Gastrointestinal nematodes, nutrition and immunity: breaking the negative spiral

Infection status of masu salmon Oncorhynchus masou by the parasite Salmonema cf. ephemeridarum (Nematoda, Cystidicolidae)

Nematodes that parasitize salmonids are found in both seawater and freshwater. Unlike seawater species such as those in family Anisakidae, freshwater species have not been well studied. In particular, the influences of these nematodes on the body condition of salmonids remain unclear. We studied the effects of Salmonema cf. ephemeridarum on the body condition of masu salmon Oncorhynchus masou. We found a positive relationship between the number of parasites and fish fork length. In contrast, we found a negative relationship between the body condition (condition factor) of fish and the number of parasites. These results suggest that nematode infection could affect host energy reserves for future growth.

Omnivore diet composition alters parasite resistance and host condition

Diet composition modulates animals' ability to resist parasites and recover from stress. Broader diet breadths enable omnivores to mount dynamic responses to parasite attack, but little is known about how plant/prey mixing might influence responses to infection. Using omnivorous deer mice (Peromyscus maniculatus) as a model, we examine how varying plant and prey concentrations in blended diets influence resistance and body condition following infestation by Rocky Mountain wood ticks (Dermacentor andersoni). In two repeated experiments, deer mice fed for 4 weeks on controlled diets that varied in proportions of seeds and insects were then challenged with 50 tick larvae in two sequential infestations. The numbers of ticks successfully feeding on mice declined by 25% and 66% after the first infestation (in the first and second experiments, respectively), reflecting a pattern of acquired resistance, and resistance was strongest when plant/prey ratios were more equally balanced in mouse diets, relative to seed-dominated diets. Diet also dramatically impacted the capacity of mice to cope with tick infestations. Mice fed insect-rich diets lost 15% of their body weight when parasitized by ticks, while mice fed seed-rich diets lost no weight at all. While mounting/maintaining an immune response may be energetically demanding, mice may compensate for parasitism with fat and carbohydrate-rich diets. Altogether, these results suggest that a diverse nutritional landscape may be key in enabling omnivores' resistance and resilience to infection and immune stressors in their environments.

Preschool child growth attainment and velocity during an agriculture intervention in rural Panama may be diminished by soil-transmitted helminths

Background

Agricultural interventions are often recommended to address undernutrition in subsistence farming communities. However, intensified agriculture exposure can increase soil transmitted helminth (STH) infections, which are linked with poor child growth. This study examined impacts of the VERASAN public health and agricultural intervention program on preschool child growth attainment (HAZ and WAZ) and relative growth velocity over 7 months [change in height-for-age (∆HAD) and weight-for-age (∆WAD) difference].

Methods

VERASAN was initiated in 15 subsistence farming communities in rural Panama experiencing chronic undernutrition. Activities targeted improved household food security, preschool child diets and growth by intensifying and diversifying household agriculture. Our objectives were to explore the relationship between VERASAN and preschool child growth attainment (HAZ and WAZ) and velocity (∆HAD and ∆WAD) during one agricultural cycle in 238 households. We compared those new to VERASAN with those involved for 1 or 5 years, and identified if agricultural practices, food security, diet diversity and treatment of pre-existing STH infection were associated with growth attainment or velocity.

Results

Prior participation in VERASAN did not directly influence WAZ, HAZ or ΔHAD but VERASAN-related benefits had an indirect influence. ΔHAD was positively associated with VERASAN-associated improvements in diet diversity and food security. HAZ and WAZ during land preparation were positively associated with diet diversity and HAZ with food security during harvest. HAZ was negatively associated with children visiting the agricultural plot, consuming leafy green vegetables and pre-existing hookworm infections. Both agricultural season and STH influenced ΔWAD. Children in VERASAN for 1 or 5 years experienced growth faltering between land preparation and growing season, but not those new to VERASAN. In contrast, between growing and harvest, ∆WAD declined in children new to VERASAN compared to children in VERASAN for longer. ΔWAD from land preparation to harvest was higher with pre-existing Ascaris infection whereas it was lower between growing season and harvest for pre-existing hookworm infection.

Conclusion

In a context of preschool child growth faltering, malnutrition and STH infections, improved food security, agricultural production and diet diversity associated with VERASAN were associated with improved growth. In contrast, STH infections were negatively associated with some, but not all, growth outcomes.

Haemonchus contortus Adopt Isolate-Specific Life History Strategies to Optimize Fitness and Overcome Obstacles in Their Environment: Experimental Evidence

Gastrointestinal nematodes (GIN) use flexible life history strategies to maintain their fitness under environmental challenges. Costs incurred by a challenge to one life trait can be recouped by increasing the expression of subsequent life traits throughout their life cycle. Anticipating how parasites respond to the challenge of control interventions is critical for the long-term sustainability of the practice and to further ensure that the parasites withstand favourable adaptive responses. There is currently limited information on whether distinct populations of a GIN species respond to the same environmental challenge in a consistent manner, with similar alterations to their life history strategies or comparable fitness outcomes. This study compared the life history traits and experimental fitness of three distinct Haemonchus contortus isolates exposed to environmental challenges at both the parasitic (i.e., passage through resistant or susceptible sheep) and free-living (i.e., exposure to diverse climatic conditions) life stages. The key findings show that H. contortus maintain their fitness under challenge with isolate-specific alterations to their life history strategies. Further, partial exploration of the H. contortus isolates transcriptomes using cDNA-AFLP methods confirmed disparate expression profiles between them. These results bring fresh insights into our understanding of the non-genetic adaptive processes of GIN that may hinder the efficacy of parasite control strategies.

Evidence of MHC class I and II influencing viral and helminth infection via the microbiome in a non-human primate

Until recently, the study of major histocompability complex (MHC) mediated immunity has focused on the direct link between MHC diversity and susceptibility to parasite infection. However, MHC genes can also influence host health indirectly through the sculpting of the bacterial community that in turn shape immune responses. We investigated the links between MHC class I and II gene diversity gut microbiome diversity and micro- (adenovirus, AdV) and macro- (helminth) parasite infection probabilities in a wild population of non-human primates, mouse lemurs of Madagascar. This setup encompasses a plethora of underlying interactions between parasites, microbes and adaptive immunity in natural populations. Both MHC classes explained shifts in microbiome composition and the effect was driven by a few select microbial taxa. Among them were three taxa (Odoribacter, Campylobacter and Prevotellaceae-UCG-001) which were in turn linked to AdV and helminth infection status, correlative evidence of the indirect effect of the MHC via the microbiome. Our study provides support for the coupled role of MHC diversity and microbial flora as contributing factors of parasite infection.

