Control Of Soil-transmitted Helminthiasis Research Articles

Social media and control of soil-transmitted helminthiasis in Bhutan.

Social media and control of soil-transmitted helminthiasis in Bhutan.

Epidemiological Findings and Policy Implications from the Nationwide Schistosomiasis and Intestinal Helminthiasis Survey in Sudan

Background: The World Health Assembly endorsed the WHO Neglected Tropical Disease (NTD) Roadmap in 2013, in which NTDs were suggested as tracers of equity in the assessment of progress towards the Sustainable Development Goals. Nationwide surveys were undertaken in all 18 states of Sudan to identify the geographical distribution and estimate the prevalence and intensity of schistosomiasis and other helminthiases from December 2016 to March 2017. Improved water and sanitation coverage at the household and school levels and the proportion of respondents who engaged in risk behaviours were assessed. Methods: Using two-stage random sampling, each locality was subdivided into one to three different ecological zones (EZs) based on proximity to water bodies. Probability-proportional-to-size sampling was used to select schools from each EZ. We estimated schistosomiasis and intestinal helminthiasis prevalence in 105,167 school children by urine concentration microscopy and Kato-Katz smears. Risk factors and the impact thereof were investigated using multi-level mixed-effect models. Findings: The overall egg-positive rates were: Schistosoma haematobium, 5·2%; S. mansoni, 0·06%; and intestinal helminths, 5·47%. Severe endemic areas were concentrated in East and South Darfur States (S. haematobium prevalence, 25·23% and 13·91%, respectively). Households and schools with latrines, and especially improved latrines (ventilated improved pit latrines or flush toilets) were associated with lower odds of schistosomiasis infection. Open defecation was strongly associated with schistosomiasis (aOR: 1·50, 95% CI: 1·35-1·66). EZ-level mass drug administration was estimated to be more cost-effective than district-level administration under all circumstances. Interpretation: Endemic schistosomiasis is concentrated in fragile border states. This study provides insight into possible programmes to effectively reduce infections by presenting possible diverse, innovative strategies to disrupt the transmission cycle. Funding Statement: This project was supported by the Korea International Cooperation Agency (KOICA) under the Integrated schistosomiasis and soil-transmitted helminthiasis control program, Sudan. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: This study protocol was reviewed and approved by the institutional review board of the Federal Ministry of Health, Sudan (FMOH/DGP/RD/TC/2016) and the Korea Association of Health Promotion (130750-20,164-HR-020).

Toward the 2020 goal of soil-transmitted helminthiasis control and elimination.

Toward the 2020 goal of soil-transmitted helminthiasis control and elimination.

Capacity gaps in health facilities for case management of intestinal schistosomiasis and soil-transmitted helminthiasis in Burundi

BackgroundSchistosomiasis and soil-transmitted helminthiasis (STH) are endemic diseases in Burundi. STH control is integrated into health facilities (HF) across the country, but schistosomiasis control is not. The present study aimed to assess the capacity of HF for integrating intestinal schistosomiasis case management into their routine activities. In addition, the current capacity for HF-based STH case management was evaluated.MethodsA random cluster survey was carried out in July 2014, in 65 HF located in Schistosoma mansoni and STH endemic areas. Data were collected by semi-quantitative questionnaires. Staff with different functions at the HF were interviewed (managers, care providers, heads of laboratory and pharmacy and data clerks). Data pertaining to knowledge of intestinal schistosomiasis and STH symptoms, human and material resources and availability and costs of diagnostic tests and treatment were collected.FindingsLess than half of the 65 care providers mentioned one or more major symptoms of intestinal schistosomiasis (abdominal pain 43.1%, bloody diarrhoea 13.9% and bloody stool 7.7%). Few staff members (15.7%) received higher education, and less than 10% were trained in-job on intestinal schistosomiasis case management. Clinical guidelines and laboratory protocols for intestinal schistosomiasis diagnosis and treatment were available in one third of the HF. Diagnosis was performed by direct smear only. Praziquantel was not available in any of the HF. The results for STH were similar, except that major symptoms were more known and cited (abdominal pain 69.2% and diarrhoea 60%). Clinical guidelines were available in 61.5% of HF, and albendazole or mebendazole was available in all HF.ConclusionsThe current capacity of HF for intestinal schistosomiasis and STH detection and management is inadequate. Treatment was not available for schistosomiasis. These issues need to be addressed to create an enabling environment for successful integration of intestinal schistosomiasis and STH case management into HF routine activities in Burundi for better control of these diseases.

