Relationship of childhood protein-energy malnutrition and parasite infections in an urban African setting

Linkages between malaria and malnutrition in co-endemic regions of India

INTRODUCTION

Malaria and malnutrition are key public health challenges in India. However, the relationship between them is poorly understood. Here, we aimed to elucidate the potential interactions between the two health conditions by identifying the areas of their spatial overlap.

METHODS

We have analysed the district-wise undernutrition and malaria data of 638 districts of India across 28 states and 8 union territories. Data on malnutrition parameters viz. stunting, wasting, underweight and anaemia, sourced from the fourth National Family Health Survey (2015-2016), and malaria Annual Parasite Index (API) data of the same year (i.e, 2015), sourced from National Center of Vector Borne Diseases Control were analysed using local Moran's I Index and logistic regression.

RESULTS

Among all the malnutrition parameters, we found underweight in children and anaemia in men to co-occur with malaria in the districts of Chhattisgarh, Jharkhand, Madhya Pradesh and Odisha. Further, districts with more than 36% underweight children (OR (95% CI): 2.31 (1.53 to 3.48)) and/or more than 23.6% male population with anaemia (OR (95% CI): 2.06 (1.37 to 3.11)) had higher odds of being malaria endemic districts (ie, Annual Parasite Index >1).

CONCLUSION

Malaria and malnutrition co-occur in the malaria-endemic parts of India. The high prevalence of undernutrition in children and anaemia among men may contribute to malaria endemicity in a particular region. Therefore, future research should be prioritised to generate data on the individual level. Further, malaria control interventions could be tailored to integrate nutrition programmes to disrupt indigenous malaria transmission in endemic districts.

A comparative cross-sectional study of prevalence and intensity of soil-transmitted helminthic infection between healthy and severe acutely malnourished pre-school aged children in Kano, Northern Nigeria

BACKGROUND

Soil-transmitted helminthic (STH) infections are common in Sub-Saharan Africa. One method used for control of these helminths is mass anti-helminthic administration in populations at risk of STH infections. In this regard, empiric treatment of children with Severe Acute Malnutrition (SAM) for STH infection is practiced in this region. It is however unclear if children with SAM suffer more from STH infection than healthy children. The objective of this study was to compare prevalence and intensity of STH infection between pre-school aged children with SAM and healthy children.

METHODS

We approached 1114 pre-school aged children attending care in two health facilities in Kano, Nigeria to partake in this study. Of this number, we recruited 620 (55.7%) children, comprising 310 well-nourished children from well-baby clinics and 310 children with SAM from Community Management for Acute Malnutrition (CMAM) centres in these facilities. We assessed their nutritional status using World Health Organisation (WHO) growth charts and collected stool samples which we analysed using Formal-Ether Concentration technique to identify STH infection and Stoll's technique to assess intensities of STH infection. We fitted a logistic regression model to determine if there was any association between nutrition status and helminthic infection, adjusting for the confounding effects of socio-economic status and age. We compared intensity of STH infection (measured as eggs per gram of faeces) between both nutrition groups using the independent t-test.

RESULTS

Overall STH prevalence in our population was low (2.7%) and we found no significant association between nutritional status and presence of STH infection (OR = 1.10, 95% CI 0.38 to 3.21). Majority of our study participants had either low or moderate (94.2%) and there was no statistically significant difference between intensity of STH infection (t value = - 1.52, P value = 0.13) in children with SAM and those who were well-nourished.

CONCLUSIONS

The overall STH prevalence among pre-school children was low in Kano and we did not find prevalence and intensity of STH infection to differ significantly between preschool children with SAM and well-nourished children. Our findings confirm the WHO recommendation that at low levels of prevalence and intensity, interventions to control STH are unnecessary.

Intervention strategies to reduce the burden of soil-transmitted helminths in India

Soil-transmitted helminth (STH) infections continue to be a major global cause of morbidity, with a large proportion of the burden of STH infections occurring in India. In addition to direct health impacts of these infections, including anaemia and nutritional deficiencies in children, these infections also significantly impact economic development, as a result of delays in early childhood cognitive development and future income earning potential. The current World Health Organization strategy for STH is focused on morbidity control through the application of mass drug administration to all pre-school-aged and school-aged children. In India, the control of STH-related morbidity requires mobilization of significant human and financial resources, placing additional burdens on limited public resources. Infected adults and untreated children in the community act as a reservoir of infection by which treated children get rapidly reinfected. As a result, deworming programmes will need to be sustained indefinitely in the absence of other strategies to reduce reinfection, including water, hygiene and sanitation interventions (WASH). However, WASH interventions require sustained effort by the government or other agencies to build infrastructure and to promote healthy behavioural modifications, and their effectiveness is often limited by deeply entrenched cultural norms and behaviours. Novel strategies must be explored to provide a lasting solution to the problem of STH infections in India other than the indefinite provision of deworming for morbidity control.

Complex interactions between malaria and malnutrition: a systematic literature review

BACKGROUND

Despite substantial improvement in the control of malaria and decreased prevalence of malnutrition over the past two decades, both conditions remain heavy burdens that cause hundreds of thousands of deaths in children in resource-poor countries every year. Better understanding of the complex interactions between malaria and malnutrition is crucial for optimally targeting interventions where both conditions co-exist. This systematic review aimed to assess the evidence of the interplay between malaria and malnutrition.

METHODS

Database searches were conducted in PubMed, Global Health and Cochrane Libraries and articles published in English, French or Spanish between Jan 1980 and Feb 2018 were accessed and screened. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale and the risk of bias across studies was assessed using the GRADE approach. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guideline were followed.

RESULTS

Of 2945 articles screened from databases, a total of 33 articles were identified looking at the association between malnutrition and risk of malaria and/or the impact of malnutrition in antimalarial treatment efficacy. Large methodological heterogeneity of studies precluded conducting meaningful aggregated data meta-analysis. Divergent results were reported on the effect of malnutrition on malaria risk. While no consistent association between risk of malaria and acute malnutrition was found, chronic malnutrition was relatively consistently associated with severity of malaria such as high-density parasitemia and anaemia. Furthermore, there is little information on the effect of malnutrition on therapeutic responses to artemisinin combination therapies (ACTs) and their pharmacokinetic properties in malnourished children in published literature.

