Soil-Transmitted Helminthiasis and Vitamin A Deficiency: Two Problems, One Policy

Effectiveness of intermittent iron and high-dose vitamin A supplementation on cognitive development of school children in southern Ethiopia: a randomized placebo-controlled trial

BACKGROUND

Iron is an essential mineral whose deficiency results in cognitive alteration, impaired emotional behaviors, and altered myelination and neurotransmission. In animal models, it has been shown that vitamin A (VA) could affect cognition.

OBJECTIVES

The study aimed to evaluate the effectiveness of intermittent iron and VA supplementation on cognitive development of schoolchildren, and to assess the interaction between these supplementations.

METHODS

Considering a 2 × 2 factorial design, 504 children were randomly assigned to 1 of the 4 arms: placebo VA and placebo iron supplement; high-dose vitamin VA and placebo iron supplement; iron supplement and placebo VA; and iron and high-dose vitamin VA supplements. Cognitive development was assessed using Raven's Coloured Progressive Matrices, digit span, Tower of London, and visual search tasks.

RESULTS

The mean [± standard deviation (SD)] age of the enrolled children was 9.6 (±1.6) y. One-fifth of the children had iron deficiency or anemia, whereas 2.9%, 3.9%, and 12.1% of children had low iron stores, iron deficiency anemia, and VA deficiency, respectively. Intermittent iron supplementation did not result in any significant improvement of children's cognitive development and had a negative effect on the performance index of the visual search task compared with placebo (-0.17 SD, 95% confidence interval: -0.32, -0.02). Effects were evident among children with stunting, thinness, or children coming from understimulating home environments. High-dose VA supplementation resulted in a significant improvement of digit span z-score with a mean difference of 0.30 SD (95% confidence interval: 0.14, 0.46) compared with placebo VA. VA had a more beneficial impact for girls, children infected with helminths, and those from food secure households.

CONCLUSION

In a population where the prevalence of iron deficiency is low, intermittent iron supplementation did not have any or negative effect on the child's cognitive development outcomes. Conversely, VA supplementation improved the child's working memory.

TRIAL REGISTRATION NUMBER

The study is registered at clinicaltrials.gov as NCT04137354 (https://clinicaltrials.gov/study/NCT04137354).

Red palm olein-enriched biscuit supplementation lowers Ascaris lumbricoides reinfection at 6-month after anthelmintic treatment among schoolchildren with vitamin A deficiency (VAD)

Notwithstanding the global efforts made to control intestinal parasitic infections, soil-transmitted helminth (STH) infections are still one of the most prevalent infections globally, especially in developing countries. A double-blinded, randomized controlled trial was conducted on 343 primary schoolchildren (8-12 years old) with vitamin A deficiency (VAD) in rural areas of Malaysia to investigate the effects of red palm olein (RPO)-enriched biscuits on STH reinfection rates and infection intensities. The effects of the RPO-enriched biscuits (experimental group, n = 153) and palm olein (PO)-enriched biscuits (control group, n = 190), were assessed at 3- and 6-month after the administration of complete triple-dose albendazole (one dose of 400 mg for three consecutive days). The overall STH infection rate at baseline was recorded at 65.6%. At 6-month, a significantly lower reinfection rate of A. lumbricoides was observed in the experimental group (35.3%) compared to the control group (60.0%) (P< 0.05), and a significant reduction in fecal egg count (epg) of A. lumbricoides was observed in the experimental group from baseline (P< 0.001), but no significant reduction was observed in the control group. No significant differences in the reduction of infection intensities of T. trichiura and hookworm were observed between experimental and control groups at 3- and 6-month (P>0.05). These findings suggest the potential beneficial effects of RPO-enriched biscuit supplementation on the reinfection of A. lumbricoides, which could be attributed to its high carotenoids content by enhancing host immune response and mucosal epithelium integrity. However, further studies are warranted to confirm whether RPO supplementation could result in similar parasite-specific beneficial effects in other community settings, as well as to explore the underlying mechanisms.

