/2/4 Hluman Resources Development and Operations Policy The World Bank July 1993 HROWP 7 lmPRUVEME'immTg'" A T L W 0% %S0T nntjuim rAKAtIlTE k0UNTRO"L Donald A.P. Bundy Joy Miller Del Rosso Papesminis sdesaresfompuiWoftheW#U= Rt lkyp=mtepamyd qlidtsWuomlys e a dwtis cbedtoftwomw dbuissi ald cit and th wie of sa a pq shood takc acm of is proim chr. lhe findu ings, _, ward _suia espansed in dbi pp:r ate ely ftbe of doe autbor(s) and sho rim be a4bu in mny manne to tbe Wodd Bank, to im affilid ogw_s,m orr,o _mbe of iu Baad of Bsocutive Dinas orth dw o=is dbg qmusm Making Nutrition Improvements at Low Cost through Parasite Control Guidelines for Designing and Implementing Mass Treatment Interventdons by Donald A.P. Bundy Joy Miller Del Rosso Donald A.P. Bundy is direco of field opations at the Welcome Trust Research Centre for Partic Infections, Impedal College, London, Head of the WHO Collaboraing Centre for the Epidemiology of Intstinal Parasitic Infecttons and consultant to the World Bank. Joy Miler Dd Rosso is a nutrition consultant to the Population, Health and Nutrition Department of the World BW ABSTRACr The 1993 World Development R"eo includes mass delivery of anthelminthic (or d ton or deworning) treatment in its "essental package of health interventions" that will address at lowest cost the diseases that cause the greatest burden. School-based mass delivery is singled out as one of the most cost-effective measures. Unti now this intervention has received little attention in Bank operations; more emphasis is deserved. Worm or parasite (technically known as intestnal heminth) infections are among the most prevalent of human infections. Most common in the least-developed countries, and among children in those countries, such infections hinder children's physical and intelletual development and reduce the productivity of adults. Reversing the nutrient leakage, anorexia, and malbsorption of food caused by such infecto can improve the growth and learning capacity of chdildren and the productive output of adults. Attractive new approaches and tools for controlling parasite infections in endemic communities are low-cost and have high return. The following guidelines were prpared to assint World Bank task managers responsible for nutrition, health, education and other related projects in the preparation of parasite control interventions. Written in question-answer format, they are intended to provide easily accessible answers to the major questions that arise when considering the incorpation of parasite control interventions into such projects. A list of references and agencies to contact for additional information is included. CONTES NEED: WHY BE CONCERNED? ......................................... . 1 RESPONSE: MASTSREATMENT IERVENTIONS .... ............. 4 ASSESSMENT: DETERMINE THE NEED FOR HELMINTH CONTROL ........ 6 IMPUEMENTATION:NVESTINGIN WORM CONTROL ................. 9 An incs ................. *.*............................. 9 Target Groups ..................................................... 10 Delivery Mechanisms . ................................... . 11 Complementy Activities. ................................... 11 Cost ................................................. 12 INFORMATION AND ASSISTANCE ............ .................. . 13 Key Refences . ....................................... 13 Orpanizfions Deaing with Parsite Control ....................... 14 NEED: WHY BE CONCERNED? What are the nuitional consequences of intestinal parasite Infection? Parasite (or helminth) infection influences nutrition in three ways. First, infection reduces food intake. Heavily infected children tend to eat less, even when food is available. Second, infection reduces intestinal absorption of certain nuttients, increasing the likelihood of deficiencies. This effect is particularly marked in roundworm infection associated with the poor absorption of vitamin A, protein, lipid and carbohydrate. Third, infection results in nutrient losses. Iron losses due to hookworm infection, for instance, increase as the worm burden increases; even relatively light infections require an infected person to more than double the daily intake of iron. In moderate whipworm infection, protein losses can be significant. The effects of nutrient losses aie particularly severe for individuals consuming marginal diets and maintaining low body stores of nutrients, the typical situation in areas where helminth infection is endemic. What are the consequences for growth and development? Are these reversible? The most intense roundworm and whipworm infections occur in school-aged children, and are associated with low weight-for-age, height-for-age and weight-for-height. Removing worms by drug treatment can accelerate growth and weight gain. Twice the normal growth rate has been observed in stunted children following drug treatment, even without improving their diet. Both nutritional and physiological benefits from deworming