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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 -
Medicina 2014A systematic review of surveys performed between 1980 and 2011 (published in MEDLINE/Pubmed and/or LILACS indexed journals, available in the baseline data from a Mass... (Review)
Review
A systematic review of surveys performed between 1980 and 2011 (published in MEDLINE/Pubmed and/or LILACS indexed journals, available in the baseline data from a Mass Deworming National Program (MDNP, 2005) was used to identify the prevalence, distribution and detection of risk areas for soil transmitted helminth infections (STH) in Argentina. We found 310 publications in the database using the pre-defined key-words (medical subject headings) for research purposes. Only 24 articles with 26 surveillance sites in 8 provinces and a total of 5495 surveyed individuals fulfilled the inclusion criteria. Frequency rates for STH had a wide range: Ascaris lumbricoides: 0-67%, hookworms: 0-90%, Trichuris trichiura: 0-24.6 and Strongyloides stercoralis: 0-83%. The estimated combined incidence varied from 0.8% to 88.6%. Baseline surveys from the MDNP reporting on 1943 children from 12 provinces confirmed the heterogeneity, with combined STH frequency rates ranging from 0 to 42.7%. Surveys included in this review showed that the distribution of STH in Argentina is not homogeneous, with areas of high incidence (> 20%) in the northeastern and northwestern provinces where mass deworming activities would be highly beneficial. In several surveys, the high overall incidence was mostly due to hookworms and S. stercoralis, a situation to be considered when selecting diagnostic and therapeutic control strategies. The scarcity or absence of data from various provinces and the availability of less than 8000 surveyed individuals should be considered.
Topics: Adolescent; Adult; Animals; Argentina; Ascariasis; Ascaris lumbricoides; Child; Child, Preschool; Helminthiasis; Humans; Prevalence; Soil; Strongyloides stercoralis; Strongyloidiasis; Trichuriasis; Trichuris
PubMed: 24561837
DOI: No ID Found -
PLoS Neglected Tropical Diseases 2012Soil-transmitted helminth (STH) infections (i.e., Ascaris lumbricoides, hookworm, and Trichuris trichiura) affect more than a billion people. Preventive chemotherapy... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Soil-transmitted helminth (STH) infections (i.e., Ascaris lumbricoides, hookworm, and Trichuris trichiura) affect more than a billion people. Preventive chemotherapy (i.e., repeated administration of anthelmintic drugs to at-risk populations), is the mainstay of control. This strategy, however, does not prevent reinfection. We performed a systematic review and meta-analysis to assess patterns and dynamics of STH reinfection after drug treatment.
METHODOLOGY
We systematically searched PubMed, ISI Web of Science, EMBASE, Cochrane Database of Systematic Reviews, China National Knowledge Infrastructure, WanFang Database, Chinese Scientific Journal Database, and Google Scholar. Information on study year, country, sample size, age of participants, diagnostic method, drug administration strategy, prevalence and intensity of infection pre- and posttreatment, cure and egg reduction rate, evaluation period posttreatment, and adherence was extracted. Pooled risk ratios from random-effects models were used to assess the risk of STH reinfection after treatment. Our protocol is available on PROSPERO, registration number: CRD42011001678.
PRINCIPAL FINDINGS
From 154 studies identified, 51 were included and 24 provided STH infection rates pre- and posttreatment, whereas 42 reported determinants of predisposition to reinfection. At 3, 6, and 12 months posttreatment, A. lumbricoides prevalence reached 26% (95% confidence interval (CI): 16-43%), 68% (95% CI: 60-76%) and 94% (95% CI: 88-100%) of pretreatment levels, respectively. For T. trichiura, respective reinfection prevalence were 36% (95% CI: 28-47%), 67% (95% CI: 42-100%), and 82% (95% CI: 62-100%), and for hookworm, 30% (95% CI: 26-34%), 55% (95% CI: 34-87%), and 57% (95% CI: 49-67%). Prevalence and intensity of reinfection were positively correlated with pretreatment infection status.
