Morbidity, mortality, and long-term consequences associated with diarrhoea from Cryptosporidium infection in children younger than 5 years: a meta-analyses study

Targeting Apicomplexan Parasites: Structural and Functional Characterization of Cryptosporidium Thioredoxin Reductase as a Novel Drug Target

Cryptosporidiosis poses a significant health threat to young children and immunocompromised individuals due to the lack of effective therapies. Here, we demonstrate that the Cryptosporidium parvum redox system is fundamentally different from their human host. Humans possess independent glutathione (GSH) and thioredoxin (Trx) pathways. Cryptosporidium lacks authentic glutathione reductase (GR), and we hypothesize that it most likely utilizes the Trx reductase (TrxR) plus Trx couple to maintain GSH in its reduced state. Given the central role of CpTrxR in the parasite's redox homeostasis, we focus on its functional and structural characterization. We find that the combination of CpTrxR andC. parvum Trx efficiently reduces oxidized GSH, in effect functioning as a GR. Auranofin, a gold-containing compound, is known to kill parasites in culture, and here we demonstrate that CpTrxR is irreversibly inhibited by this compound. The crystallographic structures of CpTrxR, a type II TrxR characterized by the distinctive C-terminal -CGGGKCG motif found exclusively in apicomplexan parasites, including Plasmodium spp., the causative agents of malaria, are presented. Our study characterizes three unprecedented catalytically competent intermediates of the C-terminal tail in the so-called "in" conformations, providing insights into the structural and functional properties of type II TrxR. These findings offer valuable information for the design of CpTrxR inhibitors, addressing the pressing need for new therapeutic options against cryptosporidiosis, particularly in populations where current treatments are insufficiently effective.

Oral Treatment of Lactoferrin Nanocapsules Modulates the Immune Response of Mice to a Cryptosporidiosis Infection

PURPOSE

The current study was to evaluate the immunomodulatory impact of either lactoferrin (LF), lactoferrin nanocapsule (LF-NC), or lactoferrin conjugation with nanazoxid (NZ). Moreover, identifying drugs can effectively eliminate and successfully treat the infection with Cryptosporidium.

METHODS

Sixty male Swiss albino mice were divided into six groups, each of 10 mice. G1 served as the control, and G2 was inoculated with 104 oocysts. Mice were orally administered NZ (200 mg/kg b.wt.), LF (150 µg/kg b.wt.), or LF-NC (150 mg/kg b.wt./day) for a period of six days post-infection. The immunomodulatory potential and drug efficacy were assessed by fecal and intestinal oocyst counts, measuring antioxidant activities and cytokine levels in addition. Intestinal tissues were examined histopathologically.

RESULTS

The cytokines TGF-β, INF-γ, and IL-10 were increased during infection and decreased following therapy. Mutually, the quantity of pathological lesions and oocysts in the ileal tissues was significantly diminished with the NZ plus LF-NC treatment. In addition, a considerable reduction of both fecal and intestinal samples, as well as a notable deterioration in oocyst counts, suggested that treatment with NZ alone or in combination with LF-NC was more effective.

CONCLUSION

LF or LF-NC was found to exert a potent immunomodulatory effect on infected mice as well as minimize pathological lesions. This therapy approaches a successful therapeutic alternative for the treatment of cryptosporidiosis with few adverse effects.

Cryptosporidium modifies intestinal microvilli through an exported virulence factor

Cryptosporidium is a common intestinal infection of vertebrates and a significant threat to public health. Within the epithelial layer of the intestine, the parasite invades and replicates. Infected cells are readily detected under a microscope by the presence of elongated microvilli, particularly around the vacuole where the parasite resides. Here, we identify a family of Cryptosporidium virulence factors that are exported into the host cell during infection and localize to the microvilli. We examine the trafficking and function of the most highly expressed family member, Microvilli protein 1 (MVP1), which appears to control the elongation of microvilli through engagement of host EBP50 and CDC42. Remarkably, this mechanism closely mirrors that of an enteropathogenic Escherichia coli virulence factor, MAP, which is also known to drive host microvilli elongation during infection. This highlights a unique instance where eukaryotic and prokaryotic virulence factors have convergently evolved to modulate host actin structures through a similar mechanism.

Parasite and host immune factors that impact the development of a mucosal vaccine for Cryptosporidium

The parasite Cryptosporidium is a leading cause of diarrhea and death in malnourished children and immunocompromised individuals and an important enteric pathogen of livestock. A mucosal vaccine to mitigate clinical disease and decrease transmission would address the public health impact of this organism, but current options are limited. The development of a rational strategy for vaccination requires an appreciation of the parasite life cycle, how Cryptosporidium interacts with its host cell (the enterocyte), and the immune mechanisms that act locally to control this organism. Here we review current knowledge of the adaptive immune mechanisms that mediate resistance to Cryptosporidium, their relevance to vaccine design, and how recent advances in parasite genetics inform vaccine development.

