Bayesian Methods for Exposure Misclassification Adjustment in a Mediation Analysis: Hemoglobin and Malnutrition in the Association Between Ascaris and IQ.

BACKGROUND: Soil-transmitted helminth infections have been found to be associated with child development. The objective was to investigate hemoglobin levels and malnutrition as mediators of the association between Ascaris infection and intelligence quotient (IQ) scores in children. METHODS: We conducted a longitudinal cohort study in Iquitos, Peru, between September 2011 and July 2016. A total of 1760 children were recruited at 1 year of age and followed up annually to 5 years. We measured Ascaris infection and malnutrition at each study visit, and hemoglobin levels were measured as of age 3. The exposure was defined as the number of detected Ascaris infections between age 1 and 5. We measured IQ scores at age 5 and used Bayesian models to correct exposure misclassification. RESULTS: We included a sample of 781 children in the analysis. In results adjusted for Ascaris misclassification, mean hemoglobin levels mediated the association between Ascaris infection and IQ scores. The natural direct effects (not mediated by hemoglobin) (95% CrI) and natural indirect effects (mediated by hemoglobin) (95% CrI) were compared with no or one infection: -0.9 (-4.6, 2.8) and -4.3 (-6.9, -1.6) for the effect of two infections; -1.4 (-3.8, 1.0) and -1.2 (-2.0, -0.4) for three infections; and -0.4 (-3.2, 2.4) and -2.7 (-4.3, -1.0) for four or five infections. CONCLUSION: Our results are consistent with the hypothesis that hemoglobin levels mediate the association between Ascaris infection and IQ scores. Additional research investigating the effect of including iron supplements in STH control programs is warranted.

Prevalence and intensity of Ascaris lumbricoides infections in relation to undernutrition among children in a tea plantation community, Sri Lanka: a cross-sectional study.

BACKGROUND: Ascaris lumbricoides infections are one of the commonnest intestinal nematode infections in the world, with a profound negative effect on nutritional status among underprivileged populations. In Sri Lanka, Ascaris infections and low nutritional status still persist in the plantation sector. However, research regarding the association between Ascaris infections and nutritional status is scarce. The main purpose of this study was to determine the association between Ascaris infections and physical growth among children in a plantation sector in Sri Lanka. METHODS: A cross sectional study was conducted among 489 children aged between 1 and 12 years ina plantation sector, Sri Lanka, from January to April 2013. Anthropometric measurements were collected to assess height-for-age (HAZ), weight-for-age (WAZ) and weight-for-height (WHZ) to determine stunting, underweight and wasting respectively. Data on socio-demographic and antihelminthic treatment were ascertained using an interviewer administrated structured questionnaire. Stool samples were subjected to wet mount preparation followed byformaldehyde-ether sedimentation technique to diagnose Ascaris infection and a Kato Katz technique was performed to determine the eggs intensity. AnthroPlus, EpiInfo and SPSS software was used to analyze data. RESULTS: Of the study sample, 38.4% showed Ascaris lumbricoides infections. Light intensity infections (51%) were common in the infected children, followed by moderate (30%) and heavy (19%) infections. Prevalence of Ascaris infections was significantly associated with de-worming more than six months prior to the study. Prevalence of undernutrition among children was 61.7%. Forty-five per cent were underweight, while 24.1% and 21.5% of children were stunted and wasted respectively. However, no significant association was found between Ascaris infections status and undernutrition. Meanwhile, heavy intensity infections were associated with decreased values of WHZ (p = 0.020). CONCLUSIONS: Ascaris infections and undernutrition are still highly prevalent and a major public health problem in the plantation sector in Sri Lanka. Health and nutrition intervention programs should be implemented to increase the nutritional status of children.

Chronic intussusception in children caused by Ascaris lumbricoides.

