School-based Deworming Interventions: An Overview
Description of the tool:
Because helminth (worm) infections can undermine the benefits of school feeding, the
WFP encourages deworming interventions and improvements to the school’s water
and sanitation facilities in al its projects. This tool summarizes why and how schools
might go about providing deworming interventions.
The information in this tool was adapted by UNESCO from the fol owing publication:
WFP/UNESCO/WHO 1999. School Feeding Handbook.
Rome, World Food
Description of the document:
Describes the work of The World Food Programme (WFP) in helping countries
throughout the world establish and maintain school feeding programmes.
for effective school health: school health
It wil have a greater impact if it
is reinforced by activities in the other three
School-based Deworming Interventions: An Overview
1. HELMINTH INFECTION, HEALTH AND EDUCATION OUTCOMES
A high prevalence of intestinal parasitic infections is closely correlated with poverty and
poor environmental hygiene, namely: a) lack of safe water supply, b) contamination of the
environment by human excreta, c) lack of shoes, and d) poor environmental or personal
hygiene. In the long run, worm infections increase susceptibility to other infections and
diminish learning ability and growth in children.
Intestinal parasitic infections negatively affect the health status of a high proportion of
school-age children in developing countries, giving rise to general discomfort and acute
symptoms such as abdominal pain, nausea and coughing. These symptoms are closely
correlated with the “intensity of intestinal parasitic infections” (commonly cal ed “worm
burden”): the greater the worm burden, the more severe are the symptoms. In addition,
hookworm infections give rise to blood loss, as the worms suck blood from the intestinal
wal . This may cause iron deficiency anaemia and a decrease in work capacity and fitness.
School-age children harbour the most intense infections with roundworm (Ascaris
hookworm (Ancylostoma duodenale
and Necator americanus
whipworm (Trichuris trichiuria).
Therefore, treatment of this age group - which is easily
accessible through the school system - achieves optimal improvements in health status
Improved health and nutritional status:
• In Zanzibar, heavily infected school children living in high transmission areas were
treated with mebendazole three times a year. The study found that a quarter of a litre
of blood can be saved per child per year for as little as I S US cents per child per
year (i.e. 5 US cents per treatment including the cost of the tablet of about 3 US
cents, and drug delivery, which amounts to about 2 US cents).
• Deworming of children can result in remarkable growth spurts. In one trial in Kenya.
Treated school-age children gained one centimetre more in height in the four months
fol owing treatment than did children who received a placebo2.
Improved educational performance:
Recent studies suggest that intestinal parasitic infections negatively affect school children's
cognitive functions.3 A study in Jamaica showed significant improvements in the auditory
short-term memory of heavily infected children after nine weeks of treatment.4
2. SCHOOL-BASED DEWORMING PROGRAMMES
The World Health Organization (WHO) recommends chemotherapy for roundworm,
whipworm and hookworm
infections targeted at school-age children as a feasible and cost-
Periodic deworming treatment is a feasible and effective short-term measure for
the control of morbidity due to intestinal parasites.
Single oral dose treatment with mebendazole (500 mg) or albendazole (400 mg) is very
effective, safe and inexpensive. The direct benefit of chemotherapy is that the worm burden
is removed, which immediately al eviates symptoms and may reduce the rate of
transmission. Furthermore, WHO recommends improved sanitation and safe water supply as
wel as health education on the prevention of intestinal parasitic infections as important
Treatment without prior screening, which offers significant logistic and
economic advantages, is recommended where surveys indicate a presence of
intestinal parasites among school-age children of over 50%.
The interval of community treatment should be determined after consideration of
epidemiological, pharmacological and socio-economic factors. From the epidemiological
standpoint, the key elements to be considered include frequency and seasonal variation of
reinfection. Ideal y, community treatment should be applied soon after an identified
transmission season is over. The work undertaken by the Asian Parasite Control
Organization (APCO) indicates that the appropriate intervals for the application of
chemotherapy should be twice annual y for prevalence rates below 50% and three times
annual y for prevalence rates exceeding 50%. It must be stressed that the decision about
intervals between treatments must be taken after the local circumstances are
The frequency of chemotherapy should be three times annually for
prevalence rates exceeding 50%, or less after consideration of local
3. INTEGRATING A SCHOOL-BASED DEWORMING PROGRAMME INTO SFPS
If a high prevalence of intestinal parasitic infections among school-age children is
confirmed, the fol owing factors should be determined prior to developing a school-based
• What is the Government policy as regards school-based deworming and the
involvement of teachers in drug delivery?
