2013年-世界发展银行全球_Monitoring_and_Evaluating_the_Impact_of_National_School-Based_Deworming_in_Kenya___Study_Design_and_Baseline_Results_14页_3mb

Summary of "Monitoring and Evaluating the Impact of National School-Based Deworming in Kenya: Study Design and Baseline Results"

Core Content

This study outlines the monitoring and evaluation (M&E) design for Kenya's national school-based deworming (SBD) programme and presents baseline results from 2012. The programme aims to control soil-transmitted helminths (STHs) and schistosomiasis through regular deworming of school-age children.

Main Objectives

• To assess the baseline prevalence and intensity of STH and schistosome infections in Kenyan schools.
• To evaluate the effectiveness of the national SBD programme through a multi-tiered M&E approach.
• To understand the spatial and demographic patterns of infection.

Key Findings

Prevalence and Intensity of STH Infections

• Overall prevalence: 32.4% of children were infected with at least one STH species.
  • Ascaris lumbricoides was the most common species (18.0%).
  • Hookworm (15.6%) and Trichuris trichiura (6.6%) followed.
• Infection intensity:
  • Mean intensity of A. lumbricoides: 1,653 epg.
  • Mean intensity of hookworm: 64 epg.
  • Mean intensity of T. trichiura: 33 epg.
• Geographical variation:
  • A. lumbricoides and T. trichiura were most prevalent in the Rift Valley (27.1% and 11.9%, respectively).
  • Hookworm was most prevalent in Western Province (25.1%).
  • The lowest prevalence was observed in Nyanza for T. trichiura (3.6%) and in the Coast for A. lumbricoides (1.0%).
• Sex differences:
  • Hookworm prevalence was higher in boys (16.8%) than girls (14.5%).
  • Hookworm intensity was also higher in boys than girls.
  • A. lumbricoides and T. trichiura prevalence did not differ significantly by sex.
  • T. trichiura intensity was higher in girls than boys.

Schistosome Infections

• Overall prevalence:
  • Schistosoma mansoni: 2.1%.
  • S. haematobium (only in the Coast Province): 14.8%.
• Infection intensity:
  • Mean intensity of S. mansoni: 12 epg.
  • Mean intensity of S. haematobium: 16 eggs/10 ml urine.
• Geographical variation:
  • S. mansoni was most prevalent in Western Province (4.1%).
  • S. haematobium was most prevalent in the Coast Province (14.8%).
• Spatial autocorrelation:
  • Positive spatial autocorrelation was observed for S. mansoni in the Coast Province.
  • No significant small-scale spatial patterns were found for S. haematobium.

Anaemia

• Prevalence:
  • Overall anaemia prevalence in 10 high-frequency schools: 31.3%.
• Haemoglobin concentration:
  • Mean haemoglobin concentration: 12.6 g/dL.
• Age variation:
  • Anaemia decreased with increasing age.
  • Haemoglobin concentration increased with age.
• Association with infections:
  • Suggestive evidence of anaemia being associated with S. mansoni infection.

M&E Study Design

• Three tiers of monitoring:
  1. National baseline survey: 200 schools (over 20,000 children) across 20 districts.
  2. Pre-post surveys: 60 schools surveyed before and after deworming to assess treatment impact.
  3. High-frequency surveys: 10 schools surveyed four times a year to monitor longitudinal changes.
• Sampling strategy:
  • Schools were selected based on STH endemicity and proportional to population size.
  • 66 districts were considered STH endemic, with 20 districts selected for sampling.
  • Provinces had varying numbers of schools: Western (60), Rift Valley (30), Coast (50), Nyanza (60).
• Data collection:
  • Stool samples for STH and urine samples for S. haematobium.
  • Blood samples for haemoglobin concentration in 10 high-frequency schools.
  • Use of Kato Katz and urine filtration methods for parasite detection.
  • Geographical data collected using GPS and linked to environmental variables.

Statistical Methods

• Data analysis:
  • Descriptive and spatial analyses were conducted.
  • Binomial and negative binomial regression models used to account for clustering.
  • Moran's I statistic tested for spatial autocorrelation.
• Environmental covariates:
  • Temperature, precipitation, elevation, NDVI, proximity to water bodies, and population density were included.
  • Factor analysis used to reduce variables and avoid multicollinearity.
  • Five factors were identified, each representing different environmental influences.

Conclusion

The study provides baseline data on the prevalence and intensity of STH and schistosome infections in Kenyan schools, highlighting significant geographical and demographic variations. These findings serve as an important reference for evaluating the effectiveness of the national SBD programme and guide future interventions. The M&E framework is robust, combining national, pre-post, and high-frequency surveys to capture both long-term and immediate impacts of deworming.