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European Journal of Dermatology : EJD Aug 2017
Review
Topics: Adult; Ancylostoma; Animals; Europe; Female; France; Humans; Larva Migrans; Male
PubMed: 28508758
DOI: 10.1684/ejd.2017.3043 -
Lancet (London, England) Jan 2017Soil-transmitted helminth infections are a major global health issue, causing substantial morbidity in the world's poorest populations. Regular delivery of anthelmintic... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Soil-transmitted helminth infections are a major global health issue, causing substantial morbidity in the world's poorest populations. Regular delivery of anthelmintic drugs is the mainstay for global soil-transmitted helminth control. Deworming campaigns are often targeted to school-aged children, who are at high risk of soil-transmitted-helminth-associated morbidity. However, findings from modelling studies suggest that deworming campaigns should be expanded community-wide for effective control of soil-transmitted helminth transmission. We aimed to do a systematic review and meta-analysis to compare the effect of mass (community-wide) and targeted (children only) anthelmintic delivery strategies on soil-transmitted helminth prevalence in school-aged children.
METHODS
In this systematic review and meta-analysis, we searched MEDLINE, Embase, and Web of Science for articles published on or before Nov 5, 2015, reporting soil-transmitted helminth prevalence before and after distribution of albendazole or mebendazole, either targeted to children or delivered to the whole community. We excluded studies in which drug delivery was restricted to infected individuals or to a subset of the community or school, or if follow-up time was less than 3 months or greater than 18 months after drug delivery. We extracted data on study year, country, drug administration strategy, drug dose, number of deworming rounds, treatment coverage, diagnostic method, follow-up interval, and soil-transmitted helminth prevalence before and after treatment. We used inverse variance weighted generalised linear models, with prevalence reduction as the outcome variable, to examine the effect of mass versus targeted drug administration, as well as baseline prevalence, number of drug doses, and follow-up time. This study is registered with PROSPERO, number CRD42016026929.
FINDINGS
Of 10 538 studies identified, 56 studies were eligible for the systematic review and 38 of these were included in meta-analysis. Results of the regression models showed that mass deworming led to a significantly greater reduction in prevalence in children than targeted deworming, for both hookworm (odds ratio 4·6, 95% CI 1·8-11·6; p=0·0020) and Ascaris lumbricoides (16·4, 2·1-125·8; p=0·0092), with no effect seen for Trichuris trichiura. There was significant heterogeneity across studies; for targeted studies I was 97% for A lumbricoides and hookworm, and 96% for T trichiura, and for mass studies, I was 89% for A lumbricoides, 49% for hookworm, and 66% for T trichiura.
INTERPRETATION
The results of this meta-analysis suggest that expanding deworming programmes community-wide is likely to reduce the prevalence of soil-transmitted helminths in the high-risk group of school-aged children, which could lead to improved morbidity outcomes. These findings are in support of recent calls for re-evaluation of global soil-transmitted helminth control guidelines.
FUNDING
None.