The selective pressure of the major histocompatibility complex (MHC) on microbial communities, and the potential role of this interaction in driving parasite resistance has been largely neglected. Using a natural population of the primate Microcebus griseorufus, we provide correlative evidence of two outstanding findings: that MHCI and MHCII diversity shapes the composition of the gut microbiota; and that select taxa associated with MHC diversity predicted adenovirus and helminth infection status. Our study highlights the importance of incorporating the microbiome when investigating parasite-mediated MHC selection.

Investigation of some trace elements and hematological and biochemical parameters in the blood of emaciated Omani goats

Background and Aim

The analysis of hematological and biochemical parameters is widely used in assessing animal health status. Limited information is available on trace element levels and their association with hematological and biochemical parameters in Omani goats suffering from emaciation. Therefore, the current study aimed to determine the levels of some trace elements in emaciated Omani goats and their relationship with hematological and biochemical parameters.

Materials and Methods

Goats suffering from emaciation and muscular dystrophy (n=18) were compared with healthy goats (n=12). Venous blood samples for the hematological, biochemical, and trace element analysis were collected from the jugular vein.

Results

Emaciated goats showed significantly lower white blood cell, lymphocyte, and red blood cell counts than the healthy goats. In contrast, the percentages of monocytes and eosinophils were higher in emaciated goats than in healthy ones. In addition, emaciated goats showed higher levels of biochemical parameters alkaline phosphatase, alanine aminotransferase, gamma-glutamyl transferase, aspartate aminotransferase, creatine kinase, and total bilirubin but lower levels of albumin than the healthy goats. The results of trace element analysis revealed lower concentrations of zinc, iron, and selenium in serum from emaciated goats than in serum from healthy goats.

Conclusion

This study identified significant differences in the serum levels of some trace elements and hematological and biochemical parameters between healthy and emaciated Omani goats. The identified differences represent valuable diagnostic biomarkers for the evaluation of the health status of Omani goats.

Predictors of helminth parasite infection in female chacma baboons (Papio ursinus)

Helminth parasite infection can impose major consequences on host fitness. Several factors, including individual characteristics of hosts, environmental conditions, and patterns of coinfection, are thought to drive variation in parasite risk. Here, we report on four key drivers of parasite infection-phase of reproduction, steroid hormone profiles, rainfall, and patterns of coinfection-in a population of wild female chacma baboons (Papio ursinus) in South Africa. We collected data on reproductive state and hormone profiles over a 3-year span, and quantified helminth parasite burdens in 2955 fecal samples from 24 female baboons. On a host level, we found that baboons are sensitive to parasite infection during the costliest phases of the reproductive cycle: pregnant females harbored higher intensities of Protospirura eggs than cycling and lactating females; lactating and cycling females had a higher probability of Oesophagostomum infection than pregnant females; and cycling females exhibited lower Trichuris egg counts than pregnant and lactating females. Steroid hormones were associated with both immunoenhancing and immunosuppressive properties: females with high glucocorticoid concentrations exhibited high intensities of Trichuris eggs but were at low risk of Oesophagostomum infection; females with high estrogen and progestagen concentrations exhibited high helminth parasite richness; and females with high progestagen concentrations were at high risk of Oesophagostomum infection but exhibited low Protospirura egg counts. We observed an interaction between host reproductive state and progestagen concentrations in infection intensity of Protospirura: pregnant females exhibited higher intensities and non-pregnant females exhibited lower intensities of Protospirura eggs with increasing progestagen concentrations. At a population level, rainfall patterns were dominant drivers of parasite risk. Lastly, helminth parasites exhibited positive covariance, suggesting that infection probability increases if a host already harbors one or more parasite taxa. Together, our results provide a holistic perspective of factors that shape variation in parasite risk in a wild population of animals.

Association of iron supplementation and deworming with early childhood development: analysis of Demographic and Health Surveys in ten low- and middle-income countries

PURPOSE

We assessed the associations of iron supplementation and deworming separately or combined with improved early childhood development (ECD) status.

METHODS

Cross-sectional data were analyzed for 29,729 children aged 36-59 months surveyed using the Demographic and Health Surveys in ten low- and middle-income countries, where iron supplementation and deworming are recommended by the World Health Organization. In each country, we estimated linear regression models for the effects of iron supplementation and deworming individually or combined on the Early Childhood Development Index (ECDI) z score, and whether this association differed between various ECD domains and the sex and residence of the child. Estimates were pooled using random-effects meta-analyses.

RESULTS

Compared with receiving neither of the two interventions, iron supplementation plus deworming was associated with an increased ECDI z score (β = 0.13, 95% confidence interval (CI) 0.03-0.22, p = 0.009), particularly in rural residences. However, iron supplementation and deworming, individually, were not associated with the ECDI z score. Iron supplementation plus deworming was associated with higher odds of on-track development in literacy-numeracy (OR = 1.57, 95% CI 1.24-2.01, p < 0.001) and learning domains (OR = 1.27, 95% CI 1.09-1.48, p = 0.003), but not with development in the social-emotional and physical domains.

CONCLUSION

Iron supplementation plus deworming, particularly for populations who are more susceptible to iron deficiency and intestinal worm infections, could be an important intervention for improving ECD. These findings may inform the argument for the necessity of implementing iron supplementation and deworming for preschool-age children.

Protein deficiency during Trichinella spiralis infection impairs lung immunity against newborn larvae

The goal of this study was to analyse the effects of a protein-deficient (PD) diet on antibody-dependent cell-mediated cytotoxicity (ADCC) in vitro against newborn larvae (NBL) of Trichinella spiralis in the lungs of infected rats. Two groups of weaning Wistar rats received a PD diet (6.5% casein) and other two received a control diet (C, 20% casein). After ten days, one group of each diet was infected (PD_I and C_I ) with muscle larvae. Lung tissue extracts (LTE) and lung cell suspension (LCS) were obtained. PD_I had lower titres of anti-NBL antibodies in LTE than C_I . In ADCC assays using control cells, NBL mortality percentage was lower with LTE from PD_I than LTE from C_I (P < .01). In assays using control cytotoxic sera, ADCC was exerted by LCS from C_I at all days post-infection (p.i.), but only by LCS from 13 days p.i. from PD_I . ADCC assays combining LTE and LCS from the same group showed a lower response for PD_I than for C_I (P < .0001). LCS from PD_I contained lower numbers of neutrophils, eosinophils and FcεRI⁺ cells than C_I . PD may diminish ADCC activity against T spiralis NBL in lungs through alterations in specific antibodies and effector cells.

