The yin and yang of human soil-transmitted helminth infections.

The major soil-transmitted helminths that infect humans are the roundworms, whipworms and hookworms. Soil-transmitted helminth infections rank among the most important neglected tropical diseases in terms of morbidity, and almost one billion people are still infected with at least one species. While anthelmintic drugs are available, they do not offer long term protection against reinfection, precipitating the need for vaccines that provide long-term immunologic defense. Vaccine discovery and development is in advanced clinical development for hookworm infection, with a bivalent human hookworm vaccine in clinical trials in Brazil and Africa, but is in its infancy for both roundworm (ascariasis) and whipworm (trichuriasis) infections. One of the greatest hurdles to developing soil-transmitted helminth vaccines is the potent immunoregulatory properties of these helminths, creating a barrier to the induction of meaningful long-term protective immunity. While challenging for vaccinologists, this phenomenon presents unique opportunities to develop an entirely new class of anti-inflammatory drugs that capitalise on these immunomodulatory strategies. Epidemiologic studies and clinical trials employing experimental soil-transmitted helminth challenge models, when coupled with findings from animal models, show that at least some soil-transmitted helminth-derived molecules can protect against the onset of autoimmune, allergic and metabolic disorders, and several natural products with the desired bioactivity have been isolated and tested in pre-clinical settings. The yin and yang of soil-transmitted helminth infections reflect both the urgency for effective vaccines and the potential for new immunoregulatory molecules from parasite products.

Epidemiology of soil-transmitted helminths following sustained implementation of routine preventive chemotherapy: Demographics and baseline results of a cluster randomised trial in southern Malawi.

Malawi has successfully leveraged multiple delivery platforms to scale-up and sustain the implementation of preventive chemotherapy (PCT) for the control of morbidity caused by soil-transmitted helminths (STH). Sentinel monitoring demonstrates this strategy has been successful in reducing STH infection in school-age children, although our understanding of the contemporary epidemiological profile of STH across the broader community remains limited. As part of a multi-site trial evaluating the feasibility of interrupting STH transmission across three countries, this study aimed to describe the baseline demographics and the prevalence, intensity and associated risk factors of STH infection in Mangochi district, southern Malawi. Between October-December 2017, a community census was conducted across the catchment area of seven primary healthcare facilities, enumerating 131,074 individuals across 124 villages. A cross-sectional parasitological survey was then conducted between March-May 2018 in the censused area as a baseline for a cluster randomised trial. An age-stratified random sample of 6,102 individuals were assessed for helminthiasis by Kato-Katz and completed a detailed risk-factor questionnaire. The age-cluster weighted prevalence of any STH infection was 7.8% (95% C.I. 7.0%-8.6%) comprised predominantly of hookworm species and of entirely low-intensity infections. The presence and intensity of infection was significantly higher in men and in adults. Infection was negatively associated with risk factors that included increasing levels of relative household wealth, higher education levels of any adult household member, current school attendance, or recent deworming. In this setting of relatively high coverage of sanitation facilities, there was no association between hookworm and reported access to sanitation, handwashing facilities, or water facilities. These results describe a setting that has reduced the prevalence of STH to a very low level, and confirms many previously recognised risk-factors for infection. Expanding the delivery of anthelmintics to groups where STH infection persist could enable Malawi to move past the objective of elimination of morbidity, and towards the elimination of STH. Trial registration: NCT03014167.

Serious limitations of the current strategy to control Soil-Transmitted Helminths and added value of Ivermectin/Albendazole mass administration: A population-based observational study in Cameroon.