Micronutrients deficiencies and its correlation with the soil-transmitted helminthic infections among children and non-pregnant women in Nepal: findings from Nepal national micronutrient status survey

Despite having a high risk of soil-transmitted helminths (STHs) infection, no national level study has been conducted to assess incidence and correlates of STHs in Nepal. Thus, we hypothesized that micronutrients and social status are linked with incidence of STHs infection among 6-59 months children and 15-49 years non-pregnant women in Nepal and Kato-Katz technique was adopted to measure the type and intensity of STHs infections using fresh stool specimens and venous blood was used to examine micronutrients biomarkers. Anthropometric measurements such as height and weight, sociodemographic and health status were determined using structured questionnaire. Logistic regression was used to assess unadjusted and adjusted odds ratio (AOR) and the 95% CIs of ORs. The bivariate association of STHs was assessed with the covariates variables. Overall, 12% children and 19% non-pregnant women had STHs infection; A. lumbricoides was the predominant helminth in both study participants. In multivariate model; age, ethnicity, anaemia and zinc deficiency were associated with STHs infections in children. Similarly, higher odds of STHs occurrence was observed among non-pregnant women with vitamin A deficiency. Findings from this study suggest that high-risk population, with a focus on those of lower socioeconomic status should be on priority of deworming program, nutrition intervention, and mass administration of preventive chemotherapy and sanitation champions supplement to reduce the STHs infections in Nepal.

Prevalence and Associated Risk Factors of Endoparasites among Under-Five Children in Debre Tabor Comprehensive Specialized Hospital, Debre Tabor, Northwest Ethiopia: A Cross-Sectional Study

Many endoparasites are still considered neglected tropical illnesses. The term “endoparasites” refers to infections caused by both helminths and protozoa. In many places in Ethiopia, particularly Debre Tabor, epidemiological data on the prevalence and associated variables of endoparasites among under-five children is unavailable. Thus, the aim of this study was to gather baseline data on the prevalence of endoparasites and their associated variables among under-five children who visited the Debre Tabor comprehensive specialized hospital in Northwest Ethiopia. A hospital-based quantitative cross-sectional study was used. The study was carried out from May 1 to November 30, 2021. Study participants were selected by a systematic sampling technique. The stool specimen was examined for the presence of different stages of intestinal parasites (adult, trophozoite, larvae, cysts, and ova) using direct wet mount, modified formal-ether sedimentation, and modified Ziehl–Neelsen methods. The IBM SPSS statistical package (version 23) was used to enter and analyze the collected data. The data was summarized using frequency tables and a bar chart. The adjusted odds ratio and $p$ value <0.05 were used to declare the final association. In the present study, a total of 258 under-five children and their mothers/guardians were involved in the study, with a response rate of 100%. More than half of the respondents, 137 (53.10%), were females, and 159 (61.63%) were in the age group of 24 to 59 months. The overall prevalence of one or more endoparasites among under-five children was 45 (17.44%). Multivariate logistic regression analysis showed that health supervision, child food freshness, regular trimming of fingernails, and children’s playground cleanliness were significantly associated with childhood endoparasites. The present study demonstrated a higher prevalence of endoparasites among under-five children. Health supervision, child food freshness, regular trimming of fingernails, and children’s playground cleanliness were significantly associated with endoparasites. Thus, strengthening health education about food, personal, and environmental hygiene for both children and their mothers/guardians is crucial.

Global Burden of Vitamin A Deficiency in 204 Countries and Territories from 1990-2019

Vitamin A deficiency (VAD) is one of the important public health issues worldwide. However, a detailed understanding of the incidence and disability-adjusted life years (DALYs) due to VAD in recent years is lacking. We aimed to estimate the incidence and DALYs of VAD at global, regional, and national levels in terms of sex, age, and socio-demographic index (SDI). Using data from the 2019 Global Burden of Disease (GBD) study, the estimated annual percentage change (EAPC) was measured to assess trends in the age-standardized incidence and DALY rates from 1990 to 2019. The global age-standardized incidence and DALY rates of VAD decreased with an EAPC of −3.11% (95% confidence interval (CI): −3.24% to −2.94%) and −2.18% (95% CI: −2.38% to −1.93%), respectively. The age-standardized incidence and DALY rates decreased least in low-SDI regions, which had the highest age-standardized incidence and DALY rates of all SDI regions. Sub-Saharan Africa, especially central sub-Saharan Africa, had the highest age-standardized incidence and DALY rates in 2019. At the national level, Somalia and Niger had the highest age-standardized incidence and DALY rates. The age-standardized incidence and DALY rates were higher in males than in females. Younger children, especially those aged < 5 years in low-SDI regions, had a higher VAD burden than other age groups. Although the global burden of VAD has decreased, future work should aim to improve the prevention and treatment strategies for VAD, particularly in children aged < 5 years in countries and territories with low SDI values, such as sub-Saharan Africa.