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.

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.

Effects of nutritional supplements on the re-infection rate of soil-transmitted helminths in school-age children: A systematic review and meta-analysis

Background

The effect of nutritional supplements on the re-infection rate of species-specific soil-transmitted helminth infections in school-aged children remains complex and available evidence on the subject matter has not been synthesized.

Methods

The review included randomised controlled trials (RCTs) and cluster RCTs investigating food supplements on school-aged children between the age of 4–17 years. A search for RCTs was conducted on eight databases from inception to 12^th June 2019. Cochrane Risk of Bias tool was used to assess the risk of bias in all included studies. Meta-analysis and narrative synthesis were conducted to describe and analyze the results of the review. Outcomes were summarized using the mean difference or standardized mean difference where appropriate.

Results

The search produced 1,816 records. Six studies met the inclusion criteria (five individually RCTs and one cluster RCT). Four studies reported data on all three STH species, while one study only reported data on Ascaris lumbricoides infections and the last study reported data on only hookworm infections. Overall, the risk of bias in four individual studies was low across most domains. Nutritional supplementation failed to statistically reduce the re-infection rates of the three STH species. The effect of nutritional supplements on measures of physical wellbeing in school-aged children could not be determined.

Conclusions

The findings from this systematic review suggest that nutritional supplements for treatment of STH in children should not be encouraged unless better evidence emerges. Conclusion of earlier reviews on general populations may not necessarily apply to children since children possibly have a higher re-infection rate.

High-dimensional analysis of intestinal immune cells during helminth infection

Single cell isolation from helminth-infected murine intestines has been notoriously difficult, due to the strong anti-parasite type 2 immune responses that drive mucus production, tissue remodeling and immune cell infiltration. Through the systematic optimization of a standard intestinal digestion protocol, we were able to successfully isolate millions of immune cells from the heavily infected duodenum. To validate that these cells gave an accurate representation of intestinal immune responses, we analyzed them using a high-dimensional spectral flow cytometry panel and confirmed our findings by confocal microscopy. Our cell isolation protocol and high-dimensional analysis allowed us to identify many known hallmarks of anti-parasite immune responses throughout the entire course of helminth infection and has the potential to accelerate single-cell discoveries of local helminth immune responses that have previously been unfeasible.

Survival costs of reproduction are mediated by parasite infection in wild Soay sheep

A trade-off between current and future fitness potentially explains variation in life-history strategies. A proposed mechanism behind this is parasite-mediated reproductive costs: individuals that allocate more resources to reproduction have fewer to allocate to defence against parasites, reducing future fitness. We examined how reproduction influenced faecal egg counts (FEC) of strongyle nematodes using data collected between 1989 and 2008 from a wild population of Soay sheep in the St. Kilda archipelago, Scotland (741 individuals). Increased reproduction was associated with increased FEC during the lambing season: females that gave birth, and particularly those that weaned a lamb, had higher FEC than females that failed to reproduce. Structural equation modelling revealed future reproductive costs: a positive effect of reproduction on spring FEC and a negative effect on summer body weight were negatively associated with overwinter survival. Overall, we provide evidence that parasite resistance and body weight are important mediators of survival costs of reproduction.

Costs and drivers of helminth parasite infection in wild female baboons

Helminth parasites can have wide-ranging, detrimental effects on host reproduction and survival. These effects are best documented in humans and domestic animals, while only a few studies in wild mammals have identified both the forces that drive helminth infection risk and their costs to individual fitness. Working in a well-studied population of wild baboons (Papio cynocephalus) in the Amboseli ecosystem in Kenya, we pursued two goals, to (a) examine the costs of helminth infections in terms of female fertility and glucocorticoid hormone levels and (b) test how processes operating at multiple scales-from individual hosts to social groups and the population at large-work together to predict variation in female infection risk. To accomplish these goals, we measured helminth parasite burdens in 745 faecal samples collected over 5 years from 122 female baboons. We combine these data with detailed observations of host environments, social behaviours, hormone levels and interbirth intervals (IBIs). We found that helminths are costly to female fertility: females infected with more diverse parasite communities (i.e., higher parasite richness) exhibited longer IBIs than females infected by fewer parasite taxa. We also found that females exhibiting high Trichuris trichiura egg counts also had high glucocorticoid levels. Female infection risk was best predicted by factors at the host, social group and population level: females facing the highest risk were old, socially isolated, living in dry conditions and infected with other helminths. Our results provide an unusually holistic understanding of the factors that contribute to inter-individual differences in parasite infection, and they contribute to just a handful of studies linking helminths to host fitness in wild mammals.

Quantitative genetics of gastrointestinal strongyle burden and associated body condition in feral horses

Variability in host resistance or tolerance to parasites is nearly ubiquitous, and is of key significance in understanding the evolutionary processes shaping host-parasite interactions. While ample research has been conducted on the genetics of parasite burden in livestock, relatively little has been done in free-living populations. Here, we investigate the sources of (co)variation in strongyle nematode faecal egg count (FEC) and body condition in Sable Island horses, a feral population in which parasite burden has previously been shown to negatively correlate with body condition. We used the quantitative genetic "animal model" to understand the sources of (co)variation in these traits, and tested for impacts of an important spatial gradient in habitat quality on the parameter estimates. Although FEC is significantly heritable (h ² = 0.43 ± 0.11), there was no evidence for significant additive genetic variation in body condition (h ² = 0.04 ± 0.07), and therefore there was also no significant genetic covariance between the two traits. The negative phenotypic covariance between these traits therefore does not derive principally from additive genetic effects. We also found that both FEC and body condition increase from east to west across the island, which indicates that the longitudinal environmental gradient is not responsible for the negative phenotypic association observed between these traits. There was also little evidence to suggest that quantitative genetic parameters were biased when an individual's location along the island's environmental gradient was not incorporated into the analysis. This research provides new and important insights into the genetic basis and adaptive potential of parasite resistance in free-living animals, and highlights the importance of environmental heterogeneity in modulating host-parasite interactions in wild vertebrate systems.