CONCLUSIONS

The evidence on the effect of malnutrition on malaria risk remains inconclusive. Further analyses using individual patient data could provide an important opportunity to better understand the variability observed in publications by standardising both malaria and nutritional metrics. Our findings highlight the need to improve our understanding of the pharmacodynamics and pharmacokinetics of ACTs in malnourished children. Further clarification on malaria-malnutrition interactions would also serve as a basis for designing future trials and provide an opportunity to optimise antimalarial treatment for this large, vulnerable and neglected population.

TRIAL REGISTRATION

PROSPERO CRD42017056934 .

Is chronic malnutrition associated with an increase in malaria incidence? A cohort study in children aged under 5 years in rural Gambia

Background

Malnutrition is common in children in sub-Saharan Africa and is thought to increase the risk of infectious diseases, including malaria. The relationship between malnutrition and malaria was examined in a cohort of 6–59 month-old children in rural Gambia, in an area of seasonal malaria transmission. The study used data from a clinical trial in which a cohort of children was established and followed for clinical malaria during the 2011 transmission season. A cross-sectional survey to determine the prevalence of malaria and anaemia, and measure the height and weight of these children was carried out at the beginning and end of the transmission season. Standard anthropometric indices (stunting, wasting and underweight) were calculated using z-scores.

Results

At the beginning of the transmission season, 31.7% of children were stunted, 10.8% wasted and 24.8% underweight. Stunting was more common in Fula children than other ethnicities and in children from traditionally constructed houses compared to more modern houses. Stunted children and underweight children were significantly more likely to have mild or moderate anaemia. During the transmission season, 13.7% of children had at least one episode of clinical malaria. There was no association between stunting and malaria incidence (odds ratio = 0.79, 95% CI: 0.60–1.05). Malaria was not associated with differences in weight or height gain.

Conclusions

Chronic malnutrition remains a problem in rural Gambia, particularly among the poor and Fula ethnic group, but it was not associated with an increased risk of malaria.

Trial registration

Trial registration: ISRCTN, ISRCTN01738840, registered: 27/08/2010 (Retrospectively registered).

Why monkeys do not get multiple sclerosis (spontaneously): An evolutionary approach

The goal of this review is to apply an evolutionary lens to understanding the origins of multiple sclerosis (MS), integrating three broad observations. First, only humans are known to develop MS spontaneously. Second, humans have evolved large brains, with characteristically large amounts of metabolically costly myelin. This myelin is generated over long periods of neurologic development—and peak MS onset coincides with the end of myelination. Third, over the past century there has been a disproportionate increase in the rate of MS in young women of childbearing age, paralleling increasing westernization and urbanization, indicating sexually specific susceptibility in response to changing exposures. From these three observations about MS, a life history approach leads us to hypothesize that MS arises in humans from disruption of the normal homeostatic mechanisms of myelin production and maintenance, during our uniquely long myelination period. This review will highlight under-explored areas of homeostasis in brain development, that are likely to shed new light on the origins of MS and to raise further questions about the interactions between our ancestral genes and modern environments.

A Literature Review of the Effect of Malaria on Stunting

Background: The current version of the Lives Saved Tool (LiST) maternal and child health impact modeling software does not include an effect of malaria on stunting.Objective: This literature review was undertaken to determine whether such a causal link should be included in the LiST model.Methods: The PubMed, Embase, and Scopus databases were searched by using broad search terms. The searches returned a total of 4281 documents. Twelve studies from among the retrieved documents were included in the review according to the inclusion and exclusion criteria.Results: There was mixed evidence for an effect of malaria on stunting among longitudinal observational studies, and none of the randomized controlled trials of malaria interventions found an effect of the interventions on stunting.Conclusions: There is insufficient evidence to include malaria as a determinant of stunting or an effect of malaria interventions on stunting in the LiST model. The paucity and heterogeneity of the available literature were a major limitation. In addition, the studies included in the review consistently fulfilled their ethical responsibility to treat children under observation for malaria, which may have interfered with the natural history of the disease and prevented any observable effect on stunting or linear growth.

Experimental testing of reciprocal effects of nutrition and parasitism in wild black capuchin monkeys

Nutritional stress may predispose individuals to infection, which in turn can have further detrimental effects on physical condition, thus creating an opportunity for reciprocal effects between nutrition and parasitism. Little experimental investigation has been conducted on this “vicious circle” hypothesis in wild animals, especially under natural conditions. We evaluated the reciprocal effects of nutritional status and parasitism using an experimental approach in two groups of wild black capuchin monkeys (Sapajus nigritus). Across two consecutive winters, we collected faecal samples from identified capuchins to determine presence and load of gastrointestinal helminthes, and measured individual body mass as a proxy of physical condition. Food availability was manipulated by provisioning monkeys with bananas, and parasite burdens by applying antiparasitic drugs to selected individuals. We found no effect of antiparasitic drugs on physical condition, but parasite loads decreased in response to high levels of food availability. Our results represent the first experimental evidence that the nutritional status may drive parasite dynamics in a primate.

Nutritional status of children in a malaria meso endemic area: cross sectional study on prevalence, intensity, predictors, influence on malaria parasitaemia and anaemia severity

BACKGROUND

The contradictory results on the interaction between nutritional status and malaria warrants further investigation in various epidemiological settings, to assert the antagonistic or synergistic relationship. This study examines the prevalence, severity and predictors of malnutrition and its influence on malaria parasitaemia and anaemia severity in children in the Mount Cameroon area.

