at a glance
Worms infect more than one third of the world’s
There is no need to examine each child for the
population, with the most intense infections in
presence of worms. Individual screening offers no
children and the poor. In the poorest countries,
safety benefits. And it is not cost-effective; it costs
children are likely to be infected from the time they
four to ten times more than the treatment itself.
stop breast-feeding, and to be continually infected
Regular deworming will help children avoid the worst
and re-infected for the rest of their lives. Only rarely
effects of infection even if there is no improvement in
does infection have acute consequences for children.
Instead, the infection is long-term and chronic, andcan negatively affect all aspects of a child’s develop-
ment: health, nutrition, cognitive development, learn-ing and educational access and achievement.
School-age children typically have the highestintensity of worm infection of any age group. In
Deworming is safe, easy and cheap addition, the most cost-effective way to deliver
deworming pills regularly to children is through
All the common worm infections in school-age
schools because schools offer a readily available,
children can be treated effectively with two single-
extensive and sustained infrastructure with a skilled
dose pills: one for all the common intestinal worms
workforce that is in close contact with the community.
(hookworms, roundworms, and whipworms) and theother for schistosomiasis (bilharzia).1 The treatment is
With support from the local health system, teachers
safe, even when given to uninfected children.
can deliver the drugs safely. Teachers need only afew hours training to understand the rationale for
The most commonly used drugs for the treatment of
deworming, and to learn how to give out the pills
common intestinal worms are albendazole (400 mg)
and keep a record of their distribution.
or mebendazole (500 mg). They are administered asa single tablet to all children, regardless of size or
Regular deworming contributes to good health and
age. One pill can cost as little as US$0.02 and only
nutrition for children of school age, which in turn
in the most highly infected communities is treatment
leads to increased enrolment and attendance,
reduced class repetition, and increased educationalattainment. The most disadvantaged children – such
Praziquantel, the drug of choice to treat schistosomia-
as girls and the poor – often suffer most from ill
sis, is slightly more expensive – on average US$0.20
health and malnutrition, and gain the most benefit
per treatment for a school aged child. Treatment once
a year is sufficient even in the most infected communi-ties. Praziquantel is given as a single dose, but the
School-based deworming has its full impact when
number of pills has to be adjusted to the size of the
delivered within an integrated school health
child. The preferred method for schoolchildren is an
program that includes the following key elements
inexpensive “dose-pole” that uses the height of the
of the FRESH (Focus Resources on Effective School
Deworming pills are heat-stable and require no cold
1. Health policies in schools that advocate the role of
chain for delivery. With a shelf life of up to four
teachers in health promotion and delivery;
years, they can be purchased in bulk to reduce costs
2. Adequate sanitation and access to safe water
to reduce worm transmission in the school
In communities where infection is common all children
should be offered treatment. The need for mass treat-
3. Skills-based health education that promotes good
ment of schoolchildren can be determined by simple
and low cost survey techniques that identify whether
4. Basic health and nutrition services that include reg-
the school is in an area of significant risk of infection.
1Any one of the following can be used to treat common intestinal
2For further information about the school health program activities
worms: albendazole, mebendazole, levamisole or pyrantel. The
and the FRESH framework, please consult School Health At A
drug of choice for the treatment of schistosomiasis is praziquantel. March 2003
How to get started ? 1. Determine whether the school is at risk of infection
• Explain that heavily infected children may
experience mild side effects when the treatment
• WHO, with its partners, keeps track of
expels their worms, and that the complaints of
epidemiological information on the distribution
one child often trigger other schoolchildren to
of worm infection for most countries, and uses
GIS technology to develop maps indicating the areas at risk of infection. If the target
4. Procure drugs and materials
school is located in one of these areas thenmass treatment is indicated.
• Use established systems, such as national
• If information is not available, use WHO
quality. Involve the health services in the
guidelines to conduct a rapid epidemiological
proper storage of drugs in health clinics, and
assessment to determine whether the school is
in delivery to schools. In addition to the pills,
in an area of high prevalence of infection.
stationery for record keeping and a dose polefor the administration of praziquantel are all
2. Determine the strategy for mass treatment based
that is required to deliver treatment in schools. on WHO recommendations 5. Treat children
• Treatment should be offered to all children in
schools where more than half the children are
• Schools and health personnel should work
believed to be infected with intestinal worms or
together to decide on a treatment day for
where any child passes blood in their urine as
delivering deworming and the other health
a result of schistosomiasis. Treatment should be
and nutrition services of the FRESH package.
offered at least once each year for intestinal
worms and at least every two years for schisto-
drug distribution by teachers, and should be
somiasis. If infection is particularly common,
ready to provide support and supervision for
the frequency of treatment may be increased to
twice a year for intestinal worms and once ayear for schistosomiasis.
