High latrine coverage is not reducing the prevalence of soil-transmitted helminthiasis in Hoa Binh province, Vietnam

Preschool child growth attainment and velocity during an agriculture intervention in rural Panama may be diminished by soil-transmitted helminths

Background

Agricultural interventions are often recommended to address undernutrition in subsistence farming communities. However, intensified agriculture exposure can increase soil transmitted helminth (STH) infections, which are linked with poor child growth. This study examined impacts of the VERASAN public health and agricultural intervention program on preschool child growth attainment (HAZ and WAZ) and relative growth velocity over 7 months [change in height-for-age (∆HAD) and weight-for-age (∆WAD) difference].

Methods

VERASAN was initiated in 15 subsistence farming communities in rural Panama experiencing chronic undernutrition. Activities targeted improved household food security, preschool child diets and growth by intensifying and diversifying household agriculture. Our objectives were to explore the relationship between VERASAN and preschool child growth attainment (HAZ and WAZ) and velocity (∆HAD and ∆WAD) during one agricultural cycle in 238 households. We compared those new to VERASAN with those involved for 1 or 5 years, and identified if agricultural practices, food security, diet diversity and treatment of pre-existing STH infection were associated with growth attainment or velocity.

Results

Prior participation in VERASAN did not directly influence WAZ, HAZ or ΔHAD but VERASAN-related benefits had an indirect influence. ΔHAD was positively associated with VERASAN-associated improvements in diet diversity and food security. HAZ and WAZ during land preparation were positively associated with diet diversity and HAZ with food security during harvest. HAZ was negatively associated with children visiting the agricultural plot, consuming leafy green vegetables and pre-existing hookworm infections. Both agricultural season and STH influenced ΔWAD. Children in VERASAN for 1 or 5 years experienced growth faltering between land preparation and growing season, but not those new to VERASAN. In contrast, between growing and harvest, ∆WAD declined in children new to VERASAN compared to children in VERASAN for longer. ΔWAD from land preparation to harvest was higher with pre-existing Ascaris infection whereas it was lower between growing season and harvest for pre-existing hookworm infection.

Conclusion

In a context of preschool child growth faltering, malnutrition and STH infections, improved food security, agricultural production and diet diversity associated with VERASAN were associated with improved growth. In contrast, STH infections were negatively associated with some, but not all, growth outcomes.

Association between water, sanitation, and hygiene access and the prevalence of soil-transmitted helminth and schistosome infections in Wolayita, Ethiopia

Background

The Geshiyaro project is a 5-year intervention to assess the impact of community- and school-based water, sanitation, and hygiene (WaSH) interventions on reducing infection with soil-transmitted helminths (STH) and schistosome parasites in combination with deworming in Wolayita zone, Ethiopia.

Methods

A population-based, cross-sectional census and parasitological mapping activity was conducted between 2018 and 2019. Individuals in the census were identified using either a registered study ID card or biometric fingerprint to enable linkage of their household WaSH data with baseline STH and schistosome prevalence for risk analysis.

Results

Prevalence of STH was 15.5% for any STH species, 9.47% for Ascaris lumbricoides, 1.78% for Trichuris trichiura, and 7.24% for hookworm. Intestinal schistosomiasis (Schistosoma mansoni) infection prevalence was 0.85% by Kato Katz, 21.6% by POC-CCA trace positive (Tr +), and 13.3% trace negative (Tr-). Microhaematuria was 2.77%, with 0.13% of people examined with S. haematobium eggs detected by urine filtration. At the household level, increased (> 30 min) time taken to collect drinking water, sharing a latrine, and lack of handwashing facilities were all associated with a greater risk of A. lumbricoides, hookworm, and S. mansoni infection. Not disposing of infant stool at the household and clothes washing/recreational freshwater contact were significantly associated with higher risk of schistosomiasis infection. Aggregating WaSH data at the community level showed odds of A. lumbricoides, hookworm, and T. trichiura infection were significantly lower as both community sanitation coverage and access to improved drinking water improved.

Conclusions

The principal finding of this study is that lack of access to WaSH, such as improved drinking water and shared toilet and hand-washing facilities, were linked to an increased risk of infection with STH and schistosome parasites. These associations are difficult to establish at an individual household level because of wide variability in access between houses but are detectable when coverage is aggregated at the community level. Maintenance of WaSH facilities as well as increased access within the whole community is important in influencing the community-wide prevalence of infection with STH and schistosome parasites.

Graphical Abstract

A review of rural and peri-urban sanitation infrastructure in South-East Asia and the Western Pacific: Highlighting regional inequalities and limited data

Rural and peri-urban communities in developing countries rely on sanitation systems which are often unsafely managed. One of the major barriers to assess safely managed sanitation is a lack of data about the existing sanitation infrastructure and levels of containment safety. The aim was to review rural and peri-urban on-site sanitation studies in order to understand different infrastructure types, associated management practices and any impacts on human health. The scope was limited to South-East Asia and Western Pacific regions in order to better identify regional inequalities. Among the 155 reviewed articles, 73 studies (47%) linked sanitation infrastructure to poor human health. Nearly all articles reported latrine ownership (n = 149, 96%) while sanitation infrastructure types were covered less frequently (n = 104, 67%). In particular, there was a lack of published literature describing back-end characteristics (dimension and materials) (n = 12, 8%) and/or management practices (n = 4, 3%). This stems from a limited application of research methodologies that characterise sanitation infrastructure and faecal sludge management (containment, emptying and on-site treatment). Inequality between regions was prevalent with three quarters of the studies on latrine back-end infrastructure from Bangladesh and India in South-East Asia. A strategic research approach is needed to address the current knowledge gaps regarding sanitation infrastructure and safe faecal sludge management.