BACKGROUND: Soil-transmitted helminth (STH) infections remain a public health concern in sub-Saharan Africa. School-based mass drug administration (MDA) using the anthelminthic drug Mebendazole/Albendazole have succeeded in controlling morbidity associated to these diseases but failed to interrupt their transmission. In areas were filarial diseases are co-endemic, another anthelminthic drug (Ivermectin) is distributed to almost the entire population, following the community-directed treatment with ivermectin (CDTI) strategy. Since Ivermectin is a broad spectrum anthelmintic known to be effective against STH, we conducted cross-sectional surveys in two health districts with very contrasting histories of Ivermectin/Albendazole-based PC in order to investigate whether CDTI might have contributed in STH transmission interruption. METHODOLOGY: Cross-sectional surveys were conducted in two health districts with similar socio-environmental patterns but with very contrasting CDTI histories (Akonolinga health district where CDTI was yet to be implemented vs. Yabassi health district where CDTI has been ongoing for two decades). Stool samples were collected from all volunteers aged >2 years old and analyzed using the Kato-Katz technique. Infections by different STH species were compared between Akonolinga and Yabassi health districts to decipher the impact of Ivermectin/Albendazole-based MDA on STH transmission. PRINCIPAL FINDINGS: A total of 610 and 584 participants aged 2-90 years old were enrolled in Akonolinga and Yabassi health districts, respectively. Two STH species (Ascaris lumbricoides and Trichuris trichiura) were found, with prevalence significantly higher in Akonolinga health district (43.3%; 95% CI: 38.1-46.6) compared to Yabassi health district (2.5%; 95% CI: 1.1-5.1) (chi-square: 90.8; df: 1; p < 0.001). CONCLUSION/SIGNIFICANCE: These findings (i) suggest that Mebendazole- or Albendazole-based MDA alone distributed only to at-risk populations might not be enough to eliminate STH, (ii) support the collateral impact of Ivermectin/Albendazole MDA on A. lumbricoides and T. trichiura infections, and (iii) suggest that Ivermectin/Albendazole-based PC could accelerate STH transmission interruption.

Sustained preventive chemotherapy for soil-transmitted helminthiases leads to reduction in prevalence and anthelminthic tablets required.

BACKGROUND: The goal of soil-transmitted helminthiases (STH) control programmes is to eliminate STH-associated morbidity in the target population by reducing the prevalence of moderate- and heavy-intensity infections and the overall STH infection prevalence mainly through preventive chemotherapy (PC) with either albendazole or mebendazole. Endemic countries should measure the success of their control programmes through regular epidemiological assessments. We evaluated changes in STH prevalence in countries that conducted effective PC coverage for STH to guide changes in the frequency of PC rounds and the number of tablets needed. METHODS: We selected countries from World Health Organization (WHO)'s Preventive Chemotherapy and Transmission control (PCT) databank that conducted ≥5 years of PC with effective coverage for school-age children (SAC) and extracted STH baseline and impact assessment data using the WHO Epidemiological Data Reporting Form, Ministry of Health reports and/or peer-reviewed publications. We used pooled and weighted means to plot the prevalence of infection with any STH and with each STH species at baseline and after ≥5 years of PC with effective coverage. Finally, using the WHO STH decision tree, we estimated the reduction in the number of tablets needed. RESULTS: Fifteen countries in four WHO regions conducted annual or semi-annual rounds of PC for STH for 5 years or more and collected data before and after interventions. At baseline, the pooled prevalence was 48.9% (33.1-64.7%) for any STH, 23.2% (13.7-32.7%) for Ascaris lumbricoides, 21.01% (9.7-32.3%) for Trichuris trichiura and 18.2% (10.9-25.5%) for hookworm infections, while after ≥5 years of PC for STH, the prevalence was 14.3% (7.3-21.3%) for any STH, 6.9% (1.3-12.5%) for A. lumbricoides, 5.3% (1.06-9.6%) for T. trichiura and 8.1% (4.0-12.2%) for hookworm infections. CONCLUSIONS: Countries endemic for STH have made tremendous progress in reducing STH-associated morbidity, but very few countries have data to demonstrate that progress. In this study, the data show that nine countries should adapt their PC strategies and the frequency of PC rounds to yield a 36% reduction in drug needs. The study also highlights the importance of impact assessment surveys to adapt control strategies according to STH prevalence.

Sustained effectiveness of weekly iron-folic acid supplementation and regular deworming over 6 years in women in rural Vietnam.