Efficacy and tolerability of moxidectin alone and in co-administration with albendazole and tribendimidine versus albendazole plus oxantel pamoate against Trichuris trichiura infections: a randomised, non-inferiority, single-blind trial

The recommended anthelmintics show low efficacy in a single-dose regimen against Trichuris trichiura. Moxidectin, a new treatment for river blindness, might complement the drug armamentarium for the treatment and control of soil-transmitted helminthiasis. However, its efficacy against T trichiura has not yet been studied. The aim of the study was to assess the efficacy of moxidectin alone and in co-administrations against T trichiura infection. A randomised, single-blind, non-inferiority trial was done in two primary schools and one secondary school in Pemba, Tanzania. Adolescents aged 12-18 years who tested positive for T trichiura were randomly assigned (5:5:3:3) with a computer-generated sequence to receive moxidectin (8 mg) plus albendazole (400 mg), albendazole (400 mg) plus oxantel pamoate (25 mg/kg; reference treatment), moxidectin (8 mg) plus tribendimidine (200 mg or 400 mg), or moxidectin (8 mg) alone. Study group assignments were masked from participants and laboratory technicians. The primary outcome was non-inferiority with a 2 percentage point margin for egg reduction rate (ERR) against T trichiura assessed as the relative change in the geometric mean egg counts from baseline to 14-21 days after treatment with the Kato-Katz method, based on the available case population. Cure rates (CR) and tolerability (assessed 3, 24, and 48 h post treatment) were secondary outcomes. The study is registered at ISRCTN (number 20398469) and is closed to accrual. 701 students were enrolled between April 1, and Aug 7, 2017. Primary outcome data were available for 634 students. We observed ERRs of 98·5% for moxidectin plus albendazole and 99·8% for albendazole plus oxantel pamoate, resulting in an absolute difference of -1·2 percentage points (95% CI -1·8 to -0·8), meeting the non-inferiority margin. 100 (51%) of 197 students receiving moxidectin plus albendazole and 166 (83%) of 200 receiving albendazole plus oxantel pamoate were cured, indicating a difference of 32 percentage points (odds ratio 5·3, 95% CI 3·3 to 8·7). ERRs were 91·6% for moxidectin-tribendimidine and 83·2% for moxidectin. Only mild adverse events (mainly headache and stomach pain) were reported. The largest number of adverse events (126 [20%] of 632 students) was observed 24 h post treatment, with no difference among the individual treatment arms (ranging from 23 [19%] of 118 students treated with moxidectin to 38 [19%] of 199 with moxidectin plus albendazole). Moxidectin plus albendazole showed non-inferiority to albendazole plus oxantel pamoate in terms of ERR; however, albendazole plus oxantel pamoate showed a considerably higher cure rate. Dose-optimisation studies with moxidectin and moxidectin plus albendazole should be considered since the efficacy of the dose used for the treatment of onchocerciasis (8 mg) in this study might not be optimal for the treatment of T trichiura infections. Thrasher Foundation.

Effect of Multiple Rounds of Mass Drug Administration under Lymphatic Filariasis Elimination Program on Prevalence of Soil-Transmitted Helminthiasis in One of the Co-endemic Districts of India

Both soil-transmitted helminthiasis and lymphatic filariasis are co-endemic in some districts of India. The study was aimed at comparing the prevalence of soil-transmitted helminthiasis (STH) infection before and after mass drug administration (MDA) given for lymphatic filariasis at Alappuzha. We examined stool samples of 219 children aged between 9 and 10 years from nine schools at Alappuzha, Kerala, in June 2015. The current STH situation was compared with that in the year 1999 (before the institution of MDA) in the same age group in the same district. WHO-recommended Kato-Katz technique was used for STH prevalence estimation. Information regarding socio-demographic variables, sanitation, personal hygiene practices was also recorded. Chi-square test was used to study association of risk factors with STH infection. A total of 79 (36.07%) children were found to be positive for STH infection. Out of all samples positive for Ascaris lumbricoides, 4 (5%) were found co-infected with Trichuris trichiura and none with hookworm. Factors like absence of household latrine, lack of hand washing before meals and practice of consuming unwashed fruits were found to be significantly associated with occurrence of STH infection. Over the years, consecutive rounds of MDA for LF have led to a decline in intestinal worm burden but with little effect on the overall prevalence of STH. Thus, STH control activities working synergistically with the Filarial Elimination Strategy can yield better results in the co-endemic areas with optimum resource utilization.

