Worm Infections in Children

From evidence to practice: A systematic review-based diagnostic algorithm for paediatric eosinophilia across socioeconomic context

AIM

Paediatric eosinophilia is a common clinical dilemma, often leading to resource- and time-consuming assessments. We aim to evaluate the main aetiologies of eosinophilia in children from different socioeconomic settings and propose a diagnostic algorithm.

METHODS

A systematic literature review was conducted through PubMed, Embase and the Cochrane Library. Studies published from January 2012 to June 2023 reporting the incidence and aetiology of peripheral eosinophilia in children were included. Evidence from studies on children originating from low- or high-income countries was compared.

RESULTS

A total of 15 observational studies, encompassing 3409 children, were included. The causes of eosinophilia varied based on the children's origin and the eosinophilia severity. In children from high-income countries, allergic diseases were the leading cause, with a prevalence of 7.7%-78.2%, while parasitosis ranged from 1.0% to 9.1%. In children from low-income countries, parasitosis was predominant, ranging from 17.7% to 88.3%, although allergic diseases were found in 2.5%-4.8% of cases. Concerning severity, allergic diseases were the leading cause of mild-to-moderate eosinophilia; parasitosis was associated with moderate-to-severe eosinophilia, while immunological disorders were mostly found in severe cases.

CONCLUSION

We developed a step-up diagnostic algorithm that considers the child's origin and eosinophilia severity and could optimise resource allocation.

An update on the current and emerging pharmacotherapy for the treatment of human ascariasis

INTRODUCTION

Globally, Ascaris lumbricoides is the commonest helminthic infection that affects people in underdeveloped countries and returning immigrants in industrialized nations. This article aims to provide latest updates on the epidemiology, clinical manifestations, and pharmacotherapy of ascariasis.

AREAS COVERED

A PubMed search was conducted using Clinical Queries and the key terms 'human ascariasis' OR 'Ascaris lumbricoides.' Ascaris lumbricoides is highly endemic in tropical and subtropic regions and among returning immigrants in industrialized nations. Predisposing factors include poor sanitation and poverty. The prevalence is greatest in young children. Most infected patients are asymptomatic. Patients with A. lumbricoides infection should be treated with anti-helminthic drugs to prevent complications from migration of the worm. Mebendazole and albendazole are indicated for children and nonpregnant women. Pregnant individuals should be treated with pyrantel pamoate.

EXPERT OPINION

Cure rates with anthelmintic treatment are high. No emerging pharmacotherapy can replace these existing drugs of good efficacy, safety profile and low cost for public health. It is opinioned that advances in the management of ascariasis include diagnostic accuracy at affordable costs, Emodepside is highly effective in single doses against ascarids in mammals and in human trials. The drug could be registered for human use in multiple neglected tropical diseases.

The role of helminths in the development of non-communicable diseases

Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.

Important Nematodes in Children

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

Transient Ascaris suum larval migration induces intractable chronic pulmonary disease and anemia in mice

Ascariasis is one of the most common infections in the world and associated with significant global morbidity. Ascaris larval migration through the host’s lungs is essential for larval development but leads to an exaggerated type-2 host immune response manifesting clinically as acute allergic airway disease. However, whether Ascaris larval migration can subsequently lead to chronic lung diseases remains unknown. Here, we demonstrate that a single episode of Ascaris larval migration through the host lungs induces a chronic pulmonary syndrome of type-2 inflammatory pathology and emphysema accompanied by pulmonary hemorrhage and chronic anemia in a mouse model. Our results reveal that a single episode of Ascaris larval migration through the host lungs leads to permanent lung damage with systemic effects. Remote episodes of ascariasis may drive non-communicable lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), and chronic anemia in parasite endemic regions.