6. Monitoring and Evaluation
• Other schools should not require routine
• Routine monitoring of deworming involves the
treatment programs; instead children should
recording of basic process indicators: the
be encouraged to seek treatment at a health
number (or %) of children treated and the
center if they suspect they are infected. One
quantity of drugs used. This assists in routine
important exception is if the school is in an
planning, and also helps reduce inappropriate
area of low (less than 10%) but persistent
use of drugs. If a more detailed evaluation is
required, the program impact can be assessed
children should be offered treatment twice
during their primary schooling: once at entry,and once when leaving school.
• Individual diagnosis has no role in school-
Contact wormcontrol@who.int to obtain:
complicated, and it is neither cost-effective nor necessary as the treatment is safe even
3. Train teachers and inform the community
• Train teachers to understand the benefits of
3. WHO Partners for Parasite Control data
deworming in schools, and to distribute the
pills and keep records. A group of 40-50teachers can be trained in less than one day.
4. Deworming and health education training
• Communicate with parents, community leaders
and local health agents about the objectives of the deworming in schools and what theyshould expect.
Evidence that school deworming is beneficial
and cost-effective Deworming contributes to Education for All
for an investment of US$4 in deworming, as compared
Studies in low-income countries of Africa, South
to US$38 to US$99 for other interventions. [4] The
America and Asia confirm that children with intense
Rockefeller hookworm control program early in the 20th
worm infections perform poorly in learning ability tests,
century in the Southern USA achieved a similar reduc-
cognitive function and educational achievement. Differ-
tion in absenteeism (23%) and long-run effects on labor
ences in test performance equivalent to a six- month
income suggest the benefit of a hookworm-free
delay in development can typically be attributed to
childhood to be around 45% of adult wages [6].
heavier infections of the sort experienced by around 60
Deworming is therefore an efficient investment in human
million school age children [1]. Absenteeism is more fre-
quent among infected than uninfected children: the
Deworming has major externalities for untreated
heavier the intensity of infection, the greater the absen-
children and the whole community
teeism, to the extent that some infected children attend
By reducing the transmission of infection in the
school half as much as their uninfected peers [2].
community as a whole, deworming substantially
Deworming can benefit children’s learning [3] and sub-
improves health and school participation for both
stantially increase primary school attendance and signif-
treated and untreated children, in treatment schools and
icantly increase a child’s ability to learn in school [4].
in neighboring schools. As a result, treating only school
Deworming is an exceptionally low cost intervention
age children can reduce the total burden of disease due
Operational research in Ghana and Tanzania has
to intestinal worm infections by 70% in the community
demonstrated that for the first five years of intervention,
as a whole [7]. These externalities are large enough to
the average yearly cost of delivered treatment – taking
justify fully subsidizing treatment. They also explain why
into account current drug prices – is typically less than
deworming is beneficial even without improvements in
US$0.50 per child in an area where both schistosomia-
sis and the common intestinal worms are present, and
Deworming targets one of the most common, long-term
less than US$0.25 per child in an area where only the
infections of children in low-income countries.
latter are present. This is the total cost which includes
For girls and boys aged 5 to 14 years in low-income
training of teachers, as well as the procurement and dis-
countries, intestinal worms account for an estimated 11
and 12 percent, respectively, of the total disease
Deworming gives a high return to education and
burden, and represent the single largest contributor to
labor income
the disease burden of this group. An estimated 20 per-
A randomized evaluation of school-based mass
cent of disability adjusted life years lost because of com-
deworming for schistosomiasis and intestinal worms in
municable disease among school children is a direct
Kenya reduced absenteeism by one-quarter. Deworming
was the most cost-effective method of improving school
The table shows the global number of cases and preva-
participation among a series of educational interven-
tions. An extra year of primary schooling was gained
Infection Number of Cases (millions) Prevalence Sources: Bundy, D.A.P. et al. (1997) Intestinal nematode infections, in Health Priorities and Burden of Disease Analysis: Methods and Applications from Global, National and Sub-national Studies (Murray, C.J.L. and Lopez, A.D., eds), Harvard University Press for the World Health Organization and the World Bank. Van der Werf, M.J. et al. (2003) Quantification of clinical morbidity associated with schistosome infection in sub-Saharan Africa. Acta Tropica (in press). References: 1. Partnership for Child Development. Heavy schistosomiasis associated with poor short-term memory and slower reaction times in Tanzanian schoolchildren. Tropical Medicine and International Health, 2002, 7:104-117. 2. Nokes C, Bundy D. Compliance and absenteeism in schoolchildren: implications for helminth control. Transactions of the Royal Society of Tropical Medicine and Hygien,1993, 87:148-1521. 3. Grigorenko, E., Sternberg, R., Ngorosho, D., Nokes, C., Jukes, M., & Bundy, D. (submitted). Effects of Antiparasitic Treatment on Dynamically-Assessed Cognitive Skills. 4. Miguel E. & Kremer M. (2002) Worms: Identifying Impacts on Health and Education in the Presence of Treatment Externalities. http://post.economics.har- vard.edu/faculty/kremer/ . 5. Partnership for Child Development. The cost of large-scale school health programmes which deliver anthelmintics to children in Ghana and Tanzania. Acta Tropica, 1999, 73: 183-204. 6. Bleakley, H (2002) Disease and Development: Evidence from hookworm eradication in the American South. Report of the Rockefeller Sanitary Commission. http://web.mit.edu/hoyt. 7. Bundy DAP, Wong MS, Lewis LL & Horton J. Control of geohelminths by delivery of targeted chemotherapy through schools. Transactions of the Royal Society of Tropical Medicine and Hygiene, 1990, 84: 115-120.