Topics: Adolescent; Ancylostomatoidea; Animals; Anthelmintics; Ascaris lumbricoides; Child; Child, Preschool; Communicable Disease Control; Helminthiasis; Humans; Soil; Trichuris
PubMed: 27979381
DOI: 10.1016/S0140-6736(16)32123-7 -
Parasites & Vectors Jan 2016Soil-transmitted helminth (STH) infections of humans fall within the World Health Organization's (WHO) grouping termed the neglected tropical diseases (NTDs). It is... (Review)
Review
Soil-transmitted helminth (STH) infections of humans fall within the World Health Organization's (WHO) grouping termed the neglected tropical diseases (NTDs). It is estimated that they affect approximately 1.4 billion people worldwide. A significant proportion of these infections are in the population of Southeast Asia. This review analyses published data on STH prevalence and intensity in Southeast Asia over the time period of 1900 to the present to describe age related patterns in these epidemiological measures. This is with a focus on the four major parasite species affecting humans; namely Ascaris lumbricoides, Trichuris trichiura and the hookworms; Necator americanus and Ancylostoma duodenale. Data were also collected on the diagnostic methods used in the published surveys and how the studies were designed to facilitate comparative analyses of recorded patterns and changes therein over time. PubMed, Google Scholar, EMBASE, ISI Web of Science, Cochrane Database of Systematic Reviews and the Global Atlas of Helminth Infections search engines were used to identify studies on STH in Southeast Asia with the search based on the major key words, and variants on, "soil-transmitted helminth" "Ascaris" "Trichuris" "hookworm" and the country name. A total of 280 studies satisfied the inclusion criteria from 11 Southeast Asian countries; Brunei, Cambodia, Indonesia, Lao People's Democratic Republic (Lao PDR), Malaysia, Myanmar, Philippines, Singapore, Thailand, Timor-Leste and Vietnam. It was concluded that the epidemiological patterns of STH infection by age and species mix in Southeast Asia are similar to those reported in other parts of the world. In the published studies there were a large number of different diagnostic methods used with differing sensitivities and specificities, which makes comparison of the results both within and between countries difficult. There is a clear requirement to standardise the methods of both STH diagnosis in faecal material and how the intensity of infection is recorded and reported in future STH research and in monitoring and evaluation (M&E) of the impact of continuing and expanding mass drug administration (MDA) programmes.
Topics: Ancylostoma; Ancylostomatoidea; Animals; Ascariasis; Ascaris lumbricoides; Asia, Southeastern; Feces; Helminthiasis; Helminths; Hookworm Infections; Humans; Prevalence; Research; Soil; Surveys and Questionnaires; Trichuriasis; Trichuris
PubMed: 26813007
DOI: 10.1186/s13071-016-1310-2 -
The Lancet. Infectious Diseases Jan 2015Interest is growing in predictive risk mapping for neglected tropical diseases (NTDs), particularly to scale up preventive chemotherapy, surveillance, and elimination... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Interest is growing in predictive risk mapping for neglected tropical diseases (NTDs), particularly to scale up preventive chemotherapy, surveillance, and elimination efforts. Soil-transmitted helminths (hookworm, Ascaris lumbricoides, and Trichuris trichiura) are the most widespread NTDs, but broad geographical analyses are scarce. We aimed to predict the spatial and temporal distribution of soil-transmitted helminth infections, including the number of infected people and treatment needs, across sub-Saharan Africa.
METHODS
We systematically searched PubMed, Web of Knowledge, and African Journal Online from inception to Dec 31, 2013, without language restrictions, to identify georeferenced surveys. We extracted data from household surveys on sources of drinking water, sanitation, and women's level of education. Bayesian geostatistical models were used to align the data in space and estimate risk of with hookworm, A lumbricoides, and T trichiura over a grid of roughly 1 million pixels at a spatial resolution of 5 × 5 km. We calculated anthelmintic treatment needs on the basis of WHO guidelines (treatment of all school-aged children once per year where prevalence in this population is 20-50% or twice per year if prevalence is greater than 50%).
FINDINGS
We identified 459 relevant survey reports that referenced 6040 unique locations. We estimate that the prevalence of hookworm, A lumbricoides, and T trichiura among school-aged children from 2000 onwards was 16·5%, 6·6%, and 4·4%. These estimates are between 52% and 74% lower than those in surveys done before 2000, and have become similar to values for the entire communities. We estimated that 126 million doses of anthelmintic treatments are required per year.
INTERPRETATION
Patterns of soil-transmitted helminth infection in sub-Saharan Africa have changed and the prevalence of infection has declined substantially in this millennium, probably due to socioeconomic development and large-scale deworming programmes. The global control strategy should be reassessed, with emphasis given also to adults to progress towards local elimination.
FUNDING
Swiss National Science Foundation and European Research Council.