METHODS

A cross-sectional study involving 454 children ≤ 14 years was carried out from February to May 2013 in Muea community. Anthropometric measures of malnutrition (z-scores < -2 standard deviations below mean) were obtained and spleen size assessed. The prevalence and density of malaria parasites were determined and haemoglobin concentration and white blood cell count obtained using an automated haematology analyzer. Univariate and multivariate analyses were used to evaluate influence of malnutrition on anaemia, malaria parasitaemia and predictors respectively.

RESULTS

The overall prevalence of malnutrition was 22.8 %, with stunting being the most common form (17.1 %), followed by underweight (8.2 %) and wasting (5.5 %). Stunting was significantly higher (P < 0.01) in males (23.1 %) than in females (11.9 %). The prevalence of malnutrition was significantly highest (P = 0.03) in children ≤5 years old (29.5 %) than their counterparts. Severe stunting, wasting and underweight were prevalent in 4.9 %, 1.6 % and 1.8 % of the children respectively. Clinical malaria parasitaemia was significantly higher (P = 0.01) in children who were stunted (16.9 %) and underweight (21.6 %) than their normal counterparts (7.5 %; 8.2 % respectively). The model demonstrated sex (P = 0.006) and age group 1.1-3 years (P = 0.03) as significant predictors of malnutrition. In children who were malaria parasite negative, the prevalence of anaemia as well as severities were significantly higher (P = 0.04 and P = 0.001 respectively) in those malnourished.

CONCLUSIONS

The presence of stunting in the community significantly augmented the prevalence and clinical presentation of Plasmodium infection. Malnutrition enhanced the severity of anaemia in malaria parasite negative children hence, their health and growth potential needs to be improved upon.

Soil-Transmitted Helminths in Southwestern China: A Cross-Sectional Study of Links to Cognitive Ability, Nutrition, and School Performance among Children

Background

Empirical evidence suggests that the prevalence of soil-transmitted helminth (STH) infections in remote and poor rural areas is still high among children, the most vulnerable to infection. There is concern that STH infections may detrimentally affect children’s healthy development, including their cognitive ability, nutritional status, and school performance. Medical studies have not yet identified the exact nature of the impact STH infections have on children. The objective of this study is to examine the relationship between STH infections and developmental outcomes among a primary school-aged population in rural China.

Methodology/Principal Findings

We conducted a large-scale survey in Guizhou province in southwest China in May 2013. A total of 2,179 children aged 9-11 years living in seven nationally-designated poverty counties in rural China served as our study sample. Overall, 42 percent of the sample’s elementary school-aged children were infected with one or more of the three types of STH—Ascaris lumbricoides (ascaris), Trichuris trichuria (whipworm) and the hookworms Ancylostoma duodenale or Necator americanus. After controlling for socioeconomic status, we observed that infection with one or more STHs is associated with worse cognitive ability, worse nutritional status, and worse school performance than no infection. This study also presents evidence that children with Trichuris infection, either infection with Trichuris only or co-infected with Trichuris and Ascaris, experience worse cognitive, nutritional and schooling outcomes than their uninfected peers or children infected with only Ascaris.

Conclusions/Significance

We find that STH infection still poses a significant health challenge among children living in poor, rural, ethnic areas of southwest China. Given the important linkages we find between STH infection and a number of important child health and educational outcomes, we believe that our results will contribute positively to the debate surrounding the recent Cochrane report.

Empirical evidence suggests that the prevalence of soil-transmitted helminth (STH) infections in remote and poor rural areas is still high among children, the most vulnerable to infection. There is concern that STH infections may detrimentally affect children’s healthy development, including their cognitive ability, nutritional status, and school performance. Medical studies have not yet identified the exact nature of the impact STH infections have on children. The objective of this study is to examine the relationship between STH infections and developmental outcomes among a primary school-aged population in rural China. We conducted a large-scale survey in Guizhou province in southwest China in May, 2013. Overall, 42 percent of elementary school-aged children were infected with one or more of the three types of STH—Ascaris lumbricoides (ascaris), Trichuris trichuria (whipworm) and the hookworms Ancylostoma duodenale or Necator americanus. After controlling for socioeconomic status, we observed that children infected with one or more STHs have worse cognitive ability, worse nutritional status, and worse school performance than their uninfected peers. While not causal, this study also presents evidence that children with Trichuris infection, either infection with Trichuris only or co-infected with Trichuris and Ascaris, have worse cognitive, nutritional and schooling outcomes than their uninfected peers or children infected with only Ascaris. Given these important linkages, we hope that our results will contribute positively to the debate surrounding the recent Cochrane report.

Microbiologic methods utilized in the MAL-ED cohort study

A central hypothesis of The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) study is that enteropathogens contribute to growth faltering. To examine this question, the MAL-ED network of investigators set out to achieve 3 goals: (1) develop harmonized protocols to test for a diverse range of enteropathogens, (2) provide quality-assured and comparable results from 8 global sites, and (3) achieve maximum laboratory throughput and minimum cost. This paper describes the rationale for the microbiologic assays chosen and methodologies used to accomplish the 3 goals.

Schistosoma mansoni infection and undernutrition among school age children in Fincha'a sugar estate, rural part of West Ethiopia

BACKGROUND

Parasitic infection like schistosomiasis is known to exert a negative effect on nutritional status of school-aged children. However, studies associating parasitic infections with undernutrition are scarce. Thus, this study was primarily to document the association between Schistosoma mansoni infection and undernutrition among school-aged children in a rural setting of Fincha'a Sugar Estate, Ethiopia.

METHODS

A cross-sectional study was conducted on a total of 453 school-aged children (5-18 years). Stool specimen was collected and examined using the standard Kato-katz technique. Children's height-for-Age Z-score (HAZ) and Body mass index-for-Age Z- score (BAZ) was determined. Z-Scores for each nutritional index were compared with the WHO child growth standards reference values. Children were considered stunted or wasted as HAZ or BAZ falls below -2 standard deviations, respectively.