Do’s and don’ts in school deworming Key references Do… Prevention and control of schistosomiasis and soil-trans-Do make deworming an integral component of a school mitted helminthiasis. Report of a WHO Expert
health program using the FRESH framework. Combine
Committee. World Health Organization, Geneva, 2002
deworming with iron and other micronutrient supple-
(WHO Technical Report Series, No. 912).
ments. Do ensure that teachers and health agents work Helminth control in school-age children. A guide for
together at all stages of the program and identify their
managers of control programmes. ISBN 92 4 154556
9, World Health Organization, Geneva, 2002. Do help teachers understand the benefits of deworm- ing, so that they are supportive and recognize that their The FRESH Toolkit, Focusing Resources on Effective
investment of time in deworming is an important contri-
School Health. World Bank, Washington DC, 2002.
bution to education. Do ensure that local health personnel make careful School Health at a Glance, World Bank, Washington
plans to manage possible side effects. Improper
management of side effects can ruin the future of the program.
The Partnership for Child Development. Better Health,Do make sure that treatment is provided for both intes- nutrition and education for the school-aged child.
tinal worms and schistosomiasis where needed.
Leading article, Transactions of the Royal Society of
Effective deworming requires both treatments.
Tropical Medicine and Hygiene, 1997, 91: 1-2.
Do make sure that treatment is given regularly and sus- tained.
Montresor A et al. Development and validation of a‘tablet pole’ for the administration of praziquantel inDo protect children throughout their development by sub-Saharan Africa. Transactions of the Royal Society of
starting treatment early (e.g. with Early Child
Tropical Medicine and Hygiene, 2001, 95:542-544.
Development programs) and continuing treatmentthroughout primary school.
The “Partners for Parasite Control”: PPC Newsletter
Do reach out to non-enrolled school aged children. This
not only enhances the public health impact of your inter-vention, but also encourages children, especially girls,to attend school. Don’t… Don’t waste time and resources trying to examine each
school or child. Deworming drugs are safe and can be
given to uninfected children. No individual diagnosis,
Don’t exclude adolescent girls from systematic treatment. The drugs are safe, even in pregnancy.
For further information, please contact Don Bundy
Don’t be afraid to give a single dose tablet of
at eservice@worldbank.org or Lorenzo Savioli at worm-
albendazole or mebendazole even to children of small
stature. The pills are safe for children over 1 year of age, regardless of their size or weight. Don’t hesitate to use a dose pole instead of a scale to decide the appropriate dose of praziquantel. It accu- rately calculates the dosages for school age children and may – in the long- term – be more reliable than deteriorating scales. Don’t wait for sanitation to improve before starting deworming – regular treatment will help all children avoid the worst effects of infection. Expanded versions of the “at a glance” series, with e-linkages to resources and more information, are available on the World Bank Health-Nutrition-Population web site: www.worldbank.org/hnp
Aortic Pressure Augmentation Predicts Adverse Cardiovascular Events in Patients With Established Coronary Artery Disease Julio A. Chirinos, Juan P. Zambrano, Simon Chakko, Anila Veerani, Alan Schob, Howard J. Willens, Abstract —Pulse pressure (PP), a marker of arterial stiffness, predicts cardiovascular risk. We aimed to determine whether augmentation pressure (AP) derived from the