BACKGROUND: Weekly iron-folic acid (IFA) supplementation and regular deworming is effective for the prevention of iron deficiency and anaemia in women of child-bearing age. Between 2006 and 2013, a program of weekly IFA and biannual deworming was implemented in Yen Bai province, Vietnam. In this study we aimed to determine the effectiveness of the program in reducing anaemia and the prevalence of hookworm infection after 72 months (six years). METHODS: This prospective cohort study followed up a cohort of 389 women of child-bearing age from baseline until six years after the introduction of the weekly IFA (one tablet containing 200 mg ferrous sulphate, 0.4mg folic acid) and deworming (one 400mg tablet of albendazole given twice yearly) program (May 2006 to 2012). In each of the six surveys (baseline and five follow-up surveys) we measured haemoglobin and ferritin, and the burden of soil transmitted helminth (STH) infections, and in the 72 month survey we also administered a questionnaire to assess adherence and possible impediments to participating in the program. RESULTS: Two hundred and fifty six (65.8%) of the original 389 women enrolled in the cohort attended the final 72 month survey. Haemoglobin levels were 122 g/L [95% C.I. 120, 124] at baseline and increased to 135g/L [95% C.I. 133, 138] after 72 months. The prevalence of anaemia was 37.8% [95% C.I. 31.0, 44.7] at baseline and reduced to 14.3% [95% C.I. 9.5, 19.1]. Hookworm infection prevalence, 75.9% [95% C.I. 68.1, 83.8] at baseline, reduced to 10.2% [95% C.I. 5.4, 15.0] with no moderate or heavy intensity infections. Seventy-two percent of participants reported still taking at least 75% of the weekly supplements, and 85.0% had taken the most recent deworming treatment. DISCUSSION: Anaemia rates fell significantly during the six-year program, and STH infections were eliminated as a public health risk. Adherence was well maintained but long-term sustainability is challenging in the absence of ongoing external support.

Control of soil-transmitted helminthiasis in Yunnan province, People's Republic of China: experiences and lessons from a 5-year multi-intervention trial.

The current global strategy for the control of soil-transmitted helminthiasis emphasises periodic administration of anthelminthic drugs to at-risk populations. However, this approach fails to address the root social and ecological causes of soil-transmitted helminthiasis. For sustainable control, it has been suggested that improvements in water, sanitation and hygiene behaviour are required. We designed a 5-year multi-intervention trial in Menghai county, Yunnan province, People's Republic of China. Three different interventions were implemented, each covering a village inhabited by 200-350 people. The interventions consisted of (i) initial health education at study inception and systematic treatment of all individuals aged ≥2 years once every year with a single dose of albendazole; (ii) initial health education and bi-annual albendazole administration; and (iii) bi-annual treatment coupled with latrine construction at family level and regular health education. Interventions were rigorously implemented for 3 years, whilst the follow-up, which included annual albendazole distribution, lasted for 2 more years. Before the third round of treatment, the prevalence of Ascaris lumbricoides was reduced by only 2.8% in the annual treatment arm, whilst bi-annual deworming combined with latrine construction and health education resulted in a prevalence reduction of 53.3% (p<0.001). All three control approaches significantly reduced the prevalence of Trichuris trichiura and hookworm, with the highest reductions achieved when chemotherapy was combined with sanitation and health education. The prevalence of T. trichiura remained at 30% and above regardless of the intervention. Only bi-annual treatment combined with latrine construction and health education significantly impacted on the prevalence of Taenia spp., but none of the interventions significantly reduced the prevalence of Strongyloides stercoralis. Our findings support the notion that in high-endemicity areas, sustainable control of soil-transmitted helminth infections necessitates measures to reduce faecal environmental contamination to complement mass drug administration. However, elimination of soil-transmitted helminthiasis will not be achieved in the short run even with a package of interventions, and probably requires improvements in living conditions, changes in hygiene behaviour and more efficacious anthelminthic drugs and treatment regimens.