Important Nematodes in Children

Intestinal nematode infections caused by soil-transmitted helminths (STH), such as the roundworm Ascaris lumbricoides, the whipworm Trichuris trichiura, and the hookworms Ancylostoma duodenale, and Necator americanus, infect more than 1 billion people throughout the world. School-aged children tend to harbor the greatest numbers of intestinal worms, and as a result, experience more adverse health consequences, such as poor growth, anemia, and cognitive decline. Clinicians should maintain a high degree of suspicion in endemic areas when patients present with surgical abdomens, particularly children. Current antihelminthic drugs are moderately effective, but reinfection is possible. Global efforts are needed to eradicate STH infections.

Supplemented nutrition decreases helminth burden and increases drug efficacy in a natural host-helminth system

Gastrointestinal (GI) helminths are common parasites of humans, wildlife, and livestock, causing chronic infections. In humans and wildlife, poor nutrition or limited resources can compromise an individual's immune response, predisposing them to higher helminth burdens. This relationship has been tested in laboratory models by investigating infection outcomes following reductions of specific nutrients. However, much less is known about how diet supplementation can impact susceptibility to infection, acquisition of immunity, and drug efficacy in natural host-helminth systems. We experimentally supplemented the diet of wood mice (Apodemus sylvaticus) with high-quality nutrition and measured resistance to the common GI nematode Heligmosomoides polygyrus. To test whether diet can enhance immunity to reinfection, we also administered anthelmintic treatment in both natural and captive populations. Supplemented wood mice were more resistant to H. polygyrus infection, cleared worms more efficiently after treatment, avoided a post-treatment infection rebound, produced stronger general and parasite-specific antibody responses, and maintained better body condition. In addition, when applied in conjunction with anthelmintic treatment, supplemented nutrition significantly reduced H. polygyrus transmission potential. These results show the rapid and extensive benefits of a well-balanced diet and have important implications for both disease control and wildlife health under changing environmental conditions.

Prevalence, risk factors, challenges, and the currently available diagnostic tools for the determination of helminths infections in human

Soil transmitted helminthes (STH) are among the major public health issues in tropical and sub-tropical countries infecting more than 2 billion humans worldwide. STH causes considerable morbidity in children, affecting their cognitive development and physical growth. Endemic areas with poor sanitation and limited access to good quality water supply have the highest burden of STH infection. Various approaches to reduce and control the worm infections include the intermittent deworming of children with anti-helminthic drugs. Individual patient management and population based studies can only be successful upon using the diagnostic techniques with high accuracy. The lack of reliable tools for the provision of correct diagnostic results about the status and intensity of infection is a major challenge, as these factors varies considerably in areas of low infection intensities. The techniques currently available for the diagnosis of parasitic infections show limited specificity and sensitivity and as such several techniques in combination are normally used in diagnosing the variety of parasite species infection. This review article was planned to study the prevalence, risk factors, and the available diagnostic techniques for soil and water transmitted helminthes infections in humans. This article also discussed the challenges in diagnosis, treatment, and management of worm infections particularly helminthes. The articles available online on important portals like google scholar, PubMed, Digital Libraries, PakMediNet, Science direct, and the Directory of Open Access Journals (DOAJ) were searched for inclusion of the data in this review study. Duplicate studies and irrelevant reports describing the general aspects of parasite infections were excluded. This review study provides a comprehensive report on the prevalence, accurate diagnostic, and chemotherapeutic protocols to reduce the burden of worms infections. WHO suggests the chemotherapy for worm infections as feasible and cost effective strategy in schools due to the lack of proper policy for the prevention of intestinal worms.

Soil-transmitted helminth infections and nutritional status of school children in government elementary schools in Jimma Town, Southwestern Ethiopia

Introduction

Soil-transmitted helminth infections and malnutrition are major health problems of school-age children in developing countries. Malnutrition and soil-transmitted helminth infections often co-exist with synergetic consequences.

Objective

The aim of this study was to determine the prevalence and intensity of soil-transmitted helminths and its association with nutritional status of school-age children.