explain this remarkable improvement. Nutritional benefits: the child is likely to eat more, absorb more and lose less from the existing diet. Physiological benefits: parasite-induced changes in blood chemistry that, for example, negatively affect growth mechanisms among children with intense whipworm infection, cn be reversed by helminth treatment. What are the consequences for sehool achievement? Studies in Jamaica show that treating helminth infection in school children improves their performance on cognitive tests. A longitudinal study of whipworm infection in the West Indies showed not only a significant improvement in learning capacity in the treatd group compared to the placebo group, but also that cognitive scores of treated children were comparable to those of uninfected children. These improvements were achieved by a single treatment, and without nutrition supplements or improvements in education. In endemic areas, children judged to be least able academically are more likely to be infected with helminths and to harbor large worm burdens. Stunting and anemia, two common consequences of worm infection, are well known to be associated with impaired learning capacity. What are the consequences for adul morbidity and productivity? Hookworm anemia - chronic iron loss due to infection - has been shown to reduce productivity. For example, the amount of latex collected daily by anemic rubber plantation 2 workers in Indoneia was nearly 20 percent lower than that colected by non-anemic workers. Studies of male roAdworkers in Kenya and female tea-pickes in Sri Lanka show that people with anemia have decreased work capacity and productivity. Although hookworm anemia may be recified arily by iron supplementation alone, sustained improvement requres anthelminthic therapy. Hookworm anemia in adult wo-nen can have additional consequences. Anemia In pregnancy is associated with higher risk of childbirth-related matern mortality, as well as low birthweight, subsequent failure of the child to grow and infant mortality. Why ar the consequences of helnlnth infection not more widely recognized? Although helminth infection is common, affecting more than a third of the world's population, its consequences - stunting, anemia, diarrhea, imaired learning capacity and reduced productity - have multiple causes. Thus, it is impossible to attribute any one of these conditions directy to worm infection by observation; carefully constructed intervention sudies are necessary. Also, the ill-effects of helminth infection develop slowly. The anemia assocated with blood loss from hookworm infection, for example, is the sequel of several months of chronic blood loss. The role of helminth infection in stunting growth tends to pass unreognized. In a study of a West Indies community, for example, among school children with chronic mucoid diarrea and stunted growth associated with whipworm infection, only 2 percent of the cases had been recognized by health personnel. What is the prevalence of helminth infecfon world wide? Roundworms and whipworms Bo 1. Global Prvalc of ntenal occur in almost any community without Hel adequate sanitatian, safe drinldng water, or hygienic health practices. Hookworms Number of Infections (estimaed) are more typically tropical. These (in billion): infections are most prevalent in poor and overcrowded commnits, both rual and Intesnal Elmnths urban. The world-wide prvalence of the Roundwozm (4scads) 1.47 major helminths is shown in Box 1. Hookworm (Necator, Ancylsa) 1.3 What causes tdesnal heimt Whiworm (Icu*) 1.0 Infectons? Otbs The feces of infected individuals Schistosomes .2 contain the eggs of helmninths and cause (river blindness) .018 other infectons either by being ingested in contanated food, water or hands, or, 3 in the case of hookworms, by larvae penetrating the sldn. None of the common helminths multiply in humans; each worm is the result of a separate infection. Intestnal worm infection commonly involves four of the more than 30 different helminth species that occur in humans. The roundwonn, (Ascaris) and two species of hookworm (Necator and Ancylostoma) live in the small intestine, while the whipworm (TQchurns) inhabits the colon. The large (20cm) roundworm feeds on the contents of the gut, and the small (2cm) whipworm and hookworm feed on the gut wall to which they attach. These helminths have complex life cycles, but the need to understand these, or even to define precisely the target organism, has been eliminated with the advent of broad-spectrum anthelminthics (deworming drugs) that are effective against all the common species. What are the clinical symptoms and consequences of parasite infections? Initially, roundworm infection may cause cough, shortness of breath and fever lasting about 12 days. Subsequently, the infections may cause digestive disorders - nausea, vomiting and abdominal pain. Intestinal obstruction is an additional complication occurring in about .2 