Interrupting seasonal transmission of Schistosoma haematobium and control of soil-transmitted helminthiasis in northern and central C\xf4te d\u2019Ivoire: a SCORE study protocol

BackgroundTo achieve a world free of schistosomiasis, the objective is to scale up control and elimination efforts in all endemic countries. Where interruption of transmission is considered feasible, countries are encouraged to implement a comprehensive intervention package, including preventive chemotherapy, information, education and communication (IEC), water, sanitation and hygiene (WASH), and snail control. In northern and central Côte d’Ivoire, transmission of Schistosoma haematobium is seasonal and elimination might be achieved. In a cluster-randomised trial, we will assess different treatment schemes to interrupt S. haematobium transmission and control soil-transmitted helminthiasis over a 3-year period. We will compare the impact of (i) arm A: annual mass drug administration (MDA) with praziquantel and albendazole before the peak schistosomiasis transmission season; (ii) arm B: annual MDA after the peak schistosomiasis transmission season; (iii) arm C: two yearly treatments before and after peak schistosomiasis transmission; and (iv) arm D: annual MDA before peak schistosomiasis transmission, coupled with chemical snail control using niclosamide.Methods/designThe prevalence and intensity of S. haematobium and soil-transmitted helminth infections will be assessed using urine filtration and Kato-Katz thick smears, respectively, in six administrative regions in northern and central parts of Côte d’Ivoire. Once a year, urine and stool samples will be collected and examined from 50 children aged 5–8 years, 100 children aged 9–12 years and 50 adults aged 20–55 years in each of 60 selected villages. Changes in S. haematobium and soil-transmitted helminth prevalence and intensity will be assessed between years and stratified by intervention arm. In the 15 villages randomly assigned to intervention arm D, intermediate host snails will be collected three times per year, before niclosamide is applied to the selected freshwater bodies. The snail abundance and infection rates over time will allow drawing inference on the force of transmission.DiscussionThis cluster-randomised intervention trial will elucidate whether in an area with seasonal transmission, the four different treatment schemes can interrupt S. haematobium transmission and control soil-transmitted helminthiasis. Lessons learned will help to guide schistosomiasis control and elimination programmes elsewhere in Africa.Trial registrationISRCTNISRCTN10926858. Registered 21 December 2016. Retrospectively registered.

Preventive chemotherapy to control soil-transmitted helminthiasis averted more than 500 000 DALYs in 2015.

Preventive chemotherapy (PC), the large-scale administration of anthelminthics, is recommended by the World Health Organization (WHO) for the control of soil-transmitted helminthiasis (STH). Since 2010, donated anthelminthics for STH have boosted the implementation of PC programmes in children, achieving global coverage of more than 60% in 2015. The WHO Global Health Estimates attribute an annual loss of over 3.3 million disability-adjusted life-years (DALYs) to STH. The aim of this study is to estimate the impact of PC programmes on child morbidity. We used data from the WHO Global Health Estimates, national coverage data on PC and the results of an evaluation of the impact of PC in 17 countries on morbidity previously conducted by our group. We estimated that the implementation of PC averted in 2015 over 44% of the DALYs that would have been caused in children by STH without the control intervention. A reduction in morbidity of over 75% is expected, if the global target is reached in 2020. If the programme is subsequently maintained, morbidity from STH will be almost totally removed by 2025. In endemic areas, preventive chemotherapy provides a significant health benefit. We consider this estimation potentially useful to evaluate the cost utility of the investment made by several endemic countries on PC to control STH.

Assessment of the burden of soil-transmitted helminthiasis after five years of mass drug administration for Onchocerciasis and Lymphatic filariasis in Kebbi State, Nigeria

There is a hypothesis that Mass drug administration (MDA) of ivermectin and albendazole for the treatment of onchocerciasis and lymphatic filariasis could have an impact on the burden of soil-transmitted helminthiasis (STH) in MDA communities. We, therefore, assessed the burden of STH (Ascaris lumbricoides, Trichuris trichiura, and hookworm) infections in nine communities from 3 LGAs (two MDA local government areas (LGAs) and one control LGA) in Kebbi State, Nigeria after 5-years (2010–2015) of MDA for onchocerciasis and/or lymphatic filariasis. We also administered questionnaire to obtain demographic information and history of MDA in the past five years. The three LGAs are Bagudo (Ivermectin MDA); Zuru (Ivermectin/Albendazole MDA) and Dandi (No MDA). The study was a cross sectional survey. The total number of people that complied with provision of stool samples and questionnaire were 1357 persons; stool samples collected were examined for STH infections in the three LGAs. Zuru LGA had the highest prevalence of STH (41.89, 95% CI: 37.08–46.81) followed by Dandi LGA (24.66, 95% CI: 20.69–28.97) and Bagudo LGA (3.36, 95% CI: 1.97–5.32). Prevalence of STH infection was not significantly different among age group and sex. Geometric mean intensity per gram of infection for both A. lumbricoides and Hookworm were highest in Zuru LGA with (1.16 GMI, 95% CI: 0.97–1.36) and (1.49 GMI, 95% CI: 1.29–1.70) respectively. Treatment coverage was less than 65% from 2010 to 2013 in the intervention LGAs. The study shows that STH is still a public health problem in Zuru LGA (IVM+ALB) and requires MDA of albendazole for STH control to continue, while Dandi LGA (No MDA history) requires MDA with albendazole to scale up treatment for STH control.