Ascariasis is the most common helminth infection and leads to significant global morbidity. Transient Ascaris larval migration through the host’s lungs is essential for larval development but leads to an exaggerated type-2 host immune response. Our work demonstrates that transient Ascaris spp. larval migration through the lungs has significant long-term consequences including changes in lung structure and function as well as vascular damage causing chronic lung disease and anemia. We propose that Ascaris spp. larval migration through the host lungs is a risk factor for the development of chronic lung disease and anemia in parasite-endemic regions globally.

Spatial variation and determinants of childhood anemia among children aged 6 to 59 months in Ethiopia: further analysis of Ethiopian demographic and health survey 2016

BACKGROUND

The magnitude of childhood anemia was increased from time to time. Thus, Even if the Ethiopian government applied tremendous efforts, anemia in children continues as a major public health problem. There is limited evidence on the spatial variation of and determinant factors of childhood anemia at the national level. Therefore, this study aimed to explore spatial distribution and determinants of anemia among children aged 6 to 59 months in Ethiopia.

METHOD

A stratified two-stage cluster sampling technique was used in Ethiopian Demographic Health Survey 2016 data. In this study 8602 children aged 6-59 months were included. Bernoulli model was used to explore the presence of purely spatial clusters of Anemia in children in age 6-59 months using Sat scan. ArcGIS version 10.3 was used to know the distribution of anemia cases across the country. A mixed-effects Logistic regression model was used to identify determinant factors of anemia.

RESULTS

The finding indicates that the spatial distribution of childhood anemia was non-random in the country with Moran's I: 0.65, p < 0.001. The SaT scan analysis identified a total of 180 significant primary clusters located in the Somali and Afar regions (LLR = 14.47, P-value< 0.001, RR = 1.47). Age of child 12-23 months (AOR = 0, 68, 95%CI: 0.55, 0.85), 24-35 months (AOR = 0.38, 95%CI: 0.31, 0.47), and36-47 months (AOR = 0.25, 95%CI, 0.20, 0.31), working mother (AOR = 0.87, 95%CI: 0.76, 0.99), anemic mother (AOR = 1.53, 95%CI, 1.35, 1.73), had fever in the last 2 weeks (AOR = 1.36,95%CI:1.13, 1.65), moderate stunting (AOR = 1.31,95%CI: 1.13, 1.50),Severely stunting (AOR = 1.82,95%CI: 1.54, 2.16), religion, wealth index, and number of under-five children in the household were statistically significant associated with childhood anemia.

CONCLUSION

Spatial variation of childhood anemia across the country was non-random. Age of the child, wealth index, stunting, religion, number of under-five children in the household, fever in the last 2 weeks, anemic mother, and working status of the mother were determinants of childhood anemia. Therefore, interventions should be a priority concern for high-risk (hot spot) areas regarding allocation of resources and improved access to health facilities, and to reduce the consequence of anemia among the generation policymakers and concerned bodies should be implemented these specific determinant factors.

Spatial variations and determinants of anemia among under-five children in Ethiopia, EDHS 2005-2016

BACKGROUND

Anemia has severe public health significance in sub-Saharan Africa. In Ethiopia, anemia has been increasing in the last two decades, reaching the highest national level in 2016, however, the geospatial distribution and determinants of anemia in children weren't well explored at a national level.

METHODS

We used the Ethiopian Demographic and Health Survey(EDHS) data from 2005-2016. The data consists of samples of households (HHs) obtained through a two-stage stratified sampling procedure. Our analysis included 19,699 children. Descriptive statistics, geospatial analysis, and Generalized Linear Mixed Model (GLMMs) were used.

RESULTS

The overall prevalence of anemia was 51.5%; the spatial distribution of anemia significantly different across clusters in each survey. Children from 6 to 11 months had higher odds of anemia compared to 24-59 months (Adjusted Odds ratio (AOR) = 3.4, 95%Confidence level (CI): 2.99-3.76). Children with the first and second birth order were less likely to be anemic compared to fifth and above (AOR = 0.60, 95%CI: 0.38-0.95, and AOR = 0.83, 95%C: 0.73-0.93) respectively. Mothers' age 15 to 24 years was associated with higher odds of anemia compared to 35 to 49 years (AOR = 1.37, 95%CI: 1.20-1.55). Children from HHs with the poorest and poorer wealth category showed a higher odds of anemia compared to the richest (AOR = 1.67, 95%CI: 1.45-1.93, and AOR = 1.25, 95%CI: 1.08-1.45) respectively. Moreover, children from HHs with one to two under-five children were less likely to be anemic compared to those three and more (AOR = 0.83, 95%CI: 0.76-0.91).