percent of infections. The symptoms of whipworm infection may include diarrhea, protein loss in urine and, in rare cases, complications of rectal prolapse and cardiac failure. Common symptoms of hookworm infection are lassitude, shortness of breath, pallor, anorexia and swelling of the legs. A frequent complication is iron deficiency anemia. Do all individuals infected with helminths suffer from these symptoms? No, parasite infecions can be asymptomatic. The most heavily infected individuals, those barboring the greatest number of worms, suffer the greatest risk of disease. The distribution of worm burdens in a population is highly skewed (Box 4, Figure 1); a few individuals have many worms, most have a few. Typically some 70 percent of worms in a population are found in less than 15 percent of those infected. This pattern is consistent for all major helminth species. Which age groups are most seriously affected by which intestal helminth infection? Roundworm and whipworm infections usually occur during the early preschool years, peak in prevalence among 4-5 year olds, then remain at high prevalence in aU subsequent age groups. Although adults are almost as likely to be infected with these helminths, children have much larger wonn burdens. The intensity of infection (the number of worms harbored by an individual) peaks in children 5-10 years old but declines rapidly in adults. Heavy wonn burdens and disease are less common in younger children, however death due to intestinal obstruction appears to be more common in children under five. Hookworm infection, on the other hand, peaks in adulthood. It is both more common and intense in adults than in children. 4 RRPONSE: MASS TRATMENT IERVENTIONS What is mass treatment? How does it compare to selective treatment? Mass treatment of worms means that all persons are offered treatment, regardless of individual infection status. Mass delivery is common, for example, in school helminth control programs in developing countries. Communities that receive mass treatment are carefiuy targeted on the basis of risk of disease while selective treatment means that only infected individuals identified through screening and diagnosis are treated. The latter requires examining individual fecal specimens prior to each round of treatment. This involves: a minimum of two patient visits, one each for diagnosis and treatment; enough microscopists to handle the target population; and an infrastructure for patient follow-up. Large-scale screening is usually beyond the technicl resources of endemic areas. Where feasible it is roughly estimated to be three to six times as costly as mass treatment. Screening may also reduce effectiveness because individuals who fil to provide a fecal specimen, a significant proportion in some communities, remain untrated, whether or not infected. What Is the effect of mass treatment against hemluiths? Box 2 shows the Bo 2. Effect of Sdhool-Based Antheinc Treatment on results of a school-based iinSlon of Infection program managed by the Ministries of Health and Education in the Caribbean I ;A n island of Montserrat. 17- Single-dose albendazole, a 15 b r o a d - s p e c t r u m 4 - anthelminthic, was offered g 1 to all schoolchildren (4-12 1t- OTtchur OVELL years of age) at four-month X intrvas for two and one- a , ADULT MS-CLASSeS half years. More than 90 8 percent of children were 5 treied at each cycle. Few 3- adults, less than 4 percent, 2 \ received treatment during o . 7 1 . . the7smeperiod. T7 5 7 SIM2X 0C&5a There was a highly significant decline in roundworm (Ascaris) and whipworm (Wdchwis) infection among schoolchildren, as expected with frequent administration of a broad-spectrum anthelminthic to this more heavily infected target group. A significant decline in both infections also occurred among the untreated adult population, due to reduced tnsmission from the school-aged 5 population. Thus, this treatment provided both an immediate benefit to infected school children and a long-term preventive benefit to the broader community. How does the cost-effectiveness of ma treatment compare to selective treatment? Under typical conditions, mass (community) treatment is both less costly and more effective than individual screening and selective treatment. The effectiveness of selective (screening) treatment is improved by enhanced compliance - becoming about equal to the effectiveness of mass treatment - but at higher cost. The mass option becomes more expensive than the selective option only if drug costs are excessively high. What frequency and coverage of treatment Is required for ma delivery of anehuintic? The rate of reinfection following treatment depends on the species of helninth and the local intensity of transmission. High initial levels of infection require more frequent cycles of treatment. Currat estimates indicate that treatment for whipworm and roundworm is required every 6-12 months, and for hookworm every two years, to