Evaluation of the effect of grape seed extract- loaded chitosan nanoparticles on cryptosporidiosis in dexamethasone immunosuppressed male mice

Cryptosporidiosis is a worldwide health problem that results in an economic loss. The disease is caused by the protozoan Cryptosporidium spp. Individuals with suppressed immunity, like those with organ transplantation, cancer and human immunodeficiency virus syndrome, suffer from the infection that may lead to the death. Nitazoxanide (NTZ) is the approved FDA treatment for cryptosporidiosis in immunocompetent individuals. There is an urgent need to find a new natural treatment that can replace NTZ in immunosuppressed hosts. The study aimed to use grape seed extract loaded chitosan nanoparticles (GSEx-CHNPs) in treatment of cryptosporidiosis in immunosuppressed male mice. GSEx was prepared by the alcoholic extraction method followed by the identification of its bioactive components. GSEx-CHNPs were synthesized by ionic gelation method and physically characterized then their activities were examined in vitro. The experimental groups, included immunocompetent and immunosuppressed groups, was treated with NPs for 14 days post infection (PI). The results showed the presence of many phenolic compounds in the GSEx. GSEx-CHNPs significantly improved the loss in animals body weight, cleared the infection and amolerated the serum cytokines levels. GSEx-CHNPs showed anti-cryptosporidial activity especially in immunosuppressed mice model. Where, it ameliorated the disturbance in the cytokine profile leading to an anti-inflammatory response.

Global, regional, and national age-sex-specific burden of diarrhoeal diseases, their risk factors, and aetiologies, 1990-2021, for 204 countries and territories: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND

Diarrhoeal diseases claim more than 1 million lives annually and are a leading cause of death in children younger than 5 years. Comprehensive global estimates of the diarrhoeal disease burden for specific age groups of children younger than 5 years are scarce, and the burden in children older than 5 years and in adults is also understudied. We used results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 to assess the burden of, and trends in, diarrhoeal diseases overall and attributable to 13 pathogens, as well as the contributions of associated risk factors, in children and adults in 204 countries and territories from 1990 to 2021.

METHODS

We used the Cause of Death Ensemble modelling strategy to analyse vital registration data, verbal autopsy data, mortality surveillance data, and minimally invasive tissue sampling data. We used DisMod-MR (version 2.1), a Bayesian meta-regression tool, to analyse incidence and prevalence data identified via systematic reviews, population-based surveys, and claims and inpatient data. We calculated diarrhoeal disability-adjusted life-years (DALYs) as the sum of years of life lost (YLLs) and years lived with disability (YLDs) for each location, year, and age-sex group. For aetiology estimation, we used a counterfactual approach to quantify population-attributable fractions (PAFs). Additionally, we estimated the diarrhoeal disease burden attributable to the independent effects of risk factors using the comparative risk assessment framework.

FINDINGS

In 2021, diarrhoeal diseases caused an estimated 1·17 million (95% uncertainty interval 0·793-1·62) deaths globally, representing a 60·3% (50·6-69·0) decrease since 1990 (2·93 million [2·31-3·73] deaths). The most pronounced decline was in children younger than 5 years, with a 79·2% (72·4-84·6) decrease in diarrhoeal deaths. Global YLLs also decreased substantially, from 186 million (147-221) in 1990 to 51·4 million (39·9-65·9) in 2021. In 2021, an estimated 59·0 million (47·2-73·2) DALYs were attributable to diarrhoeal diseases globally, with 30·9 million (23·1-42·0) of these affecting children younger than 5 years. Leading risk factors for diarrhoeal DALYs included low birthweight and short gestation in the neonatal age groups, child growth failure in children aged between 1-5 months and 2-4 years, and unsafe water and poor sanitation in older children and adults. We estimated that the removal of all evaluated diarrhoeal risk factors would reduce global DALYs from 59·0 million (47·2-73·2) to 4·99 million (1·99-10·0) among all ages combined. Globally in 2021, rotavirus was the predominant cause of diarrhoeal deaths across all ages, with a PAF of 15·2% (11·4-20·1), followed by norovirus at 10·6% (2·3-17·0) and Cryptosporidium spp at 10·2% (7·03-14·3). In children younger than 5 years, the fatal PAF of rotavirus was 35·2% (28·7-43·0), followed by Shigella spp at 24·0% (15·2-37·9) and adenovirus at 23·8% (14·8-36·3). Other pathogens with a fatal PAF greater than 10% in children younger than 5 years included Cryptosporidium spp, typical enteropathogenicEscherichia coli, and enterotoxigenic E coli producing heat-stable toxin.

INTERPRETATION

The substantial decline in the global burden of diarrhoeal diseases since 1990, particularly in children younger than 5 years, supports the effectiveness of health interventions such as oral rehydration therapy, enhanced water, sanitation, and hygiene (WASH) infrastructure, and the introduction and scale-up of rotavirus vaccination. Targeted interventions and preventive measures against key risk factors and pathogens could further reduce this burden. Continued investment in the development and distribution of vaccines for leading pathogens remains crucial.