CONCLUSIONS

The geospatial distribution of anemia among children varies in Ethiopia; it was highest in the East, Northeast, and Western regions of the country. Several factors were associated with anemia; therefore, interventions targeting the hotspots areas and specific determinant factors should be implemented by the concerned bodies to reduce the consequences of anemia on the generation.

Advances in vaccine development for human trichuriasis

Trichuriasis known as whipworm infection caused by Trichuris trichiura, is a highly prevalent soil-transmitted helminthiasis in low- and middle-income countries located in tropical and subtropical areas and affecting approximately 360 million people. Children typically harbour the largest burden of T. trichiura and they are usually co-infected with other soil-transmitted helminth (STH), including Ascaris lumbricoides and hookworm. The consequences of trichuriasis, such as malnutrition and physical and cognitive growth restriction, lead to a massive health burden in endemic regions. Despite the implementation of mass drug administration of anthelminthic treatment to school-age children, T. trichiura infection remains challenging to control due to the low efficacy of current drugs as well as high rates of post-treatment re-infection. Thus, the development of a vaccine that would induce protective immunity and reduce infection rate or community faecal egg output is essential. Hurdles for human whipworm vaccine development include the lack of suitable vaccine antigen targets and animal models for human T. trichiura infection. Instead, rodent whipworm T. muris infected mouse models serve as a major surrogate for testing immunogenicity and efficacy of vaccine candidates. In this review, we summarize recent advances in animal models for T. trichiura antigen discovery and testing of vaccine candidates, while providing an overall view of the current status of T. trichiura vaccine development.

Hookworm infection in infants: a case report and review of literature

BACKGROUND

Hookworm infections (Necator americanus, Ancylostoma duodenale) are common in rural areas of tropical and subtropical countries. Human acquisition results from direct percutaneous invasion of infective larvae from contaminated soil. Overall, almost 472 million people in developing rural countries are infected. According to simulation models, hookworm disease has a global financial impact of over US$100 billion a year. Hookworm infection in newborn or infancy is rare, and most of the cases reported in literature are from endemic countries. Here, we describe the case of an infant with an Ancylostoma duodenale infection and review the literature currently available on this topic.

CASE PRESENTATION

An Italian 2-month-old infant presented with vomit and weight loss. Her blood exams showed anemia and eosinophilia and stool analysis resulted positive for hookworms' eggs, identified as Ancylostoma duodenale with real time-PCR. Parasite research on parents' stools resulted negative, and since the mother travelled to Vietnam and Thailand during pregnancy, we assumed a transplacental transmission of the infection. The patient was treated successfully with oral Mebendazole and discharged in good conditions.

DISCUSSION

Hookworm helminthiasis is a major cause of morbidity in children in the tropics and subtropics, but rare in developed countries. Despite most of the patients is usually asymptomatic, children are highly exposed to negative sequelae such as malnutrition, retarded growth and impaired cognitive development. In infants and newborns, the mechanism of infection remains unclear. Although infrequent, vertical transmission of larvae can occur through breastfeeding and transplacentally. Hookworm infection should be taken into account in children with abdominal symptoms and unexplained persistent eosinophilia. The treatment of infants infected by hookworm has potential benefit, but further studies are needed to define the best clinical management of these cases.

Parasitic infections in Swiss children: Are we overtesting?

