Parasitic infections of the gut in children

Phylogenomic reconstruction of Cryptosporidium spp. captured directly from clinical samples reveals extensive genetic diversity

Cryptosporidium is a leading cause of severe diarrhea and mortality in young children and infants in Africa and southern Asia. More than twenty Cryptosporidium species infect humans, of which C. parvum and C. hominis are the major agents causing moderate to severe diarrhea. Relatively few genetic markers are typically applied to genotype and/or diagnose Cryptosporidium. Most infections produce limited oocysts making it difficult to perform whole genome sequencing (WGS) directly from stool samples. Hence, there is an immediate need to apply WGS strategies to 1) develop high-resolution genetic markers to genotype these parasites more precisely, 2) to investigate endemic regions and detect the prevalence of different genotypes, and the role of mixed infections in generating genetic diversity, and 3) to investigate zoonotic transmission and evolution. To understand Cryptosporidium global population genetic structure, we applied Capture Enrichment Sequencing (CES-Seq) using 74,973 RNA-based 120 nucleotide baits that cover ~92% of the genome of C. parvum. CES-Seq is sensitive and successfully sequenced Cryptosporidium genomic DNA diluted up to 0.005% in human stool DNA. It also resolved mixed strain infections and captured new species of Cryptosporidium directly from clinical/field samples to promote genome-wide phylogenomic analyses and prospective GWAS studies.

Oxidative Stress in Parasitic Diseases-Reactive Oxygen Species as Mediators of Interactions between the Host and the Parasites

Oxidative stress plays a significant role in the development and course of parasitic infections, both in the attacked host organism and the parasite organism struggling to survive. The host uses large amounts of reactive oxygen species (ROS), mainly superoxide anion (O2•-) and hydrogen peroxide (H2O2), to fight the developing parasitic disease. On the other hand, the parasite develops the most effective defense mechanisms and resistance to the effects of ROS and strives to survive in the host organism it has colonized, using the resources and living environment available for its development and causing the host's weakening. The paper reviews the literature on the role of oxidative stress in parasitic diseases, which are the most critical epidemiological problem worldwide. The most common parasitosis in the world is malaria, with 300-500 million new cases and about 1 million deaths reported annually. In Europe and Poland, the essential problem is intestinal parasites. Due to a parasitic infection, the concentration of antioxidants in the host decreases, and the concentration of products of cellular components oxidation increases. In response to the increased number of reactive oxygen species attacking it, the parasites have developed effective defense mechanisms, including primarily the action of antioxidant enzymes, especially superoxide dismutase and nicotinamide adenine dinucleotide phosphate hydrogen (NADPH)-dependent complexes glutathione and thioredoxin.

Summer diarrhea in children: a monocentric French epidemiological observational study

Pediatric diarrhea is a major public health problem worldwide. In France, continuous surveillance shows a winter epidemic peak and a more modest summer recrudescence. Few studies describe the infectious agents responsible for pediatric summer diarrhea in France. The objectives were to estimate the prevalence of infectious diarrhea and describe the pathogens responsible for summer diarrhea in children; and to describe common factors that can be used as guidance on the etiology of these diarrheas. A cross-sectional, single-center, epidemiological observational study was conducted in the pediatric emergency department of a French hospital between June and September in 2019 and 2020. Multiplex gastrointestinal pathogen panels were used for diagnostics. A multiple correspondence analysis was used to determine profiles of patients. A total of 95 children were included, of whom 82.1% (78/95) were under five years old. The prevalence of infectious summer diarrhea was 81.1% (77/95, 95%CI 71.7-88.4%). A total of 126 infectious agents were detected (50.0% bacteria, 38.1% viruses, 11.9% parasites). The main enteric pathogens were enteropathogen Escherichia coli (24/126), rotavirus (17/126) and Salmonella (16/126). A co-detection was found in 51.9% (40/77) of cases. Four patient profiles, considering the severity and the pathogen involved, were highlighted.