Chronic intussusception (CI) is defined as an intussusception lasting for 14 days or more. Because the clinical manifestations are non-specific, the diagnosis is usually delayed. Symptoms include intermittent abdominal pain, sometimes an abdominal mass is palpable and there is a marked weight loss. Diagnosis is based on typical features revealed by ultrasound or barium enema and CT investigations. Therapy is surgical with obligatory exclusion of possible underlying lesions. We report a case of a 3.5-year-old girl with chronic intussusception. Laboratory blood findings revealed sideropenic anemia and stools positive for Ascaris lumbricoides. Anti-parasitic therapy with mebendazole was repeatedly administered with early improvements but soon after symptoms relapsed. During surgery an ileocolic chronic intussusception extending to hepatic flexure was found. Postoperative control examinations proved complete healing. We suspected that Ascaris lumbricoides infestation was an etiologic factor for the development of chronic intussusception in the child.

Trichuris and hookworm infections associated with anaemia during pregnancy.

OBJECTIVE: To assess the following associations between the second and third trimesters of pregnancy: (i) the intensity of soil-transmitted helminth (STH) infection and haemoglobin/anaemia, (ii) the effect of mebendazole treatment on the occurrence of STH infection, and (iii) the effect of mebendazole treatment on haemoglobin/anaemia. METHODS: Data originated from a trial of 1042 pregnant women recruited in their second trimester and followed to delivery. Baseline assessments included socio-demographic/health information from questionnaires, haemoglobin/anaemia from HemoCue ascertainment of fingerprick blood, and the presence and intensity of STH (Ascaris lumbricoides, hookworms and Trichuris trichiura) infections from Kato-Katz examination. All women were given iron supplements; half were randomly allocated to receive single dose 500 mg mebendazole, and half, placebo. Haemoglobin/anaemia and STH infection status were determined again in the third trimester of pregnancy. RESULTS: Complete information was available from 935 (89.7%) women. Mebendazole significantly reduced the prevalence and intensity of all three STH infections. Higher intensities of hookworm and Trichuris infections in the second trimester were associated with a higher risk of anaemia in the third trimester. Overall, women with moderate/heavy Trichuris infection were found to be at a higher risk of anaemia; the highest risk was observed among those with moderate/heavy hookworm co-infection (adjusted OR = 2.77; 95% CI: 1.26, 6.11). Mebendazole treatment did not reduce the risk of anaemia. CONCLUSION: Higher intensities of both Trichuris and hookworm infections are associated with anaemia in pregnancy. The importance of Trichuris infections during pregnancy requires renewed attention.

Interaction of zinc or vitamin A supplementation and specific parasite infections on Mexican infants' growth: a randomized clinical trial.

BACKGROUND: The efficacy of micronutrient supplementation on growth may be modified by specific gastrointestinal parasite infections. METHODS: We carried out a double-blind placebo-controlled trial to evaluate the effect of vitamin A and zinc supplementation on gastro-intestinal pathogen infections and growth among 584 infants in Mexico City. Children aged 5-15 months were assigned to receive either a vitamin A supplement every 2 months (20,000 IU of retinol for infants < or =; 1 year or 45,000 IU for infants >1 year), a daily supplement of 20 mg of zinc, a combined vitamin A-zinc supplement or a placebo, and were followed up for 1 year. Weight and length were measured once a month and morbidity histories were recorded twice a week for 12 months. Monthly stool samples were screened for Giardia duodenalis, Ascaris lumbricoides and Entamoeba spp. Growth velocity slopes, generated from the linear regression of individual child length, and height-for-age z-scores on time were analyzed as end points in regression models, adjusting for the presence of parasite infections. RESULTS: The main effect of vitamin A supplementation was in height improvement (P<0.05), and was only found in the model evaluating infants with any parasite. There was an interaction effect of slower growth (P<0.05) found in infants infected with any parasite and supplemented with vitamin A in slower growth (P<0.05). In addition, the interaction of zinc supplementation and Giardia duodenalis or A. lumbricoides was associated with reduced growth (P<0.05). CONCLUSION: Gastro-intestinal parasite infections may modify the effect that zinc or vitamin A supplementation has on childhood growth.