Prevalence and associated risk factors of soil-transmitted helminth infections in Kandahar, Afghanistan

Background

Soil-transmitted helminth (STH) infections are still a major health problem, especially in resource-limited countries. The community-based prevalence of STH is unknown in Afghanistan. Main objectives of this study were to estimate the prevalence and associated factors of STH among children in Daman district of Kandahar province in Afghanistan.

Methods

This was a community-based cross-sectional study, with data collected during five months (June–October, 2020) from children living in five villages of Daman district in Kandahar, Afghanistan. All the stool samples were examined by saline wet mount method. Data were analyzed by using descriptive statistics, Chi square test, and multivariate logistic regression.

Results

A total of 1426 children were studied, with majority (61.8%) of males and the mean age of 6.3 years. The overall prevalence of any intestinal parasitic infection was 39.8%. The overall prevalence of STH infection was 22.7%, with Ascaris lumbricoides (18.7%) as the most prevalent STH species, followed by hookworm (7.5%) and Trichuris trichiura (1.4%). Single, double, and triple STH infections were present in 14.9%, 7.2%, and 0.6% of the children, respectively. Multivariate logistic regression revealed that not washing hands after defecating/before eating (AOR 7.0, 95% CI 3.4–14.0), living in mud house (AOR 3.5, 95% CI 1.6–7.4), walking barefoot (AOR 2.2, 95% CI 1.6–3.1), living in overcrowded house (AOR 1.6, 95% CI 1.1–2.3), and practicing open defecation (AOR 1.4, 95% CI 1.1–2.0) as the risk factors associated with the predisposition of rural children for getting STH in Daman district of Afghanistan.

Conclusions

Prevalence of STH is high among children of Daman district in Afghanistan. Most of the risk factors are related to poverty, decreased sanitation, and improper hygiene. Improvement of socioeconomic status, sanitation, and health education to promote public awareness about health and hygiene together with periodic mass deworming programs are better strategies for the control of STH infections in Afghanistan. Also, government and international donor agencies in Afghanistan should help in improving socio-economic status of the rural areas through provision of basic facilities such as piped water, electricity, good housing, and proper toilets.

Effect of sanitation improvements on soil-transmitted helminth eggs in courtyard soil from rural Bangladesh: Evidence from a cluster-randomized controlled trial

Improved sanitation has been hypothesized to reduce soil-transmitted helminth (STH) infections by reducing the prevalence and concentration of STH eggs/larvae in soil. We evaluated the effect of a randomized sanitation program (providing households with an improved dual-pit latrine, tools for child/animal feces management, and behavioral messaging) on reducing the prevalence and concentration of STH eggs in soil from household courtyards. We collected soil samples from 1405 households enrolled in the sanitation intervention (n = 419) and control (n = 914) groups of a cluster-randomized controlled trial (WASH Benefits) in rural Bangladesh approximately 2 years after the initiation of the interventions. We analyzed samples for Ascaris lumbricoides, Trichuris trichiura, and hookworm eggs by microscopy. We estimated prevalence ratios (PR) and egg count ratio (ECR) to compare the prevalence of STH eggs and arithmetic and geometric mean egg counts for STH eggs per gram of soil in the sanitation and control arms. Among intervention households, latrines achieved high and sustained user uptake by adults while child open defecation remained common and most households did not dispose of child feces hygienically. In courtyard soil from control households, the prevalence of any STH eggs was 75.7% and the prevalence of any larvated STH eggs was 67.3%. A. lumbricoides was detected in 63.0% of control samples and T. trichiura in 55.7% of control samples; hookworm was not detected in any sample. In the control arm, the arithmetic mean egg count for any STH was 3.96 eggs/dry gram, while the geometric mean was 1.58 eggs/dry gram. There was no difference between the intervention and control groups in the prevalence of any STH eggs (PR = 0.98 (95% CI: 0.91, 1.05)) or mean egg counts (ECR = 0.08 (95% CI: -0.10, 0.26) for geometric mean and 0.07 (95% CI: -0.22, 0.37) for arithmetic mean). Adjusted models gave similar results. A compound-level sanitation intervention that provided improved latrines and tools for disposal of child and animal feces did not have an impact on STH eggs in soil. In order to effectively reduce the prevalence and concentration of STH eggs in the environment, sustained, widespread use of sanitation strategies to isolate and hygienically dispose of child and animal feces may need to complement traditional strategies for containment of adult human feces. Trial Registration: NCT01590095.

Vietnam: country report on children's environmental health

As a developing country, Vietnam is facing many problems such as environmental pollution caused by industrialization, urbanization and the ethnic minority gap. Besides, Vietnam is one of the 10 countries most vulnerable to the effects of climate change and natural disasters. Vietnam has more than 26.3 million children under 16 years of age, with the ratio being 114 boys/100 girls. Children are especially vulnerable to environmental risks. This review includes much data collected during 2010-2018 on children's environmental health in Vietnam.

Gender-based differences in water, sanitation and hygiene-related diarrheal disease and helminthic infections: a systematic review and meta-analysis

BACKGROUND

Qualitative evidence suggests that inadequate water, sanitation and hygiene (WASH) may affect diarrheal and helminthic infection in women disproportionately. We systematically searched PubMed in June 2014 (updated 2016) and the WHO website, for relevant articles.

METHODS

Articles dealing with the public health relevance of helminthic and diarrheal diseases, and highlighting the role of gender in WASH were included. Where possible, we carried out a meta-analysis.