Methods

School-based cross-sectional study was carried out from April to May 2014 among 404 elementary school-age children in Jimma Town, Southwest Ethiopia. Data on background characteristics were collected using structured interviewer administered questionnaire. Anthropometric measurements were taken according to World Health Organization standard. Fresh single stool sample was collected from each study participant and examined using direct wet mount and McMaster techniques. Anthropometric indices were generated using WHO AnthroPlus software. Multivariable logistic regression models were fitted to isolate independent predictors of intestinal parasitic infection and nutritional status using STATA-MP software. All tests were two-sided and P < 0.05 was used to declare statistical significance.

Results

The overall prevalence of intestinal parasites and soil-transmitted helminths were 68.6% (n = 277) and 55.0% (n = 222), respectively. A total of eight species of intestinal parasites were identified in this study, Trichuris trichiura being the most common parasite identified followed by Ascaris lumbricoides. Study participants who had a habit of open defecation were two times more likely to be infected with soil-transmitted helminths (adjusted odds ratio = 1.9, 95% confidence interval: 1.0-3.4). The overall prevalence of stunting and thinness were 21.0% (n = 85) and 6.9% (n = 28), respectively. The odds of stunting was significantly high (adjusted odds ratio = 4.0, 95% confidence interval: 1.7-9.7) among children who had fathers working as daily labourers and children with personal dietary diversity score of ⩽3 (adjusted odds ratio = 3.5, 95% confidence interval: 1.5-8.0). T. trichiura infection (adjusted odds ratio = 9.4, 95% confidence interval: 2.0-44.8) was identified as an independent predictor of stunting among school-age children.

Conclusion

Both the prevalence of soil-transmitted helminths and stunting are high among school-age children in Jimma Town. Although there was no statistically significant association between the STHs, in general, T. trichiura was reported as predictor of stunting. The results imply the need for strengthening strategies for reduction of parasitic infection to curb the pervasively high prevalence of stunting.

Prevalence and factors associated with intestinal parasitic infection among under-five children in and around Haro Dumal Town, Bale Zone, Ethiopia

BACKGROUND

Intestinal parasitic infection is diversified illness and diseases caused millions morbidity among under-five children lives in developing countries particularly vulnerable rural communities. Deworming coverage in such community is low. The aim of this study was to determine the prevalence and associated risk factors of intestinal parasitic infections (IPIs) among under-five children live in and around Haro Dumal Town.

METHODS

Community-based cross-sectional study was conducted in 561 randomly selected under-five children from June to August, 2018. The stool samples were collected and examined by basic parasitological techniques. Data related to socio-demographic and risk factors were collected using a self administered questionnaire. Statistical data analysis was done using SPSS version 21 and the bivariate and multivariate logistic regression used to compute the association between variables. P-value of < 0.05 was statistical significance.

THE RESULTS

Of the 561 total under-five children, 216 (38.5%) were found to be infected with intestinal parasites. E.histolytica/dispar (15.3%) was the most prevalent parasite, followed by hook worm (14.4%) and T.trichuria (13.9%). Regarding risk factors, geo-phage [(AOR = 4.7; 95%CI: 2.0-10.4), P < 0.001], tungiasis [(AOR = 3.1; 95%CI: 1.1-6.6), P < 0.001], eating raw vegetable [(AOR = 1.3; 95%CI: 1.4-3.3), P < 0.001] were significantly associated with intestinal parasitic infections.

CONCLUSION

Intestinal parasitic infections (IPIs) were found to be highly prevalent in the study area. Hence, improving sanitation, controlling ecto-parasite such as tungiasis, provision of safe water and successful mass-deworming are important.

Soil-transmitted helminth infections

More than a quarter of the world's population is at risk of infection with the soil-transmitted helminths Ascaris lumbricoides, hookworm (Ancylostoma duodenale and Necator americanus), Trichuris trichiura, and Strongyloides stercoralis. Infected children and adults present with a range of medical and surgical conditions, and clinicians should consider the possibility of infection in individuals living in, or returning from, endemic regions. Although safe and effective drugs are donated free to endemic countries, only half of at-risk children received treatment in 2016. This Seminar describes the epidemiology, lifecycles, pathophysiology, clinical diagnosis, management, and public health control of soil-transmitted helminths. Previous work has questioned the effect of population-level deworming; however, it remains beyond doubt that treatment reduces the severe consequences of soil-transmitted helminthiasis. We highlight the need for refined diagnostic tools and effective control options to scale up public health interventions and improve clinical detection and management of these infections.