[Case report: an intestinal obstruction due to ascariasis]. / Olgu Sunumu: Ascariasise Bagli Intestinal Obstrüksiyon.

Ascaris lumbricoides (A. lumbricoides) with which one billion people around the world is infected is also widely seen in Turkey. This case report presents an ascariasis infection which displayed typical radiological findings in Kocaeli, a non-endemic region of Turkey. The patient was admitted to hospital with symptoms of heavy abdominal pain, nausea-vomiting and weakness. The symptoms had started weakly three weeks earlier and the patient had applied to a private health care center. After a through examination with several appropriate tests including a barium small-bowel enema, a morphological finding similar to helminth was observed filling the lumen of the jejunum. When rectal swabs were examined A. lumbricoides oocytes were discovered. The patient was treated for two days with nasogastric drainage, piperazine (3.5 gr/day) in addition to a supportive therapy. The patient was surgically diagnosed to have a jejunal obstruction due to ascariasis.

Failure of twice-weekly iron supplementation to increase blood haemoglobin and serum ferritin concentrations: results of a randomized controlled trial.

In order to increase the intestinal absorption of iron whilst simultaneously minimising the side-effects and thus increasing compliance, once- or twice-weekly, instead of daily, iron supplementation has been widely recommended. In a randomized, placebo-controlled, double-blind study in western Kenya, a tablet of ferrous dextran (containing 60 mg elemental iron) or an identical-looking placebo tablet was provided twice-weekly for 12 months to each child or adult investigated. At baseline each subject had a moderately low blood concentration of haemoglobin (Hb). Initial Hb and serum ferritin (SF) concentrations were determined and each subject was tested for malarial and helminth infection and treated, if necessary, with the appropriate anthelminthic drug(s). Overall, 200 children (aged 4-15 years) and 129 adults (aged 16-63 years) completed the 12-month study. At baseline, 47.5% of the children and 58.1% of the adults were anaemic, hookworm (detected in 60.0% of the children and 69.9% of the adults) was the most common helminth infection, and malaria was endemic. The results of bivariate analyses indicated that twice-weekly iron supplementation had no significant effect on blood Hb or SF concentrations, either in the children or the adults investigated. The results were confirmed in multiple linear-regression analyses, which revealed that the predictors of the final Hb concentration in the children investigated were age and infection, after enrollment, with Ascaris lumbricoides. Gender and the serum concentration of alpha-1-antichymotrypsin (ACT) at final follow-up were predictors of the final SF concentration in the children. In adults, the predictors of the final Hb concentration were gender and HIV infection, and the predictors of the final SF concentration were age and the serum concentration of ACT at the final follow-up. Twice-weekly iron supplementation did not increase Hb or iron stores in children or adults. Since compliance appeared to be high, this lack of effect may be the result of an inadequate dose of iron or of subjects who have deficiencies in micronutrients other than iron.

Non-operative management of intestinal obstruction due to ascaris lumbricoides.

OBJECTIVE: To compare, evaluate and analyze three different non-operative modalities of treatment of intestinal obstruction due to ascaris lumbricoides. DESIGN: A non-randomized, cohort and comparative study. PLACE AND DURATION OF STUDY: Department of Pediatric Surgery, National Institute of Child Health, Karachi from March 2001 to October 2002. PATIENTS AND METHODS: A total of 45 patients with the diagnosis of intestinal obstruction due to ascaris lumbricoides were included in the study. They were divided in 3 groups of 15 patients each. Group I patients were given I/V fluids only, group II patients were given hyoscinbutylbromide in infusion and group III patients were given hypertonic saline enema. The outcome of all groups was compared in terms of improvement in obstruction and hospital stay. The data was analyzed by SPSS 11.0 by using ANOVA and HSD Tuckey test for multiple comparisons. RESULTS: The non-operative treatment was successful in all of the patients. In group III improvement of intestinal obstruction occurred in 1.6 +/- 1.11 days (p value=0.001), whereas it was 2.6 +/-1.11 days in group II and 3.4 +/-1.35 days in group I. The mean hospital stay in group III was 4 +/-1.69 days (p value=0.003), whereas it was 6.27 +/- 2.31 days in group II and 5.87 +/-1.25 days in group I. CONCLUSION: We recommend that hypertonic saline enema is a better non-operative treatment modality of intestinal obstruction, due to ascaris lumbricoides, in patients who do not have peritonitis. It is associated with early improvement of obstruction coupled with reduced hospital stay.