Topics: Africa South of the Sahara; Ancylostomatoidea; Animals; Anthelmintics; Ascaris lumbricoides; Helminthiasis; Humans; Intestinal Diseases, Parasitic; Neglected Diseases; Prevalence; Spatio-Temporal Analysis; Trichuris
PubMed: 25486852
DOI: 10.1016/S1473-3099(14)71004-7 -
The Cochrane Database of Systematic... Apr 2012Allergic rhinitis is a disorder of the nasal membranes and surrounding tissues, and a worldwide cause of illness and disability. Helminths are complex tissue-dwelling or... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Allergic rhinitis is a disorder of the nasal membranes and surrounding tissues, and a worldwide cause of illness and disability. Helminths are complex tissue-dwelling or lumen-dwelling organisms that inhabit larger organisms and are frequently asymptomatic. Helminths modulate the natural immune responses of their human hosts, and may prevent or cure immune-mediated or allergic diseases (e.g. allergic rhinitis) in the host. Non-randomised studies support this hypothesis.
OBJECTIVES
To assess the safety and effectiveness of helminth therapy in people with allergic rhinitis.
SEARCH METHODS
We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the search was 24 June 2011.
SELECTION CRITERIA
All randomised controlled trials where the intervention was any helminth species or combination of helminth species, administered to people with allergic rhinitis in any dose, by any route and for any duration of exposure. We accepted both intermittent and persistent allergic rhinitis patients.
DATA COLLECTION AND ANALYSIS
We independently extracted data and assessed eligibility and risk of bias using a standardised data collection form. We resolved any disagreement through discussion. We combined dichotomous data using risk ratio (RR) and continuous data using mean difference (MD), presenting both with 95% confidence intervals (CI).
MAIN RESULTS
We found five reports of two single-centre, placebo-controlled, double-blinded studies (130 participants). Participants in both studies were a mix of adults with either intermittent or persistent allergic rhinitis. Both studies had a low risk of bias. One study, with 12 weeks' follow-up, used a single percutaneous application of 10 Necator americanus (i.e. human hookworm) larvae. The other study, with 24 weeks' follow-up, used three-weekly oral dosing with 2500 Trichuris suis (i.e. pig whipworm) eggs in aqueous suspension. Of 17 outcomes evaluated in this review, eight were positive (i.e. favoured helminths). Participants taking helminths had no reduction in allergic rhinitis symptoms, percentage of well days (i.e. days with minimal symptoms and no use of medication for allergic rhinitis), lung function measures and quality of life scores. Total use of medication for allergic rhinitis (eye drops, nasal sprays, tablets) did not change; however, in the helminth group there was a statistically significant reduction in the percentage of days during the grass pollen season when participants needed to take tablets as rescue medication for their allergic rhinitis symptoms (MD -14.0%, 95% CI -26.6 to -1.40); in a typical 60-day pollen season this 14% reduction translates into 19 days when tablets would be needed in the helminth group versus 27 days when tablets would be needed in the placebo group. Participants taking helminths percutaneously (i.e. as hookworm larvae) had local skin itching and redness in the first few days after administration. Participants taking helminths were more likely to report any gastrointestinal adverse event (RR 1.79, 95% CI 1.31 to 2.45), moderate or severe abdominal pain (RR 7.67, 95% CI 1.87 to 31.57), moderate or severe flatulence (RR 2.01, 95% CI 1.06 to 3.81) and moderate or severe diarrhoea (RR 1.99, 95% CI 1.18 to 3.37). There was no difference between the helminth and placebo groups in the incidence of serious adverse events, and in study withdrawals.
AUTHORS' CONCLUSIONS
There is currently insufficient evidence on the efficacy, tolerability and likely costs of helminth therapy to support its use in the routine management of allergic rhinitis. Administered to humans in carefully measured doses, helminths appear to be safe. More preclinical studies should be performed, before larger and extended duration trials of helminths for allergic rhinitis are carried out. Future studies should collect and report comparative data on the costs of helminth therapy versus conventional pharmacotherapy.
