool; Humans; Malaria
PubMed: 33222799
DOI: 10.1016/S2214-109X(20)30325-9 -
Malaria Journal Sep 2023Global interest in malaria elimination has prompted research on active test and treat (TaT) strategies. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Global interest in malaria elimination has prompted research on active test and treat (TaT) strategies.
METHODS
A systematic review and meta-analysis were conducted to assess the effectiveness of TaT strategies to reduce malaria transmission.
RESULTS
A total of 72 empirical research and 24 modelling studies were identified, mainly focused on proactive mass TaT (MTaT) and reactive case detection (RACD) in higher and lower transmission settings, respectively. Ten intervention studies compared MTaT to no MTaT and the evidence for impact on malaria incidence was weak. No intervention studies compared RACD to no RACD. Compared to passive case detection (PCD) alone, PCD + RACD using standard diagnostics increased infection detection 52.7% and 11.3% in low and very low transmission settings, respectively. Using molecular methods increased this detection of infections by 1.4- and 1.1-fold, respectively.
CONCLUSION
Results suggest MTaT is not effective for reducing transmission. By increasing case detection, surveillance data provided by RACD may indirectly reduce transmission by informing coordinated responses of intervention targeting.
Topics: Humans; Malaria
PubMed: 37661286
DOI: 10.1186/s12936-023-04670-8 -
PLoS Neglected Tropical Diseases Feb 2015Toxoplasmosis is an important, widespread, parasitic infection caused by Toxoplasma gondii. The chronic infection in immunocompetent patients, usually considered as... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Toxoplasmosis is an important, widespread, parasitic infection caused by Toxoplasma gondii. The chronic infection in immunocompetent patients, usually considered as asymptomatic, is now suspected to be a risk factor for various neurological disorders, including epilepsy. We aimed to conduct a systematic review and meta-analysis of the available literature to estimate the risk of epilepsy due to toxoplasmosis.
METHODS
A systematic literature search was conducted of several databases and journals to identify studies published in English or French, without date restriction, which looked at toxoplasmosis (as exposure) and epilepsy (as disease) and met certain other inclusion criteria. The search was based on keywords and suitable combinations in English and French. Fixed and random effects models were used to determine odds ratios, and statistical significance was set at 5.0%.
PRINCIPAL FINDINGS
Six studies were identified, with an estimated total of 2888 subjects, of whom 1280 had epilepsy (477 positive for toxoplasmosis) and 1608 did not (503 positive for toxoplasmosis). The common odds ratio (calculated) by random effects model was 2.25 (95% CI 1.27-3.9), p = 0.005.
CONCLUSIONS
Despite the limited number of studies, and a lack of high-quality data, toxoplasmosis should continue to be regarded as an epilepsy risk factor. More and better studies are needed to determine the real impact of this parasite on the occurrence of epilepsy.
Topics: Chronic Disease; Epilepsy; Humans; Middle Aged; Odds Ratio; Risk Factors; Toxoplasma; Toxoplasmosis
PubMed: 25695802
DOI: 10.1371/journal.pntd.0003525 -
PloS One 2023Toxoplasmosis is one of the most common infections in humans and animals, which is caused by an obligate intracellular opportunistic parasite known as Toxoplasma gondii... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Toxoplasmosis is one of the most common infections in humans and animals, which is caused by an obligate intracellular opportunistic parasite known as Toxoplasma gondii (T. gondii). Some data have shown that both Rhesus (Rh)-positive and Rh-negative individuals differ in response to biological factors, including Toxoplasma infection. Therefore, this systematic review and meta-analysis was conducted to investigate the scientific evidence regarding the possible association between the Rh blood group and Toxoplasma infection and to determine the seroprevalence of T. gondii in the Rh blood group system.
METHODS
The research was conducted on PubMed, ScienceDirect, ProQuest, and Google Scholar databases until January 2023. Twenty-one cross-sectional studies were included with a total of 10910 people. The data were synthesized using a random effect model with 95% confidence intervals (CIs).
RESULTS
The overall prevalence of T. gondii was calculated at 32.34% (CI 95%: 28.23-36.45%) and 33.35% (CI 95%: 19.73-46.96%) in Rh-positive and Rh-negative blood groups. In addition, the pooled OR for the relationship between the Rh blood group and the seroprevalence of T. gondii was 0.96 (95% CI: 0.72-1.28).
CONCLUSIONS
This meta-analysis showed a high prevalence of Toxoplasma infection in both Rh-negative and positive blood groups. This systematic review and meta-analysis revealed that no significant association was found between toxoplasmosis and Rh factor. Because of the limited number of studies in this field, more research is recommended to determine the exact relationship between toxoplasmosis and the Rh factor.