Effects on haemoglobin of multi-micronutrient supplementation and multi-helminth chemotherapy: a randomized, controlled trial in Kenyan school children.

OBJECTIVE: To assess the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on haemoglobin concentration (Hb), using schools as a health delivery system. STUDY AREA AND POPULATION: Nine hundred seventy-seven children between 9 and 18 y of age from 19 primary schools in Bondo District, western Kenya, were included in the trial. The 746 (76.4%) children on whom baseline Hb was available were included in this study. DESIGN: The study was a randomized, placebo-controlled, double-blind, two-by-two factorial trial of the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on Hb after 8 months. INTERVENTION: Single treatment of infected children with albendazole (600 mg) for geohelminths and praziquantel (40 mg/kg) for Schistosoma mansoni and daily supplementation with 13 micronutrients. RESULTS: : Multi-micronutrient supplementation (3.5 g/l, 95% CI 1.7, 5.3; P=0.0002) and anthelminthic treatment (2.0 g/l, 95% CI 0.2, 3.9; P=0.03) increased Hb independently (interaction, P=0.33). The effects were also independent of baseline Hb and general nutritional status. The treatment effect was due to reductions in S. mansoni and hookworm intensities of infection, in that Hb increased by 0.4 and 0.2 g/l, respectively, per 100 epg reductions in egg output. Interestingly, among S. mansoni-infected children, the effect of treatment seemed stronger in those with compared to those without co-existing malaria parasitaemia (interaction, P=0.09). CONCLUSION: Multi-micronutrient supplementation and multi-helminth chemotherapy increased Hb among school children, irrespective of initial Hb and nutritional status.

Intestinal helminth infections, anaemia and labour productivity of female tea pluckers in Bangladesh.

We conducted a randomized clinical intervention trial over 24 weeks on a tea estate in north-east Bangladesh to investigate the effect of iron supplementation and anthelmintic treatment on the labour productivity of adult female tea pluckers. A total of 553 full-time tea pluckers, not pregnant and not breastfeeding, were randomly assigned to one of the four intervention groups: group 1 received iron supplementation on a weekly basis, group 2 received anthelmintic treatment at the beginning and half-way through the trial (week 12), group 3 received both iron supplementation as group 1 and anthelmintic treatment as group 2, and group 4 was a control group and received placebos. No significant difference in labour productivity was found between the four intervention groups over the trial period. However, there was a negative association for all three worms (Ascaris lumbricoides, Trichuris trichiura and hookworms) between the intensity of helminth infections (eggs/g faeces) and all measures of labour productivity. Lower haemoglobin values and anaemia (< 120 g/l Hb) were both associated with lower labour productivity and more days sick and absent. Taller women with greater arm circumference were able to pluck more green leaves, earn higher wages and were absent less often.

The effect of anthelmintic treatment on helminth infection and anaemia.

A 24-week randomized double blind intervention trial was conducted on adult female tea pluckers from an estate in Bangladesh to investigate the impact of iron supplementation and anthelmintic treatment on changes in ferritin and haemoglobin levels as well as on prevalence and intensity of helminth infections. A total of 553 women were randomly assigned to 1 of 4 intervention groups: group 1 received iron supplementation on a weekly basis, group 2 received anthelmintic treatment at the beginning and half way through the trial, group 3 received both iron supplementation as group 1 and anthelmintic treatment as group 2, and group 4 was a control group and received placebos for both iron supplementation and anthelmintic treatment. Prevalence and intensity of helminth infections (egg counts/g stool) of Ascaris lumbricoides, Trichuris trichiura and hookworms significantly fell in the 2 groups receiving anthelmintic treatment and there were some reductions in the 2 groups not receiving anthelminthic treatment. Haemoglobin and haematocrit concentrations increased significantly in the iron supplemented groups with smaller increases in the anthelmintic only group. All women showed a decrease in serum ferritin levels post-trial with greater losses in the 2 dewormed groups. Significant negative associations were found between hookworm egg counts and ferritin levels and Trichuris trichiura egg counts and haemoglobin concentration.