RESULTS

In studies of individuals 5 years or older, cholera showed lower prevalence in males (OR 0.56; 95% CI 0.34-0.94), while Schistosoma mansoni (1.38; 95% CI 1.14-1.67), Schistosoma japonicum (1.52; 95% CI 1.13-2.05), hookworm (1.43; 95% CI 1.07-1.89) and all forms of infectious diarrhea (1.21; 95% CI 1.06-1.38) showed a higher prevalence in males. When studies included all participants, S. mansoni and S. japonicum showed higher prevalence with males (OR 1.40; 95% CI 1.27-1.55 and 1.84; 95% CI 1.27-2.67, respectively). Prevalence of Trichiuris and hookworm infection showed effect modification with continent.

CONCLUSIONS

Evidence of gender differences in infection may reflect differences in gender norms, suggesting that policy changes at the regional level may help ameliorate gender related disparities in helminthic and diarrheal disease prevalence.

A Faecal Contamination Index for interpreting heterogeneous diarrhoea impacts of water, sanitation and hygiene interventions and overall, regional and country estimates of community sanitation coverage with a focus on low- and middle-income countries

OBJECTIVES

The impact on diarrhoea of sanitation interventions has been heterogeneous. We hypothesize that this is due to the level of prevailing faecal environmental contamination and propose a Faecal Contamination Index (FAECI) of selected WASH indicators (objective 1). Additionally, we provide estimates of the proportion of the population living in communities above certain sanitation coverage levels (objective 2).

METHODS

Objective 1: Faecal contamination post-intervention was estimated from WASH intervention reports. WASH indicators composing the FAECI included eight water, sanitation and hygiene practice indicators, which were selected for their relevance for health and data availability at study- and country-level. The association between the estimated level of faecal environmental contamination and diarrhoea was examined using meta-regression. Objective 2: A literature search was conducted to identify health-relevant community sanitation coverage thresholds. To estimate total community coverage with basic sanitation in low- and middle-income countries, at relevant thresholds, household surveys with data available at primary sampling unit (PSU)-level were analysed according to the identified thresholds, at country-, regional- and overall level.

RESULTS

Objective 1: We found a non-linear association between estimated environmental faecal contamination and sanitation interventions' impact on diarrhoeal disease. Diarrhoea reductions were highest at lower faecal contamination levels, and no diarrhoea reduction was found when contamination increased above a certain level. Objective 2: Around 45% of the population lives in communities with more than 75% of coverage with basic sanitation and 24% of the population lives in communities above 95% coverage, respectively.

CONCLUSIONS

High prevailing faecal contamination might explain interventions' poor effectiveness in reducing diarrhoea. The here proposed Faecal Contamination Index is a first attempt to estimate the level of faecal contamination in communities. Much of the world's population currently lives in faecally contaminated environments as indicated by low community sanitation coverage.

Does safe disposal of child faeces matter? An assessment of access to improved sanitation and child faeces disposal behaviour and diarrhoea in rural Nepal

Background

Improper disposal of child faeces is a major source of faecal pathogens that cause diarrhoeal disease. However, this has received relatively less attention in sanitation evaluation literature, which has tended to focus on sanitation provision, implicitly assuming that child faeces disposal behaviour also improves with sanitation. We examined the impact of improved sanitation without safe disposal (households with improved sanitation but not disposing of child faeces in improved sanitation) and improved sanitation with safe disposal (households with improved sanitation and disposal of child faeces in improved sanitation) on diarrhoeal prevalence in rural Nepal.

Methods

Data from the Nepal Demographic Health Survey 2011 for 3377 children <5 y of age were used to answer the research question using quasi-experimental methods.

Results

Improved sanitation with safe disposal was associated with a 3.3 percentage point (standard error [SE] 0.016) to 6.6 percentage point (SE 0.023) lower prevalence of diarrhoea among children <5 y of age compared with matched households without access to improved sanitation. No effect was observed for households having improved sanitation without safe disposal compared with matched households without access to improved sanitation. Improved sanitation with safe disposal was also associated with a 4.0 percentage point (SE 0.023) lower prevalence of diarrhoea in low economic status households (bottom two quintiles).

Conclusions

Our results suggest that sanitation programmes need to focus on behavioural interventions as well as increasing access to sanitation facilities.

Impact of the health education and preventive equipment package (HEPEP) on prevention of Strongyloides stercoralis infection among rural communities in Northeast Thailand: a cluster randomized controlled trial

Background

Strongyloidiasis is prevalent in northeast Thailand. This study aimed to evaluate the impact of the Health Education and Preventive Equipment Package (HEPEP), a package we developed to improve awareness and aid in the prevention of Strongyloides stercoralis infection among rural communities in northeast Thailand.

Methods

This was an intervention trial conducted in 12 villages (six interventions and six controls) in rural areas of northeast Thailand from March 2016 to September 2017. Single stool sample was collected from each participant and examined using agar plate culture (APC) technique. Each participant was interviewed using a pre-tested questionnaire, treated with single dose of ivermectin (200 μg/Kg), and allocated to either the intervention or control group. Members of the intervention group were given “Practices to Prevent Strongyloidiasis” poster and vinyl boards containing information aimed at raising awareness of S. stercoralis and strongyloidiasis. In addition, they were given a poster lecture regarding the lifecycle of S. stercoralis before being treated with ivermectin. Aside from that, they were also given a protective equipment package. Monthly refresher courses were provided by village health volunteers (VHVs) regarding the health information they had received and proper equipment usage. The control group, on the other hand, was only provided with a five-minute lecture regarding strongyloidiasis. Assessment of new infection was conducted 3 months later in 327 and 318 participants in the intervention group and control group, respectively.