Background

A wide variation of causes can lead to gastrointestinal symptoms in children- an infection with parasites is one of them. The expansion of international travel might lead to an increase in testing children for a correspondent infection. Currently there are no guidelines available, which patients should be tested for a possible parasitical infection.

The aim of the study was to characterize Swiss children suffering from intestinal parasites, in order to provide more knowledge for the clinician who should be tested.

Methods

This is a retrospective study of Swiss pediatric patients, whose stools have been tested for parasites and helminths.

Results

A total of 1855 stool samples, belonging to 572 different children with an average age of 7.9 years, were tested within a 10-year period. The prevalence of a positive result was 4.2%, of which all were positive for Blastocystis, and 12.5% had a co-infection with Endolimax nana.

Conclusion

Immigrants, immune compromised children with diarrhea and pediatric patients with bloody or protracted diarrhea should have 2 different stool specimens examined for a possible parasitical infection.

Human Ascariasis: An Updated Review

Background:

Ascaris lumbricoides is the most common helminthic infection. More than 1.2 billion people have ascariasis worldwide.

Objective:

This article aimed to provide an update on the evaluation, diagnosis, and treatment of ascariasis.

Methods:

A PubMed search was conducted in February 2020 in Clinical Queries using the key terms “ascariasis” OR “Ascaris lumbricoides”. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews published within the past 10 years. The search was restricted to English literature. The information retrieved from the above search was used in the compilation of the present article. Patents were searched using the key term “ascariasis” OR “Ascaris lumbricoides” in www.freepatentsonline.com.

Results:

Ascaris lumbricoides is transmitted through the ingestion of embryonated eggs from fecal- contaminated material. Ascariasis has high endemicity in tropical and subtropical areas. Predisposing factors include poverty, poor sanitation, inadequate sewage disposal, and poor personal hygiene. The prevalence is greatest in children younger than 5 years of age. The majority of patients with intestinal ascariasis are asymptomatic. For those with symptoms, anorexia, nausea, bloating, abdominal discomfort, recurrent abdominal pain, abdominal distension, and intermittent diarrhea are not uncommon. Other clinical manifestations vary widely, depending on the underlying complications. Complications include Löeffler syndrome, intestinal obstruction, biliary colic, recurrent pyogenic cholangitis, cholecystitis, acalculous cholecystitis, obstructive jaundice, cholelithiasis, pancreatitis, and malnutrition. The diagnosis is best established by microscopic examination of fecal smears or following concentration techniques for the characteristic ova. Patients with A. lumbricoides infection warrant anthelminthic treatment, even if they are asymptomatic, to prevent complications from migration of the parasite. Albendazole and mebendazole are the drugs of choice for children and nonpregnant individuals with ascariasis. Pregnant women with ascariasis should be treated with pyrantel pamoate. Recent patents related to the management of ascariasis are also discussed.

Conclusion:

The average cure rate with anthelminthic treatment is over 95%. Unfortunately, most treated patients in endemic areas become re-infected within months. Health education, personal hygiene, improved sanitary conditions, proper disposal of human excreta, and discontinuing the use of human fecal matter as a fertilizer are effective long-term preventive measures. Targeting deworming treatment and mass anthelminthic treatment should be considered in regions where A. lumbricoides is prevalent.

Impact of Anthelmintic Price Increases on Practice Patterns of Healthcare Providers Caring for Immigrant and Refugee Populations in the United States

In the United States, prices of long-established, generic anthelmintic medications have markedly risen. In the past decade, albendazole and mebendazole have increased in price by > 8,000%, whereas praziquantel has increased by > 500%. To determine the effect of these price increases on the practice patterns of healthcare providers, we conducted a cross-sectional electronic survey of clinics in the United States that primarily care for immigrant and refugee patient populations. Among 32 clinics, 53.1% reported that price increases impacted how providers diagnosed and treated helminth infections. A third (34.4%) of clinics reported that price increases have left them unable to treat known helminth infections. Other ways in which price increases impacted practice patterns included prescribing anthelmintics other than albendazole, mebendazole, or praziquantel when possible (34.4%); avoiding screening asymptomatic patients for helminth infections (15.6%); advising patients to acquire medications from another country (15.6%) or the patient's home country (9.4%); reducing anthelmintic dosing regimens to fewer pills (9.4%); and advising patients to purchase medications on the Internet (6.3%). These findings suggest price increases have negatively impacted the diagnosis and treatment of helminth infections in this population, and have resulted in the inability to treat known helminth infections. These findings have significant implications for the morbidity and mortality of infected individuals, as well as for public health in the United States.