Topics: Adult; Ancylostomatoidea; Animals; Helminths; Humans; Immunotherapy; Randomized Controlled Trials as Topic; Rhinitis, Allergic, Perennial; Rhinitis, Allergic, Seasonal; Trichuris
PubMed: 22513973
DOI: 10.1002/14651858.CD009238.pub2 -
PLoS Medicine Jan 2012In countries of high endemicity of the soil-transmitted helminth parasites Ascaris lumbricoides, Trichuris trichiura, and hookworm, preventive chemotherapy (i.e.,... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
In countries of high endemicity of the soil-transmitted helminth parasites Ascaris lumbricoides, Trichuris trichiura, and hookworm, preventive chemotherapy (i.e., repeated administration of anthelmintic drugs to at-risk populations) is the main strategy to control morbidity. However, rapid reinfection of humans occurs after successful deworming, and therefore effective preventive measures are required to achieve public health goals with optimal efficiency and sustainability.
METHODS AND FINDINGS
We conducted a systematic review and meta-analysis to assess the effect of sanitation (i.e., access and use of facilities for the safe disposal of human urine and feces) on infection with soil-transmitted helminths. PubMed, Embase, ISI Web of Science, and the World Health Organization Library Database were searched without language restrictions and year of publication (search performed until December 31, 2010). Bibliographies of identified articles were hand-searched. All types of studies reporting data on sanitation availability (i.e., having access at own household or living in close proximity to sanitation facility), or usage, and soil-transmitted helminth infections at the individual level were considered. Reported odds ratios (ORs) of the protective effect of sanitation on soil-transmitted helminth infections were extracted from the papers or calculated from reported numbers. The quality of published studies was assessed with a panel of criteria developed by the authors. Random effects meta-analyses were used to account for observed heterogeneity. Thirty-six publications, consisting of 39 datasets, met our inclusion criteria. Availability of sanitation facilities was associated with significant protection against infection with soil-transmitted helminths (OR = 0.46 to 0.58). Regarding the use of sanitation, ORs of 0.54 (95% confidence interval [CI] 0.28-1.02), 0.63 (95% CI 0.37-1.05), and 0.78 (95% CI 0.60-1.00) were determined for T. trichiura, hookworm, and A. lumbricoides, respectively. The overall ORs, combining sanitation availability and use, were 0.51 (95% CI 0.44-0.61) for the three soil-transmitted helminths combined, 0.54 (95% CI 0.43-0.69) for A. lumbricoides, 0.58 (95% CI 0.45-0.75) for T. trichiura, and 0.60 (95% CI 0.48-0.75) for hookworm.
CONCLUSIONS
Despite a number of limitations (e.g., most studies used a cross-sectional design and were of low quality, with potential biases and considerable heterogeneity), our results reveal that sanitation is associated with a reduced risk of transmission of helminthiases to humans. Access to improved sanitation should be prioritized alongside preventive chemotherapy and health education to achieve a durable reduction of the burden of helminthiases.
Topics: Ancylostomatoidea; Animals; Ascariasis; Ascaris lumbricoides; Hookworm Infections; Humans; Nematoda; Nematode Infections; Sanitation; Soil; Trichuriasis; Trichuris
PubMed: 22291577
DOI: 10.1371/journal.pmed.1001162 -
Parasitology Oct 2011Drug development for paediatric applications entails a number of challenges, such as the wide age spectrum covered - from birth to adolescence - and developmental... (Review)
Review
Drug development for paediatric applications entails a number of challenges, such as the wide age spectrum covered - from birth to adolescence - and developmental changes in physiology during biological maturation that influence the efficacy and toxicity of drugs. Safe and efficacious antiparasitic drugs for children are of pivotal importance given the large proportion of burden attributable to parasitic diseases in this age group, and growing efforts to administer, as widely as possible, antiparasitic drugs to at-risk populations, such as infants and school-aged children, often without prior diagnosis. The purpose of this review is to investigate whether antiparasitic drugs have been adequately studied for use in paediatrics. We approached this issue through a systematic review using PubMed and the Cochrane Central Register of Trials covering a period of 10 years and 8 months until the end of August 2010 to identify trials that investigated efficacy, safety and pharmacokinetic (PK) parameters of antiparasitic drugs for paediatrics. Overall, 269 clinical drug trials and 17 PK studies met our inclusion criteria. Antimalarial drugs were the most commonly studied medicines (82·6%). Most trials were carried out in Africa and children aged 2-11 years were the age group most often investigated. Additionally, we critically examined available drug formulations for anthelminthics and identified a number of shortcomings that are discussed. Finally, we shed new light on current proposals to expand 'preventive chemotherapy' to preschool-aged children and emphasise that new research, including risk-benefit analyses, are needed before such a strategy can be adopted more widely.