Impact of Micronutrients on the Immune Response of Animals

Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response. Decreased levels of natural killer, granulocyte, and phagocytic cell activity and T and B cell proliferation and trafficking are associated with inadequate levels of micronutrients, as well as increased susceptibility to various adverse health conditions, including inflammatory disorders, infection, and altered vaccine efficacy. In addition, most studies of micronutrient modulation of immune responses have been done in rodents and humans, thus limiting application to the health and well-being of livestock and companion animals. This exploratory review elucidates the role of vitamins and minerals on immune function and inflammatory responses in animals (pigs, dogs, cats, horses, goats, sheep, and cattle), with reference to rodents and humans.

Prevalence of gastrointestinal parasites in bonnet macaque and possible consequences of their unmanaged relocations

Relocation is one of the mitigating measures taken by either local people or related officers to reduce the human-bonnet macaque Macaca radiata conflict in India. The review on relocations of primates in India indicates that monkeys are unscreened for diseases or gastrointestinal parasites (henceforth endoparasites) before relocation. We collected 161 spatial samples from 20 groups of bonnet macaque across their distribution range in south India and 205 temporal samples from a group in Chiksuli in the central Western Ghats. The isolation of endoparasite eggs/cysts from the fecal samples was by the centrifugation flotation and sedimentation method. All the sampled groups, except one, had an infection of at least one endoparasite taxa, and a total of 21 endoparasite taxon were recorded. The number of helminth taxon (16) were more than protozoan (5), further, among helminths, nematodes (11) were more common than cestodes (5). Although the prevalence of Ascaris sp. (26.0%), Strongyloides sp. (13.0%), and Coccidia sp. (13.0%) were greater, the load of Entamoeba coli, Giardia sp., Dipylidium caninum and Diphyllobothrium sp. were very high. Distant groups had more similarity in composition of endoparasites taxon than closely located groups. Among all the variables, the degree of provisioning was the topmost determinant factor for the endoparasite taxon richness and their load. Temporal sampling indicates that the endoparasite infection remains continuous throughout the year. Monthly rainfall and average maximum temperature in the month did not influence the endoparasite richness. A total of 17 taxon of helminths and four-taxon of protozoan were recorded. The prevalence of Oesophagostomum sp., and Strongyloides sp., and mean egg load of Spirurids and Trichuris sp. was higher than other endoparasite taxon. The overall endoparasite load and helminth load was higher in immatures than adults, where, adult females had the highest protozoan load in the monsoon. The findings indicate that relocation of commensal bonnet macaque to wild habitat can possible to lead transmission of novel endoparasites that can affect their population. Thus, we suggest avoidance of such relocations, however, if inevitable the captured animals need to be screened and treated for diseases and endoparasites before relocations.

Protein malnutrition impairs the immune control of Trichinella spiralis infection

OBJECTIVES

We aimed to analyze the effect of a protein-deficient diet on mucosal and systemic immunity during a Trichinella spiralis infection.

METHODS

Two groups of weaning Wistar rats received a protein-deficient diet (6.5% casein) and the other two groups received a control diet (20% casein). After 10 d, one group of each diet was infected (PD_I and C_I) with muscle larvae (infecting stage). Food intake and body weight were assessed over time. Blood eosinophils counts, antibodies in serum, and tissue extracts were assessed at different days postinfection. Histologic studies were done in the lungs and intestines, and adult worm (AW) fecundity index score and muscle parasite burden were determined.

RESULTS

Food and protein intake were lower in PD_I than in C_I. Body weight was lower in PD_I than in a non-infected protein-deficient diet. Eosinophils counts were lower in PD_I than in C_I. Total and specific antibodies were lower in PD_I than C_I. PD_I had a reduced number of mast and goblet cells in the lungs and intestines compared with C_I. The persistence of AW in the intestines and migrant larvae at the lungs was longer in PD_I than in C_I.. The AW fecundity index score was higher in PD_I than in C_I. Finally, PD_I evidenced a higher muscular parasite burden than C_I.

CONCLUSIONS

Protein deficiency affects the mucosal and systemic immune response to Trichinella spiralis and delays the expulsion and increases the fecundity index score of AW, which leads to a higher parasite burden in the muscles.

Debilitating disease in a polyparasitised woylie (Bettongia penicillata): A diagnostic investigation

During monitoring of critically endangered woylie (Bettongia penicillata) populations within the south-west of Western Australia, an adult female woylie was euthanased after being found in extremely poor body condition with diffuse alopecia, debilitating skin lesions and severe ectoparasite infestation. Trypanosoma copemani G2 and Sarcocystis sp. were detected molecularly within tissue samples collected post-mortem. Potorostrongylus woyliei and Paraustrostrongylus sp. nematodes were present within the stomach and small intestine, respectively. Blood collected ante-mortem revealed the presence of moderate hypomagnesaemia, mild hypokalaemia, mild hyperglobulinaemia and mild hypoalbuminaemia. Diffuse megakaryocytic hypoplasia was evident within the bone marrow. We propose various hypotheses that may explain the presence of severe ectoparasite infection, skin disease and poor body condition in this woylie. Given the potential deleterious effects of parasite infection, the importance of monitoring parasites cannot be over-emphasised.

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Severe ectoparasite infestation, skin disease and poor body condition in a woylie.

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Trypanosoma copemani genotype 2 and Sarcocystis sp. identified molecularly in tissues.

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Clinical signs similar to those observed during the woylie decline.

Anthropogenic food provisioning and immune phenotype: Association among supplemental food, body condition, and immunological parameters in urban environments

Direct or indirect supplemental feeding of free-ranging animals occurs worldwide, resulting in significant impacts on population density or altered demographic processes. Another potential impact of increased energy intake from supplemental feeding is altered immunocompetence. As immune system maintenance is energetically costly, there may be trade-offs between immune responses and other energy-demanding physiological processes in individual animals. Although increased availability of food sources through supplemental feeding is expected to increase the overall immunocompetence of animals, empirical data verifying the association between supplemental feeding and different immune parameters are lacking. Understanding the potential influence of supplemental feeding on immune phenotypes is critical, as it may also impact host-pathogen dynamics in free-ranging animals. Using urban stray cats as a study model, we tested for associations between the intensity of supplemental feeding due to cat caretaker activity (CCA); body condition; and immune phenotype (bacterial killing assay (BKA), immunoglobulin G (IgG) concentration, and leukocyte counts). Significantly higher bacterial killing ability was observed in cats from high CCA districts, whereas higher IgG concentration and eosinophil counts were observed in cats from low CCA districts. Other leukocyte counts and body condition indices showed no significant association with CCA. We observed varying patterns of different immune components in relation to supplemental feeding. Out data suggest that supplemental feeding influences immune phenotype, not only by means of energy provisioning, but also by potentially reducing exposure rates to parasite infections through stray cat behavioral changes.