Topics: Animals; Humans; Toxoplasma; Rh-Hr Blood-Group System; Seroepidemiologic Studies; Cross-Sectional Studies; Antibodies, Protozoan; Toxoplasmosis; Risk Factors
PubMed: 37406027
DOI: 10.1371/journal.pone.0287992 -
European Journal of Neurology Dec 2021According to the hygiene hypothesis, infections by agents such as parasites have a protective role against the risk of developing multiple sclerosis (MS). Among... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND AND PURPOSE
According to the hygiene hypothesis, infections by agents such as parasites have a protective role against the risk of developing multiple sclerosis (MS). Among parasites, Toxoplasma gondii, an intracellular parasite, showed evidence of a protective effect. This study was undertaken to summarize the available evidence on the association between T. gondii infection and MS.
METHODS
A systematic review of all the available articles published up to November 2020 has been conducted independently by two investigators in the following databases: PubMed, Scopus, Lissa, and SciELO. The association between T. gondii infection and MS has been pooled with a random effects model.
RESULTS
From 562 articles, seven were included in the systematic review and meta-analysis for a global population of 752 MS cases and 1282 controls. T. gondii infection was associated with MS with a pooled odds ratio of 0.68 (95% confidence interval = 0.50-0.93).
CONCLUSIONS
The available evidence supports the hypothesis that T. gondii infection represents a protective factor against the development of MS.
Topics: Antibodies, Protozoan; Humans; Multiple Sclerosis; Risk Factors; Seroepidemiologic Studies; Toxoplasma; Toxoplasmosis
PubMed: 34374174
DOI: 10.1111/ene.15055 -
Scientific Reports May 2023Reports of an association between ovalocytosis and protection against Plasmodium infection are inconsistent. Therefore, we aimed to synthesise the overall evidence of... (Meta-Analysis)
Meta-Analysis
Reports of an association between ovalocytosis and protection against Plasmodium infection are inconsistent. Therefore, we aimed to synthesise the overall evidence of the association between ovalocytosis and malaria infection using a meta-analysis approach. The systematic review protocol was registered with PROSPERO (CRD42023393778). A systematic literature search of the MEDLINE, Embase, Scopus, PubMed, Ovid, and ProQuest databases, from inception to 30 December 2022, was performed to retrieve studies documenting the association between ovalocytosis and Plasmodium infection. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. Data synthesis included a narrative synthesis and a meta-analysis to calculate the pooled effect estimate (log odds ratios [ORs]) and 95% confidence intervals (CIs) using the random-effects model. Our database search retrieved 905 articles, 16 of which were included for data synthesis. Qualitative synthesis revealed that over half of the studies showed no association between ovalocytosis and malaria infections or severity. Furthermore, our meta-analysis demonstrated no association between ovalocytosis and Plasmodium infection (P = 0.81, log OR = 0.06, 95% CI - 0.44 to 0.19, I: 86.20%; 11 studies). In conclusion, the meta-analysis results demonstrated no association between ovalocytosis and Plasmodium infection. Hence, the role of ovalocytosis in relation to protection against Plasmodium infection or disease severity should be further investigated in larger prospective studies.
Topics: Humans; Prospective Studies; Malaria; Patient Acuity; Elliptocytosis, Hereditary
PubMed: 37137935
DOI: 10.1038/s41598-023-34170-3 -
Journal of Psychiatric Research Sep 2022The relationship between toxoplasma gondii (T. gondii) infection and bipolar disorder (BD) is poorly understood. This review explores this relationship by estimating the... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The relationship between toxoplasma gondii (T. gondii) infection and bipolar disorder (BD) is poorly understood. This review explores this relationship by estimating the strength of the association between the two conditions using data from published studies.
METHODS
Following PRISMA guidelines, we performed a review and meta-analysis of published articles obtained from a systematic search of PubMed, PsycINFO, EMBASE and the Cochrane library up to January 10th, 2021. We included observational studies that compared seroprevalence of IgG class antibodies against T. gondii in patients with a diagnosis of BD with healthy controls. We excluded studies that included <10 participants in each study arm and patients with a serious concomitant medical illness. Discrepancies between the two independent researchers were resolved by consulting a third experienced researcher. Summary data were extracted from published reports. Analysis was conducted using both fixed-effects and random-effects models. The study is registered with PROSPERO number CRD42021237809.
FINDINGS
The search yielded 23 independent studies with a total of 12690 participants (4021 with BD and 8669 controls). Persons with BD had a greater odd of seropositivity with toxoplasmosis than controls, both in the fixed-effects model (OR = 1.34 [95%CI: 1.19 to 1.51]) and the random-effects model (OR = 1.69 [95%CI: 1.21 to 2.36]). No publication bias was detected but reported results showed a high heterogeneity (I2 = 84% [95%CI:77%-89%]).
