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Water, Sanitation and Hygiene (WASH) and environmental risk factors for soil-transmitted helminth intensity of infection in Timor-Leste, using real time PCR

View Article: PubMed Central - PubMed

ABSTRACT

Background: No investigations have been undertaken of risk factors for intensity of soil-transmitted helminth (STH) infection in Timor-Leste. This study provides the first analysis of risk factors for intensity of STH infection, as determined by quantitative PCR (qPCR), examining a broad range of water, sanitation and hygiene (WASH) and environmental factors, among communities in Manufahi District, Timor-Leste.

Methods: A baseline cross-sectional survey of 18 communities was undertaken as part of a cluster randomised controlled trial, with additional identically-collected data from six other communities. qPCR was used to assess STH infection from stool samples, and questionnaires administered to collect WASH, demographic, and socioeconomic data. Environmental information was obtained from open-access sources and linked to infection outcomes. Mixed-effects multinomial logistic regression was undertaken to assess risk factors for intensity of Necator americanus and Ascaris infection.

Results: 2152 participants provided stool and questionnaire information for this analysis. In adjusted models incorporating WASH, demographic and environmental variables, environmental variables were generally associated with infection intensity for both N. americanus and Ascaris spp. Precipitation (in centimetres) was associated with increased risk of moderate-intensity (adjusted relative risk [ARR] 6.1; 95% confidence interval [CI] 1.9–19.3) and heavy-intensity (ARR 6.6; 95% CI 3.1–14.1) N. americanus infection, as was sandy-loam soil around households (moderate-intensity ARR 2.1; 95% CI 1.0–4.3; heavy-intensity ARR 2.7; 95% CI 1.6–4.5; compared to no infection). For Ascaris, alkaline soil around the household was associated with reduced risk of moderate-intensity infection (ARR 0.21; 95% CI 0.09–0.51), and heavy-intensity infection (ARR 0.04; 95% CI 0.01–0.25). Few WASH risk factors were significant.

Conclusion: In this high-prevalence setting, strong risk associations with environmental factors indicate that anthelmintic treatment alone will be insufficient to interrupt STH transmission, as conditions are favourable for ongoing environmental transmission. Integrated STH control strategies should be explored as a priority.

No MeSH data available.


Related in: MedlinePlus

Intensity of Ascaris infection by age group.
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pntd.0005393.g001: Intensity of Ascaris infection by age group.

Mentions: From 24 communities, 2827 eligible people provided baseline survey data, of whom 2152 participants (1038 males, 1114 females) completed both an individual questionnaire and provided a stool sample and were included in this analysis (Table 1, [18]). Using our infection intensity cut-points, more than half (52%) of participants had heavy-intensity N, americanus infection; 10% had heavy-intensity Ascaris infection (Table 1). There was very low prevalence of water or sanitation infrastructure, and most households owned few assets. Most heavy-intensity Ascaris infection occurred in children (Fig 1). Heavy-intensity N. americanus infections were more spread across age groups (Fig 2). Heavy-intensity Ascaris infection varied significantly by socioeconomic quintile (P = 0.012); N. americanus infection intensity did not (P = 0.468).


Water, Sanitation and Hygiene (WASH) and environmental risk factors for soil-transmitted helminth intensity of infection in Timor-Leste, using real time PCR
Intensity of Ascaris infection by age group.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383321&req=5

pntd.0005393.g001: Intensity of Ascaris infection by age group.
Mentions: From 24 communities, 2827 eligible people provided baseline survey data, of whom 2152 participants (1038 males, 1114 females) completed both an individual questionnaire and provided a stool sample and were included in this analysis (Table 1, [18]). Using our infection intensity cut-points, more than half (52%) of participants had heavy-intensity N, americanus infection; 10% had heavy-intensity Ascaris infection (Table 1). There was very low prevalence of water or sanitation infrastructure, and most households owned few assets. Most heavy-intensity Ascaris infection occurred in children (Fig 1). Heavy-intensity N. americanus infections were more spread across age groups (Fig 2). Heavy-intensity Ascaris infection varied significantly by socioeconomic quintile (P = 0.012); N. americanus infection intensity did not (P = 0.468).

View Article: PubMed Central - PubMed

ABSTRACT

Background: No investigations have been undertaken of risk factors for intensity of soil-transmitted helminth (STH) infection in Timor-Leste. This study provides the first analysis of risk factors for intensity of STH infection, as determined by quantitative PCR (qPCR), examining a broad range of water, sanitation and hygiene (WASH) and environmental factors, among communities in Manufahi District, Timor-Leste.

Methods: A baseline cross-sectional survey of 18 communities was undertaken as part of a cluster randomised controlled trial, with additional identically-collected data from six other communities. qPCR was used to assess STH infection from stool samples, and questionnaires administered to collect WASH, demographic, and socioeconomic data. Environmental information was obtained from open-access sources and linked to infection outcomes. Mixed-effects multinomial logistic regression was undertaken to assess risk factors for intensity of Necator americanus and Ascaris infection.

Results: 2152 participants provided stool and questionnaire information for this analysis. In adjusted models incorporating WASH, demographic and environmental variables, environmental variables were generally associated with infection intensity for both N. americanus and Ascaris spp. Precipitation (in centimetres) was associated with increased risk of moderate-intensity (adjusted relative risk [ARR] 6.1; 95% confidence interval [CI] 1.9–19.3) and heavy-intensity (ARR 6.6; 95% CI 3.1–14.1) N. americanus infection, as was sandy-loam soil around households (moderate-intensity ARR 2.1; 95% CI 1.0–4.3; heavy-intensity ARR 2.7; 95% CI 1.6–4.5; compared to no infection). For Ascaris, alkaline soil around the household was associated with reduced risk of moderate-intensity infection (ARR 0.21; 95% CI 0.09–0.51), and heavy-intensity infection (ARR 0.04; 95% CI 0.01–0.25). Few WASH risk factors were significant.

Conclusion: In this high-prevalence setting, strong risk associations with environmental factors indicate that anthelmintic treatment alone will be insufficient to interrupt STH transmission, as conditions are favourable for ongoing environmental transmission. Integrated STH control strategies should be explored as a priority.

No MeSH data available.


Related in: MedlinePlus