achieve appropriatey low rates of reinfection - = eradication. These rates of treatment assume high levels of coverage, 80-90 percent of the target population, since if a substantial proportion of individuals remain untreated the rate of reinfection will be greate. Coverage and frequency of treatment are inversely related, higher frequency being required in areas where coverage is low. How does the cost-benefit ratio of anthinthc intervention compare with other health interventions? Companng the discounted healthy Lhfe years gained from anthelminthic treatment to other health interventions, school-based worm control programs are at least as cost-beneficial as other child health interventions commonly implemented at the community level (Box 3). Anthelminthic treatment through schools is estimated to cost about US$19 per healthy year of life gained. This is about the same as DPr plus polio immuniation, and less than oral rehydration therapy. This captures only part of the benefit of helminth control; other benefits are improved learning capacty, and reversal of anorexia, malabsorption and nutrient leakage. Thus, mass delivery of antheliminthics may serve as a low-cost approach to enhancing the benefits of a school feeding program. If helninth infection is not eradicated by mass btatment, aren't peopl likely to become reinfected? Yes, reinfection may be inevitable. However, eradication of helminth infection is not necessary for reducing the disease and consequences assoated with heavy infections. The individual benefits immediately from the removal of worm burdens. Moreover, reducing the 6 x 3. Cost-Benefit of School-Based Programs Compared with othe Health lntervenions US $ per Discounted Healthy Life Year gained. Leucasmia CterLts ,Q-. . ax,/ 4o OPT + pollo C(Iow mortalIty) *E- ORT C low mortalt a. * ""4 s Cholera lmuunIzatl - 145.f ,/, .t,~ O I ea Clow morta Ilty) o .. , eAntenatal edlng /OPT polIo (high nortalIty) GMG Clow risk) - W Antheimintic (schools) eo ." ] ux._ X -- Pneuwoccal Imnunization ORT Chloh mortalIty3)-- 0" A M ,,ch_ BC6 (high rlsk) AnelmIlIntic (sCWI <. _ -IAtiblotics CARI) i91eles Immunizatlo --e- Vlt A supplament ^ ~~~~~~~~~~~~~Me- les (high mortality) World Bank Health Sector Pr-irltles Rview, *Jamison & Mosley, 1993. In pross. number of individuals infected in the community slows the rate of reinfecdtion, fte build-up of heavy worm burdens, and thus prevents the dise associated with intense infections. ASSESSMENT: DETERMNE THE NEED FORI ELMNR CONTROL How is the level of morbidity from inteinal helminth Infection assessed? Illness from helminth infection is generally assessed on a regional or provincial level since it is unlikely to be a homogeneous national problem. Hospital records may be helpful in highlighting areas of high occurrence of dise, yet they generally tend to be uninformative because most cases are not reported to health authorities. Data on the intensity of worm infection in communities are obtained by examining the feces of individuals for helninth eggs. The density of eggs in feces - usually expressed as eggs per gram or EPG - gives a crude estimate of worm number, and hence the risk of morbidity. Counting eggs is labor-intensive, slow and expensive, however, and such data are rarely available. Rapid assessment procedures for intestinal helminth morbidity currently do not exist. 7 What X an altemative to assesing the level of morbidity from hehninth Infection? Data showing the presence or absence of infection -- not involving counting egg density in individual stool samples - are easier to collect, more commonly available, and can provide a useful esfimate of potential morbidity. Such prevalence data, if unavailable, can be collected through regional school surveys of 5-12 year-old children or similar surveys of adults via prmary health care (PHC) clinics. More th 50 stoo's can be examned daily for the presence or absence of infection by a trained technician using the Kato procedure, the cheapest and most efficient available. The major inputs required for such a survey include: a person to collect stools from each school, usually a local PHC worker or teacher, a techician for stool examination, usually recruited temporarily wthin a central hospital laboratory; and a stool collection pot and microscope slide per examination. How can prevalence data be used to determcne the need for hehlmath control? As noted, a few individuals in a population have intense infections (heavy worm burdens) while most have few worms (see Box 4, Figure 1). Paired data giving both the prevalence of roundworm infection (percent of population infected) and intensity (average worm burden) for different communities are presented in Box 4, Figure 2. Each data point represents the average intensity and prevalence for a separate community. As observed, mean intensity of infection increases as prevalence rises, but in a strikingly non-linear fashion. Up to 60 percent prevalence, the