RESULT

The overall prevalence of Schistosoma mansoni infection was 53.2%. Out of the total school children examined, 11.5% and 13.2% were stunted and wasted, respectively. Multivariate logistic regression analysis was done to determine the relationship between Schistosoma mansoni infection and nutritional status controlling for other factors. Accordingly, stunting was not significantly associated while wasting was negatively associated with Schistosoma mansoni infection. Paternal occupation was the best predictor of stunting and wasting such that, unemployed fathers have 4.28 (95% CI; 2.13, 8.63) (p < 0.001) and 3.83, 95% CI; 1.89, 7.79) (p < 0.001) chance of having stunted and wasted children, respectively.

CONCLUSION

Schistosoma mansoni infection is highly prevalent in the study area. The high prevalence of wasting, and moderate level of stunting among study subjects in this study area indicate that they are affected by both infection and undernutrition. Therefore, regular preventive chemotherapy against S. mansoni and other control measures are recommended. Moreover, possibilities of synchronized nutritional rehabilitation and creation of employment opportunities to the families should be looked for.

Relative undernourishment and food insecurity associations with Plasmodium falciparum among Batwa pygmies in Uganda: evidence from a cross-sectional survey

Although malnutrition and malaria co-occur among individuals and populations globally, effects of nutritional status on risk for parasitemia and clinical illness remain poorly understood. We investigated associations between Plasmodium falciparum infection, nutrition, and food security in a cross-sectional survey of 365 Batwa pygmies in Kanungu District, Uganda in January of 2013. We identified 4.1% parasite prevalence among individuals over 5 years old. Severe food insecurity was associated with increased risk for positive rapid immunochromatographic test outcome (adjusted relative risk [ARR] = 13.09; 95% confidence interval [95% CI] = 2.23–76.79). High age/sex-adjusted mid-upper arm circumference was associated with decreased risk for positive test among individuals who were not severely food-insecure (ARR = 0.37; 95% CI = 0.19–0.69). Within Batwa pygmy communities, where malnutrition and food insecurity are common, individuals who are particularly undernourished or severely food-insecure may have elevated risk for P. falciparum parasitemia. This finding may motivate integrated control of malaria and malnutrition in low-transmission settings.

Hookworm infection among school age children in Kintampo north municipality, Ghana: nutritional risk factors and response to albendazole treatment

Children (n = 812) 6-11 years of age attending 16 schools in the Kintampo North Municipality of Ghana were screened for participation in a study on hookworm infection, nutrition, and response to albendazole. The prevalence of Necator americanus hookworm infection (n = 286) was 39.1%, and significant predictors of infection included age, malaria parasitemia, lack of health care, school area, levels of antibodies against hookworm, and low consumption of animal foods. The cure rate after a single dose (400 mg) albendazole was 43%, and the mean fecal egg count reduction rate was 87.3%. Data for an in vitro egg hatch assay showed a trend toward reduced albendazole susceptibility in post-treatment hookworm isolates (P = 0.06). In summary, hookworm infection is prevalent among school age children in the Kintampo North Municipality and animal food intake inversely correlates with infection status. Modest cure rates and fecal egg count reduction rates reinforce the need for further investigation of potential benzimidazole resistance in Ghana.

[Malaria infection and nutritional status: results from a cohort survey of children from 6-59 months old in the Kivu province, Democratic Republic of the Congo]

BACKGROUND

Despite a reduction in the magnitude of endemic malaria reported in recent years, malaria and protein-energy malnutrition (PEM) still remain major causes of morbidity and mortality in sub-Saharan Africa among children under five. The relationship between malaria and malnutrition remains a topic of controversy. We aimed to investigate malaria infection according to nutritional status in a community-based survey.

METHODS

A cohort of 790 children aged 6 to 59 months and residing in eastern Democratic Republic of the Congo was followed-up from April 2009 to March 2010 with monthly visits. Data on nutritional status, morbidity between visits, use of insecticide-treated nets and malaria parasitemia were collected at each visit. The Z scores height for age, weight for age and weight for height were computed using the reference population defined by the WHO in 2006. Thresholds for Z scores were defined at -3 and -2. A binary logistic model of the generalized estimating equation (GEE) was used to quantify the association between PEM indicators and malaria parasitemia. Odds ratio (OR) and their 95% confidence interval (95% CI) were computed.

RESULTS

After adjustment for season, children with severe stunting (height for age Z score<-3) were at lower risk of malaria parasitemia greater or equal to 5000 trophozoits/μL of blood as compared to those in with a better nutritional status (height for age Z score≥-2) (OR=0.48, 95% CI: 0.25-0.91).

CONCLUSION

Severely stunted children are at a lower risk of high-level malaria parasitemia.

Malaria parasitaemia among infants and its association with breastfeeding peer counselling and vitamin A supplementation: a secondary analysis of a cluster randomized trial

Background

Malaria is the second highest contributor to the disease burden in Africa and there is a need to identify low cost prevention strategies. The objectives of this study were to estimate the prevalence of malaria parasitaemia among infants and to measure the association between peer counselling for exclusive breastfeeding (EBF), vitamin A supplementation, anthropometric status (weight and length) and malaria parasitaemia.

Methods

A cluster randomized intervention trial was conducted between 2006 and 2008 where 12 of 24 clusters, each comprising one or two villages, in Eastern Uganda were allocated to receive peer counselling for EBF. Women in their third trimester of pregnancy (based on the last normal menstrual period) were recruited in all 24 clusters and followed up until their children's first birthday. Blood was drawn from 483 infants between 3 and 12 months of age, to test for malaria parasitaemia.

Results

The prevalence of malaria parasitaemia was 11% in the intervention areas and 10% in the control areas. The intervention did not seem to decrease the prevalence of malaria (PR 1.7; 95% CI: 0.9, 3.3). After controlling for potential confounders, infants not supplemented with Vitamin A had a higher prevalence for malaria compared to those who had been supplemented (PR 6.1; 95% CI: 2.1, 17.6). Among children supplemented with vitamin A, every unit increase in length-for-age Z (LAZ) scores was associated with a reduced prevalence in malaria (PR 0.5; 95% CI:0.4, 0.6). There was no association between LAZ scores and malaria among children that had not been supplemented.