Results

The HEPEP had 41% greater efficacy in preventing S. stercoralis infection in the intervention group than the measures taken in the control group (adjusted Odds Ratio (aOR) = 0.59; 95%CI: 0.41 to 0.85, P-value = 0.005). The intervention group also scored significantly higher on all aspects of a test of S. stercoralis knowledge compared with the control group (mean difference (mean dif.) = 2.89, P-value = < 0.05).

Conclusions

The HEPEP was the first model that has been found to be effective in controlling of S. stercoralis in rural communities in the northeast Thailand. The results should encourage policy makers and public health personnel to improve control programs, as well as health promotion, with regard to parasites.

Trial registration

Thai Clinical Trials Registry (TCTR), Medical Research Foundation of Thailand, Medical Research Network of the Consortium of Thai Medical Schools: MedResNet (Thailand) (identification number: TCTR20180404002) Registered 4 April 2018 (retrospectively registered).

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6081-6) contains supplementary material, which is available to authorized users.

Soil-transmitted helminth infections associated with wastewater and sludge reuse: a review of current evidence

OBJECTIVE

To review current evidence on infections related to the concentration of soil-transmitted helminth (STH) eggs in wastewater, sludge and vegetables irrigated with wastewater or grown on sludge-amended soils.

METHOD

Search of Web of Science, Science Direct, PubMed and Google Scholar databases for publications reporting on STH egg concentration in wastewater, sludge and vegetables and for epidemiological studies on wastewater/sludge reuse and STH infections.

RESULTS

STH egg concentrations were variable but high in wastewater and sludge especially in developing countries. They ranged from 6 to 16 000 eggs/L in wastewater and from 0 to 23 000 eggs/g in sludge and far exceed limits set in the WHO guideline for wastewater/sludge reuse. Numbers of STH eggs on vegetables ranged from 0 to 100 eggs/g. The concentration of STH eggs in wastewater, sludge and vegetables therefore relates to risks of infection through different exposure routes.

CONCLUSION

Epidemiological evidence reveals an increased prevalence of STH infections associated with direct exposure to wastewater or sludge (farmers) and consumption of vegetables grown on soil treated with it. This calls for increased efforts to reduce the adverse health impact of wastewater and sludge reuse in line with the WHO multi-barrier approach.

Turning poop into profit: Cost-effectiveness and soil transmitted helminth infection risk associated with human excreta reuse in Vietnam

Human excreta is a low cost source of nutrients vital to plant growth, but also a source of pathogens transmissible to people and animals. We investigated the cost-savings and infection risk of soil transmitted helminths (STHs) in four scenarios where farmers used either inorganic fertilizer or fresh/composted human excreta supplemented by inorganic fertilizer to meet the nutrient requirements of rice paddies in the Red River Delta, Vietnam. Our study included two main components: 1) a risk estimate of STH infection for farmers who handle fresh excreta, determined by systematic review and meta-analysis; and 2) a cost estimate of fertilizing rice paddies, determined by nutrient assessment of excreta, a retailer survey of inorganic fertilizer costs, and a literature review to identify region-specific inputs. Our findings suggest that farmers who reuse fresh excreta are 1.24 (95% CI: 1.13–1.37, p-value<0.001) times more likely to be infected with any STH than those who do not handle excreta or who compost appropriately, and that risk varies by STH type (Ascaris lumbricoides RR = 1.17, 95% CI = 0.87–1.58, p-value = 0.29; Hookworm RR = 1.02, 95% CI = 0.50–2.06, p-value = 0.96; Trichuris trichiura RR = 1.38, 95% CI = 0.79–2.42, p-value = 0.26). Average cost-savings were highest for farmers using fresh excreta (847,000 VND) followed by those who composted for 6 months as recommended by the WHO (312,000 VND) and those who composted for a shorter time (5 months) with lime supplementation (37,000 VND/yr); however, this study did not assess healthcare costs of treating acute or chronic STH infections in the target group. Our study provides evidence that farmers in the Red River Delta are able to use a renewable and locally available resource to their economic advantage, while minimizing the risk of STH infection.

Each year, hundreds of millions of people worldwide are infected with intestinal worms spread by contaminated soil, also known as soil transmitted helminths (STHs). These worms are most common in tropical climates in areas lacking good hygiene and sanitation, and negatively impact child development, quality of life, and economic wellbeing. Reuse of human excreta for fertilizer is a common practice in many low to middle income countries because farmers require a low cost source of nutrients to grow food crops eaten by people and animals. Excreta can contain microbes, such as STHs, that cause disease in people; however, composting is a known method of killing STHs. Therefore, our goal was to determine if Vietnamese rice farmers involved in this practice are at higher risk of STH infection, and to calculate the amount of money saved by farmers composting for different lengths of time, and supplementing with various commercial fertilizers. We suggest that farmers compost excreta for six months to reduce disease exposure and optimize household savings. Optimizing practices to improve food production and protect farmer health is critical for poverty alleviation in low to middle income countries.

Advantages and limitations for users of double pit pour-flush latrines: a qualitative study in rural Bangladesh

Background

In rural Bangladesh, India and elsewhere, pour-flush pit latrines are the most common sanitation system. When a single pit latrine becomes full, users must empty it themselves and risk exposure to fresh feces, pay an emptying service to remove pit contents or build a new latrine. Double pit pour-flush latrines may serve as a long-term sanitation option including high water table areas because the pits do not need to be emptied immediately and the excreta decomposes into reusable soil.