wotm burden changes relvely litdte; thereafter, smal changes in prevalence result in dispoportionately lare changes in intensity. For example, as prevalence increases from 80 percent to 90 percent, average roundworm burden increases from 10 to 34 worms. Since worm burden determdnes morbidity, this relationship has important consequences for the nisk of disease asshowrn in Box 4, Figure 3. This figure shows the proportion of the popultion likely to have a worm burden large enough to cause disease compared to the prevalence of infection. Each curve represents a different estmate of the risk of disease, moving from the risk associated with five or more worms to a threshold of 30 worms. All the curves show the same pattern: the risk of disease increases disrortionately with increasing prevalence of infection ir fthe community. In the case of roundworm, for example, where the threshold for the worm burden that causes disease is conservatively assumed to be about 25 worms, a prevalence of infection of 60 percent is assocated with litde or no morbidity, while a pealence of 90 percent results in almost half of the population exceeding the threshold for morbidity. Thus, if prevalence surveys show that more than 60 pement of the population is infected, the communities are at significant risk of helminth disease and treatment should be high priority. 8 Bx 4. Relatlonahlp between Prevalene of Helninth Infectlon and Level of Helmlnth-Induced Morbidity Figure 1 Figure 2 14 1 ts to so. U So 4 J e s11 o z 11g to X to to i U OO so Figure 3 a,0 3~c 9 DMPEMEMB M AT MM: INVET WORMd CONTRQL Anthel1minthim Which henhs (drugsusuly In tablet form, that destroy parastes) are useful In which s o? Some Box S. Effectveness On reported cure rates) of Selectd Anthelmlnithls anthelminthics Frequently Used at the Commuwty Level (albendazole and mebendazole) are Cm effecdve across a Roundworm Hookworm Whipworm broad spectrum Albendazole >60 >60 >60 while others Levamizole >60 >60 20-59 (piperazine) are Mebendazole >60 >60 >60 effective for one Piprzine >60 - - speces in single Pyrantel >60 >60 dose (Box 5). A narrow-spectrum Notes: - denotes indistguiable from zeo. All are one-day drug may offer treatment except mebendazole for hookworm and whipworm which so me co s t are 3 day tramts. (Data from WHO.) advantage in certain areas where a single helminth species is prevalent; however additional costs are incured in confirming the uniqueness of infection. For the majority of endemic areas a broad-spectrum drug is preferable, since whipworm infection is ubiquitous and only effectively treated by broad-spectrum anthelminthiics. Is the use of anthenhcs co did for certain groups? Albendazole and mebendazole are currently contraindicated in pregnancy. Indeed, no anthelminthic is recommended for use in pregnancy. This presents few problems when treating children of school age, but has the unsatis consequence that women of child-bearing age must be excluded from treatment. Can more than one atelnthic be adm ed at the same time? In some areas, programs of treatment for helminth infecons other than those above (e.g. praziquantel for schistosomiasis and ivermetn for onchoceciasis) may be in place or are planned. Since infection with multiple species is common, there are obvious cost advantages in using the same delivery system for all anthelmintUics requred locally. Thenr may be similar advantage in companion delivery of micronutrient supplements (vitamin A and iodine). The World Health Oraion is cutrenly invesgating the safety of adminisng albdzole and praziquantel concurrently. Untl these studhes are completed, WHO guidelne recommend that 10 these drugs should be taken at least a week apart to avoid potential interaction. The inwmctions of other drug combinations have not yet been assessed. Are logistics an obstacle to anthelminthic delivery? Generally, no. Anthelminthic tablets are taken orally, have a storage life of seval years, and require protection only from moisture and extremes of temperature. Their transport and storage are straightforward. Among the commonly used anthelminthics listed (Box 5), albendazole and mebendazole are prescribed as a fixed dose, regardless of a person's weight. For the other anthelminthics, the dose is dependent upon body weight, introducing a complication in delivery since the appropriate individual dosage must be calculated. t Grumm Why are school-aged children high priority for tratment? School-aged children have the heaviest burdens of roundworms and whipworms, therefore are more at risk of disease and, at the same time, are a major source of infection. Fortunately, children in school are a highly accessible group, and schools offer opportunities for surveillance, health education and community mobilization. Targeting anthelminthic treatment at school children is the lowest cost option, in some cases perhaps the only affordable option, for reducing community tnisson of hehninth