Feeding Immunity: Physiological and Behavioral Responses to Infection and Resource Limitation

Resources are a core currency of species interactions and ecology in general (e.g., think of food webs or competition). Within parasite-infected hosts, resources are divided among the competing demands of host immunity and growth as well as parasite reproduction and growth. Effects of resources on immune responses are increasingly understood at the cellular level (e.g., metabolic predictors of effector function), but there has been limited consideration of how these effects scale up to affect individual energetic regimes (e.g., allocation trade-offs), susceptibility to infection, and feeding behavior (e.g., responses to local resource quality and quantity). We experimentally rewilded laboratory mice (strain C57BL/6) in semi-natural enclosures to investigate the effects of dietary protein and gastrointestinal nematode (Trichuris muris) infection on individual-level immunity, activity, and behavior. The scale and realism of this field experiment, as well as the multiple physiological assays developed for laboratory mice, enabled us to detect costs, trade-offs, and potential compensatory mechanisms that mice employ to battle infection under different resource conditions. We found that mice on a low-protein diet spent more time feeding, which led to higher body fat stores (i.e., concentration of a satiety hormone, leptin) and altered metabolite profiles, but which did not fully compensate for the effects of poor nutrition on albumin or immune defenses. Specifically, immune defenses measured as interleukin 13 (IL13) (a primary cytokine coordinating defense against T. muris) and as T. muris-specific IgG1 titers were lower in mice on the low-protein diet. However, these reduced defenses did not result in higher worm counts in mice with poorer diets. The lab mice, living outside for the first time in thousands of generations, also consumed at least 26 wild plant species occurring in the enclosures, and DNA metabarcoding revealed that the consumption of different wild foods may be associated with differences in leptin concentrations. When individual foraging behavior was accounted for, worm infection significantly reduced rates of host weight gain. Housing laboratory mice in outdoor enclosures provided new insights into the resource costs of immune defense to helminth infection and how hosts modify their behavior to compensate for those costs.

Strongyloides stercoralis is associated with significant morbidity in rural Cambodia, including stunting in children

Background

Strongyloides stercoralis is a soil-transmitted nematode that can replicate within its host, leading to long-lasting and potentially fatal infections. It is ubiquitous and highly prevalent in Cambodia. The extent of morbidity associated with S. stercoralis infection is difficult to assess due to the broad spectrum of symptoms and, thus, remains uncertain.

Methodology/Principal findings

Clinical signs were compared among S. stercoralis infected vs. non-infected participants in a cross-sectional survey conducted in 2012 in eight villages of Northern Cambodia, and before and after treatment with a single oral dose of ivermectin (200μg/kg BW) among participants harboring S. stercoralis. Growth retardation among schoolchildren and adolescents was assessed using height-for-age and thinness using body mass index-for-age. S. stercoralis prevalence was 31.1% among 2,744 participants. Urticaria (55% vs. 47%, OR: 1.4, 95% CI: 1.1–1.6) and itching (52% vs. 48%, OR: 1.2, 95% CI: 1.0–1.4) were more frequently reported by infected participants. Gastrointestinal, dermatological, and respiratory symptoms were less prevalent in 103 mono-infected participants after treatment. Urticaria (66% vs. 11%, OR: 0.03, 95% CI: 0.01–0.1) and abdominal pain (81 vs. 27%, OR: 0.07, 95% CI: 0.02–0.2) mostly resolved by treatment. S. stercoralis infection was associated with stunting, with 2.5-fold higher odds in case of heavy infection.

Conclusions/Significance

The morbidity associated with S. stercoralis confirmed the importance of gastrointestinal and dermatological symptoms unrelated to parasite load, and long-term chronic effects when associated with malnutrition. The combination of high prevalence and morbidity calls for the integration of S. stercoralis into ongoing STH control measures in Cambodia.

Strongyloides stercoralis is an intestinal parasite that infects humans by penetrating intact skin. It thrives particularly in tropical countries with poor sanitation. Because it can replicate within its host, it causes long-lasting infections and is potentially fatal in patients with a disseminated infection. S. stercoralis is largely neglected due to the difficulty in detecting it with standard field diagnostic techniques but has recently been found to be very common in Cambodia, with prevalence rates exceeding 40%. It is difficult to identify symptoms associated with infection in endemic areas because co-infections with other helminths or protozoan parasites, which cause similar health problems, are common. We compared clinical signs in infected vs. non-infected participants living in eight villages in Northern Cambodia, and before and after treatment with ivermectin, the drug of choice against S. stercoralis, among 103 patients infected with S. stercoralis only. We also assessed the association between infection and growth retardation among children and adolescents. Of the participants, 31.1% were infected with S. stercoralis. Infected participants were more likely to report itching and urticaria. After treatment, fewer participants reported urticaria, abdominal pain, vomiting and, to a lesser extent, nausea, diarrhea, cough, and tiredness. S. stercoralis infection was associated with growth retardation as expressed by stunting.

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.

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

Background

Weekly iron-folic acid (IFA) supplementation and regular deworming is effective for the prevention of iron deficiency and anaemia in women of child-bearing age. Between 2006 and 2013, a program of weekly IFA and biannual deworming was implemented in Yen Bai province, Vietnam. In this study we aimed to determine the effectiveness of the program in reducing anaemia and the prevalence of hookworm infection after 72 months (six years).

Methods

This prospective cohort study followed up a cohort of 389 women of child-bearing age from baseline until six years after the introduction of the weekly IFA (one tablet containing 200 mg ferrous sulphate, 0.4mg folic acid) and deworming (one 400mg tablet of albendazole given twice yearly) program (May 2006 to 2012). In each of the six surveys (baseline and five follow-up surveys) we measured haemoglobin and ferritin, and the burden of soil transmitted helminth (STH) infections, and in the 72 month survey we also administered a questionnaire to assess adherence and possible impediments to participating in the program.