CONCLUSION
STH reinfections occur rapidly after treatment, particularly for A. lumbricoides and T. trichiura. Hence, there is a need for frequent anthelmintic drug administrations to maximize the benefit of preventive chemotherapy. Integrated control approaches emphasizing health education and environmental sanitation are needed to interrupt transmission of STH.
Topics: Animals; Anthelmintics; Ascariasis; Drug Therapy; Helminthiasis; Hookworm Infections; Humans; Recurrence; Trichuriasis
PubMed: 22590656
DOI: 10.1371/journal.pntd.0001621 -
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 -
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 -
JAMA Oct 2007The neglected tropical diseases include 13 conditions that occur in areas of extreme poverty and are poverty promoting. The neglected tropical diseases produce a disease... (Review)
Review
CONTEXT
The neglected tropical diseases include 13 conditions that occur in areas of extreme poverty and are poverty promoting. The neglected tropical diseases produce a disease burden almost as great as that associated with human immunodeficiency virus/AIDS, tuberculosis, or malaria, yet are virtually unknown by health care workers in North America, because they occur almost exclusively in the poorest regions of the world. Seven of the most prevalent diseases have existing oral drug treatments. Identifying treatments that are effective against more than 1 disease could facilitate efficient and inexpensive treatment.
OBJECTIVES
To systematically review the evidence for drug treatments and to increase awareness that neglected tropical diseases exist and that treatments are available.
DATA SOURCES AND STUDY SELECTION
Using a MEDLINE search (1966 through June 2007), randomized controlled trials (RCTs) were reviewed that examined simultaneous treatment of 2 or more of the 7 most prevalent neglected tropical diseases using oral drug therapy.
DATA SYNTHESIS
Twenty-nine RCTs were identified, of which 3 targeted 4 diseases simultaneously, 20 targeted 3 diseases, and 6 targeted 2 diseases. Trials were published between 1972 and 2005 and baseline prevalence of individual diseases varied among RCTs. Albendazole plus diethylcarbamazine significantly reduced prevalence of elephantiasis (16.7% to 5.3%), hookworm (10.3% to 1.9%), roundworm (34.5% to 2.3%), and whipworm (55.5% to 40.3%). Albendazole plus ivermectin significantly reduced prevalence of elephantiasis (12.6% to 4.6%), hookworm (7.8% to 0%), roundworm (33.5% to 6.1%), and whipworm (42.7% to 8.9%). Levamisole plus mebendazole significantly reduced prevalence of hookworm (94.0% to 71.8%), roundworm (62.0% to 1.4%), and whipworm (93.1% to 74.5%). Pyrantel-oxantel significantly reduced hookworm (93.4% to 85.2%), roundworm (22.8% to 1.4%), and whipworm (86.8% to 59.5%), while albendazole alone significantly reduced prevalence of hookworm (8.1% to 1.3%), roundworm (28.4% to 0.9%), and whipworm (51.9% to 31.9%). No RCT examined treatment of river blindness or trachoma as part of an intervention to target 2 or more neglected tropical diseases. Adverse events were generally inadequately reported.
CONCLUSIONS
At least 2 of the most prevalent neglected tropical diseases can be treated simultaneously with existing oral drug treatments, facilitating effective and efficient treatment. Increasing awareness about neglected tropical diseases, their global impact, and the availability of oral drug treatments is an essential step in controlling these diseases.
Topics: Administration, Oral; Anti-Bacterial Agents; Antiparasitic Agents; Ascariasis; Chagas Disease; Developing Countries; Dracunculiasis; Drug Therapy; Elephantiasis, Filarial; Hookworm Infections; Humans; Leishmaniasis; Leprosy; Onchocerciasis, Ocular; Parasitic Diseases; Poverty; Schistosomiasis; Trachoma; Trichuriasis; Tropical Medicine; Trypanosomiasis
PubMed: 17954542
DOI: 10.1001/jama.298.16.1911