Topics: Adolescent; Ancylostomatoidea; Animals; Antiparasitic Agents; Chemistry, Pharmaceutical; Child; Child, Preschool; Drug-Related Side Effects and Adverse Reactions; Humans; Infant; Parasitic Diseases; Pediatrics; Schistosoma mansoni; Treatment Outcome
PubMed: 21349223
DOI: 10.1017/S0031182011000023 -
PLoS Neglected Tropical Diseases Sep 2008Hookworm infection is among the major causes of anaemia in poor communities, but its importance in causing maternal anaemia is poorly understood, and this has hampered... (Review)
Review
BACKGROUND AND OBJECTIVES
Hookworm infection is among the major causes of anaemia in poor communities, but its importance in causing maternal anaemia is poorly understood, and this has hampered effective lobbying for the inclusion of anthelmintic treatment in maternal health packages. We sought to review existing evidence on the role of hookworm as a risk factor for anaemia among pregnant women. We also estimate the number of hookworm infections in pregnant women in sub-Saharan Africa (SSA).
METHODS
Structured searches using MEDLINE and EMBASE as well as manual searches of reference lists were conducted, and unpublished data were obtained by contacting authors. Papers were independently reviewed by two authors, and relevant data were extracted. We compared haemoglobin concentration (Hb) according to intensity of hookworm infection and calculated standardised mean differences and 95% confidence intervals. To estimate the number of pregnant women, we used population surfaces and a spatial model of hookworm prevalence.
FINDINGS
One hundred and five reports were screened and 19 were eligible for inclusion: 13 cross-sectional studies, 2 randomised controlled trials, 2 non-randomised treatment trials and 2 observational studies. Comparing uninfected women and women lightly (1-1,999 eggs/gram [epg]) infected with hookworm, the standardised mean difference (SMD) was -0.24 (95% CI: -0.36 to -0.13). The SMD between women heavily (4000+ epg) infected and those lightly infected was -0.57 (95% CI: -0.87 to -0.26). All identified intervention studies showed a benefit of deworming for maternal or child health, but since a variety of outcomes measures were employed, quantitative evaluation was not possible. We estimate that 37.7 million women of reproductive age in SSA are infected with hookworm in 2005 and that approximately 6.9 million pregnant women are infected.
CONCLUSIONS
Evidence indicates that increasing hookworm infection intensity is associated with lower haemoglobin levels in pregnant women in poor countries. There are insufficient data to quantify the benefits of deworming, and further studies are warranted. Given that between a quarter and a third of pregnant women in SSA are infected with hookworm and at risk of preventable hookworm-related anaemia, efforts should be made to increase the coverage of anthelmintic treatment among pregnant women.
Topics: Africa South of the Sahara; Ancylostomatoidea; Anemia; Animals; Ecosystem; Female; Geography; Hookworm Infections; Humans; Pregnancy; Pregnancy Complications; Risk Factors
PubMed: 18820740
DOI: 10.1371/journal.pntd.0000291 -
JAMA Apr 2008More than a quarter of the human population is likely infected with soil-transmitted helminths (Ascaris lumbricoides, hookworm, and Trichuris trichiura) in highly... (Meta-Analysis)
Meta-Analysis Review
CONTEXT
More than a quarter of the human population is likely infected with soil-transmitted helminths (Ascaris lumbricoides, hookworm, and Trichuris trichiura) in highly endemic areas. Preventive chemotherapy is the mainstay of control, but only 4 drugs are available: albendazole, mebendazole, levamisole, and pyrantel pamoate.