Methods

Double pit pour-flush latrines were implemented in rural Bangladesh for ‘hardcore poor’ households by a national NGO, BRAC. We conducted interviews, focus groups, and spot checks in two low-income, rural areas of Bangladesh to explore the advantages and limitations of using double pit latrines compared to single pit latrines.

Results

The rural households accepted the double pit pour-flush latrine model and considered it feasible to use and maintain. This latrine design increased accessibility of a sanitation facility for these low-income residents and provided privacy, convenience and comfort, compared to open defecation. Although a double pit latrine is more costly and requires more space than a single pit latrine the households perceived this sanitation system to save resources, because households did not need to hire service workers to empty pits or remove decomposed contents themselves. In addition, the excreta decomposition process produced a reusable soil product that some households used in homestead gardening. The durability of the latrine superstructures was a problem, as most of the bamboo-pole superstructure broke after 6–18 months of use.

Conclusions

Double pit pour-flush latrines are a long-term improved sanitation option that offers users several important advantages over single pit pour-flush latrines like in rural Bangladesh which can also be used in areas with high water table. Further research can provide an understanding of the comparative health impacts and effectiveness of the model in preventing human excreta from entering the environment.

Ascaris lumbricoides egg die-off in an experimental excreta storage system and public health implication in Vietnam

OBJECTIVES

We studied the influence of different additive materials (lime, and rice husk) and aeration conditions on Ascaris lumbricoides egg die-off in 24 vaults of an experimental excreta storage unit.

METHODS

Excreta samples were collected once every two weeks over a 181-day period. Temperature, pH, and moisture content were recorded. A. lumbricoides eggs were quantitatively analyzed by the Romanenko method, which identified and counted live and dead eggs.

RESULTS

From the first sampling (0 storage day) to the final sampling (181 storage days) the average percentage of viable A. lumbricoides eggs decreased gradually from 76.72 ± 11.23% (mean ± SD) to 8.26 ± 5.20%. The storage time and the high pH value significantly increased the die-off of helminth eggs. Over 181 storage days, all vaults option effectively reduced A. lumbricoides eggs die-off.

CONCLUSIONS

The best vault option, with aeration and 10% lime per total weight, met the WHO standard for excreta treatment on the 111th storage day.

Evidence for Public Health Risks of Wastewater and Excreta Management Practices in Southeast Asia: A Scoping Review

The use of wastewater and excreta in agriculture is a common practice in Southeast Asia; however, concerns remain about the potential public health risks of this practice. We undertook a scoping review to examine the extent, range, and nature of literature, as well as synthesize the evidence for associations between wastewater and excreta management practices and public health risks in Southeast Asia. Three electronic databases (PubMed, CAB Direct, and Web of Science) were searched and a total of 27 relevant studies were included and evaluated. The available evidence suggested that possible occupational health risks of wastewater and excreta management practices include diarrhea, skin infection, parasitic infection, bacterial infection, and epilepsy. Community members can be at risk for adverse health outcomes through consuming contaminated fish, vegetables, or fruits. Results suggested that practices including handling, treatment, and use of waste may be harmful to human health, particularly farmer’s health. Many studies in this review, however, had limitations including lack of gender analyses, exposure assessment, and longitudinal study designs. These findings suggest that more studies on identifying, quantitatively assessing, and mitigating health risks are needed if sustainable benefits are to be obtained from wastewater and excreta reuse in agriculture in Southeast Asia.

Developing and evaluating health education learning package (HELP) to control soil-transmitted helminth infections among Orang Asli children in Malaysia

BACKGROUND

This study was carried out to develop a health education learning package (HELP) about soil-transmitted helminth (STH) infections, and to evaluate what impact such a package could have in terms of reducing the incidence and intensity of STH infections among Orang Asli schoolchildren in Pahang, Malaysia.

METHODS

To identify the key risk factors of STH in Orang Asli communities, we applied an extensive mixed methods approach which involved an intensive literature review, as well as community-based discussions with children, their parents, teachers and health personnel, whilst also placing the children under direct observation. To evaluate the package, 317 children from two schools in Lipis, Pahang were screened for STH infections, treated by a 3-day course of albendazole and then followed up over the next 6 months. The knowledge of teachers, parents and children towards STH infections were assessed at baseline and after 3 months.

RESULTS

The developed package consists of a half day workshop for teachers, a teacher's guide book to STH infections, posters, a comic book, a music video, a puppet show, drawing activities and an aid kit. The package was well-received with effective contributions being made by teachers, children and their parents. The incidence rates of hookworm infection at different assessment points were significantly lower among children in the intervention school compared to those in the control school. Similarly, the intensity of trichuriasis, ascariasis and hookworm infections were found to be significantly lower among children in the HELP group compared to those in the control group (P < 0.05). Moreover, the package significantly improved the knowledge, attitude and practices (KAP) of Orang Asli people and the knowledge of teachers towards STH infections.

CONCLUSION

A school-based health education learning package (HELP) was developed which displayed a significant impact in terms of reducing the intensity of all three main STH infections, as well as in reducing the prevalence of hookworm infections. Moreover, the knowledge levels of both teachers and the Orang Asli population regarding STH was significantly improved, a fact which greatly helped in attracting community participation and thus raising the general level of awareness regarding these forms of infections.

Transmission of helminth eggs through hands in a high-risk community

BACKGROUND

The role that hands play in the transmission of Ascaris is not well understood.