infection. Where resources are limited, targeting school-aged children is likely to achieve the most general benefit - including benefits for pre-school children and women of child-bearing age. Seasonal school absenteeism, although a common problem, need not be a major obstacle provided the intervention is app-nipately timed. Low enrllment may, however, vitiate the effectiveness of this approach. Which other age groups should be considered targets for treatment? Where possible and affordable, it is desirable to also direcdy provide dewormig treatment to preschool children. Young children, heavily infected with helminths, are at higher risk for malnutrition and its long-term consequences. The available epidemiological evidence, however, indicates that intense infecdon with worms is much less common in this age group than in children 4 years of age and older. Schools can serve as the focal point for the delivery of teatment to younger children and those not attending school for other reawo. Adults may also be a target for treatment, particularly where hookworm anemia presents a problem for a workforce. Delivery could then be organized via plantation or workplace clinics, with hookworm treatment required only at two-year intervals. 11 What are the msbc for Implemeig a school-based delivery system? A common approach involves the distribution of anthcelminthics in schools by the school administrators and teachers while drug purchase and monitoring is undetaken by the health authorities. This division preserves sectoral responsibility for health while takdng maximum advantage of the scale of the education infrastructure, usually far larger th health. An alternative stLucture involves the use of mobile health teams, which visit schools, but rmn under direct supervision of the health sector. This approach has proved succesful m some settings, but obviously requires specfic equipment th incurs costs, raising questions as to its affordability and sustainabilit. Another approach that may be particularly useful in highly ppulated urban areas involves non-govermental organizations in program implementation. What are the other routes for mass treatment delivery? Anthelminthics may, of course, be delivered through any existing health system. The primary health care infrastructue is an obvious route and one that is already likey to be playing some role in anthelinthic treatment. Maternal and child health programs, in particular, should focus on parsitic infection in vunerable young children. Treatment of adult hookworm infections, via PHC or workplace clinics, may be effective. To reduce transmission among all age groups, however, school-aged children - the major source of community infection - must receive treatment. ifant-based treatment may help to prevent disease in this age group, but will not control reted morbidity for the community as a whole. Broadening the scope of PHC programs to regularly include all school-aged children is unlikly to be affordable, unless undertaken as part of a school-based program. CA=_ Ala*s What activties need to accompany delivery of anthemn to school children? Education. Educational programs to change practces related to the ransmission of parsite infections are necessary to support mass anthelminthic delivery. Improving hygiene will extend the benefits of drug ther, reducing the frequency and coverage of treatment required. Educational efforts also can encourage compliance with anthelminthic treatment. Approaches involving children, schoolteachers and parents have been shown to be most effective. At the same time delivezy of antheminthics can serve as a focal point for participatory health educaton in the curiculum, and encouraging community support for improving sanitation in the community. Educationalpackages can be deveoped by government health education agencies, siuated administively i eitr the health or education sectors, and be supplemented by mateials from 12 the commeial health sector and mitenatonal agencies. School-based educational programs can also be linked to those under MCH programs and to mass media campaigns to increase outreach and impact. 1mining. All teachers involved in school-based programs and other workers involved in the delivery of anthelmindiics should receive training. Ideally, training is offered as part of continuing education or other worker training programs, rather than being established as a specific program tat would require additional resources to implement. What are the costs of anhelminthlc Drug costs depend on the drugs used. Current (1991) quotes from the UNICEF Essential Drug Ptice List indicate that mebendazole costs US$ 0.07 per dose, while pipemaine costs US$ 0.05 per 500mg dose. Acquiring the drugs through local sources is likely to be more expensive but with bulk purchase a single dose of an anthlminthic typically costs less than US$ 0.25. What are the delUvery costs associated with mam treatment helnith control? Management