A preliminary survey of school-based water, sanitation, hygiene (WASH) resources and soil-transmitted helminthiasis in eight public schools in Odeda LGA, Ogun State, Nigeria

AbstractThis cross-sectional study was undertaken to assess the status of school-based water, sanitation and hygiene (WASH) resources and soil-transmitted helminthiasis (STH) in Odeda, Ogun State, Nigeria. The status and condition of WASH resources were determined in eight selected schools (three with WASH support and five without). Stool samples were also collected from 428 pupils from both school categories and screened for STH infections. Findings showed that water and sanitation conditions of WASH resource programming schools were better than those in schools without WASH support. However, pupils’ knowledge about STH infections and basic hygiene were not significantly different between both categories of school (P > 0·05). The prevalence of Hookworm, Ascariasis and Trichuriasis cases recorded were 26·2, 18·2 and 1·6% respectively, with an overall prevalence of 33·4%. By school categories, Ascariasis (14·9vs20·6), Hookworm (17·7vs32·0), Trichuriasis (1·7vs1·6) and, any STH prevalence (27·4vs37·5) were recorded for schools with WASH resource programming and those without respectively. A greater portion of the infected children 95 (66·4%) were from schools without WASH support. Our findings imply that WASH resource may have very positive impact on the control of STH among school children. However, there is need for improvement on coverage, adequacy and maintenance of WASH facilities in school.

Water Resource, Hygienic Practice, and Soil Transmitted Helminthiasis in Some Rural Communities of Osun State, Nigeria

Provision of water, sanitation and hygiene (WASH) resources has been advocated as necessary add-on strategy for sustainable control of soil-transmitted helminthiasis (STH) alongside annual mass drug administration (MDA) of albendazole to endemic communities. This study investigated the burden of STH and status of WASH resources in eight rural communities in Aiyedaade LGA, Osun State, Nigeria. Four of the communities were supported with improved water and hygiene resources (Category A), and another four supported only with improved water resources (Category B). Two hundred and sixteen (216) fresh stool samples were collected from consenting community members and screened for Ascaris lumbricoides, Hookworm and Trichuris trichiura infections using ether concentration method. The status and condition of WASH resources were determined using questionnaire and physical observation. An overall prevalence of 35.2% was observed for any STH infection. Species’ prevalence of Ascaris lumbricoides, Hookworm and Trichuris trichiura prevalence was 33.8%, 22.7%, and 0.5% respectively. Intensity of STH infection was significantly higher in Category A communities than in Category B communities. The prevalence of STH in Category A communities was higher (42.0%) than that in Category B communities (30.1%). There were significant differences (p = 0.000) in STH infections between the two categories. The status of improved water supply was not significantly different (p = 0.3153) in the two categories. Knowledge, attitude, and practices about STH, its transmission and control were low in both categories of communities. These results imply that current implementation of WASH which tends to focus on resource distribution, equity, and coverage, is unlikely to impact on STH transmission and control. Therefore, it is necessary for WASH providers to consider STH transmission control in their planning and implementation of WASH intervention for STH endemic communities.

Successful Control of Soil-Transmitted Helminthiasis in School Age Children in Burkina Faso and an Example of Community-Based Assessment via Lymphatic Filariasis Transmission Assessment Survey.