• Is there an operational National Intestinal Parasite Control Programme? If so, what
are its objectives, strategy (treatment interval, drug used, channel - health centre-
based and/or school-based?) and geographic coverage?
• What is the national institutional capacity for parasitological diagnosis? Are there
trained laboratory technicians and are basic diagnostic tools available?
When should a school-based deworming intervention be undertaken?
When the prevalence of intestinal parasites among school-age children is above
Minimal capacity for parasitological diagnosis is required even if the prevalence of
intestinal parasites is above 50% and individual screening prior to treatment is not
necessary. Changes in the intensity and prevalence of intestinal parasitic infections
should be documented through periodic smal -scale parasitological surveys in order to
determine: a) whether the deworming intervention should continue, and b) whether the
frequency of treatment should be modified (i.e. from twice to three times a year, or vice
3.2 Objectives of a School-based Deworming Programme
By reducing the intensity and prevalence of intestinal parasitic infections in children,
deworming aims at strengthening the educational and nutritional benefits school feeding.
3.3 Training Requirements
One-day training seminars should be conducted for selected staff from the Ministries of
Health and Education. These training seminars should cover the fol owing subjects: a)
the negative effects of intestinal parasites on health and educational outcomes: b)
justification for a school-based deworming programme; c) characteristics of the drug and
treatment schedule; and d) prevention of intestinal parasitic infections through
improvements in water and sanitation facilities as wel as hygiene practices.
Staff could include: one teacher from each school (preferably the teacher in charge of
health education), and one person from the health sector at the peripheral level. The
health staff would serve as supervisors of the distribution. The teachers trained in drug
delivery would be responsible for holding health education sessions on treatment days.
3.4 Mechanism for Drug Delivery
The recommended deworming treatment intervals are two to three times a year with a
single dose of a deworming drug; 400 mg albendazole, 500 mg mebendazole, pyrantel
(250 mg chewable tablet, dosage 10 mg/kg single administration) or levamisole (40 mg
chewable tablet, dosage 2.5 mg/kg single administration). Albendazole is the most
effective against hookworm, which is an important contributing factor to anaemia. The
deworming drugs can be stored and delivered through the WFP-assisted SFP. The drugs
should be col ected by the schools together with the food. The teachers would deliver the
drugs to the children on specific treatment days. Other children who are present in the
school on the day of delivery could also receive treatment.
The cost of one tablet of a deworming drug (e.g. albendazole) ranges between 3
and 5 US cents (including shipment).
3.5 Monitoring and Evaluation
Data on coverage of the deworming programme should be gathered. Changes in the
prevalence and intensity of intestinal parasitic infections and other parameters (e.g.
nutritional status) can be monitored by the Ministry of Health, wish reports being sent for
information to WFP for information purpose.
The reporting system should be management-oriented, al owing those involved to
identify problems and initiate corrective measures. In each school covered by the
programme, a record should be kept by the trained schoolteacher responsible for
1 Excerpted from WFP/UNESCO/WHO 1999. School Feeding Handbook.
Rome, World Food Programme.
2 Stephenson LS et al.
Weight gain of Kenyan school children infected with hookworm, Trichuris trichiura
and Ascaris lumbricoides
is improved fol owing once- or twice-yearly treatment with albendazole. Journal
1993, 123: 1036-46.
3 Nokes C and Bundy DAP. Does helminth infection affect mental processing and educational achievements?
1994, 10 (1): 14-18.
4 Nokes C et al.
Parasitic helminth infection and cognitive functions in school children. Proceedings of the
Royal Society of London,
1992, 247: 77-81.
5 Report of the Informal Consultation on the Use of Chemotherapy for the Control of Morbidity due to Soil-
Transmitted Nematodes in Humans.
World Health Organization, Geneva 29 April-1 May 1996.
Savi oli, L. et al. Intestinal Worms Beware: Developments in the Use of Anthelminthic Chemotherapy.
Book Review in 1987 was the first successful drug for was the only treatment for diabetes with drugs to prevent a single stroke. the presence of elevated glucose and pathological signs or symptoms. This cost of diagnosing and treating people (Baltimore: The Johns Hopkins University Press, hyperlipidemia before the advent of better spent on other programs, such treats. Indeed, one of the
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