Conclusion

Peer counselling for exclusive breastfeeding did not decrease the prevalence of malaria parasitaemia. Children that had not received Vitamin A supplementation had a higher prevalence of malaria compared to children that had been supplemented.

Trial registration

Clinicaltrials.gov: NCT00397150.

Epidemiology of hookworm infection in Kintampo North Municipality, Ghana: patterns of malaria coinfection, anemia, and albendazole treatment failure

A cross-sectional pilot study of hookworm infection was carried out among 292 subjects from 62 households in Kintampo North, Ghana. The overall prevalence of hookworm infection was 45%, peaking in those 11-20 years old (58.5%). In children, risk factors for hookworm infection included coinfection with malaria and increased serum immunoglobulin G reactivity to hookworm secretory antigens. Risk factors for infection in adults included poor nutritional status, not using a latrine, not wearing shoes, and occupation (farming). Although albendazole therapy was associated with an overall egg reduction rate of 82%, 37 subjects (39%) remained infected. Among those who failed therapy, treatment was not associated with a significant reduction in egg excretion, and nearly one-third had higher counts on repeat examination. These data confirm a high prevalence of low-intensity hookworm infection in central Ghana and its association with poor nutritional status. The high rate of albendazole failure raises concern about emerging resistance.

Exploring the relationship between chronic undernutrition and asymptomatic malaria in Ghanaian children

Background

A moderate association has been found between asymptomatic parasitaemia and undernutrition. However, additional investigation using the gold standard for asymptomatic parasitaemia confirmation, polymerase chain reaction (PCR), is needed to validate this association. Anthropometric measurements and blood samples from children less than five years of age in a rural Ghanaian community were used to determine if an association exists between chronic undernutrition and PCR-confirmed cases of asymptomatic malaria.

Methods

This was a descriptive cross-sectional study of 214 children less than five years of age from a community near Kumasi, Ghana. Blood samples and anthropometric measurements from these children were collected during physical examinations conducted in January 2007 by partners of the Barekuma Collaborative Community Development Programme.

Results

Findings from the logistic model predicting the odds of asymptomatic malaria indicate that children who experienced mild, moderate or severe stunting were not more likely to have asymptomatic malaria than children who were not stunted. Children experiencing anaemia had an increased likelihood (OR = 4.15; 95% CI: 1.92, 8.98) of asymptomatic malaria. Similarly, increased spleen size, which was measured by ultrasound, was also associated with asymptomatic malaria (OR = 2.17; 95% CI: 1.44, 3.28). Fast breathing, sex of the child, and age of the child were not significantly associated with the asymptomatic malaria.

Conclusions

No significant association between chronic undernutrition and presence of asymptomatic malaria was found. Children who experience anaemia and children who have splenomegaly are more likely to present asymptomatic malaria. Programmes aimed at addressing malaria should continue to include nutritional components, especially components that address anaemia.

Epidemiology and control of human gastrointestinal parasites in children

Parasites found in the human gastrointestinal tract can be largely categorized into two groups, protozoa and helminths. The soil-transmitted helminths (Ascaris lumbricoides, hookworm and Trichuris trichiura) are the most prevalent, infecting an estimated one-sixth of the global population. Infection rates are highest in children living in sub-Saharan Africa, followed by Asia and then Latin America and the Caribbean. The current momentum towards global drug delivery for their control is at a historical high through the efforts of numerous initiatives increasingly acting in coordination with donors, governments and local communities. Together, they have delivered enormous quantities of drugs, especially anthelmintics to children through nationwide annual or biannual mass drug administration largely coordinated through schools. However, a much larger and rapidly growing childhood population in these regions remains untreated and suffering from more than one parasite. Mass drug administration has profound potential for control but is not without considerable challenges and concerns. A principal barrier is funding. Stimulating a research and development pipeline, supporting the necessary clinical trials to refine treatment, in addition to procuring and deploying drugs (and sustaining these supply chains), requires substantial funding and resources that do not presently exist. Limited options for chemotherapy raise concerns about drug resistance developing through overuse, however, satisfactory pharmaco-epidemiology and monitoring for drug resistance requires more developed health infrastructures than are generally available. Further, the limited pharmacopeia does not include any effective second-line options if resistance emerges, and the research and development pipeline is severely depressed. Herein, we discuss the major gastrointestinal protozoa and helminths reviewing their impact on child health, changing epidemiology and how this relates to their control.

Impact of child malnutrition on the specific anti-Plasmodium falciparum antibody response

Background

In sub-Saharan Africa, preschool children represent the population most vulnerable to malaria and malnutrition. It is widely recognized that malnutrition compromises the immune function, resulting in higher risk of infection. However, very few studies have investigated the relationship between malaria, malnutrition and specific immunity. In the present study, the anti-Plasmodium falciparum IgG antibody (Ab) response was evaluated in children according to the type of malnutrition.

Methods

Anthropometric assessment and blood sample collection were carried out during a cross-sectional survey including rural Senegalese preschool children. This cross-sectional survey was conducted in July 2003 at the onset of the rainy season. Malnutrition was defined as stunting (height-for-age <-2 z-scores) or wasting (weight-for-height <-2 z-scores). The analysis was performed on all malnourished children in July (n = 161, either stunted, n = 142 or wasted, n = 19), pair-matched to well-nourished controls. The IgG Ab response to P. falciparum whole extracts (schizont antigens) was assessed by ELISA in sera of the included children.

Results

Both the prevalence of anti-malarial immune responders and specific IgG Ab levels were significantly lower in malnourished children than in controls. Depending on the type of malnutrition, wasted children and stunted children presented a lower specific IgG Ab response than their respective controls, but this difference was significant only in stunted children (P = 0.026). This down-regulation of the specific Ab response seemed to be explained by severely stunted children (HAZ ≤ -2.5) compared to their controls (P = 0.03), while no significant difference was observed in mildly stunted children (-2.5 < HAZ <-2.0). The influence of child malnutrition on the specific anti-P. falciparum Ab response appeared to be independent of the intensity of infection.