Hypertonic saline enema in gastrointestinal ascariasis.

Many dangerous surgical complications like intestinal obstruction, acute appendicitis with perforation, ileal perforation in a typhoid patient, Meckel's diverticulitis, disruption of post operative intestinal anastomosis, volvulus, and intussusception are known to occur due to ascariasis, with considerable morbidity and mortality. In this retrospective study of 250 cases of gastrointestinal ascariasis admitted in paediatric surgical wards of Govt. Medical College, Jabalpur (MP), the authors analysed the results of conservative (especially the use of hypertonic saline enema-given just like an ordinary soap water enema but substituting freshly made hypertonic saline in place of soap water) and surgical treatment. The success rate of conservative treatment was 95.6%. Hypertonic saline passes through the incompetent ileo-caecal valve (present in 80% of children) and irritates the worm bolus commonly situated in the terminal ileum, causing it to disintegrate. It also helps to increase the intestinal motility and passage of worms into the colon. The use of hypertonic saline enema is safe and effective in the conservative treatment of gastrointestinal ascariasis. Authors feel that it is the most grossly under utilized part of conservative treatment and deserves to be known and used on wider scale.

Vitamin A supplementation but not deworming improves growth of malnourished preschool children in eastern Zaire.

A randomized controlled trial was conducted in eastern Zaire to assess the effects of high dose vitamin A supplementation and regular deparasitation on the growth of 358 moderately malnourished preschool children, discharged from the hospital. The treatment groups received either vitamin A (60 mg of oily solution of retinyl palmitate, 30 mg if aged <12 mo) every 6 mo or mebendazole (500 mg) every 3 mo; the control group received no supplementation. Anthropometric data were gathered at baseline and after 6 and 12 mo of follow-up. Serum retinol concentrations were measured at baseline and after 3 mo. The three groups did not differ in sociodemographic indicators, age and sex composition, nutritional status and serum retinol concentrations at baseline. In children who were vitamin A deficient at baseline, adjusted mean weight and mid-upper arm circumference (MUAC) increments were higher in the vitamin A-supplemented group than in the control group [annual increment in weight and MUAC in vitamin A vs. control group: 2.088 vs. 1.179 kg (P = 0.029) and 2.24 vs. 0.95 cm (P = 0.012), respectively], whereas growth increment did not differ between the dewormed group and the control group. In children who were not vitamin A deficient at baseline, growth increment did not differ between the vitamin A-supplemented and control groups, whereas weight gain was lower in the dewormed group than in the control group. Vitamin A-supplemented boys gained more weight and height than control boys, whereas vitamin A-supplemented girls gained less height than control girls. Dewormed boys and girls gained less weight than control boys and girls. Programs to improve vitamin A status by high dose vitamin A supplementation may improve growth of preschool children who are vitamin A deficient, whereas deworming does not.

Vitamin A status of Indonesian children infected with Ascaris lumbricoides after dosing with vitamin A supplements and albendazole.

In developing countries, both marginal vitamin A status and intestinal helminths are common among children. Indonesian children (n = 309, 0.6-6.6 y), known to be infected with Ascaris lumbricoides, were randomized into six different treatment groups (A-F). The treatments included 210 mumol vitamin A supplement and a dose of 400 mg albendazole (5-propylthio-1H-benzimidazol-2-yl carbamic acid methyl ester) administered orally either at the same health visit (Groups B and F) or at different contact times during a 1-mo period (groups A, C, D and E). Vitamin A status was assessed both before and 3-4 wk after the treatments by the modified relative dose response (MRDR) test. Vitamin A supplementation was most important in improving the vitamin A status (P < 0.0001) of these children, whereas treatment for ascariasis alone (P = 0.370) and the statistical interaction between treatment for ascariasis and vitamin A (P = 0.752) were not. Serum retinol concentrations marginally improved (P = 0.051) in two of the groups that received vitamin A and albendazole but not in the third group that received vitamin A only. The MRDR test proved a better discriminator of the effects of these treatments on vitamin A status than changes in serum retinol concentrations.