Prevalence and associated risk factors of intestinal parasitic infections among children in pastoralist and agro-pastoralist communities in the Adadle woreda of the Somali Regional State of Ethiopia

BACKGROUND

Intestinal parasitic infections (IPIs) can cause illness, morbidity, and occasional mortality in children. Agro-pastoralist and pastoralist children in the Somali Regional State of Ethiopia (ESRS) are especially at risk for IPIs, as access to safe water, sanitation, and health services is lacking. Minimal data on the prevalence of IPIs and associated risk factors exists in this region.

METHODOLOGY

We assessed the prevalence of IPIs and associated risk factors during the wet season from May-June 2021 in 366 children aged 2 to 5 years in four agro-pastoralist and four pastoralist kebeles (wards) in Adadle woreda (district) of the Shebelle zone, ESRS. Household information, anthropometric measurements, and stool samples were obtained from included children. Parasites were identified microscopically using Kato-Katz and direct smear methods. Risk factors were assessed using general estimating equation models accounting for clustering.

PRINCIPAL FINDINGS

Overall prevalence of IPIs was 35%: 30.6% for single infections and 4.4% for poly-parasitic infections. Intestinal protozoan prevalence was 24.9%: 21.9% Giardia intestinalis, and 3.0% Entamoeba spp.. Intestinal helminth prevalence was 14.5%: 12.8% Ascaris lumbricoides, 1.4% hookworm (Ancylostoma duodenale /Necator americanus.), and 0.3% Hymenolepis nana. G. intestinalis infection was associated with drinking water sourced from the river (aOR 15.6, 95%CI 6.84, 35.4) and from collected rainwater (aOR 9.48, 95%CI 3.39, 26.5), with toilet sharing (aOR 2.93, 95%CI 1.36, 6.31) and with household ownership of cattle (1-5 cattle: aOR 1.65, 95%CI 1.13, 2.41; 6+ cattle: aOR 2.07, 95%CI 1.33, 3.21) and chickens (aOR 3.80, 95%CI 1.77, 8.17). A. lumbricoides infection was associated with children 36 to 47 months old (aOR 1.92, 95%CI 1.03, 3.58).

CONCLUSIONS/SIGNIFICANCE

Improving access to safe water, sanitation, and hygiene services in Adadle and employing a One Health approach would likely improve the health of children living in (agro-) pastoralist communities in Adadle and the ESRS; however, further studies are required.

Ribosomal RNA Transcription Machineries in Intestinal Protozoan Parasites: A Bioinformatic Analysis

PURPOSE

Ribosome biogenesis is a key process in all living organisms, energetically expensive and tightly regulated. Currently, little is known about the components of the ribosomal RNA (rRNA) transcription machinery that are present in intestinal parasites, such as Giardia duodenalis, Cryptosporidium parvum, and Entamoeba histolytica. Thus, in the present work, an analysis was carried out looking for the components of the rRNA transcription machinery that are conserved in intestinal parasites and if these could be used to design new treatment strategies.

METHODS

The different components of the rRNA transcription machinery were searched in the studied parasites with the NCBI BLAST tool in the EuPathDB Bioinformatics Resource Center database. The sequences of the RRN3 and POLR1F orthologs were aligned and important regions identified. Subsequently, three-dimensional models were built with different bioinformatic tools and a structural analysis was performed.

RESULTS

Among the protozoa examined, C. parvum is the parasite with the fewest identifiable components of the rRNA transcription machinery. TBP, RRN3, POLR1A, POLR1B, POLR1C, POLR1D, POLR1F, POLR1H, POLR2E, POLR2F and POLR2H subunits were identified in all species studied. Furthermore, the interaction regions between RRN3 and POLR1F were found to be conserved and could be used to design drugs that inhibit rRNA transcription in the parasites studied.

CONCLUSION

The inhibition of the rRNA transcription machinery in parasites might be a new therapeutic strategy against these microorganisms.