INTERPRETATION
The findings support the relationship between toxoplasmosis infection and BD and suggests a need for studies designed to explore possible causal relationship. Such studies may also improve our understanding of the pathophysiology of BD and open other avenues for its treatment.
FUNDING
P.O.R. Sardegna F.S.E. 2014-2020.
Topics: Antibodies, Protozoan; Bipolar Disorder; Humans; Immunoglobulin G; Risk Factors; Seroepidemiologic Studies; Toxoplasma; Toxoplasmosis
PubMed: 35870353
DOI: 10.1016/j.jpsychires.2022.07.013 -
Microbial Pathogenesis Sep 2021Toxoplasmosis is one of the most common parasitic infections in humans, which is caused by Toxoplasma gondii. It is usually asymptomatic but primary infection in a... (Meta-Analysis)
Meta-Analysis
Toxoplasmosis is one of the most common parasitic infections in humans, which is caused by Toxoplasma gondii. It is usually asymptomatic but primary infection in a pregnant woman can cause severe consequences in the fetus such as miscarriage. This study aimed to estimate the global prevalence of T. gondii infection in women with spontaneous abortion. It also evaluates the possible relationship between recent Toxoplasma infection and miscarriage. Five electronic databases were reviewed. We used the random effects model and 95% confidence intervals(CI) to determine the overall prevalence and odds ratio (OR). Heterogeneity was calculated using Cochran's Q test and I statistic. The included studies were divided into three sub-groups based on antibody class against T. gondii and the existence of parasite DNA. Based on PCR, the pooled random-effects estimates that the prevalence of T. gondii infection in women with abortion was 10% (95% CI 7-14%). The pooled random effect favored a statistically significant increased risk of latent Toxoplasma infection [OR = 1.84; 95% CI: 1.41-2.40, P < 0.001] and recent infection [OR = 3.72; 95% CI: 2.21-6.26, P < 0.001] in women with spontaneous abortions. In recent infections, significant pooled ORs of positive association were observed in women with miscarriage [OR = 4.2; 95% CI: 2.04-8.85; χ2 = 17.2; I = 42.0%, P = 0.07]. This study demonstrates that recent T. gondii infection is associated with an elevated risk of spontaneous abortion. Further studies concerning all risk factors related to toxoplasmosis, and undertaking confirmatory tests at the time of abortion should be performed to investigate the impact of T. gondii infection and spontaneous abortion.
Topics: Abortion, Spontaneous; Antibodies, Protozoan; Female; Humans; Immunoglobulin M; Pregnancy; Risk Factors; Seroepidemiologic Studies; Toxoplasma; Toxoplasmosis
PubMed: 34186117
DOI: 10.1016/j.micpath.2021.105070 -
The Cochrane Database of Systematic... Aug 2023Insecticide-based interventions, such as long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS), remain the backbone of malaria vector control.... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Insecticide-based interventions, such as long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS), remain the backbone of malaria vector control. These interventions target mosquitoes that prefer to feed and rest indoors, but have limited capacity to prevent transmission that occurs outdoors or outside regular sleeping hours. In low-endemicity areas, malaria elimination will require that these control gaps are addressed, and complementary tools are found. The use of topical repellents may be particularly useful for populations who may not benefit from programmatic malaria control measures, such as refugees, the military, or forest goers. This Cochrane Review aims to measure the effectiveness of topical repellents to prevent malaria infection among high- and non-high-risk populations living in malaria-endemic regions.
OBJECTIVES
To assess the effect of topical repellents alone or in combination with other background interventions (long-lasting insecticide-treated nets, or indoor residual spraying, or both) for reducing the incidence of malaria in high- and non-high-risk populations living in endemic areas.
SEARCH METHODS
We searched the following databases up to 11 January 2023: the Cochrane Infectious Diseases Group Specialised Register; CENTRAL (in the Cochrane Library); MEDLINE; Embase; CAB Abstracts; and LILACS. We also searched trial registration platforms and conference proceedings; and contacted organizations and companies for ongoing and unpublished trials.
SELECTION CRITERIA
We included randomized controlled trials (RCTs) and cluster-randomized controlled trials (cRCTs) of topical repellents proven to repel mosquitoes. We also included non-randomized studies that complied with pre-specified inclusion criteria: controlled before-after studies (CBA), controlled interrupted time series (ITS), and controlled cross-over trials.
