                Effectiveness of a post-deworming education intervention to reduce soil-transmitted helminth infections and absenteeism in grade 5 school-children in a community of extreme poverty, Peruvian AmazonMartín Casapía 1 – Project Director Mathieu Maheu-Giroux 2 – Research Coordinator (Canada) Theresa W. Gyorkos 2, 3 – Principal Investigator 1- Asociación Civil Selva Amazónica, Iquitos, Perú 2- Division of Clinical Epidemiology, McGill University Health Centre, Montreal, QC, Canada 3- Department of Epidemiology, Biostatistics, and Occupational Health of McGill University, Montreal, QC, Canada December 2009
Table of Contents
Executive summary
Belén, a community of extreme poverty in Peru, has listed intestinal parasites such as soil-transmitted helminths (STH) (Ascaris, Trichuris, and hookworm) among their top-five health priorities during recent multidisciplinary participatory workshops [1]. Furthermore, a school survey conducted in 2006 in this community demonstrated a very high prevalence of STH infections, with 86% of Grade 5 students infected with one or more species of parasites [2]. To efficiently control this disease cluster, WHO, PAHO, and others recommend the inclusion of an education strategy in school-based deworming programs [3-6]. However, the effectiveness of such a strategy on the rate of STH re-infection and on education indicators, such as absenteeism, remains to be fully understood. The proposed research aims to evaluate the effectiveness of a post-deworming education intervention targeted to Grade 5 school children enrolled in Belén’s schools using a cluster-randomized trial design. Results will be used to inform school-based deworming programs in Peru and other similar endemic areas in Latin America and, indeed, around the world.
Context of the present protocol submission
The present submission details a 4-month project based entirely in Peru, which will be conducted within a larger 5-year research program (2006-2011) already funded by the CIHR (RI-MUHC account 6360). The 5-year project is an Interdisciplinary Capacity Enhancement (ICE) grant. As such, the ICE project included overall objectives only. The plan was to develop specific projects within the ICE grant in conjunction with local co-investigators and collaborators, and the local community. Ethics review was not required for the overall 5-year project. Instead, as projects would be developed, they would individually be submitted for appropriate ethics approval, both in Peru and in Canada. Ethics approval from Peruvian Health officials for the current project is underway. English and Spanish versions of the parents/tutor informed consent form, the students assent form and the questionnaire are attached in the Annex.
Location of study conduct
The Belén district of Iquitos is located on the banks of the Itaya/Amazon River in Peru. Due to the propensity of this area for seasonal flooding, the houses are constructed on wooden stilts or on floating platforms. Most inhabitants do not have access to reliable potable water for drinking or improved sanitation systems. Human waste contaminates the water directly from floating latrines or indirectly from land-based latrines, leading to a state of extensive fecal contamination.
Study rationale
Because of the very high prevalence of STH in Grade 5 school children in Belén, Peru, efficient and sustainable control methods are needed. There has been no systematic review on the proposed research topic. Few studies have investigated the effectiveness of a post-deworming education intervention on STH (Ascaris, Trichuris, and/or hookworm) prevalence or re-infection rates, or on absenteeism, and only five studies have previously examined school-based education interventions. These studies yielded mixed evidence and results are difficult to interpret because of methodological limitations. Therefore, in this current state of scientific equipoise, our proposed cluster-randomized trial is needed to inform both policy and practice related to school-based deworming programs in Peru and in other endemic countries.