Intestinal Parasitic Infections among Intellectually Disabled Individuals in Bandar Abbas County, Southern Iran

Intellectually disabled individuals are more prone to parasitic infections due to their unusual behaviors, immune and nutrient deficiencies, and living conditions. The current study is aimed at evaluating the prevalence of intestinal parasites in institutionalized intellectually disabled individuals in Bandar Abbas County in the south of Iran. Subjects of the study were 119 individuals, living in an intellectually disabled individual care center. Demographic features of the subjects including age, sex, intellectual disability type, and duration of their stay in the center were recorded. A stool sample was taken from each subject and evaluated by direct wet mount and formalin-ethyl-acetate concentration methods. Samples were also examined, using trichrome and modified acid-fast permanent staining. The mean age of the subjects was 27.6 (±2.24), ranging from 4 to 60 years old. Of the 119 participants, 55 (46.2%) were male, and 64 cases (53.8%) were female. Overall, 31 individuals (26.1%, 95% CI: 18.4-34.9) were found to be infected with at least one type of intestinal parasite. Blastocystis hominis, as the most common detected parasite, was detected in 13 (10.1%), Entamoeba coli in 12 (10.1%), Giardia lamblia in 5 (4.2%), Cryptosporidium in 2 (1.7%), Iodamoeba butchlii in 2 (1.7%), and Endolimax nana in 1 (0.8%) of participants. Three cases had coinfection with Blastocystis hominis and Entamoeba coli, one case was infected with Blastocystis hominis and Giardia lamblia, and one case was coinfected with Giardia lamblia and Entamoeba coli. There were no statistically significant associations between intestinal parasitic infection and gender, age, type of intellectual disability, or duration of stay in the care center ( $P>0.05$ ). The findings of the present study indicate a relatively high prevalence of parasitic infections in people with intellectual disabilities in Bandar Abbas, southern Iran. Noteworthy is the high prevalence of Blastocyst and also the presence of Cryptosporidium infection in these people. Periodic treatment of these people and improvement of their maintenance conditions can be considered for the prevention and control of intestinal parasitic infection in these people.

Influence of Environmental Pollution and Living Conditions on Parasite Transmission among Indigenous Ecuadorians

The purpose of this study was to evaluate the influence of environmental pollution and the living conditions of indigenous Ecuadorians on the transmission of enteroparasites in an Andean agricultural area located at high altitude. Environmental pollution was recorded after observation in each community. The parasites were identified by microscopic sediment analysis using physiological saline solution from macerated arthropods, washed vegetables, and human stools, utilizing four coproparasitological techniques (direct examination, Kato–Katz, ether concentration, and Ziehl–Neelsen). The results show that the inadequate disposal of human and animal excreta that contaminate soil and water, incorrect food hygiene, inadequate sanitary infrastructure in houses, a lack of animal veterinary care, and rodent proliferation are important reservoirs of zoonotic parasites. The use of excrement as fertilizer increases the number of flies, which act as mechanical vectors, and vegetables grown in areas with disperse infective parasitic forms act as vehicles that are marketed at the local, regional, and international levels. These analyses verify contamination levels of 52.7% in mechanical vectors, 70.6% in vegetables, and 98.2% in human stools. The agricultural communities analyzed maintained poor hygienic–sanitary and environmental conditions, which had a significant influence on the transmission of enteroparasites that affect human health.

Parasitic Infections in Internationally Adopted Children: A Twelve-Year Retrospective Study

Parasitic infections (PIs) are among the most frequent infectious diseases globally. Previous studies reported discrepant results regarding the prevalence of PIs in internationally adopted children (IAC). Data from IAC referred to our paediatric university hospital in 2009–2021 were collected to evaluate the frequency of PIs by the use of stool microscopic examination, antigen assays for Giardia lamblia and Cryptosporidium parvum, and serological tests for Toxocara canis, Strongyloides stercoralis, Schistosoma mansoni, Echinococcus spp., Taenia solium, and Trypanosoma cruzi. Uni- and multivariate logistic regression analyses were performed to evaluate risk factors for PIs and eosinophilia. The proportion of IAC with at least one positive test was 26.83% (640/2385); 2.13% (n = 51) had positive tests for 2 or 3 parasites. A positive assay for helminthic infection was retrieved in 11.07% of children (n = 264), and 17.86% (n = 426) presented with eosinophilia. The most common positive tests were anti-Toxocara canis antibodies (n = 312; 13.8%), followed by positive stool antigen for Giardia lamblia (n = 290; 12.16%), and positive microscopic stool examination for Blastocystis hominis (n = 76; 3.19%). A statistically significant association was found between PIs and region of origin (children from Latin America and Africa were more likely to present PIs than children from Eastern Europe), age 5–14 years, and eosinophilia. No significant association was observed between PIs and gender, vitamin D deficiency, or anemia. In conclusion, PIs are relevant in IAC and an accurate protocol is needed to evaluate IAC once they arrive in their adoptive country.