Results

Two hundred and fifty six (65.8%) of the original 389 women enrolled in the cohort attended the final 72 month survey. Haemoglobin levels were 122 g/L [95% C.I. 120, 124] at baseline and increased to 135g/L [95% C.I. 133, 138] after 72 months. The prevalence of anaemia was 37.8% [95% C.I. 31.0, 44.7] at baseline and reduced to 14.3% [95% C.I. 9.5, 19.1]. Hookworm infection prevalence, 75.9% [95% C.I. 68.1, 83.8] at baseline, reduced to 10.2% [95% C.I. 5.4, 15.0] with no moderate or heavy intensity infections. Seventy-two percent of participants reported still taking at least 75% of the weekly supplements, and 85.0% had taken the most recent deworming treatment.

Discussion

Anaemia rates fell significantly during the six-year program, and STH infections were eliminated as a public health risk. Adherence was well maintained but long-term sustainability is challenging in the absence of ongoing external support.

Weekly iron-folic acid (IFA) supplementation combined with regular deworming for women of child bearing age is effective in the prevention of iron deficiency and anaemia. Following a baseline survey, a weekly IFA and regular deworming project was implemented in Yen Bai province, Vietnam in 2006, and after 12 months expanded to the entire province. Haematological parameters, soil transmitted helminth (STH) burden and adherence to the program were monitored periodically until 2012. We found anaemia prevalence fell from 37.8% to 14.3% during the six-year period, and haemoglobin levels increased from 122 g/L to 135g/L. STH infections were essentially eliminated as a public health risk. Seventy-two percent of participants continued to take at least 75% of the weekly supplements, and 85.0% took the most recent deworming treatment. These results show that prevention of anaemia in women of child-bearing age with weekly IFA and regular deworming is feasible and effective over a prolonged period. However, long-term sustainability may be a major challenge in some settings in the absence of ongoing external support.

Parasites, nutrition, immune responses and biology of metabolic tissues

Nutritional immunology, immunometabolism and identification of novel immunotherapeutic targets are areas of active investigation in parasitology. There is a well-documented crosstalk among immune cells and cells in metabolically active tissues that is important for homeostasis. The numbers and function of these cells are altered by obesity leading to inflammation. A variety of helminths spend some part of their life cycle in the gastrointestinal tract and even entirely enteral nematode infections exert beneficial effects on glucose and lipid metabolism. The foundation of this review is the ability of enteric nematode infections to improve obesity-induced type 2 diabetes and the metabolic syndrome, which are significant health issues in developed areas. It considers the impact of nutrition and specific nutritional deficiencies, which are occur in both undeveloped and developed areas, on the host's ability mount a protective immune response against parasitic nematodes. There are a number of proposed mechanisms by which parasitic nematodes can impact metabolism including effects gastrointestinal hormones, altering epithelial function and changing the number and/or phenotype of immune cells in metabolic tissues. Nematodes can also exert their beneficial effects through Th2 cytokines that activate the transcription factor STAT6, which upregulates genes that regulate glucose and lipid metabolism.

Impact of single annual treatment and four-monthly treatment for hookworm and Ascaris lumbricoides, and factors associated with residual infection among Kenyan school children

Background

School-based deworming is widely implemented in various countries to reduce the burden of soil-transmitted helminths (STHs), however, the frequency of drug administration varies in different settings. In this study, we compared the impact of a single annual treatment and 4-monthly treatment over a follow-up among Kenyan school children, and investigated the factors associated with residual infection.

Methods

We performed a secondary analysis of data from a randomized trial investigating whether deworming for STHs alters risk of acquiring malaria. Children received either a single treatment or 4-monthly albendazole treatments were followed longitudinally from February 2014 to October 2014. The relative impact of treatment and factors associated with residual infections were investigated using mixed-effects regression models. Predisposition to infection was assessed based on Spearman’s rank and Kendall’s Tau correlation coefficients.

Results

In the 4-monthly treatment group, the proportion of children infected with hookworm decreased from 59.9 to 5.7%, while Ascaris lumbricoides infections dropped from 55.7 to 6.2%. In the single treatment group, hookworm infections decreased over the same time period from 58.7 to 18.3% (12.6% absolute difference in reduction, 95% CI: 8.9–16.3%), and A. lumbricoides from 56.7 to 23.3% (17.1% absolute difference in reduction, 95% CI: 13.1–21.1%). There was strong evidence for predisposition to both STH types. Residual hookworm infection among children on 4-monthly treatment were associated with male sex and baseline nutritional status, whereas A. lumbricoides infection was associated with individual and school-level infection at baseline, latrine cleanliness at schools.

Conclusions

This study found that 4-monthly treatment w more effective than single annual treatment. Repeated treatments led to dramatic reductions in the intensities of STHs, but did not completely clear infections among school children in Kenya, a presumed reflection of reinfection in a setting where there is ongoing transmission.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0244-z) contains supplementary material, which is available to authorized users.

Effectiveness of Albendazole for Hookworm Varies Widely by Community and Correlates with Nutritional Factors: A Cross-Sectional Study of School-Age Children in Ghana

Mass drug administration (MDA) targeting school-age children is recommended by the World Health Organization for the global control of soil-transmitted helminth (STH) infections. Although considered safe and cost-effective to deliver, benzimidazole anthelminthics are variably effective against the three most common STHs, and widespread use has raised concern about the potential for emerging resistance. To identify factors mediating response to albendazole, we conducted a cross-sectional study of hookworm infection in the Kintampo North Municipality of Ghana in 2011. Among 140 school-age children residing in five contiguous communities, the hookworm prevalence was 59% (82/140). The overall cure rate following administration of single-dose albendazole (400 mg) was 35% (27/76), with a community-wide fecal egg reduction rate (ERR) of 61% (95% confidence interval: 51.8-71.1). Significant disparities were observed in albendazole effectiveness by community, with a cure rate as low as 0% (N = 24) in Jato Akuraa and ERRs ranging from 53% to 95% across the five study sites. Individual host factors associated with response to deworming treatment included time since last meal, pretreatment blood hemoglobin level, and mid-upper arm circumference. These data demonstrate significant community-level variation in the effectiveness of albendazole, even among populations living in close proximity. Identification of host factors that influence response to albendazole, most notably the timing of drug administration and nutritional factors, creates an opportunity to enhance the effectiveness of deworming through targeted interventions. These findings also demonstrate the importance of measuring anthelminthic response as part of the monitoring and evaluation of community-based deworming programs.

Opportunities and challenges of Integral Projection Models for modelling host-parasite dynamics

Epidemiological dynamics are shaped by and may in turn shape host demography. These feedbacks can result in hard to predict patterns of disease incidence. Mathematical models that integrate infection and demography are consequently a key tool for informing expectations for disease burden and identifying effective measures for control.