BackgroundBurkina Faso is endemic with soil-transmitted helminth infections. Over a decade of preventive chemotherapy has been implemented through annual lymphatic filariasis (LF) mass drug administration (MDA) for population aged five years and over, biennial treatment of school age children with albendazole together with schistosomiasis MDA and biannual treatment of pre-school age children through Child Health Days. Assessments were conducted to evaluate the current situation and to determine the treatment strategy for the future.Methodology/Principal FindingsA cross-sectional assessment was conducted in 22 sentinel sites across the country in 2013. In total, 3,514 school age children (1,748 boys and 1,766 girls) were examined by the Kato-Katz method. Overall, soil-transmitted helminth prevalence was 1.3% (95% CI: 1.0–1.8%) in children examined. Hookworm was the main species detected, with prevalence of 1.2% (95% CI: 0.9–1.6%) and mean egg counts of 2.1 epg (95% CI: 0–4.2 epg). Among regions, the Centre Ouest region had the highest hookworm prevalence of 3.4% (95% CI: 1.9–6.1%) and mean egg counts of 14.9 epg (95% CI: 3.3–26.6 epg). A separate assessment was conducted in the Centre Nord region in 2014 using community-based cluster survey design during an LF transmission assessment survey (TAS). In this assessment, 351 children aged 6–7 years and 345 children aged 10–14 years were examined, with two cases (0.6% (95% CI: 0.2–2.1%)) and seven cases (2.0% (95% CI: 1.0–4.1%)) of hookworm infection was identified respectively. The results using both age groups categorized the region to be 2% to <10% in STH prevalence according to the pre-defined cut-off values.Conclusions/SignificanceThrough large-scale preventive chemotherapy, Burkina Faso has effectively controlled STH in school age children in the country. Research should be conducted on future strategies to consolidate the gain and to interrupt STH transmission in Burkina Faso. It is also demonstrated that LF TAS provides one feasible and efficient platform to assess the STH situation for post LF MDA decision making.

The challenge of unreported and unprogrammed deworming for soil-transmitted helminth control programs.

Soil-transmitted helminthiasis (STH) affects more than one billion people worldwide. WHO aims to control STH as a public health problem by providing periodic anthelminthic treatment to ≥75% of all at-risk children. Tracking progress toward this 2020 goal relies on accurate reporting of drug coverage. For STH, this is difficult because an unknown-but substantial-proportion of deworming occurs outside nationally-administered STH control programs, so-called 'unprogrammed deworming.' Further, coordination of intersectoral efforts needed to administer drugs to different risk groups-and to report coverage to WHO-is inadequate. This paper describes these challenges and offers suggestions to overcome them.

Efficacy and safety of albendazole plus ivermectin, albendazole plus mebendazole, albendazole plus oxantel pamoate, and mebendazole alone against Trichuris trichiura and concomitant soil-transmitted helminth infections: a four-arm, randomised controlled trial

Existing anthelmintic drugs (eg, albendazole and mebendazole) have low efficacy against the intestinal nematode species Trichuris trichiura and the drug pipeline is exhausted. We aimed to investigate the strategy of combination chemotherapy with existing drugs to establish whether their efficacy could be enhanced and broadened. In this randomised controlled trial, we compared three drug combinations and one standard drug alone in children aged 6-14 years in two schools on Pemba Island, Tanzania infected with T trichiura and concomitant intestinal nematodes. We assigned children, via a randomisation list with block sizes of either four or eight, to orally receive albendazole (400 mg) plus ivermectin (200 μg/kg); albendazole (400 mg) plus mebendazole (500 mg); albendazole (400 mg) plus oxantel pamoate (20 mg/kg); or mebendazole (500 mg) alone. The primary endpoints were the proportion of children cured of T trichiura infection and the reduction of T trichiura eggs in stool based on geometric means, both analysed by available case. This study is registered with ISRCTN, number ISRCTN80245406. We randomly assigned 440 eligible children infected with T trichiura between Sept 2, and Oct 18, 2013, to one of the four treatment groups (110 children per group). Data for 431 children were included in the analysis for the primary endpoints. Albendazole plus oxantel pamoate (74 of 108 children cured [68·5%, 95% CI 59·6-77·4]; egg reduction 99·2%, 98·7-99·6) and albendazole plus ivermectin (30 of 109 cured [27·5%, 19·0-36·0]; egg reduction 94·5%, 91·7-96·3) were significantly more effective against T trichiura than mebendazole alone (nine of 107 cured [8·4%, 3·1-13·8]; egg reduction 58·5%, 45·2-70·9). Albendazole plus mebendazole had similar low efficacy (nine of 107 cured [8·4%, 3·1-13·8; egg reduction 51·6%, 35·0-65·3) to mebendazole alone. About a fifth of the children reported adverse events, which were mainly mild. Abdominal cramps and headache were the most common adverse events after treatment; abdominal cramps were reported by 13 (12·0%) children for albendazole plus ivermectin, 10 (9·3%) for albendazole plus mebendazole, 20 (18·2%) for albendazole plus oxantel pamoate, and 16 (14·5%) for mebendazole; headaches were reported by 5 (4·6%) children for albendazole plus ivermectin, 6 (5·6%) for albendazole plus mebendazole, 12 (10·9%) for albendazole plus oxantel pamoate, and 7 (6·4%) for mebendazole. Our head-to-head comparison of three combination chemotherapies showed the highest efficacy for albendazole plus oxantel pamoate for the treatment of infection with T trichiura. Further studies should investigate the combination of albendazole plus oxantel pamoate so that it can be considered for soil-transmitted helminthiasis control programmes. Medicor Foundation and Swiss National Science Foundation.