Intestinal Schistosomiasis and Giardiasis Co-Infection in Sub-Saharan Africa: Can a One Health Approach Improve Control of Each Waterborne Parasite Simultaneously?

Both intestinal schistosomiasis and giardiasis are co-endemic throughout many areas of sub-Saharan Africa, significantly impacting the health of millions of children in endemic areas. While giardiasis is not considered a neglected tropical disease (NTD), intestinal schistosomiasis is formally grouped under the NTD umbrella and receives significant advocacy and financial support for large-scale control. Although there are differences in the epidemiology between these two diseases, there are also key similarities that might be exploited within potential integrated control strategies permitting tandem interventions. In this review, we highlight these similarities and discuss opportunities for integrated control of giardiasis in low and middle-income countries where intestinal schistosomiasis is co-endemic. By applying new, advanced methods of disease surveillance, and by improving the provision of water, sanitation and hygiene (WASH) initiatives, (co)infection with intestinal schistosomiasis and/or giardiasis could not only be more effectively controlled but also better understood. In this light, we appraise the suitability of a One Health approach targeting both intestinal schistosomiasis and giardiasis, for if adopted more broadly, transmission of both diseases could be reduced to gain improvements in health and wellbeing.

Infections with Giardia duodenalis and Entamoeba histolytica/Entamoeba dispar as Hidden and Prevalent Conditions in Periurban Communities in the State of Rio de Janeiro, Brazil

This study aims to assess the prevalence, distribution, and etiological profile of intestinal parasitism in children living in periurban areas in Cachoeiras de Macacu, Rio de Janeiro, Brazil. A community-based cross-sectional survey (n = 479) was carried out. Prevalence of infection with G. duodenalis and E. histolytica/E. dispar was 8.6% (n = 41) and 13.4% (n = 64), respectively. Infection with G. duodenalis was significantly more frequent among children living in poor families (24/187 (12.8%) vs. 16/272 (5.9%); prevalence ratio (PR) = 2.18; 95% confidence interval (CI) = 1.19–3.99; p=0.011). This difference was also significant for infection with any pathogenic parasite (43/187 (23%) vs. 40/272 (14/7%); PR = 1.56; 95% CI = 1.06–2.30; p=0.026). In addition, people residing in houses with more than four inhabitants showed significantly higher positivity for infections with G. duodenalis and with E. histolytica/E. dispar (22/138 (15.9%) vs. 16/311 (5.1%); PR = 3.09; 95% CI = 1.68–5.71; p < 0.001 for G. duodenalis and 32/138 (23.2%) vs. 30/311 (9.6%); PR = 2.40; 95% CI = 1.52–3.79; p < 0.001 for E. histolytica/E. dispar). Laboratory diagnosis of protozoan enteric infections and effective drugs for their treatment are unmet goals in the primary health care system. Therefore, giardiasis and amebiasis are neglected conditions.

Factors defining the stability of poly(lactide-co-glycolide) spheres for the sustained release of a cysteine protease inhibitor

Colloidal stability and the regularity of the release kinetics benefit from the high circularity and the narrow size dispersion of polymeric particles as drug delivery carriers. A method for obtaining such particles composed of poly(lactide-co-glycolide) (PLGA), averaging at 1.0 ± 0.3 µm in size, is reported here, along with the analysis of the effects of different synthesis parameters on their morphological characteristics. As in agreement with the classical nucleation theory, the particle size and the degree of cohesion were inversely proportional to supersaturation. Consequently, the optimal conditions for the precipitation of small and narrowly dispersed particles involved an abrupt elevation of supersaturation. Owing to the high colloidal stability of the particles, centrifugation exhibited a counterintuitive effect on them, refining their morphological features and promoting their individuation. Polyvinyl alcohol (PVA) was used as a steric repulsion additive and its effect on the stability of PLGA spheres was concentration-dependent, with the particles aggregating, partially coalescing and losing their distinct features both with no PVA in the system and at PVA concentrations higher than the optimal. At its narrowest, the particle size distribution was bimodal, exhibiting the average circularity of 0.997 ± 0.003 and the average roundness of 0.913 ± 0.054. PLGA spheres were loaded with an inhibitor of EhCP4, a cysteine protease from E. histolytica, a parasite causing amoebic dysentery in the tropical and developing world. The burst release of the drug at early time points was followed by a zero-order release period, yielding a biphasic profile that can be of benefit in the delivery of anti-infective agents. The release profile fitted poorly with the Hixson-Crowell kinetic model and excellently with the Higuchi and the Korsmeyer-Peppas ones, indicating that the release is conditioned by diffusion rather than by the degradation of the polymer. The release and the erosion proceeded independently from one another, suggesting that the pore formation, water penetration and swelling are the primary driving forces for the release of the drug.