A major challenge is capturing the details of infection within individuals and quantifying their downstream impacts to understand population‐scale outcomes. For example, parasite loads and antibody titres may vary over the course of an infection and contribute to differences in transmission at the scale of the population. To date, to capture these subtleties, models have mostly relied on complex mechanistic frameworks, discrete categorization and/or agent‐based approaches.

Integral Projection Models (IPMs) allow variance in individual trajectories of quantitative traits and their population‐level outcomes to be captured in ways that directly reflect statistical models of trait–fate relationships. Given increasing data availability, and advances in modelling, there is considerable potential for extending this framework to traits of relevance for infectious disease dynamics.

Here, we provide an overview of host and parasite natural history contexts where IPMs could strengthen inference of population dynamics, with examples of host species ranging from mice to sheep to humans, and parasites ranging from viruses to worms. We discuss models of both parasite and host traits, provide two case studies and conclude by reviewing potential for both ecological and evolutionary research.

Investment in constitutive immune function by North American elk experimentally maintained at two different population densities

Natural selection favors individuals that respond with effective and appropriate immune responses to macro or microparasites. Animals living in populations close to ecological carrying capacity experience increased intraspecific competition, and as a result are often in poor nutritional condition. Nutritional condition, in turn, affects the amount of endogenous resources that are available for investment in immune function. Our objective was to understand the relationship between immune function and density dependence mediated by trade-offs between immune function, nutritional condition, and reproduction. To determine how immune function relates to density-dependent processes, we quantified bacteria killing ability, hemolytic-complement activity, and nutritional condition of North American elk (Cervus elaphus) from populations maintained at experimentally high- and low-population densities. When compared with elk from the low-density population, those from the high-density population had higher bacteria killing ability and hemolytic-complement activity despite their lower nutritional condition. Similarly, when compared with adults, yearlings had higher bacteria killing ability, higher hemolytic-complement activity, and lower nutritional condition. Pregnancy status and lactational status did not change either measure of constitutive immunity. Density-dependent processes affected both nutritional condition and investment in constitutive immune function. Although the mechanism for how density affects immunity is ambiguous, we hypothesize two possibilities: (i) individuals in higher population densities and in poorer nutritional condition invested more into constitutive immune defenses, or (ii) had higher parasite loads causing higher induced immune responses. Those explanations are not mutually exclusive, and might be synergistic, but overall our results provide stronger support for the hypothesis that animals in poorer nutritional condition invest more in constitutive immune defenses then animals in better nutritional condition. This intriguing hypothesis should be investigated further within the larger framework of the cost and benefit structure of immune responses.

Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE)

An increasing recognition has emerged of the complexities of the global health agenda—specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and the development and function of the immune and inflammatory response and 2) the specific impact of the inflammatory response on the selection, use, and interpretation of nutrient biomarkers. The goal of the Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE) is to provide guidance for those users represented by the global food and nutrition enterprise. These include researchers (bench and clinical), clinicians providing care/treatment, those developing and evaluating programs/interventions at scale, and those responsible for generating evidence-based policy. The INSPIRE process included convening 5 thematic working groups (WGs) charged with developing summary reports around the following issues: 1) basic overview of the interactions between nutrition, immune function, and the inflammatory response; 2) examination of the evidence regarding the impact of nutrition on immune function and inflammation; 3) evaluation of the impact of inflammation and clinical conditions (acute and chronic) on nutrition; 4) examination of existing and potential new approaches to account for the impact of inflammation on biomarker interpretation and use; and 5) the presentation of new approaches to the study of these relations. Each WG was tasked with synthesizing a summary of the evidence for each of these topics and delineating the remaining gaps in our knowledge. This review consists of a summary of the INSPIRE workshop and the WG deliberations.

Height, zinc and soil-transmitted helminth infections in schoolchildren: a study in Cuba and Cambodia

Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle-income countries and are both known to affect child growth. However, studies combining data on zinc and STH are lacking. In two studies in schoolchildren in Cuba and Cambodia, we collected data on height, STH infection and zinc concentration in either plasma (Cambodia) or hair (Cuba). We analyzed whether STH and/or zinc were associated with height for age z-scores and whether STH and zinc were associated. In Cuba, STH prevalence was 8.4%; these were mainly Ascaris lumbricoides and Trichuris trichiura infections. In Cambodia, STH prevalence was 16.8%, mostly caused by hookworm. In Cuban children, STH infection had a strong association with height for age (aB-0.438, p = 0.001), while hair zinc was significantly associated with height for age only in STH uninfected children. In Cambodian children, plasma zinc was associated with height for age (aB-0.033, p = 0.029), but STH infection was not. Only in Cambodia, STH infection showed an association with zinc concentration (aB-0.233, p = 0.051). Factors influencing child growth differ between populations and may depend on prevalences of STH species and zinc deficiency. Further research is needed to elucidate these relationships and their underlying mechanisms.

IL-17 and neutrophils: unexpected players in the type 2 immune response

The study of immunity to helminth infection has been central to understanding the function of type 2 cytokines and their targets. Although type 2 cytokines are considered anti-inflammatory and promote tissue repair, they also contribute to allergy and fibrosis. Here, we utilise data from helminth infection models, to illustrate that IL-17 and neutrophils, typically associated with pro-inflammatory responses, are intimately linked with type 2 immunity. Neutrophils work with IL-4Rα-activated macrophages to control incoming larvae but this comes at a cost of enhanced tissue damage. Chitinase like proteins (CLPs) bridge these diverse outcomes, inducing both protective IL-17 and reparative Th2 responses. Dysregulation of CLPs, IL-17 and neutrophils likely contribute to disease severity and pathology associated with type 2 immunity.

Quadruple burden of HIV/AIDS, tuberculosis, chronic intestinal parasitoses, and multiple micronutrient deficiency in ethiopia: a summary of available findings

Human immunodeficiency virus (HIV), tuberculosis (TB), and helminthic infections are among the commonest public health problems in the sub-Saharan African countries like Ethiopia. Multiple micronutrient deficiencies also known as the “hidden hunger” are common in people living in these countries either playing a role in their pathogenesis or as consequences. This results in a vicious cycle of multiple micronutrient deficiencies and infection/disease progression. As infection is profoundly associated with nutritional status resulting from decreased nutrient intake, decreased nutrient absorption, and nutrient losses, micronutrient deficiencies affect immune system and impact infection and diseases progression. As a result, micronutrients, immunity, and infection are interrelated. The goal of this review is therefore to provide a summary of available findings regarding the “quadruple burden trouble” of HIV, TB, intestinal parasitic infections, and multiple micronutrient deficiencies to describe immune-modulating effects related to disorders.