Increased birth weight associated with regular pre-pregnancy deworming and weekly iron-folic acid supplementation for Vietnamese women.

BACKGROUND: Hookworm infections are significant public health issues in South-East Asia. In women of reproductive age, chronic hookworm infections cause iron deficiency anaemia, which, upon pregnancy, can lead to intrauterine growth restriction and low birth weight. Low birth weight is an important risk factor for neonatal and infant mortality and morbidity. METHODOLOGY: We investigated the association between neonatal birth weight and a 4-monthly deworming and weekly iron-folic acid supplementation program given to women of reproductive age in north-west Vietnam. The program was made available to all women of reproductive age (estimated 51,623) in two districts in Yen Bai Province for 20 months prior to commencement of birth weight data collection. Data were obtained for births at the district hospitals of the two intervention districts as well as from two control districts where women did not have access to the intervention, but had similar maternal and child health indicators and socio-economic backgrounds. The primary outcome was low birth weight. PRINCIPAL FINDINGS: The birth weights of 463 infants born in district hospitals in the intervention (168) and control districts (295) were recorded. Twenty-six months after the program was started, the prevalence of low birth weight was 3% in intervention districts compared to 7.4% in control districts (adjusted odds ratio 0.29, 95% confidence interval 0.10 to 0.81, p = 0.017). The mean birth weight was 124 g (CI 68 - 255 g, p<0.001) greater in the intervention districts compared to control districts. CONCLUSIONS/SIGNIFICANCE: The findings of this study suggest that providing women with regular deworming and weekly iron-folic acid supplements before pregnancy is associated with a reduced prevalence of low birth weight in rural Vietnam. The impact of this health system-integrated intervention on birth outcomes should be further evaluated through a more extensive randomised-controlled trial.

Spatial co-distribution of neglected tropical diseases in the east African great lakes region: revisiting the justification for integrated control.

OBJECTIVE: To determine spatial patterns of co-endemicity of schistosomiasis mansoni and the soil-transmitted helminths (STHs) Ascaris lumbricoides, Trichuris trichiura and hookworm in the Great Lakes region of East Africa, to help plan integrated neglected tropical disease programmes in this region. METHOD: Parasitological surveys were conducted in Uganda, Tanzania, Kenya and Burundi in 28 213 children in 404 schools. Bayesian geostatistical models were used to interpolate prevalence of these infections across the study area. Interpolated prevalence maps were overlaid to determine areas of co-endemicity. RESULTS: In the Great Lakes region, prevalence was 18.1% for Schistosoma mansoni, 50.0% for hookworm, 6.8% for A. lumbricoides and 6.8% for T. trichiura. Hookworm infection was ubiquitous, whereas S. mansoni, A. lumbricoides and T. trichiura were highly focal. Most areas were endemic (prevalence >or=10%) or hyperendemic (prevalence >or=50%) for one or more STHs, whereas endemic areas for schistosomiasis mansoni were restricted to foci adjacent large perennial water bodies. CONCLUSION: Because of the ubiquity of hookworm, treatment programmes are required for STH throughout the region but efficient schistosomiasis control should only be targeted at limited high-risk areas. Therefore, integration of schistosomiasis with STH control is only indicated in limited foci in East Africa.

Long-term weekly iron-folic acid and de-worming is associated with stabilised haemoglobin and increasing iron stores in non-pregnant women in Vietnam.

