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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

Prevalence (A) and average intensity of infection (natural-log scale) (B) by survey round and STH species.Infection levels were measured in 153 schools at baseline (2012) and follow-up (2014).
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pntd.0004108.g002: Prevalence (A) and average intensity of infection (natural-log scale) (B) by survey round and STH species.Infection levels were measured in 153 schools at baseline (2012) and follow-up (2014).

Mentions: In the 153 schools surveyed at baseline in 2012, the combined STH prevalence was 34.8%, with A. lumbricoides most prevalent (23.2%), followed by hookworm (14.6%) and T. trichiura (6.3%). At follow-up, after two rounds of MDA, STH prevalence dropped to 19.7%; with prevalence decreasing to 15.4%, 1.7%, and 5.4% for A. lumbricoides, hookworms and T. trichiura, respectively (Fig 2 and Table 1). The mean intensity of A. lumbricoides infection fell significantly from 2,147 epg at baseline to 1,248 epg at follow-up and hookworm from 63 epg to 7 epg; mean T. trichiura intensity changed from 40 epg to 21 epg over the same time period, but the change was non-significant (Fig 2 and Table 1). The prevalence of moderate and heavy infection was reduced from 11.1% (95% CI: 7.8; 15.7) at baseline to 7.4% (95% CI: 5.6; 9.9) at follow-up (OR 0.63, 95% CI: 0.59; 0.68, p<0.001).


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)

Prevalence (A) and average intensity of infection (natural-log scale) (B) by survey round and STH species.Infection levels were measured in 153 schools at baseline (2012) and follow-up (2014).
© Copyright Policy
Related In: Results  -  Collection

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

pntd.0004108.g002: Prevalence (A) and average intensity of infection (natural-log scale) (B) by survey round and STH species.Infection levels were measured in 153 schools at baseline (2012) and follow-up (2014).
Mentions: In the 153 schools surveyed at baseline in 2012, the combined STH prevalence was 34.8%, with A. lumbricoides most prevalent (23.2%), followed by hookworm (14.6%) and T. trichiura (6.3%). At follow-up, after two rounds of MDA, STH prevalence dropped to 19.7%; with prevalence decreasing to 15.4%, 1.7%, and 5.4% for A. lumbricoides, hookworms and T. trichiura, respectively (Fig 2 and Table 1). The mean intensity of A. lumbricoides infection fell significantly from 2,147 epg at baseline to 1,248 epg at follow-up and hookworm from 63 epg to 7 epg; mean T. trichiura intensity changed from 40 epg to 21 epg over the same time period, but the change was non-significant (Fig 2 and Table 1). The prevalence of moderate and heavy infection was reduced from 11.1% (95% CI: 7.8; 15.7) at baseline to 7.4% (95% CI: 5.6; 9.9) at follow-up (OR 0.63, 95% CI: 0.59; 0.68, p<0.001).

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