Roundworm obstruction: sonographic diagnosis.

We describe the sonographic findings in five pediatric patients with roundworm obstruction. All patients were referred with a clinical diagnosis of acute appendicitis. On ultrasonography (US), an individual worm, when viewed along its longitudinal axis, appeared as a hypoechoic tubular structure with well-defined, echogenic walls. Frequently, the individual body segments could be distinctly visualized. The alimentary canal of the worm was seen either as a single central echogenic line (when in a collapsed state) or as two parallel hyperechoic bands with a hypoechoic center (when distended). When examined transaxially, the individual worm resembled a target with its circular, echogenic body wall and its central dot-like alimentary canal. On prolonged scanning, the worms always showed curling movements. In two patients, a bolus of worms mixed with fecal matter and air produced an unusual appearance of a complex, echogenic mass (helminthoma). Although, an individual worm occasionally resembled an inflamed appendix, visualization of the alimentary canal and individual body segments along with its curling movements helped establish the correct diagnosis. All patients promptly responded to a hypertonic saline enema and no patient was subjected to surgery. Sonographic findings in roundworm obstruction are fairly characteristics to advocate the routine use of sonography for diagnosing this entity.

Ascariasis masiva en un niño / Infant massive ascariasis

Se presenta el caso clínico de un niño de un año ocho meses de edad con ascariasis masiva que presentó como complicación una obstrucción intestinal, que no fue necesaria operar. Fue tratado con maniobras que permitieron la eliminación de 156 Ascaris lumbricoides de 20 a 25 centímetros de largo. Efectuada visita domiciliaria y analizadas muestras de tierra de la suela de los zapatos, antejardín de la casa y de la plazuela cercana a la vivienda se encontraron quistes de Entamoeba histolytica huevos de Trichuris trichiura, Toxocara sp. y larvas de gusanos que no se pudieron identificar

Use of human colostrum in the management of chronic infantile diarrhoea due to enteropathogenic E. coli infection with associated intestinal parasite infestations and undernutrition.

This study reports the management of infants with chronic diarrhoea by colostrum feeding. Eight children with chronic diarrhoea, ranging from 9 months to 3 years of age and all from low socio-economic families, formed the basis of this study. They were undernourished and marasmic. Stool examination showed enteropathogenic E. coli in all eight cases, Ascaris lambricoidis in four, and Giardia lamblia in one. Patients with chronic diarrhoea, in whom no cause was found were excluded from this study. All eight patients were administered 20 ml fresh human colostrum daily for 7 days. In addition, those patients, who had giardiasis, received metronidazole treatment, while cases with ascariasis were given antihelminthic therapy irrespective of the groups they belonged to. Our results indicated effective antidiarrhoea action of colostrum in some patients with chronic diarrhoea of infective origin.

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.

The biological suppression of malaria: an ecological and nutritional interrelationship of a host and two parasites.

The interrelationship of malaria and severe ascariasis was studied in Anjouan children with a previously described syndrome of enlarged parotids, localized forehead edema, heavy infestation with Ascaris lumbricoides, and unusual freedom from malaria. After treatment of 37 such children with the ascaricide piperazine, 35 had resolution of parotid enlargement and forehead edema, but 19 developed attacks of malaria. Children treated with placebo had neither resolution of clinical findings nor attacks of malaria. We propose that suppression of the malaria in these children is a nutritional consequence of severe ascariasis and may represent an ecological balance for optimum co-survival of the host and the two parasites.