Seroprevalence of Toxocara Infection in Association with Different Risk Factors among Children of 4-12 Years Old Referred to Some Medical Centers in Aras Free Zone, Northwest Iran

Background:

Toxocariosis is a parasitic disease caused by the larval stage of Toxocara species from dog and cat. It has a worldwide distribution with higher prevalence in children. This study aimed to determine seroprevalence of Toxocara infection and its association with some risk factors among children of Aras Free Zone (Jolfa City) in Northwest of Iran.

Methods:

Sera were collected from 514 children aged 4–12 yr old attending to some medical centers in the study area from May 2018 to Feb 2019. Anti-Toxocara IgG antibodies assay was performed using commercial ELISA kit (Nova Tec, Germany). The seropositivity rate was determined and its association with different demographic criteria and risk factors were statistically analyzed.

Results:

The overall seroprevalence was 2.3% (12/514). Risk factors of children’s age group and contact with either pet animals (dog and cat) and/or soil were significantly associated with seropositivity. However, there was not any relationship between Toxocara infection and gender of children, place of residency (urban or rural) and their mothers’ education level.

Conclusion:

Both girls and boys are at risk of Toxocara infection in the study area. Younger age of childhood and contact with sources of infection were important associated factors. More probably, additional criteria are involved in the initiation of infection.

Infectious Diseases among Refugee Children

In recent years, there has been a substantial increase in refugee and asylum-seeking adults, adolescents and children to high-income countries. Infectious diseases remain the most frequently identified medical diagnosis among U.S.-bound refugee children. Medical screening and immunization are key strategies to reduce the risk of infectious diseases in refugee, internationally adopted, and immigrant children. Notable infectious diseases affecting refugee and other newly arriving migrants include latent or active tuberculosis, human immunodeficiency virus type 1 (HIV), hepatitis B, hepatitis C, vaccine-preventable diseases, malaria, and other parasitic infections. The U.S. Centers for Disease Control and Prevention and the American Academy of Pediatrics have published guidelines for health assessment of newly arriving immigrant, refugee, and internationally adopted children. Although, data on the health risks and needs of refugee exists in some high-income countries, there is an urgent need to develop robust evidence-informed guidance on screening for infectious diseases and vaccination strategies on a broader scale to inform national policies. Innovative approaches to reach migrant communities in the host nations, address health and other complex barriers to improve access to high-quality integrated health services, and strong advocacy to mobilize resources to improve health, safety, and wellbeing for refugee children and their families are urgent priorities.

Ascaris Larval Infection and Lung Invasion Directly Induce Severe Allergic Airway Disease in Mice