Prevalence and subtype distribution of Blastocystis sp. infecting children from a rural community in Panama

Blastocystis sp. is a commonly reported intestinal parasite with a worldwide distribution. Phylogenetic analyses describe at least 17 subtypes for this parasite, and nine of them have been found in humans. However, the prevalence and some epidemiological characteristics of this parasitic infection in rural communities are not well known. The objective of this cross-sectional study was to evaluate the prevalence, subtypes, and epidemiological factors related to Blastocystis sp. Infection in children from of a small rural community in the central area of Panama. For this, 66 fecal samples from children (1 to 12 years old), were initially analyzed for the presence of parasites by a formalin-ethyl acetate/concentration method. Molecular detection and identification of Blastocystis sp. subtypes were carried out by amplification and sequencing of a partial fragment of the small-subunit ribosomal RNA gene. Using data from a questionnaire, analyses of epidemiological conditions potentially associated with Blastocystis sp. transmission were also conducted. Microscopic diagnostics showed that 33.3% (22/66) of the analyzed samples presented entero-parasites. Among them, Blastocystis sp. was the most prevalent, with 21.2% (14/66), followed by the E. histolytica/dispar/moshkovskii complex 4.5% (3/66), Giardia lamblia 1.5% (1/66) and Strongyloides stercoralis 1.5% (1/66). PCR-based analyses detected a prevalence of Blastocystis sp. infection of 74.2% (49/66) in apparently healthy children. Phylogenetic analysis revealed two different subtypes of this parasite: ST1 with 42.2% (28/66) infected, and ST3 with 31.8% (21/66) infected. In addition, recent diarrhea was significantly associated with Blastocystis sp. infection. None of the other risk factors evaluated was statistically associated with infection. These results highlight the need to further investigate clinical, epidemiological, and genetic characteristics of Blastocystis sp. infections in this community.

Intestinal parasitic infection among household contacts of primary cases, a comparative cross-sectional study

Background

Intestinal parasitic infection affects 3.5 billion people in the world and mostly affecting the low socio-economic groups. The objectives of this research works were to estimate the prevalence and determinants of intestinal parasitic infection among family members of known intestinal parasite infected patients.

Methods and materials

A comparative cross-sectional study design was implemented in the urban and rural settings of Mecha district. The data were collected from August 2017toMarch 2019 from intestinal parasite infected patient household members. Epi-info software was used to calculate the sample size, 4531 household members were estimated to be included. Data were collected using interview technique, and collecting stool samples from each household contact of intestinal parasite patients. Descriptive statistics were used to estimate the prevalence of intestinal parasites among known contacts of intestinal parasite patients/family members. Binary logistic regression was used to identify the determinant factors of intestinal parasitic infection among family members.

Results

The prevalence of intestinal parasite among household contacts of intestinal parasite-infected family members was 86.14% [95% CI: 86.14% - 87.15%]. Hookworm infection was the predominant type of infection (18.8%). Intestinal parasitic infection was associated with sex, environmental sanitation, overcrowding, personal hygiene, residence, substandard house, role in the household, source of light for the house, trimmed fingernails, family size, regular handwashing practice. Protozoa infection was associated with habit of ingesting raw vegetable, playing with domestic animals, water source and the presence of household water filtering materials.

Conclusion

High prevalence of intestinal parasitic infection was observed among household contacts of primary cases.