OBJECTIVE
To assess the efficacy of single-dose oral albendazole, mebendazole, levamisole, and pyrantel pamoate against A lumbricoides, hookworm, and T trichiura infections.
DATA SOURCES
A systematic search of PubMed, ISI Web of Science, ScienceDirect, the World Health Organization library database, and the Cochrane Central Register of Controlled Trials (1960 to August 2007).
STUDY SELECTION
From 168 studies, 20 randomized controlled trials were included.
DATA EXTRACTION AND DATA SYNTHESIS
Information on study year and country, sample size, age of study population, mean infection intensity before treatment, diagnostic method used, time between evaluations before and after treatment, cure rate (the percentage of individuals who became helminth egg negative following treatment with an anthelminthic drug), egg reduction rate, adverse events, and trial quality was extracted. Relative risk, including a 95% confidence interval (CI), was used to measure the effect of the drugs on the risk of infection prevalence with a random-effects model.
RESULTS
Single-dose oral albendazole, mebendazole, and pyrantel pamoate for infection with A lumbricoides resulted in cure rates of 88% (95% CI, 79%-93%; 557 patients), 95% (95% CI, 91%-97%; 309 patients), and 88% (95% CI, 79%-93%; 131 patients), respectively. Cure rates for infection with T trichiura following treatment with single-dose oral albendazole and mebendazole were 28% (95% CI, 13%-39%; 735 patients) and 36% (95% CI, 16%-51%; 685 patients), respectively. The efficacy of single-dose oral albendazole, mebendazole, and pyrantel pamoate against hookworm infections was 72% (95% CI, 59%-81%; 742 patients), 15% (95% CI, 1%-27%; 853 patients), and 31% (95% CI, 19%-42%; 152 patients), respectively. No pooled relative risks could be calculated for pyrantel pamoate against T trichiura and levamisole for any of the parasites investigated.
CONCLUSIONS
Single-dose oral albendazole, mebendazole, and pyrantel pamoate show high cure rates against A lumbricoides. For hookworm infection, albendazole was more efficacious than mebendazole and pyrantel pamoate. Treatment of T trichiura with single oral doses of current anthelminthics is unsatisfactory. New anthelminthics are urgently needed.
Topics: Albendazole; Ancylostomatoidea; Animals; Anthelmintics; Ascariasis; Ascaris lumbricoides; Hookworm Infections; Humans; Levamisole; Mebendazole; Pyrantel Pamoate; Soil; Trichuriasis; Trichuris
PubMed: 18430913
DOI: 10.1001/jama.299.16.1937 -
PLoS Neglected Tropical Diseases Mar 2008Pre-school age children account for 10%-20% of the 2 billion people worldwide who are infected with soil-transmitted helminths (STHs): Ascaris lumbricoides (roundworm),... (Review)
Review
Pre-school age children account for 10%-20% of the 2 billion people worldwide who are infected with soil-transmitted helminths (STHs): Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), and Ancylostoma duodenale/Necator americanus (hookworms). Through a systematic review of the published literature and using information collated at World Health Organization headquarters, this paper summarizes the available evidence to support the recommendation that pre-school children should be included in regular deworming programmes. The first section describes the burden of STH disease in this age group, followed by a summary of how infection impacts iron status, growth, vitamin A status, and cognitive development and how STHs may exacerbate other high mortality infections. The second section explores the safety of the drugs themselves, given alone or co-administered, drug efficacy, and the importance of safe administration. The third section provides country-based evidence to demonstrate improved health outcomes after STH treatment. The final section provides country experiences in scaling up coverage of pre-school children by using other large scale public health interventions, including vitamin A programmes, immunization campaigns, and Child Health days. The paper concludes with a number of open research questions and a summary of some of the operational challenges that still need to be addressed.
Topics: Ancylostoma; Animals; Anthelmintics; Ascaris lumbricoides; Child; Child, Preschool; Female; Helminthiasis; Humans; Infant; Male; Necator americanus; Preventive Medicine; Soil; Trichuris
PubMed: 18365031
DOI: 10.1371/journal.pntd.0000126