Ascaris lumbricoides (roundworm) is the most common helminth infection globally and a cause of lifelong morbidity that may include allergic airway disease, an asthma phenotype. We hypothesize that Ascaris larval migration through the lungs leads to persistent airway hyperresponsiveness (AHR) and type 2 inflammatory lung pathology despite resolution of infection that resembles allergic airway disease. Mice were infected with Ascaris by oral gavage. Lung AHR was measured by plethysmography and histopathology with hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) stains, and cytokine concentrations were measured by using Luminex Magpix. Ascaris-infected mice were compared to controls or mice with allergic airway disease induced by ovalbumin (OVA) sensitization and challenge (OVA/OVA). Ascaris-infected mice developed profound AHR starting at day 8 postinfection (p.i.), peaking at day 12 p.i. and persisting through day 21 p.i., despite resolution of infection, which was significantly increased compared to controls and OVA/OVA mice. Ascaris-infected mice had a robust type 2 cytokine response in both the bronchoalveolar lavage (BAL) fluid and lung tissue, similar to that of the OVA/OVA mice, including interleukin-4 (IL-4) (P < 0.01 and P < 0.01, respectively), IL-5 (P < 0.001 and P < 0.001), and IL-13 (P < 0.001 and P < 0.01), compared to controls. By histopathology, Ascaris-infected mice demonstrated early airway remodeling similar to, but more profound than, that in OVA/OVA mice. We found that Ascaris larval migration causes significant pulmonary damage, including AHR and type 2 inflammatory lung pathology that resembles an extreme form of allergic airway disease. Our findings indicate that ascariasis may be an important cause of allergic airway disease in regions of endemicity.

Modification and optimization of the FECPAKG2 protocol for the detection and quantification of soil-transmitted helminth eggs in human stool

BACKGROUND

Standard diagnosis of human soil-transmitted helminth (STH) infections is based on the microscopic detection of helminth eggs in stool and supports programmatic decision making in control programs. However, the current standard diagnostic techniques still show a number of limitations. Recently, the FECPAKG2 method was developed to detect helminth infections and asses drug efficacy in sheep or cattle. It includes a device that takes digital images of helminth eggs that have been concentrated into one microscopic field of view and stores these images online for future evaluation. The goal of this study was to introduce a standard operating procedure (SOP) for the detection and quantification of human STH eggs using the FECPAKG2 and to optimize 2 crucial steps of the protocol, namely the sedimentation step (aimed at separating sinking eggs from floating debris) and the accumulation step (aimed at concentrating the eggs by flotation).

METHODOLOGY/PRINCIPAL FINDINGS

A total of 55 stool samples from naturally infected children were used from 4 different geographical areas (Ethiopia, Laos, Tanzania and Brazil). The results showed that Trichuris eggs generally moved slower than eggs of the other two STH species during both sedimentation in water in the FECPAKG2 sedimenter as during accumulation in flotation solution in the FECPAKG2 cassettes. The highest number of eggs were present in the slurry of the sedimenter after overnight sedimentation (Ascaris: 95.7%, Trichuris: 89.8% and hookworm: 94.2% of the eggs). A minimum of 24 minutes were needed to ensure the accumulation of at least 80% of the eggs from all three STH species in the FECPAKG2 cassette (Ascaris: 96.1%; Trichuris: 88.2% and hookworm: 87.6%).

CONCLUSIONS/SIGNIFICANCE

This study introduces for the first time a SOP for the FECPAKG2 method. Different aspects of the method for diagnosing human STH infections were optimized. Our study forms the basis for a thorough and objective evaluation of the system as a diagnostic tool that could be implemented in STH control programs.

The Global State of Helminth Control and Elimination in Children

Helminth infections, including soil-transmitted helminths and schistosomiasis, remain one of the most common infections in the world with over 1 billion people infected. These infections cause significant morbidity, particularly in young children, that may last a lifetime, including growth and cognitive stunting. There is an urgent need for the control and elimination of helminth infections from areas of poverty to reduce morbidity in children. Mass drug administration programs were adopted by the World Health Assembly in 2001 and have evolved to provide coverage with multiple anthelmintic medications in a single rapid impact package and more extensive coverage within a community.

The Hygiene Hypothesis and Its Inconvenient Truths about Helminth Infections

Current iterations of the hygiene hypothesis suggest an adaptive role for helminth parasites in shaping the proper maturation of the immune system. However, aspects of this hypothesis are based on assumptions that may not fully account for realities about human helminth infections. Such realities include evidence of causal associations between helminth infections and asthma or inflammatory bowel disease as well as the fact that helminth infections remain widespread in the United States, especially among populations at greatest risk for inflammatory and autoimmune diseases.