DATA COLLECTION AND ANALYSIS
Four review authors independently assessed trials for inclusion, and extracted the data. Two authors independently assessed the risk of bias (RoB) using the Cochrane RoB 2 tool. A fifth review author resolved any disagreements. We analysed data by conducting a meta-analysis, stratified by whether studies included populations considered to be at high-risk of developing malaria infection (for example, refugees, forest goers, or deployed military troops). We combined results from cRCTs with RCTs by adjusting for clustering and presented results using forest plots. We used the GRADE framework to assess the certainty of the evidence. We only included data on Plasmodium falciparum infections in the meta-analysis.
MAIN RESULTS
Thirteen articles relating to eight trials met the inclusion criteria and were qualitatively described. We included six trials in the meta-analysis (five cRCTs and one RCT). Effect on malaria incidence Topical repellents may slightly reduce P falciparum infection and clinical incidence when both outcomes are considered together (incidence rate ratio (IRR) 0.74, 95% confidence interval (CI) 0.56 to 0.98; 3 cRCTs and 1 RCT, 61,651 participants; low-certainty evidence); but not when these two outcomes were considered independently. Two cRCTs and one RCT (12,813 participants) evaluated the effect of topical repellents on infection incidence (IRR 0.76, 95% CI 0.56 to 1.02; low-certainty evidence). One cRCT (48,838 participants) evaluated their effect on clinical case incidence (IRR 0.66, 95% CI 0.32 to 1.36; low-certainty evidence). Three studies (2 cRCTs and 1 RCT) included participants belonging to groups considered at high-risk of being infected, while only one cRCT did not include participants at high risk. Adverse events Topical repellents are considered safe. The prevalence of adverse events among participants who used topical repellents was very low (0.6%, 283/47,515) and limited to mild skin reactions. Effect on malaria prevalence Topical repellents may slightly reduce P falciparum prevalence (odds ratio (OR) 0.81, 95% CI 0.67 to 0.97; 3 cRCTs and 1 RCT; 55,366 participants; low-certainty evidence). Two of these studies (1 cRCT and 1 RCT) were carried out in refugee camps, and included exclusively high-risk populations that were not receiving any other background vector control intervention.
AUTHORS' CONCLUSIONS
There is insufficient evidence to conclude that topical repellents can prevent malaria in settings where other vector control interventions are in place. We found the certainty of evidence for all outcomes to be low, primarily due to the risk of bias. A protective effect was suggested among high-risk populations, specially refugees, who might not have access to other standard vector control measures. More adequately powered clinical trials carried out in refugee camps could provide further information on the potential benefit of topical repellents in this setting. Individually randomized studies are also likely necessary to understand whether topical repellents have an effect on personal protection, and the degree to which diversion to non-protected participants affects overall transmission dynamics. Despite this, the potential additional benefits of topical repellents are most likely limited in contexts where other interventions are available.
Topics: Animals; Humans; Insecticides; Mosquito Vectors; Malaria, Falciparum; Controlled Before-After Studies; Culicidae
PubMed: 37602418
DOI: 10.1002/14651858.CD015422.pub2 -
Microbial Pathogenesis Oct 2020Toxoplasma gondii (T. gondii) is a foodborne parasite that is investigated in many psychiatric diseases, such as autism spectrum disorders (ASD). Therefore, a systematic... (Meta-Analysis)
Meta-Analysis Review
Toxoplasma gondii (T. gondii) is a foodborne parasite that is investigated in many psychiatric diseases, such as autism spectrum disorders (ASD). Therefore, a systematic literature review was conducted searching seven electronic databases on the prevalence of T. gondii antibodies among autism patients. The current study involved sensitivity analysis, meta-regression, subgroup analysis, publication bias test, and quality assessment of studies. On the basis of the findings, the odds ratio (OR) of latent Toxoplasma infection 1.93 (95% confidence intervals (CI): 1.01-3.66) was associated with ASD risk. However, there was no relationship between acute infection and ASD 0.39 (95% CI: 0.18-0.87). The obtained results of Begg's and Egger's tests showed no publication bias (P = 0.851 and P = 0.297, respectively). The sensitivity analysis confirmed robust and stable estimates with a significant level of heterogeneity (I = 78.1%, P < 0.000). Of the investigated patients' characteristics, only the gender variable was analyzed, indicating the combined ORs of 2.63 (95% CI: 0.29-23.63) in females and 2.62 (95% CI: 0.94-7.30) in male participants. This study showed that toxoplasmosis plays an important role as a risk factor for autism. However, further prospective investigations are highly recommended to illuminate the developmental pathways to this disorder and provide new strategies for the prevention and treatment of this disease.
Topics: Antibodies, Protozoan; Autistic Disorder; Female; Humans; Male; Odds Ratio; Risk Factors; Seroepidemiologic Studies; Toxoplasma; Toxoplasmosis
PubMed: 32777351
DOI: 10.1016/j.micpath.2020.104434