BACKGROUND: The prevalence of anaemia and iron deficiency in women remains high worldwide. WHO recommends weekly iron-folic acid supplementation where anaemia rates in non-pregnant women of reproductive age are higher than 20%. In 2006, a demonstration project consisting of weekly iron-folic acid supplementation and regular de-worming was set up in two districts in a northern province in Vietnam where anaemia and hookworm rates were 38% and 76% respectively. In 2008 the project was expanded to all districts in the province, targeting some 250,000 women. The objectives of this study were to: 1) examine changes in haemoglobin, iron stores and soil transmitted helminth infection prevalence over three years and 2) assess women's access to and compliance with the intervention. METHODS AND FINDINGS: The study was a semi-cross-sectional, semi-longitudinal panel design with a baseline survey, three impact surveys at three-, twelve- and thirty months after commencement of the intervention, and three compliance surveys after ten weeks, eighteen and thirty six months. RESULTS: After thirty months, mean haemoglobin stabilised at 130.3 g/L, an increase of 8.2 g/L from baseline, and mean serum ferritin rose from 23.9 µg/L to 52 µg/L. Hookworm prevalence fell from 76% to 22% over the same period. After thirty six months, 81% of the target population were receiving supplements and 87% were taking 75% or more of the supplements they received. CONCLUSIONS: Weekly iron-folic acid supplementation and regular de-worming was effective in significantly and sustainably reducing the prevalence of anaemia and soil transmitted helminth infections and high compliance rates were maintained over three years.

The effect of iron fortification and de-worming on anaemia and iron status of Vietnamese schoolchildren.

Previous data from Vietnam show that anaemia is highly prevalent among schoolchildren, who are considered not to be iron deficient. Trichuris infection doubled the risk of anaemia. The present study aimed to evaluate the hypothesis that de-worming is more effective than iron fortification in an anaemic, infection-prone population. In a trial with a 2 x 2 factorial design, 425 anaemic children aged 6-8 years were randomly assigned to receive either iron-fortified noodles or placebo, and mebendazole or placebo. Outcomes considered were change in haematological indicators of iron status (Hb, serum ferritin (SF), serum transferrin receptor (TfR) and haemoglobinopathies analysis); inflammations (C-reactive protein (CRP)); parasite infection status (hookworm, Trichuris and Ascaris infection); and IgE. ANOVA and logistic regression were used to assess the effects of iron fortification and de-worming on Hb, SF, TfR, body iron and anaemia. Hb improved in all groups after 6 months of intervention. Iron fortification significantly improved Hb, SF and body iron (2.6 g/l, 16.3 microg/l and 1 mg/kg, respectively). Prevalence of elevated IgE was very high at baseline (99%) and significantly reduced to about 75% in all groups after intervention. De-worming unexpectedly showed no effect on Hb, iron status and IgE level. It is concluded that iron fortification slightly improved anaemia and iron status in anaemic schoolchildren in rural Vietnam that were not considered iron deficient. Chronic infection or other unidentified factors may play an important role in the seasonal reduction of anaemia seen in all treatment groups.

["The demon that turned into worms": the translation of public health in the British Caribbean, 1914-1920]. / "O demônio que se transformou em vermes": a tradução da saúde pública no Caribe Britânico, 1914-1920.

The earliest programs of the Rockefeller Foundation's International Health Commission - IHC were pilot projects for the treatment of hookworm disease in the British colonies of British Guiana and Trinidad. These pioneering ventures into international health have often been portrayed as governed by rigid biomedical principles. In contrast to this view, the article emphasizes the degree to which the exigencies of a public health project that sought to make biomedicine intelligible within the medical systems of subject populations combined with the knowledge of local IHC staff members of Indo-Caribbean descent to generate some fascinating experiments in ethno-medical translation. One term in particular "The Demon that Turned into Worms" is focused on to show how these efforts at medical translation may have legitimized and promoted medical pluralism.

A double-blind randomized controlled trial of antenatal mebendazole to reduce low birthweight in a hookworm-endemic area of Peru.