Clinical aspects of paediatric visceral leishmaniasis in North-west Ethiopia

OBJECTIVE

Visceral leishmaniasis (VL) in north-west Ethiopia is causing an overwhelming case load among adult migrant workers that masked the disease burden in children. This study describes the clinical profile and explores comorbidities in paediatric VL patients.

METHODS

A prospective study at two hospitals in this region (Gondar and Humera) was conducted in a year period, 2011-2012. The clinical manifestations and comorbidities such as malnutrition, intestinal parasitosis and vitamin D deficiency and HIV infection were assessed, and treatment outcomes noted.

RESULTS

A total of 122 children with VL were detected during the study period with median age of 8.5 years (IQR 5-12 years); 23% were under 5 years. Eighty-five (69.7%) cases were male. The clinical manifestations were similar to the adult patients. High rates of malnutrition, intestinal parasitosis (47.5%) and hypovitaminosis D (56.4%) were detected. The proportion of stunting and wasting was 63% and 22.2% in children aged under five years, and 50.5% and 75.9% in 5-year and older children, respectively, using WHO standard growth curves. Only one child had HIV infection. In 95% of the cases, sodium stibogluconate (20 mg/kg/day for 30 days) was used for treatment. The treatment success rate at end of therapy was 98.3%, but the definitive outcome at 6 months could not be determined because of a high loss to follow-up (80.2%).

CONCLUSION

While HIV co-infection was rare, malnutrition, intestinal parasitosis and vitamin D deficiency were frequent indicating the need for further research on their role in the pathophysiology. Meanwhile, systematic assessment and management of malnutrition and intestinal parasitosis in VL programmes is recommended.

Helminth infections and micronutrients in school-age children: a systematic review and meta-analysis

BACKGROUND

Helminth infections and micronutrient deficiencies are highly prevalent in developing countries. Neither condition typically causes overt disease, but they do lead to indirect morbidity such as impaired physical and cognitive development.

OBJECTIVE

We aimed to systematically review current evidence on the relation of helminth infections with micronutrient status in school-age children worldwide.

DESIGN

We included both observational studies and randomized controlled trials (RCTs). We applied a random-effects meta-analysis to estimate 1) cross-sectional associations between helminths and micronutrient status, 2) effects of anthelminthic treatment on micronutrient status, and 3) effects of micronutrient supplementation on helminth infection and reinfection.

RESULTS

Meta-analyses of observational studies showed an association between helminth infections and serum retinol [standardized mean difference (SMD): -0.30; 95% CI: -0.48, -0.13] but not serum ferritin (SMD: 0.00; 95% CI: -0.7, 0.7). Conversely, meta-analyses of anthelminthic treatment RCTs showed a positive effect on ferritin (SMD: 0.16; 95% CI: 0.09, 0.22) but not retinol (SMD: 0.04; 95% CI: -0.06, 0.14). The number of studies on micronutrients other than ferritin and retinol was not sufficient for pooling. Meta-analyses of micronutrient-supplementation RCTs showed only a modest protective effect for multimicronutrient interventions on helminth infection and reinfection rates (OR: 0.77; 95% CI: 0.61, 0.97).

CONCLUSIONS

In this review, we show evidence of distinct associations between helminth infections and micronutrients in school-age children. More studies are needed on micronutrients other than iron and vitamin A and on possible helminth species-specific effects. A thorough comprehension of the interplay between helminth infections and micronutrients will help guide integrated and sustainable intervention strategies in affected children worldwide.

Influence of nutrition on infection and re-infection with soil-transmitted helminths: a systematic review

Background

The relationship between nutrition and soil-transmitted helminthiasis is complex and warrants further investigation. We conducted a systematic review examining the influence of nutrition on infection and re-infection with soil-transmitted helminths (i.e. Ascaris lumbricoides, hookworm, Trichuris trichiura and Strongyloides stercoralis) in humans. Emphasis was placed on the use of nutritional supplementation, alongside anthelminthic treatment, to prevent re-infection with soil-transmitted helminths.

Methods

We searched eight electronic databases from inception to 31 July 2013, with no restriction of language or type of publication. For studies that met our inclusion criteria, we extracted information on the soil-transmitted helminth species, nutritional supplementation and anthelminthic treatment. Outcomes were presented in forest plots and a summary of findings (SoF) table. An evidence profile (EP) was generated by rating the evidence quality of the identified studies according to the GRADE system.

Results

Fifteen studies met our inclusion criteria; eight randomised controlled trials and seven prospective cohort studies. Data on A. lumbricoides were available from all studies, whereas seven and six studies additionally contained data on T. trichiura and hookworm, respectively. None of the studies contained data on S. stercoralis. Positive effects of nutritional supplementation or the host’s natural nutritional status on (re-)infection with soil-transmitted helminths were reported in 14 studies, while negative effects were documented in six studies. In terms of quality, a high, low and very low quality rating was assigned to the evidence from four, six and five studies, respectively.

Conclusions

Our findings suggest that the current evidence-base is weak, precluding guidelines on nutrition management as a potential supplementary tool to preventive chemotherapy targeting soil-transmitted helminthiasis. Moreover, several epidemiological, immunological and methodological issues have been identified, and these should be considered when designing future studies.

Effect of Bifidobacterium animalis on mice infected with Strongyloides venezuelensis

The administration of viable Bifidobacterium animalis was tested to induce resistance against Strongyloides venezuelensis infection in mice. Effects on parasite burden, worm length, egg output, and intestinal mucosal histology were evaluated. The oral administration of B. animalis, strain 04450B, starting 14 days before the inoculation of nematode larvae significantly decreased the worm burden and egg output. In probiotic treated animals, the percent reduction of adult worms in the intestine was of 33% and the reduction of egg production was of 21%, compared with those of the control group. The duodenum villous height and villous/crypt ratio were significantly higher in probiotic-treated mice, indicating that this group could be experiencing less intestinal damage. The present findings revealed that the administration of B. animalis for the amelioration of host response to nematode infections is biologically plausible and could have some potential for impacting public health. Meanwhile, further study is needed to delineate the nature and identity of the factor(s) involved in these beneficial effects.