The Epidemiology of Human Strongyloidiasis

An epidemiologic approach for the understanding of the public health relevance of Strongyloides stercoralis is currently much needed, due to the renewed interest in the control of soil-transmitted helminthiasis (STH). Despite this fact, the biologic difference of S. stercoralis compared to the other STH in terms of life cycle, diagnostic approach and therapeutic options leaves this nematode under uncertainties that hamper the development of control strategies. However, evidence regarding distribution and prevalence allows for the identification of its global distribution, with lack of adequate water and sanitation supplies as the most significant risk factors. The clinical aspects of this infection in immunocompromised populations also highlight its potentially severe morbidity in groups that are at higher risk for complications during infection. The availability of more accurate diagnostic tools appears as a key element for the performance of more reliable surveys, case control studies and even monitoring for the emergence of drug resistance.

Control of soil-transmitted helminthiasis in Yunnan province, People's Republic of China: Experiences and lessons from a 5-year multi-intervention trial

The current global strategy for the control of soil-transmitted helminthiasis emphasises periodic administration of anthelminthic drugs to at-risk populations. However, this approach fails to address the root social and ecological causes of soil-transmitted helminthiasis. For sustainable control, it has been suggested that improvements in water, sanitation and hygiene behaviour are required. We designed a 5-year multi-intervention trial in Menghai county, Yunnan province, People's Republic of China. Three different interventions were implemented, each covering a village inhabited by 200–350 people. The interventions consisted of (i) initial health education at study inception and systematic treatment of all individuals aged ≥2 years once every year with a single dose of albendazole; (ii) initial health education and bi-annual albendazole administration; and (iii) bi-annual treatment coupled with latrine construction at family level and regular health education. Interventions were rigorously implemented for 3 years, whilst the follow-up, which included annual albendazole distribution, lasted for 2 more years. Before the third round of treatment, the prevalence of Ascaris lumbricoides was reduced by only 2.8% in the annual treatment arm, whilst bi-annual deworming combined with latrine construction and health education resulted in a prevalence reduction of 53.3% (p<0.001). All three control approaches significantly reduced the prevalence of Trichuris trichiura and hookworm, with the highest reductions achieved when chemotherapy was combined with sanitation and health education. The prevalence of T. trichiura remained at 30% and above regardless of the intervention. Only bi-annual treatment combined with latrine construction and health education significantly impacted on the prevalence of Taenia spp., but none of the interventions significantly reduced the prevalence of Strongyloides stercoralis. Our findings support the notion that in high-endemicity areas, sustainable control of soil-transmitted helminth infections necessitates measures to reduce faecal environmental contamination to complement mass drug administration. However, elimination of soil-transmitted helminthiasis will not be achieved in the short run even with a package of interventions, and probably requires improvements in living conditions, changes in hygiene behaviour and more efficacious anthelminthic drugs and treatment regimens.

Parasitological and nutritional status of school-age and preschool-age children in four villages in Southern Leyte, Philippines: Lessons for monitoring the outcome of Community-Led Total Sanitation

While preventive chemotherapy remains to be a major strategy for the prevention and control of soil-transmitted helminthiases (STH), improvements in water, sanitation, and hygiene (WASH) comprise the long-term strategy to achieve sustained control of STH. This study examined the parasitological and nutritional status of school-age and preschool-age children in four villages in Southern Leyte, Philippines where two of the villages attained Open-Defecation-Free (ODF) status after introduction of Community-Led Total Sanitation (CLTS).A total of 341 children (89.0% of the total eligible population) submitted stool samples which were examined using the Kato-Katz technique. Results showed that 27.9% of the total stool samples examined had at least one type of STH (cumulative prevalence), while 7.9% had moderate-heavy intensity infections. Between the two villages where CLTS was introduced, Buenavista had a significantly higher cumulative prevalence of STH at 67.4% (p<0.001) and prevalence of moderate-heavy intensity STH at 23.5% (p=0.000), while Caubang had a significantly lower cumulative prevalence at 4.9% and prevalence of moderate-heavy intensity at 1.8%. On the other hand, the non-CLTS villages of Bitoon and Saub had similar rates for cumulative prevalence (16.7% and 16.8%, respectively; p=0.984) and prevalence of moderate-heavy intensity STH (2.0% and 3.1%, respectively; p=1.000). The findings may be explained by factors that include possible reversion to open defecation, non-utilization of sanitary facilities, and mass drug administration (MDA) coverage, although further studies that can accurately assess the impact of CLTS are recommended. While this study was descriptive, the data indicate no clear pattern among the parasitological and nutritional parameters, as well as the presence of CLTS in the village, suggesting the need to monitor the ODF status of villages on a regular basis even after the end of CLTS activities to ensure the sustainability of the CLTS approach. In order to achieve effective control of STH, deeper collaboration between the WASH and STH sectors are recommended where partners can work together in the area of monitoring and evaluation that may include improved parasitological and nutritional status in high-risk groups, as well as sustainable behavior change as outcome indicators.