METHODS

A newly developed method to quantify the presence helminth eggs on hands was tested among a group of farmers in Vietnam. High turbidity in hand rinse samples meant that the adopted sugar solution had to be replaced by zinc sulphate as a flotation solution.

RESULTS

The survey found 34% (31/90) of study participant hands' were positive for helminth eggs, though concentrations were low and ranged from 0-10 eggs/2 hands. The use of fresh excreta in agriculture was the only variable that showed an association with the concentrations of eggs found on hands.

CONCLUSIONS

The results highlight the need to promote handwashing with soap to prevent the transmission of soil-transmitted helminth infections.

Water, sanitation, hygiene, and soil-transmitted helminth infection: a systematic review and meta-analysis

BACKGROUND

Preventive chemotherapy represents a powerful but short-term control strategy for soil-transmitted helminthiasis. Since humans are often re-infected rapidly, long-term solutions require improvements in water, sanitation, and hygiene (WASH). The purpose of this study was to quantitatively summarize the relationship between WASH access or practices and soil-transmitted helminth (STH) infection.

METHODS AND FINDINGS

We conducted a systematic review and meta-analysis to examine the associations of improved WASH on infection with STH (Ascaris lumbricoides, Trichuris trichiura, hookworm [Ancylostoma duodenale and Necator americanus], and Strongyloides stercoralis). PubMed, Embase, Web of Science, and LILACS were searched from inception to October 28, 2013 with no language restrictions. Studies were eligible for inclusion if they provided an estimate for the effect of WASH access or practices on STH infection. We assessed the quality of published studies with the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. A total of 94 studies met our eligibility criteria; five were randomized controlled trials, whilst most others were cross-sectional studies. We used random-effects meta-analyses and analyzed only adjusted estimates to help account for heterogeneity and potential confounding respectively. Use of treated water was associated with lower odds of STH infection (odds ratio [OR] 0.46, 95% CI 0.36-0.60). Piped water access was associated with lower odds of A. lumbricoides (OR 0.40, 95% CI 0.39-0.41) and T. trichiura infection (OR 0.57, 95% CI 0.45-0.72), but not any STH infection (OR 0.93, 95% CI 0.28-3.11). Access to sanitation was associated with decreased likelihood of infection with any STH (OR 0.66, 95% CI 0.57-0.76), T. trichiura (OR 0.61, 95% CI 0.50-0.74), and A. lumbricoides (OR 0.62, 95% CI 0.44-0.88), but not with hookworm infection (OR 0.80, 95% CI 0.61-1.06). Wearing shoes was associated with reduced odds of hookworm infection (OR 0.29, 95% CI 0.18-0.47) and infection with any STH (OR 0.30, 95% CI 0.11-0.83). Handwashing, both before eating (OR 0.38, 95% CI 0.26-0.55) and after defecating (OR 0.45, 95% CI 0.35-0.58), was associated with lower odds of A. lumbricoides infection. Soap use or availability was significantly associated with lower infection with any STH (OR 0.53, 95% CI 0.29-0.98), as was handwashing after defecation (OR 0.47, 95% CI 0.24-0.90). Observational evidence constituted the majority of included literature, which limits any attempt to make causal inferences. Due to underlying heterogeneity across observational studies, the meta-analysis results reflect an average of many potentially distinct effects, not an average of one specific exposure-outcome relationship.

CONCLUSIONS

WASH access and practices are generally associated with reduced odds of STH infection. Pooled estimates from all meta-analyses, except for two, indicated at least a 33% reduction in odds of infection associated with individual WASH practices or access. Although most WASH interventions for STH have focused on sanitation, access to water and hygiene also appear to significantly reduce odds of infection. Overall quality of evidence was low due to the preponderance of observational studies, though recent randomized controlled trials have further underscored the benefit of handwashing interventions. Limited use of the Joint Monitoring Program's standardized water and sanitation definitions in the literature restricted efforts to generalize across studies. While further research is warranted to determine the magnitude of benefit from WASH interventions for STH control, these results call for multi-sectoral, integrated intervention packages that are tailored to social-ecological contexts.

School-Based Intervention: Evaluating the role of Water, Latrines and Hygiene Education on Trachoma and Intestinal Parasitic Infections in Ethiopia

OBJECTIVE

We sought to evaluate the impact of a hygiene and sanitation intervention program among school-children to control active trachoma and intestinal parasitic infections.

METHODS

This longitudinal epidemiologic study was conducted among 630 students in rural Ethiopia. Baseline and follow-up surveys were conducted to evaluate the impact of a three pronged intervention program i) constructing of ventilated improved pit latrines, ii) provision of clean drinking water, and iii) and hygiene education. Socio-demographic information was collected using a structured questionnaire. Presence of trachoma and intestinal parasitic infections were evaluated using standard procedures.

RESULTS

At baseline 15% of students had active trachoma while 6.7% of them were found to have active trachoma post intervention (p<0.001). Similar improvements were noted for parasitic infections. At baseline 7% of students were reported to have helminthic infections and 30.2% protozoa infections. However, only 4% of students had any helminthic infection and 13.4% (p<0.001) of them were found to have any protozoa infection. Improvements were noted in students' knowledge and attitudes towards hygiene and sanitation.

CONCLUSIONS

The results of our study demonstrated that provision of comprehensive and targeted sanitation intervention program was successful in reducing the burden of trachoma and intestinal parasitic infection among school children.