OBJECTIVE: To assess the effect on birthweight of antenatal mebendazole plus iron vs. placebo plus iron in a highly hookworm-endemic area. METHODS: Double-blind, randomized controlled trial set in rural and peri-urban communities in the Peruvian Amazon region. A total of 1042 second trimester pregnant women between the ages of 18 and 44 years were recruited from April to November 2003, and followed to July 2004. Women were randomly assigned to receive either mebendazole (500 mg single dose) plus iron supplements (60 mg elemental iron daily) or placebo plus iron supplements. The primary outcome was mean infant birthweight and secondary measures included proportion of low birthweight babies and maternal anaemia. RESULTS: The prevalence of hookworm infection was 47.5%. There were no differences between intervention groups in mean birthweight (3104 g vs. 3090 g, P = 0.629), proportion of low birthweight (<2500 g; 8.1%vs. 8.7%, P = 0.755) or maternal anaemia in the third trimester [33.0% (158/479) vs. 32.3% (152/471), P = 0.815]. However, the proportion of very low birthweight (<1500 g) was significantly lower in the mebendazole group [0% (0/479) vs. 1.5% (7/471), P = 0.007]. CONCLUSIONS: This trial provides additional evidence for the use of anthelmintics, over and above iron supplementation, within antenatal care programmes in hookworm-endemic areas. Benefits of de-worming may be higher in countries not having an antenatal iron supplementation programme or where intensity of hookworm infections is higher.

Instruction in behavior modification can significantly alter soil-transmitted helminth (STH) re-infection following therapeutic de-worming.

Five elementary ("prototypic") schools located in five districts in central Java were selected and the children examined for helminth infections (Ascaris, Trichuris, hookworm). They were de-wormed with a course of mebendazole and provided with 6-7 months of "behavioral remediation instruction" (BRI). In other ("control") schools, children were treated with mebendazole but were not provided BRI. The objective was to determine the effectiveness of BRI in minimizing infection/re-infection following deworming. After the 6-7 month course of BRI in the prototypic schools, all the children (in both the prototypic and control schools) were re-examined for geohelminth infection. The schools in two of the five districts were omitted from further analysis because the overall prevalence of infection was low (<10%) and the infections were dominated by hookworm which are only moderately susceptible to mebendazole. Comparisons of prototypic and control schools in the other three districts provided compelling evidence that BRI was quite effective in reducing both the frequency and intensity of infection with Ascaris and Trichuris. We suggest that instructing children and adults corrects personal habits which are conducive to infection and can be an effective and safe substitute for repeated deworming, reducing the opportunity for the emergence of drug-resistant helminthes, which should prolong the time benzimidazoles may be used for treatment of geohelminth infection.

Common intestinal parasites.

Intestinal parasites cause significant morbidity and mortality. Diseases caused by Enterobius vermicularis, Giardia lamblia, Ancylostoma duodenale, Necator americanus, and Entamoeba histolytica occur in the United States. E. vermicularis, or pinworm, causes irritation and sleep disturbances. Diagnosis can be made using the "cellophane tape test." Treatment includes mebendazole and household sanitation. Giardia causes nausea, vomiting, malabsorption, diarrhea, and weight loss. Stool ova and parasite studies are diagnostic. Treatment includes metronidazole. Sewage treatment, proper handwashing, and consumption of bottled water can be preventive. A. duodenale and N. americanus are hookworms that cause blood loss, anemia, pica, and wasting. Finding eggs in the feces is diagnostic. Treatments include albendazole, mebendazole, pyrantel pamoate, iron supplementation, and blood transfusion. Preventive measures include wearing shoes and treating sewage. E. histolytica can cause intestinal ulcerations, bloody diarrhea, weight loss, fever, gastrointestinal obstruction, and peritonitis. Amebas can cause abscesses in the liver that may rupture into the pleural space, peritoneum, or pericardium. Stool and serologic assays, biopsy, barium studies, and liver imaging have diagnostic merit. Therapy includes luminal and tissue amebicides to attack both life-cycle stages. Metronidazole, chloroquine, and aspiration are treatments for liver abscess. Careful sanitation and use of peeled foods and bottled water are preventive.

Conforming strategies of public health campaigns to disease specificity and national contexts: Rockefeller Foundation's early campaigns against hookworm and malaria in Brazil.