Spatio-temporal distribution of soil-transmitted helminth infections in Brazil.

BackgroundIn Brazil, preventive chemotherapy targeting soil-transmitted helminthiasis is being scaled-up. Hence, spatially explicit estimates of infection risks providing information about the current situation are needed to guide interventions. Available high-resolution national model-based estimates either rely on analyses of data restricted to a given period of time, or on historical data collected over a longer period. While efforts have been made to take into account the spatial structure of the data in the modelling approach, little emphasis has been placed on the temporal dimension.MethodsWe extracted georeferenced survey data on the prevalence of infection with soil-transmitted helminths (i.e. Ascaris lumbricoides, hookworm and Trichuris trichiura) in Brazil from the Global Neglected Tropical Diseases (GNTD) database. Selection of the most important predictors of infection risk was carried out using a Bayesian geostatistical approach and temporal models that address non-linearity and correlation of the explanatory variables. The spatial process was estimated through a predictive process approximation. Spatio-temporal models were built on the selected predictors with integrated nested Laplace approximation using stochastic partial differential equations.ResultsOur models revealed that, over the past 20 years, the risk of soil-transmitted helminth infection has decreased in Brazil, mainly because of the reduction of A. lumbricoides and hookworm infections. From 2010 onwards, we estimate that the infection prevalences with A. lumbricoides, hookworm and T. trichiura are 3.6%, 1.7% and 1.4%, respectively. We also provide a map highlighting municipalities in need of preventive chemotherapy, based on a predicted soil-transmitted helminth infection risk in excess of 20%. The need for treatments in the school-aged population at the municipality level was estimated at 1.8 million doses of anthelminthic tablets per year.ConclusionsThe analysis of the spatio-temporal aspect of the risk of infection with soil-transmitted helminths contributes to a better understanding of the evolution of risk over time. Risk estimates provide the soil-transmitted helminthiasis control programme in Brazil with useful benchmark information for prioritising and improving spatial and temporal targeting of interventions.Electronic supplementary materialThe online version of this article (doi:10.1186/1756-3305-7-440) contains supplementary material, which is available to authorized users.