Conclusion

Child malnutrition, and particularly stunting, may down-regulate the anti-P. falciparum Ab response, both in terms of prevalence of immune responders and specific IgG Ab levels. This study provides further evidence for the influence of malnutrition on the specific anti-malarial immune response and points to the importance of taking into account child malnutrition in malaria epidemiological studies and vaccine trials.

Two quantitative trait loci influence whipworm (Trichuris trichiura) infection in a Nepalese population

BACKGROUND

Whipworm (Trichuris trichiura) infection is a soil-transmitted helminth infection that affects >1 billion people. It is a serious public health problem in many developing countries and can result in deficits in growth and cognitive development. In a follow-up study of significant heritability for whipworm infection, we conducted the first genome scan for quantitative trait loci (QTL) influencing the heritability of susceptibility to this important parasitic disease.

METHODS

Whipworm egg counts were determined for 1,253 members of the Jirel population of eastern Nepal. All individuals in the study sample belonged to a single pedigree including >26,000 pairs of relatives that are informative for genetic analysis.

RESULTS

Linkage analysis of genome scan data generated for the pedigree provided unambiguous evidence for 2 QTL influencing susceptibility to whipworm infection, one located on chromosome 9 (logarithm of the odds ratio [LOD] score, 3.35; genomewide P = .0138) and the other located on chromosome 18 (LOD score, 3.29; genomewide P = .0159). There was also suggestive evidence that 2 loci located on chromosomes 12 and 13 influenced whipworm infection.

CONCLUSION

The results of this first genome scan for T. trichiura egg counts provides new information on the determinants of genetic predisposition to whipworm infection.

Age patterns in undernutrition and helminth infection in a rural area of Brazil: associations with ascariasis and hookworm

OBJECTIVE

To investigate the nutritional status of individuals from a rural area of Brazil, and associations with helminth infections in an age-stratified sample.

METHOD

A total of 1113 individuals aged from 6 months to 83 years from the rural community of Americaninhas in Minas Gerais were investigated. Assessments comprised anthropometric measurements of weight, height and body composition, examining faecal samples for helminth eggs, and peripheral blood assays for albumin, haemoglobin and ferritin concentrations.

RESULTS

Ten percent of the participants were underweight, 12.8% were overweight and 28.3% of the children and adolescents were stunted. 11.6% had low lean body mass and 28.8% had low fat body mass. Hypoalbuminaemia was seen in 5.5%, anaemia in 12.5% and iron deficiency in 13.1%, although the prevalence of these two indices increased with age. Multivariate analysis showed that, after controlling for age, sex and socio-economic status, stunting was significantly associated with Ascaris lumbricoides infection among children and adolescents, whereas low body mass was significantly associated with hookworm infection among adults and the elderly.

CONCLUSIONS

Helminth infections are associated with undernutrition in endemic populations, with important differences between the effects of hookworm and A. lumbricoides on age-related nutritional status.

Malaria and anaemia among children in two communities of Kumasi, Ghana: a cross-sectional survey

BACKGROUND

A survey in Kumasi, Ghana found a marked Plasmodium falciparum prevalence difference between two neighbouring communities (Moshie Zongo and Manhyia). The primary objective of this follow-up study was to determine whether this parasite rate difference was consistent over time. Secondary objectives were to compare prevalences of clinical malaria, anaemia, intestinal parasite infections, and malnutrition between these communities; and to identify potential risk factors for P. falciparum infection and anaemia.

METHODS

A cross-sectional house-to-house survey of P. falciparum parasitaemia, clinical malaria, anaemia, anthropometric indices, and intestinal helminths was conducted in April-May 2005. Data collection included child and household demographics, mosquito avoidance practices, distance to nearest health facility, child's travel history, symptoms, and anti-malarial use. Risk factors for P. falciparum and anaemia (Hb < 11 g/dl) were identified using generalized linear mixed models.

RESULTS

In total, 296 children were tested from 184 households. Prevalences of P. falciparum, clinical malaria, anaemia, and stunting were significantly higher in Moshie Zongo (37.8%, 16.9%, 66.2% and 21.1%, respectively) compared to Manhyia (12.8%, 3.4%, 34.5% and 7.4%). Of 197 children tested for helminths, four were positive for Dicrocoelium dendriticum. Population attributable risks (PAR%) of anaemia were 16.5% (P. falciparum) and 7.6% (malnutrition). Risk factors for P. falciparum infection were older age, rural travel, and lower socioeconomic status. Risk factors for anaemia were P. falciparum infection, Moshie Zongo residence, male sex, and younger age.

CONCLUSION

Heterogeneities in malariometric indices between neighbouring Kumasi communities are consistent over time. The low helminth prevalence, and the twofold higher PAR% of anaemia attributable to P. falciparum infection compared to malnutrition, indicate the importance of malaria as a cause of anaemia in this urban population.

Parasite risk factors for stunting in grade 5 students in a community of extreme poverty in Peru

Malnutrition in school-age children is common in developing countries and includes both stunting and underweight. Stunting, which represents a chronic state of nutritional stress, leads to adverse health, educational and cognitive effects. Although much research is focused on preschool-age children, recent studies show both the high prevalence of stunting and the effectiveness of interventions in school-age children. The objectives of the current study were to determine the risk factors for stunting only, and stunting and underweight. A survey was conducted in 1074 grade 5 children (mean age 10 years) from 17 schools in Belen, Peru, a community of extreme poverty. Prevalence of underweight and stunting were 10.5 and 34.5%, respectively, co-prevalence was 9.3%. Based on multivariable logistic regression analyses, significant independent risk factors (odds ratio: OR) for stunting and underweight were: age (per 1 year increment) (OR=1.55; 95% confidence interval (CI): 1.33, 1.81); diarrhoea in the last week (OR=1.96; 95% CI: 1.17, 3.29) and hookworm infection (OR=1.74; 95% CI: 1.05, 2.86). Significant independent risk factors for stunting only were: age (per 1 year increment) (OR=1.51; 95% CI: 1.35, 1.70); anaemia (OR=1.98; 95% CI: 1.26, 3.11); and moderate and heavy Trichuris and Ascaris co-infection (OR=1.95; 95% CI: 1.35, 2.82). Our results indicate a high prevalence of stunting, in addition to other adverse health indicators, in the study population. Due to the interrelation between many of these health and nutrition problems, interventions at both the school and community levels, including de-worming, feeding programs and health and hygiene education, are needed to reduce malnutrition in this and other similar populations living in conditions of extreme poverty.

