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Understanding Heterogeneity in the Impact of National Neglected Tropical Disease Control Programmes: Evidence from School-Based Deworming in Kenya.

Nikolay B, Mwandawiro CS, Kihara JH, Okoyo C, Cano J, Mwanje MT, Sultani H, Alusala D, Turner HC, Teti C, Garn J, Freeman MC, Allen E, Anderson RM, Pullan RL, Njenga SM, Brooker SJ - PLoS Negl Trop Dis (2015)

Bottom Line: The reduction in prevalence and intensity of A. lumbricoides and hookworms varied significantly by county and within counties by school.Multivariable analysis of factors associated with programme impact showed that absolute A. lumbricoides reductions varied by environmental conditions and access to improved sanitation at schools or within the community.Larger reduction in prevalence and intensity of hookworms were found in schools located within areas with higher community level access to improved sanitation and within counties with higher economic and health service delivery indicator scores.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.

ABSTRACT

Background: The implementation of soil-transmitted helminth (STH) treatment programmes occurs in varied environmental, social and economic contexts. Programme impact will be influenced by factors that affect the reduction in the prevalence and intensity of infections following treatment, as well as the subsequent rate of reinfection. To better understand the heterogeneity of programme impact and its underlying reasons, we investigated the influence of contextual factors on reduction in STH infection as part of the national school based deworming (SBD) programme in Kenya.

Materials and methods: Data on the prevalence and intensity of infection were collected within the monitoring and evaluation component of the SBD programme at baseline and after delivery of two annual treatment rounds in 153 schools in western Kenya. Using a framework that considers STH epidemiology and transmission dynamics, capacity to deliver treatment, operational feasibility and financial capacity, data were assembled at both school and district (county) levels. Geographic heterogeneity of programme impact was assessed by descriptive and spatial analyses. Factors associated with absolute reductions of Ascaris lumbricoides and hookworm infection prevalence and intensity were identified using mixed effects linear regression modelling adjusting for baseline infection levels.

Principal findings: The reduction in prevalence and intensity of A. lumbricoides and hookworms varied significantly by county and within counties by school. Multivariable analysis of factors associated with programme impact showed that absolute A. lumbricoides reductions varied by environmental conditions and access to improved sanitation at schools or within the community. Larger reduction in prevalence and intensity of hookworms were found in schools located within areas with higher community level access to improved sanitation and within counties with higher economic and health service delivery indicator scores.

Conclusions: The study identifies factors associated with the impact of school-based deworming and in particular highlights how access to water, sanitation and hygiene and environmental conditions influence the impact of deworming programmes.

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Related in: MedlinePlus

Omnidirectional semivariogram analysis of absolute reduction estimates adjusted for baseline infection (left panel) and additionally for other associated variables (right panel).Values were obtained from normal score transformation of linear regression residuals. Exponential models were fitted to the empirical semivariogram.
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pntd.0004108.g005: Omnidirectional semivariogram analysis of absolute reduction estimates adjusted for baseline infection (left panel) and additionally for other associated variables (right panel).Values were obtained from normal score transformation of linear regression residuals. Exponential models were fitted to the empirical semivariogram.

Mentions: Spatial analysis of observed absolute reductions in prevalence and intensity (adjusted for baseline infection levels) indicated marked spatial dependency of reductions in A. lumbricoides and hookworm intensity (Fig 5). However, after removal of large scale trends by adjusting for associated factors in multivariable models, no clear spatial dependence was observed for the reduction in any of the infections (Fig 5). Comparing empirical semivariograms to the computed random permutation envelopes showed no evidence of spatial clustering in the residuals.


Understanding Heterogeneity in the Impact of National Neglected Tropical Disease Control Programmes: Evidence from School-Based Deworming in Kenya.

Nikolay B, Mwandawiro CS, Kihara JH, Okoyo C, Cano J, Mwanje MT, Sultani H, Alusala D, Turner HC, Teti C, Garn J, Freeman MC, Allen E, Anderson RM, Pullan RL, Njenga SM, Brooker SJ - PLoS Negl Trop Dis (2015)

Omnidirectional semivariogram analysis of absolute reduction estimates adjusted for baseline infection (left panel) and additionally for other associated variables (right panel).Values were obtained from normal score transformation of linear regression residuals. Exponential models were fitted to the empirical semivariogram.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4589351&req=5

pntd.0004108.g005: Omnidirectional semivariogram analysis of absolute reduction estimates adjusted for baseline infection (left panel) and additionally for other associated variables (right panel).Values were obtained from normal score transformation of linear regression residuals. Exponential models were fitted to the empirical semivariogram.
Mentions: Spatial analysis of observed absolute reductions in prevalence and intensity (adjusted for baseline infection levels) indicated marked spatial dependency of reductions in A. lumbricoides and hookworm intensity (Fig 5). However, after removal of large scale trends by adjusting for associated factors in multivariable models, no clear spatial dependence was observed for the reduction in any of the infections (Fig 5). Comparing empirical semivariograms to the computed random permutation envelopes showed no evidence of spatial clustering in the residuals.

Bottom Line: The reduction in prevalence and intensity of A. lumbricoides and hookworms varied significantly by county and within counties by school.Multivariable analysis of factors associated with programme impact showed that absolute A. lumbricoides reductions varied by environmental conditions and access to improved sanitation at schools or within the community.Larger reduction in prevalence and intensity of hookworms were found in schools located within areas with higher community level access to improved sanitation and within counties with higher economic and health service delivery indicator scores.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.

ABSTRACT

Background: The implementation of soil-transmitted helminth (STH) treatment programmes occurs in varied environmental, social and economic contexts. Programme impact will be influenced by factors that affect the reduction in the prevalence and intensity of infections following treatment, as well as the subsequent rate of reinfection. To better understand the heterogeneity of programme impact and its underlying reasons, we investigated the influence of contextual factors on reduction in STH infection as part of the national school based deworming (SBD) programme in Kenya.

Materials and methods: Data on the prevalence and intensity of infection were collected within the monitoring and evaluation component of the SBD programme at baseline and after delivery of two annual treatment rounds in 153 schools in western Kenya. Using a framework that considers STH epidemiology and transmission dynamics, capacity to deliver treatment, operational feasibility and financial capacity, data were assembled at both school and district (county) levels. Geographic heterogeneity of programme impact was assessed by descriptive and spatial analyses. Factors associated with absolute reductions of Ascaris lumbricoides and hookworm infection prevalence and intensity were identified using mixed effects linear regression modelling adjusting for baseline infection levels.

Principal findings: The reduction in prevalence and intensity of A. lumbricoides and hookworms varied significantly by county and within counties by school. Multivariable analysis of factors associated with programme impact showed that absolute A. lumbricoides reductions varied by environmental conditions and access to improved sanitation at schools or within the community. Larger reduction in prevalence and intensity of hookworms were found in schools located within areas with higher community level access to improved sanitation and within counties with higher economic and health service delivery indicator scores.

Conclusions: The study identifies factors associated with the impact of school-based deworming and in particular highlights how access to water, sanitation and hygiene and environmental conditions influence the impact of deworming programmes.

Show MeSH
Related in: MedlinePlus