of mass drug delivery by a mobile health team (supervising 200 schools per year) might add US$ 0.20-0.40 cents per child per year, while using a school health worker for a broad range of health-related activities (25 percent of time of one teacher per 500 students) would add 1-2 percent to annual education costs per child. Few mass progrms for intestn helminths have been costed in detil, but one school- based program in the Caribbean was estimated to bave an all-inclusive cost of US$ 1.50 per capita of the total popWulation for 8 cycles over 2.5 years. A single ntamet would be considerably less than US$ 1.00, and might be frther reduced if eisting tranWort facilties (e.g. school deliveries) or health systems were used. Adding additional therpies, such as micronutrients, to the same delivery system could be achieved for litte more than the cost of the additional therapy itself. 13 PORMATIOQN AND ASSISTANCE Key References Berldey, S. & Jamison, D. 1991. "A Conference on the Health of School-age Children. Summary Report." New York: Rockefeller Foundation (mimeographed document). Bundy, D.A.P. et al. 1990. "Control of Gastrointestinal Helminths by Age-Targeted Chemotherapy Delivered through Schools.' Transacdons of the Royal Socety of Tropical Medicine and Hygiene. i, 115-120. Nokes, C. et al. 1992. "Parasitic Helminth Infections and Cognitive Function in School Children." Proceedings of die Royal Society, Series B 24, 77-81. Pawlowsli, Z.S., Schad, G.A. & Scott G.J. 1991. Hookworm Infecton and Hookwom, Anemia. Approaches to Prevention and Control. WHO, Geneva. Politt, E. 1990. Malnutrition and lnfectdon in the Classroom. Paris: UNESCO. Savioli, L., Bundy, D.A.P. & Tomidns, A.M. 1992. "Intestinal Parasitic Infections: A Soluble Public Health Problem." ransactions of the Royal Society of Tropic Medicine and Hygiene, B6. 353-354. Stephenson, L.S. 1987. The bipact of Helminth I4fecions on Humm Nrition. London: Taylor and Francis. Tomins, A. & Watson, F. 1989. Malnutrion and Infecon. A Review. New York: United Nations Administrative Committee on Coordination/Subcommittee on Nutrition, State of the Art Series, Nutriton Policy Discussion Paper No. 5. Warren, K. et al. 1993, in prs. "Hehinth Infection." In The World Bank Heath Sector Priories Review. Washington, D.C.: World Bank WHO. 1992. Bench Aids for the Diagnosis of Intestnal Hemnhs. Programme on Intesnal Parasitic Infections, Division of Communicable Diseases, WHO, Geneva. 1990. "Informal Consultation on Intesdnal Parasitic Infections." Geneva July 9-12, 1990. Geneva. World Health Organization, mimeographed document No. WHO/CDS/IP/90. 1. 1987. Prevenion and Control of Intestnal Parasiic Ifections. Report of a WHO Expert Committee. Geneva: World Health Organition, Technical Report Series, No. 749. 14 Organizations Dealing with Parasite Control Centre for International Child Health Institute of Child Health 30, Guilford Street London WC1N 1EH IRC Intemational Water and Sanitation Centre PO Box 93190 2509 AD The Hague The Netherlands Partnership for Child Developmen Scientific Coordinating Centre West Beit Imperial CoUege of Science, Technology and Medicine Prince Consort Road London SW7 2BB Progm Against Micronutient Malnutrition Emory University School of Public Health 1599 Clifton Road NE Atlanta Georgia 30329 USA ProgQmme on nitsdnl Parasitic infecDons Division of Communicable Diseases WHO CH-1211 Geneva 27 Switzerland Human Resources Development and Operations Policy Working Paper Series Contact for Title Author Date paper HROWP1 Social Development Is Nancy Birdsall March 1993 L Malca Economic Development 37720 HROWP2 Factors Affecting Achievement Eduardo Velez April 1993 B. Diallo in Primary Education: A Ernesto Schiefelbein 30887 Review of the Literature for Jorge Valenzuela Latin America and the Caribbean HROWP3 Social Policy and Fertility Thomas W. Merrick May 1993 0. Nadora Transitions 31091 HROWP4 Poverty, Social Sector Norman L Hicks May 1993 J1 Abner Development and the Role of 38875 the World Bank HROWP5 Incorporating Nutrition into F. James Levinson June 1993 0. Nadora Bank-Assisted Social Funds 31091 HROWP6 Global Indicators of Nutritional Rae Galloway June 19193 0. Nadora Risk (II) 31091 HRO Dissemination Notes Contact for Tide Date note No. 1 Tobacco Death Toll February 19, 1993 L Malca 37720 No. 2 The Benefits of Education for Women March 8, 1993 L Malca 37720 No. 3 Poverty and Income Distribution in Latin March 29, 1893 L Malca America 37720 No. 4 BIAS is Herel April 12, 1993 L Malca (Committee on Business Innovation and 37720 Simplification) No. 5 Acute Respiratory Infections April 26, 1993 L Malca 37720 No. 6 From Manpower Planning to Labor Market May 10, 1993 L Malca Analysis 37720 No. 7 Enhancing Investrnents in Education Through May 24, 1993 L Malca Better Nutrition and Health 37720 No. 8 Indigenous People in Latin America June 7, 1993 L Malca 37720 No 9 The Economic Cost of Malaria in Africa June 28, 1993 L Malca 37720