Impact of vitamin E or selenium deficiency on nematode-induced alterations in murine intestinal function

The effects of deficiencies in the antioxidant nutrients, vitamin E and selenium, on the host response to gastrointestinal nematode infection are unknown. The aim of the study was to determine the effect of antioxidant deficiencies on nematode-induced alterations in intestinal function in mice. BALB/c mice were fed control diets or diets deficient in selenium or vitamin E and the response to a secondary challenge inoculation with Heligmosomoides polygyrus was determined. Egg and worm counts were assessed to determine host resistance. Sections of jejunum were mounted in Ussing chambers to measure changes in permeability, absorption, and secretion, or suspended in organ baths to determine smooth muscle contraction. Both selenium and vitamin E deficient diets reduced resistance to helminth infection. Vitamin E, but not selenium, deficiency prevented nematode-induced decreases in glucose absorption and hyper-contractility of smooth muscle. Thus, vitamin E status is an important factor in the physiological response to intestinal nematode infection and may contribute to antioxidant-dependent protective mechanisms in the small intestine.

Molecular characterization of Ancylostoma ceylanicum Kunitz-type serine protease inhibitor: evidence for a role in hookworm-associated growth delay

Hookworm infection is a major cause of iron deficiency anemia and malnutrition in developing countries. The Ancylostoma ceylanicum Kunitz-type inhibitor (AceKI) is a 7.9-kDa broad-spectrum inhibitor of trypsin, chymotrypsin, and pancreatic elastase that has previously been isolated from adult hookworms. Site-directed mutagenesis of the predicted P1 inhibitory reactive site amino acid confirmed the role of Met(26) in mediating inhibition of the three target serine proteases. By using reverse transcription-PCR, it was demonstrated that the level of AceKI gene expression increased following activation of third-stage larvae with serum and that the highest level of expression was reached in the adult stage of the parasite. Immunohistochemistry studies performed with polyclonal immunoglobulin G raised against recombinant AceKI showed that the inhibitor localized to the subcuticle of the adult hookworm, suggesting that it has a potential in vivo role in neutralizing intestinal proteases at the surface of the parasite. Immunization with recombinant AceKI was shown to confer partial protection against hookworm-associated growth delay without a measurable effect on anemia. Taken together, the data suggest that AceKI plays a role in the pathogenesis of hookworm-associated malnutrition and growth delay, perhaps through inhibition of nutrient absorption in infected hosts.

Nutritional status in two Mbyá-Guaraní communities from Misiones (Argentina)

Growth and nutritional status of children and adults in two Mbyá-Guaraní communities from Argentina, was assessed. Height, weight, sitting height, upper arm circumference, triceps and subscapular skinfold were measured on 120 individuals aged from 2 to 60 between March and May, 2001. Data were transformed to z-scores using United States references (NHANES I and NHANES II). A z-score of less than -2 was used as the cut-off point to determine the prevalence of stunting and wasting respectively. Mean z-scores for weight, height, and upper arm circumference lie below the reference (0 > Z > -3), while in sitting height ratio and muscular area for females they were above the US standard (0 < Z < 2). Skinfold thicknesses and muscular area for males were similar to the reference (2 > Z > -1). Our findings are in agreement with others South American Indian research that the prevalence of stunting (36.7%) is significantly higher than wasting (1.8%). The presence of parasitic infections and nutritional environment previously described in this population could be related to the short stature.

Effects of multivitamin-multimineral supplementation on appetite of stunted young Beninese children

In the developing world, food intake of young children is often insufficient for growth. Reduced appetite due to several factors including micronutrient deficiencies might be an explanation. We hypothesized that a multivitamin-multimineral supplementation will improve appetite of stunted children in south of Benin. Multivitamin-multimineral supplements (VITALIA-tablets) contain 11 vitamins and 8 minerals. Stunted children (Ht/Age Z score < -2) of 17-32 months old were randomly assigned to multivitamin-multimineral (n = 48) or placebo (n = 53) group. Supplementation was daily and supervised throughout 6 weeks. Knee-heel length, length, weight, arm circumference and appetite were assessed once a week for the three weeks preceding and the three weeks following the six-week intervention period. Growth was additionally assessed 4 months after intervention. Each appetite test day, morbidity data and mother's report on child's appetite throughout the preceding day were recorded. Reported appetite, intake of test food and knee-heel length increased after supplementation in both groups (p < 0.05), but were not different between groups. Growth was similar 4 months after the intervention. Morbidity was comparable in both groups before as well as after supplementation. We conclude that 6-week multivitamin-multimineral supplementation alone failed to improve appetite and growth of stunted young children.

Gastrointestinal nematodes, nutrition and immunity: breaking the negative spiral

Nutritionists have long understood that intestinal nematode parasites have deleterious effects on host nutritional status, but only recently has the importance of malnutrition as a predisposing factor to intestinal nematodes been recognized. Here we review experimental and field studies on the effects of protein, energy, zinc, vitamin A, and iron deficiencies on gastrointestinal (GI) nematodes of humans, livestock, and laboratory rodents, and draw certain conclusions about the state of our current understanding. In general, malnutrition promotes the establishment, survival, and fecundity of these parasites, but the magnitude of the effect depends on factors such as host species, parasite species, particular infection protocol used, magnitude of the infection, severity of the nutritional deficiency, and presence of single or multiple infections and single or multiple nutritional deficiencies. We highlight the Th2 arm of the immune system as a component of primary importance in the association between malnutrition and GI nematode infections. We summarize what is known about underlying mechanisms that may account for the observed patterns. Finally, we suggest future research directions.