Prevalence and risk factors associated with the presence of Soil-Transmitted Helminths in children studying in Municipal Corporation of Delhi Schools of Delhi, India

To determine the type, prevalence, intensity and the potential risk factors for helminths infection harboured by primary school aged children from selected schools of Delhi, India. Stool samples collected from 347 boys and girls studying in grades I-IV (aged 5-15 years) were examined by the semi-quantitative Kato-Katz method for presence of eggs of soil-transmitted helminths. Questionnaire data on the potential risk factors, associated variables and consequences of infection were categorized as individual, household, hygiene/sanitation related and behavioural factors. Associations between infection and these factors were assessed by multiple logistic regressions. The overall prevalence of infection with any of the helminths was 29.7 %. The prevalence of single infection with Ascaris lumbricoides was 8.1 % while that of hookworm and Trichuris trichiura was 3.7 % each. Strongest predictors for the helminths presence were never deworming (OR = 1.76; 95 % CI: 1.05, 2.95), no facility for defection (OR = 4.31; 95 % CI: 1.22, 15.22), using left hand for cleaning anal region (OR = 2.01; 95 % CI: 1.18, 3.43) and not reporting pain in stomach (OR = 1.93; 95 % CI: 1.14, 3.26). Though the infection intensities were low, we highlighted some of the potential risk factors that increase the susceptibility to these infections. Periodic deworming along with improvement in hygiene and sanitation practices through concerted efforts, not only from the school infrastructure but also the community at large, will help prevent helminths transmission and reinfection.

Inactivation of pathogens in feces by desiccation and urea treatment for application in urine-diverting dry toilets

Ecological sanitation technologies can be effective in providing health and environmental pollution control if they can efficiently reduce the pathogenicity of microorganisms carried in fecal material to safe levels. This study evaluated the sanitizing effects of different additives for dry treatment of feces from urine-diverting dry toilets, based on inactivation of Enterococcus faecalis, Salmonella enterica serovar Typhimurium, bacteriophages MS2 and ΦX, and Ascaris suum. The additives, ash (A) and oyster shell (O) in different amounts and urea (U) to optimize the process, were compared with no additive, solely urea, and sawdust as controls (C) and were covered ([x%O:A]) or uncovered (x%O:A). The main inactivation factors found were desiccation, ammonia content, and pH. S. Typhimurium and E. faecalis were more affected by the ammonia content. A combination of neutral to high pH and desiccation was most effective for inactivation of MS2, and desiccation was most effective for inactivation of ΦX and A. suum. The inactivation rate was modeled for all combinations studied. The most promising treatments were [150%O:A+U], 150%O:A+U, and 150%O:A. According to the models, these could inactivate, for example, 7 log(10) units of all bacteria and bacteriophages within 83, 125, and 183 days, respectively. The inactivation of A. suum was modeled, albeit the measured decay in egg viability was low.

Ascaris lumbricoides and Trichuris trichiura infections associated with wastewater and human excreta use in agriculture in Vietnam

BACKGROUND

We assessed the risk of helminth infections in association with the use of wastewater and excreta in agriculture in Hanam province, northern Vietnam. In two cross-sectional surveys, we obtained samples from 1,425 individuals from 453 randomly selected households. Kato-Katz thick smear and formalin-ether concentration techniques were used for helminth diagnosis in two stool samples per person. Socio-demographic and water, sanitation and hygiene related characteristics, including exposure to human and animal excreta and household wastewater management, were assessed with a questionnaire.

RESULTS

Overall 47% of study participants were infected with any helminth (Ascaris lumbricoides 24%, Trichuris trichiura 40% and hookworm 2%). Infections with intestinal protozoa were rare (i.e. Entamoeba histolytica 6%, Entamoeba coli 2%, Giardia lamblia 2%, Cryptosporidium parvum 5% and Cyclospora cayetanensis 1%). People having close contact with polluted Nhue River water had a higher risk of helminth infections (odds ratio [OR]=1.5, 95% confidence interval [CI] 1.1-2.2) and A. lumbricoides (OR=2.1, 95% CI 1.4-3.2), compared with those without contact. The use of human excreta for application in the field had an increased risk for a T. trichiura infection (OR=1.5, 95% CI 1.0-2.3). In contrast, tap water use in households was a protective factor against any helminth infection (i.e. T. trichiura OR=0.6, 95% CI 0.4-0.9). Prevalences increased with age and males had generally lower prevalences (OR=0.8, 95% CI 0.6-1.0), participants performing agricultural (OR=1.5, 95% CI 1.1-2.1) and having a low educational level (OR=1.7, 95% CI 1.2-2.4) were significantly associated with helminth infections. None of the factors related to household's sanitary condition, type of latrine, household's SES, use of animal excreta, and personal hygiene practices were statistically significant associated with helminth infection.

CONCLUSIONS

Our study suggests that in agricultural settings, direct contact with water from Nhue River and the use of human excreta as fertiliser in the fields are important risk factors for helminth infection. Daily use of clean water is likely to reduce the risk of worm infection. Deworming policies and national programs should give more attention to these agricultural at risk populations.

Effect of sanitation on soil-transmitted helminth infection: systematic review and meta-analysis

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.

Epidemiology of hookworm infection in Kintampo North Municipality, Ghana: patterns of malaria coinfection, anemia, and albendazole treatment failure

A cross-sectional pilot study of hookworm infection was carried out among 292 subjects from 62 households in Kintampo North, Ghana. The overall prevalence of hookworm infection was 45%, peaking in those 11-20 years old (58.5%). In children, risk factors for hookworm infection included coinfection with malaria and increased serum immunoglobulin G reactivity to hookworm secretory antigens. Risk factors for infection in adults included poor nutritional status, not using a latrine, not wearing shoes, and occupation (farming). Although albendazole therapy was associated with an overall egg reduction rate of 82%, 37 subjects (39%) remained infected. Among those who failed therapy, treatment was not associated with a significant reduction in egg excretion, and nearly one-third had higher counts on repeat examination. These data confirm a high prevalence of low-intensity hookworm infection in central Ghana and its association with poor nutritional status. The high rate of albendazole failure raises concern about emerging resistance.