The early experience of Rockefeller Foundation in Brazil, starting in 1915, reflected the idea of extending learned experience in Southern US to a wide international context. Health education and the creation of permanent local health services were expressed as main guidelines for cooperation with State and federal Brazilian agencies. Translating to the shaping of public health models the terms of scientific hygiene associated with the pastorian revolution, RF pictured different actions as part of a three step rationale of survey, experiment and demonstrations. In this paper we focus on Lewis Hackett's campaign, designed as a demonstration campaign of the "intensive method" of hookworm control, with the final purpose of enlisting local agencies in long-term action (1919-1924) and the malaria campaign in Rio de Janeiro State Lowlands (1922-1928) led initially by Mark Boyd as an "experimental control work" of field observation, campaign, control and maintenance to set guidelines to malaria control in tropical areas. The course and ultimate results of these experiences showed the need to adapt formal models to complex national and State-building context and to disease specificity, leading to pragmatic adaptations in the issue of control and eradication and on the shaping of vertical and horizontal health services. The failure of these two experiences in terms of disease control helped to strengthen the move, predominant in the next two decades, to vertical campaigns with least dependency on local social and political dynamics, as in the exemplar case of Frederick Soper's Anopheles gambiae eradication campaign (1938-1942).

Effective community intervention to improve hemoglobin status in preschoolers receiving once-weekly iron supplementation.

The effect of weekly iron supplementation with and without deworming on hemoglobin was investigated in a double-masked, placebo-controlled field trial. Subjects were 289 preschoolers who were randomly divided into three groups. Groups 1 and 2 received 30 mg Fe once weekly and group 3 received a placebo. Group 1 additionally received anthelminthic treatment. Supplements were administered by the mothers, who were educated about iron deficiency beforehand. In the iron-supplemented groups prevalence of anemia decreased from 37.2% to 16.2% (P < 0.001). Hemoglobin increased by an average of 6.9 +/- 9.8 g/L in the two iron-supplemented groups (n = 191), which was greater (P < 0.001) than the increase of 1.9 +/- 8.0 g/L in the placebo group. None of the subjects had hookworm, and anthelminthic treatment did not have an additional effect. Iron supplements administered once weekly by mothers reduced anemia without major involvement of health staff.

PIP: The authors investigated the effect of weekly iron supplementation with and without deworming upon hemoglobin in a double-blind, placebo-controlled field trial conducted in the West Javanese village of Setia Asih. 289 children aged 2-5 years were randomly divided into three equal-sized treatment groups for the study. Groups one and two received 30 mg iron once weekly, while group three received a placebo. Group one also received anthelminthic treatment. Supplements were administered by the mothers who were taught about iron deficiency beforehand. In the iron-supplemented groups, the prevalence of anemia decreased from 37.2% to 16.2% and hemoglobin increased by an average of 6.9 +or- 9.8 g/l. However, hemoglobin increased only 1.9 +or- 8.0 g/l in the placebo group. No subjects had hookworms, so anthelminthic treatment had no additional effect.

[Deficiency anemias in tropical countries]. / Mangelanämien in tropischen Ländern.

Nutritional anaemias are common in tropical areas. The commonest cause is iron deficiency, which mainly arises from impaired absorption of iron from food. Substances which inhibit iron absorption in various diets play an important role in the pathogenesis of iron deficiency anaemia. Iron deficiency is further aggravated by blood loss in hook-worm infestation. Folic acid and vitamin B 12 deficiency are less important causes of nutritional anaemia. The efforts of the World Health Organization to supplement iron in food are described.

Sociocultural factors in the control and prevention of parasitic diseases.

Control and prevention of parasitic disease depends on an adequate knowledge of interactions among factors such as human behavior, the environment, and the life cycles of parasites. Sociocultural factors in large part determine transmission and persistence of parasites. The main determinants are poverty, low educational level, deficiencies in home technologies, high demographic density, and ruralism. Selected interventions designed to improve any of these situations may fail if they are applied in an isolated manner. The holistic implementation of interventions has proved successful in the control and prevention of parasitic infections in several parts of the word. The implementation of several kinds of interventions simultaneously, that is, a holistic approach, combined with an awareness of a society's infrastructure, can produce favorable results. For such an awareness--when it provokes action--can improve the overall quality of life.