Scientific background
Globally, STH (Ascaris, Trichuris, and hookworm) infections are one of the most important neglected disease clusters worldwide as they affect over two billion people and they contribute significant morbidity and disability, especially in the high risk group of school-age children [7]. STH are the leading cause of physical and intellectual growth and development delays and impairment of children in endemic areas [8-10]. Furthermore, it is in school-age children that peak prevalences and peak intensities of STH infections occur [11]. The World Health Organization (WHO), UNICEF, and the World Bank, among others, recommend establishing school-based deworming programs as the most cost-effective means to combat the adverse health outcomes of these parasitic diseases. The rationale for these school-based interventions is to reduce the highest STH-attributable burden of disease (by treating the highest risk group of school-age children). By doing so, this intervention also reduces environmental contamination, and consequently, infection in the wider community [12]. Further, school-based deworming programs have been shown to be “a crucial, and neglected, step towards improving public health and to reaching several of the Millennium Development Goals” (MDG) [13, 14], which call for concerted improvements in poverty reduction, nutritional status, education, gender equality, and environmental degradation. For example, treatment with deworming drugs (eg. albendazole) led to a 25% reduction in primary school absenteeism in Kenya [15], prevented 82% of stunting and was associated with a 35% weight gain among children in Indian slums [16]. Despite their usefulness, school-based deworming programs have several constraints: many endemic communities don’t have them (only 64 of 130 endemic countries reported any school-based deworming activity at all in 2006); positive effects are temporary (in the absence of any behavioural or environmental change, due to re-infection) [17], thereby requiring repeated treatment; and deworming programs incur costs, even if the drug itself is free of charge or of low cost [3, 18].
The inclusion of a health education strategy in school-based deworming programs is therefore recommended as a way to improve their effectiveness [3-6, 19]. The specific objectives of the health education strategy are to prevent re-infection and improve school effects, like absenteeism. STH infections being acquired through the fecal-oral transmission route (Ascaris and Trichuris) or contact with contaminated soil (hookworm), the approach of health education programs is to promote behavioural changes that would reduce exposure and risk of contamination. Other advantages of these education programs is that they can reduce the cost of deworming, increase the level of overall health knowledge within the community, reduce morbidity attributable to STH infections and promote optimal productivity as adults [6, 20, 21].
A literature review on the efficacy or effectiveness of school-based health education interventions on the prevalence or infection rates of STH infections retrieved only five studies, none of them from Latin America. An annotated summary of these studies demonstrates a state of scientific equipoise regarding our proposed research question (Table 1). Furthermore, evidence from these studies is difficult to interpret and to generalize because: some did not have appropriate comparison groups; the health education intervention was sometimes implemented together with environmental sanitation programs or other interventions; there was often no statistical adjustment for confounders nor any correction for within-school clustering of students; some had low sample sizes, targeted different age groups, had variable follow-up periods and were often only descriptive in nature. The cumulative evidence is therefore equivocal, not only because some studies showed a negative effect, an absence of effect, or a positive effect of the health education intervention on STH prevalence or re-infection rates, but also because the methodological basis for this evidence is less than rigorous.
Table 1: Annotated review of studies conducted on the efficacy or effectiveness of health education intervention on STH prevalence or re-infection rates
Location (Year)
|
Study Design
|
# schools
|
# children
|
Limitations
|
Results
|
Ref.
|
China
(1997)
|
Observational
|
6 schools
(4 received the intervention)
|
6,188
|
- No adjustment for school clustering
- No measure of effect reported
- Intervention consisted of a health intervention plus environmental sanitation
|
Schools with the environmental sanitation and health intervention had lower re-infection rates.
|
[22]
|
Indonesia
(2005)
|
Observational
|
45 schools
(5 received the intervention)
|
3,463
|
- Descriptive study
- No statistical analysis
- No adjustment for potential individual confounders
|
Schools receiving the health education intervention had lower prevalence at 7 months
|
[23]
|
Indonesia
(1998)
|
Factorial RCT
|
5 schools
(4 treated and 1 control)
|
336
|
- Individual confounders not taken into account
- Low sample size
|
No effect differences were found between the ‘deworming group’ and the ‘deworming plus education’ group
|
[24]
|
Seychelles
(1994)
|
Observational
|
23 schools
(all received the intervention)
|
1,244
|
- No comparison group
- No statistical analysis
- Intervention consisted of health education, environmental sanitation, and deworming
|
Deworming, environmental sanitation, and health education reduces the prevalence of STH
|
[25]
|
Thailand
(2004)
|
Observational
|
4 schools
(all received the intervention)
|
428
|
- No comparison group
- Low sample size
|
Prevalence of STH was higher at the end of the health education intervention compared to baseline
|
[26]
| |