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.

[Risk factors for multiple intestinal parasites in an indigenous community of the State of Pernambuco, Brazil]

An investigation into the ethno-epidemiological profile of the Pankararu indigenous group in the State of Pernambuco, Brazil, identified multiple intestinal parasites in nearly all members of the community. To detect possible environmental risk factors, we used the data base from a previous survey to test relations between daily living conditions (housing, sanitation, water supply and treatment, and garbage disposal) and the number of different parasite species found in the same household. The sample consisted of 84 families from the original sample of 112. Selection was based on the number of stool tests performed in the family. The mean number of parasite species was 5.0 per family, for a mean family size of 6.1 members. This number was greater for wattle-and-daub houses (mean 6.0 parasite species vs. 4.9 for brick houses; p < 0.03) and when water used in the household was not treated (mean 5.1 parasite species, vs. 4.5 for treated water; p < 0.05). Other household characteristics and hygienic habits did not significantly influence this number. We concluded that multiple intestinal parasitism in the Pernambuco Pankararu community is frequent, to the point of being the rule, and that it relates essentially to water source and treatment.

Nutritional modulation of malaria morbidity and mortality

This review critically examines the relationship between nutritional status and malaria. The data indicate that protein-energy malnutrition is associated with greater malaria morbidity and mortality in humans. In addition, controlled trials of either vitamin A or zinc supplementation show that these nutrients can substantially reduce clinical malaria attacks. Data for iron indicate that supplementation may minimally aggravate certain malariometric indices in some settings and also strongly improve hematologic status. Withholding of iron supplements from deficient population is, therefore, not currently indicated. Available evidence for other nutrients describe varied effects, with some deficiencies being exacerbative (e.g., thiamine), protective (e.g., vitamin E), or both exacerbative and protective in different settings (e.g., riboflavin, vitamin C). The roles of folate, other B vitamins, unsaturated fatty acids, amino acids, and selenium are also examined. Study of the interactions between nutrition and malaria may provide insight to protective mechanisms and result in nutrient-based interventions as low-cost and effective adjuncts to current methods of malaria prevention and treatment.

Severe linear growth retardation in rural Zambian children: the influence of biological variables

BACKGROUND

The prevalence of stunting in preschool children in Zambia is high; stunting has detrimental effects on concurrent psychomotor development and later working capacity.

OBJECTIVE

Our objective was to investigate biological variables that may contribute to linear growth retardation in preschool children in Samfya District, Zambia.

DESIGN

Children aged 6-9 mo (n = 108) and 14-20 mo (n = 102) attending mother-and-child health clinics were included. With a mixed-longitudinal design, they were followed up 9 and 21 mo later. Height and weight of children and their mothers were measured. Biochemical measures (eg, serum zinc, retinol, thyrotropin, iron, and acute phase protein concentrations), malaria parasitemia, and intestinal parasitosis were assessed.

RESULTS

Height-for-age z scores (HAZ) were low, indicating a high prevalence of stunting (36-79%). Ninety percent of the children were anemic, 53-71% had elevated acute phase proteins, and 80% had malaria parasitemia. Regression analyses showed that maternal height predicted the children's height at 6-9 mo (regression coefficient = 0.05; 95% CI: 0.02, 0.08). The children's height at an early age (6-9 and 14-20 mo) showed a strong relation with their height at later ages (22-30 and 34-41 mo). Serum micronutrient status did not show a significant relation with later HAZ.

CONCLUSION

Unlike other studies, we did not identify specific biological factors, such as health and micronutrient status, which contribute to the retardation of linear growth. The normal zinc and iodine statuses of the children suggest that at least these factors are not causal.

Energy deficits suppress both systemic and gut immunity during infection

Protein-energy malnutrition and gastrointestinal nematode infections widely coexist in developing countries. Evidence is provided demonstrating the profound impact of dietary energy deficiency on immune function. Energy-restricted (ER) mice infected with a gastrointestinal nematode showed impaired lymphocyte proliferation and reduced production of Th2 cytokines and lower levels of IgE, parasite-specific IgG1, and eosinophils, which led to higher worm burdens and fecundity. We conclude that mild ER, without concurrent protein malnutrition, can modulate protective immunity from (a) activation early during a primary infection to (b) the expression of acquired immunity during reinfection in both systemic and gut-associated lymphoid tissues.

Nutritional status of children admitted to hospital with different diseases and its relationship to outcome in The Gambia, West Africa

Admission records from two paediatric units in The Gambia were used to explore the relationship between admission weight and different diseases. In total 13579 hospitalized children were analysed. For comparison, 7399 children were recruited from several surveys of well subjects to provide anthropometric values for healthy Gambian children. Compared to the control children, mean admission weights were lower for malaria (weight for age z-score: -1.602), cerebral malaria (-1.547), transfused malarial anaemia (-1.764), pneumonia (-1.725), meningitis (-1.362), gastro-enteritis (-2.497) and malnutrition (-3.786). Children with bronchiolitis did not have a significantly different weight for age than the controls. Outcome of the hospital admission was recorded and related to the weight on admission. In all disease categories the death rate rose with decreasing admission weight with the exception of bronchiolitis. For all diseases taken together, case fatality was 7.2% for children with a weight for age z-score above -2 Standard Deviations (SD), 9.3% between -2 and -3 SD, 15.6% between -3 and -4 SD and 22.7% for children with weight for age SD z-scores less than -4. Malnourished children are more susceptible to several infectious diseases frequently seen in developing countries and nutritional interventions, as well as standard treatment, may improve outcome.