Soil-transmitted helminth infections in South America

Frédérique Chammartin and colleagues' systematic review1Chammartin F Scholte RGC Guimarães LH Tanner M Utzinger J Vounatsou P Soil-transmitted helminth infection in South America: a systematic review and geostatistical meta-analysis.Lancet Infect Dis. 2013; 13: 507-518Summary Full Text Full Text PDF PubMed Scopus (89) Google Scholar and geostatistical meta-analysis aimed to produce high-resolution estimates of the risk and number of people infected with Ascaris lumbricoides, Trichuris trichiura, and hookworm across South America. According to PRISMA guidelines,2Liberati A Altman DG Tetzlaff J et al.The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.PLoS Med. 2009; 6: e1000100Crossref PubMed Scopus (9479) Google Scholar the conduct of systematic reviews consists of several explicit and reproducible steps that have to be available to readers. However, two issues with the methods and results of Chammartin and colleagues' study could compromise confidence in the findings. First, in the search strategy, Chammartin and colleagues did not include important databases of Latin America or South America origin such as Latin America and the Caribbean Literature on Health Sciences (LILACS) or Scientific Electronic Library Online (SciELO). According to this systematic review, no data were available for Uruguay. However, replication of the Article's search strategy in regional databases for Uruguay identified one potentially relevant report3Acuña AM DaRosa D Colombo H et al.Parasitosis intestinales en guarderías comunitaris de Montevideo.Rev Med Uruguay. 1999; 15: 24-33Google Scholar in a journal not indexed in Pubmed, but in LILACS and SciELO. Exclusion of LILACS and SciELO is a database bias that could lead to false conclusions. For example, inclusion of only articles from MEDLINE and not LILACS generated a variation in the value of the odds ratio in a systematic review of Chagas disease.4Sinha MK Montir VM Reporting bias and other biases affecting systematic reviews and meta-analyses: a methodological commentary.Expert Rev Pharmacoecon Outcomes Res. 2006; 6: 603-611Crossref PubMed Scopus (8) Google Scholar Readers of systematic reviews should be aware of the possibility of reporting bias and other biases that might limit the quality of these reviews.4Sinha MK Montir VM Reporting bias and other biases affecting systematic reviews and meta-analyses: a methodological commentary.Expert Rev Pharmacoecon Outcomes Res. 2006; 6: 603-611Crossref PubMed Scopus (8) Google Scholar Even though the investigators could have reasons for the omission of the databases from their systematic review, they should be transparent about key decisions such as this and describe them for readers.2Liberati A Altman DG Tetzlaff J et al.The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.PLoS Med. 2009; 6: e1000100Crossref PubMed Scopus (9479) Google Scholar Second, in the results the investigators mentioned that reports included in the systematic review were uploaded into the free open-access database Global Neglected Tropical Disease (GNTD). Although every article is well described in this database, it is difficult for the readers to know which of them is included in the systematic review because of the absence of a section in both the systematic review and the GNTD database where the articles included in the systematic review are explicitly mentioned. We decided to download information from the GNTD database for all articles related to the countries included in the systematic review; 181 articles were available (appendix). We applied the selection criteria and 14 articles were excluded because they were hospital-based surveys or did not include any prevalence data for A lumbricoides, T trichura, or hookworm infection, leaving 167 articles containing relevant prevalence data. Our result differs from the systematic review's results—eg, for Paraguay only one article is uploaded but Chammartin and colleagues reported two. We agree with Lissete van Lieshout and Maria Yazdanbakhsh's Comment5van Lieshout L Yazdanbakhsh M Landscape of neglected tropical diseases: getting it right.Lancet Infect Dis. 2013; 13: 469-470Summary Full Text Full Text PDF PubMed Scopus (12) Google Scholar that Chammartin and colleagues use robust and cutting-edge statistical methods; however, we question the reliability of the data produced and whether these data represent all the information reported in South America. We declare that we have no conflicts of interest. Download .pdf (.16 MB) Help with pdf files Supplementary appendix Soil-transmitted helminth infection in South America: a systematic review and geostatistical meta-analysisOur findings offer important baseline support for spatial targeting of soil-transmitted helminthiasis control, and suggest that more information about the prevalence of soil-transmitted helminth infection is needed, especially in countries in which we estimate prevalence of infection to be high but for which current data are scarce. Full-Text PDF

Bayesian geostatistical modelling of soil-transmitted helminth survey data in the People’s Republic of China

BackgroundSoil-transmitted helminth infections affect tens of millions of individuals in the People’s Republic of China (P.R. China). There is a need for high-resolution estimates of at-risk areas and number of people infected to enhance spatial targeting of control interventions. However, such information is not yet available for P.R. China.MethodsA geo-referenced database compiling surveys pertaining to soil-transmitted helminthiasis, carried out from 2000 onwards in P.R. China, was established. Bayesian geostatistical models relating the observed survey data with potential climatic, environmental and socioeconomic predictors were developed and used to predict at-risk areas at high spatial resolution. Predictors were extracted from remote sensing and other readily accessible open-source databases. Advanced Bayesian variable selection methods were employed to develop a parsimonious model.ResultsOur results indicate that the prevalence of soil-transmitted helminth infections in P.R. China considerably decreased from 2005 onwards. Yet, some 144 million people were estimated to be infected in 2010. High prevalence (>20%) of the roundworm Ascaris lumbricoides infection was predicted for large areas of Guizhou province, the southern part of Hubei and Sichuan provinces, while the northern part and the south-eastern coastal-line areas of P.R. China had low prevalence (<5%). High infection prevalence (>20%) with hookworm was found in Hainan, the eastern part of Sichuan and the southern part of Yunnan provinces. High infection prevalence (>20%) with the whipworm Trichuris trichiura was found in a few small areas of south P.R. China. Very low prevalence (<0.1%) of hookworm and whipworm infections were predicted for the northern parts of P.R. China.ConclusionsWe present the first model-based estimates for soil-transmitted helminth infections throughout P.R. China at high spatial resolution. Our prediction maps provide useful information for the spatial targeting of soil-transmitted helminthiasis control interventions and for long-term monitoring and surveillance in the frame of enhanced efforts to control and eliminate the public health burden of these parasitic worm infections.