Soil-transmitted helminth infections and risk factors in preschool children in southern rural Lao People's Democratic Republic

The current widespread school-based control of soil-transmitted helminth (STH) infections is also advocated for preschool children. The objective of this study was to assess infection with STHs as well as their determinants in preschool children (<60 months) in southern rural Lao People's Democratic Republic (Lao PDR). A cluster survey was carried out from October to December 2006 in three districts of Savannakhet Province. The prevalence of Ascaris lumbricoides, hookworm and Trichuris trichiura was 27.4% (95% CI 27.0-27.6%), 10.9% (95% CI 10.7-11.0%) and 10.9% (95% CI 10.7-11.1%), respectively. Of the children studied, 28.4% had a monoparasitic infection and 9.3% had a polyparasitic infection. Older children had a higher risk for hookworm infection [odds ratio (OR) = 1.75, 95% CI 1.03-3.01; P = 0.041] and multiple infections (OR = 1.81, 95% CI 1.01-3.20; P = 0.044). Low socioeconomic status was associated with A. lumbricoides (OR = 0.61, 95% CI 0.38-0.98; P = 0.043) and monoparasitic infections (OR = 0.62, 95% CI 0.38-0.99; P = 0.049). In Lao PDR, deworming of preschool children is warranted. Preventive measures should address important risk factors. Health education regarding personal hygiene, appropriate water management and the construction and proper use of latrines are additional essential elements.

Bethony J, Hotez PJ, Young ND, Gasser RB. Soil-transmitted helminths of humans in Southeast Asia--towards integrated control

Soil-transmitted helminths (STHs) pose significant public health challenges in many countries of Southeast Asia (SEA). Overall, approximately one-third of the world's cases of ascariasis, trichuriasis, and hookworm disease occur in the 11 major SEA countries. Various countries are at different stages in their response to controlling these diseases. For instance, in Malaysia and Thailand, the major burden of disease is confined to rural/remote, indigenous and/or refugee populations. In countries, such as Cambodia, Lao People's Democratic Republic and Vietnam, the burden remains high, although extensive deworming programmes are underway and are yielding encouraging results. The present chapter reviews the current status of STH infections in SEA, identifies knowledge gaps and offers a perspective on the development of improved, integrated surveillance and control in this geographical region. It indicates that advances in our understanding of the epidemiology of these parasites, through the strategic use of molecular and predictive (e.g. geographical information systems (GIS) and remote sensing (RS)) technologies, could readily underpin future research and control programmes. It is hoped that the gradual move towards integrated treatment/control programmes will assist substantially in decreasing the chronic disease burden linked to STHs, thus increasing human health and welfare, and supporting socio-economic growth and development in SEA countries.

Effects of annual mass treatment with ivermectin for onchocerciasis on the prevalence of intestinal helminths

We evaluated the effect of annual ivermectin (IV) distribution for onchocerciasis on the prevalence of soil transmitted helminth (STH) infections in school-aged (SAC) and preschool-aged (PAC) children by comparing children in villages that had received treatment for 13 years to those from socioeconomically similar villages in untreated areas. We enrolled 1,031 SAC and 211 PAC for Kato Katz examinations. Treated areas had a lower prevalence of Ascaris (SAC: 3% versus 12%, P < 0.0001; PAC: 3% versus 10%, P < 0.051) and Trichuris (SAC: 6% versus 10%, P = 0.012; PAC: 1% versus 8%, P = 0.019), but not hookworm (SAC: 38% versus 42%, P = 0.20; PAC: 21% versus 27%, P = 0.30). The prevalence of Ascaris or Trichuris in treated areas was below the WHO threshold for mass antihelminthic treatment (MDA), but not for hookworm. We conclude that benzimidazole MDA in IV treatment areas is indicated to effectively control hookworm.

Survival of Ascaris eggs and hygienic quality of human excreta in Vietnamese composting latrines

BACKGROUND

For centuries farmers in Vietnam have fertilized their fields with human excreta collected directly from their household latrines. Contrary to the official guideline of six-month storage, the households usually only store human excreta for three to four months before use, since this is the length of time that farmers have available to produce fertilizer between two cropping seasons. This study aimed to investigate whether hygienically safe fertilizer could be produced in the latrines within this period of time.

METHODS

By inoculating eggs of the helminth parasite indicator Ascaris suum into heaps of human excreta, a die-off experiment was conducted under conditions similar to those commonly used in Vietnamese latrines. Half a ton of human excreta was divided into five heaps containing increasing concentrations of lime from 0% to 11%.

RESULTS

Regardless of the starting pH, which varied from 9.4 to 11.6, a >99% die-off of eggs was obtained after 105 to 117 days of storage for all lime concentrations and 97% of eggs were non-viable after 88 days of storage. The most critical parameter found to determine the die-off process was the amount of ammonia (urine) in the excreta which indicates that longer storage periods are needed for parasite egg die-off if urine is separated from the excreta.

CONCLUSION

By inactivating >99% of all A. suum eggs in human excreta during a storage period of only three months the commonly used Double Vault Composting (DVC) latrine, in which urine is not separated, could therefore potentially provide a hygienic acceptable fertilizer.