FUNDING

Bill & Melinda Gates Foundation.

Undernutrition and Intestinal Infections in Children: A Narrative Review

Undernutrition affects thousands of children under five years old worldwide, and various factors are related to its onset, among which we highlight enteric infections and gastrointestinal barrier dysfunction. The cycle of intestinal infections and undernutrition has long-term consequences, such as cognitive deficits, poor growth, and metabolic diseases in adulthood. This review explores factors linked to childhood undernutrition, focusing on intestinal infections and markers of intestinal permeability that affect child development. This narrative review was conducted using Medline/PubMed, Web of Science, and Scopus, from July 2024 to March 2025. Studies involving children under five years old and addressing undernutrition, intestinal infections, or intestinal permeability markers were included. Exclusion criteria comprised studies without therapeutic focus, and books, case reports, or academic theses. No language restrictions were applied, and registration on global platforms was not required. Overall, the studies reported a close relationship between enteric pathogens, diarrheal and non-diarrheal stools, and undernutrition. Among the pathogens most frequently found in the feces of malnourished children were Shigella, enterotoxigenic Escherichia coli, enteroaggregative E. coli (EAEC), and Cryptosporidium. The studies also showed the relationship between gastrointestinal barrier function and undernutrition, with the deterioration of nutrient absorption and, consequently, repercussions on development, linear growth, and weight in children. Although the studies analyzed had different designs and heterogeneity in the age range of the studied children, it was possible to observe the relationship between the infection/undernutrition cycle. Future studies should optimize personalized nutrient-based therapies, assess long-term effects on gut health and growth, and explore the gut microbiome's role in enteric infection susceptibility and undernutrition.

Effect of urea and squaramide IMPDH inhibitors on C. parvum: in vitro trial design impacts the assessment of drug efficacy

The protozoan parasite Cryptosporidium is the etiological agent of cryptosporidiosis, a ubiquitous diarrheic disease affecting humans and animals. Treatment options are limited, highlighting an urgent need for novel therapeutics. Despite decades of research and a wide diversity of strategies to tackle parasite metabolic pathways, no completely effective drug has been identified to date. Within targeted parasite enzymatic and metabolic pathways, the synthesis of nucleotide mediated by the inosine 5'-monophosphate dehydrogenase (IMPDH) enzyme is the focus of significant research efforts. Based on our prior studies of bacterial IMPDH inhibitors, we report herein the development and characterisation of novel inhibitors targeting Cryptosporidium parvum IMPDH (CpIMPDH). Specifically, we synthesised heteroaryl-containing urea and squaramide analogues to evaluate their potential in vitro anti-Cryptosporidium activity. Initial screening identified nine active compounds with the most potent candidates achieving IC50 values as low as 2.2 μM. Subsequent time-course experiments revealed that the molecules effectively inhibit parasite invasion and early intracellular development but failed to tackle C. parvum growth when introduced at 30 h post infection. The present work introduces a new family of squaramide-derived IMPDH inhibitors and also interrogates the need to standardise commonly accepted protocols used for assessing anti-cryptosporidial drug activity.

Prevalence and Molecular Characterization of Cryptosporidium Species in Diarrheic Children in Cameroon

Cryptosporidiosis remains a major cause of diarrhea-related childhood death, particularly in developing countries. Although effective anti-retroviral therapy has significantly reduced the cryptosporidiosis burden in western nations, the situation in developing countries remains alarming due to limited therapeutic options and a lack of preventive measures. To better control disease transmission and develop effective prevention strategies, a thorough understanding of the genetic diversity of circulating species is crucial. While cryptosporidiosis has previously been reported in Cameroon, information on the genetic diversity of parasite strains is lacking. In a large cross-sectional study conducted between March 2020 and March 2021 in four regions of Cameroon, Southwest, Littoral, Center and West, a total of 1119 fecal samples of children (n = 1119) were collected and genetically analyzed. This study aimed to assess the genetic diversity of Cryptosporidium strains circulating in this patient cohort in Cameroon. Using modified Ziehl-Neelsen fecal smear staining, an overall prevalence of 8.5% (96/1119) was recorded. PCR analysis revealed a prevalence of 15.4% in the Center, 7.2% in the Littoral, 10.5% in the West, and 13.1% in the Southwest regions. Molecular analysis identified Cryptosporidium. hominis and Cryptosporidium parvum as circulating species, with all subtype families suggesting anthroponotic transmission. No zoonotic subtypes of C. parvum were detected. These findings confirm that cryptosporidiosis transmission in Cameroon is primarily anthroponotic. Nonetheless, much larger epidemiological surveys, including other patient cohorts, are necessary for final confirmation of this statement.

Cryptosporidium in Rabbits: A Global Systematic Review and Meta-Analysis of Prevalence, Species/Genotypes Distribution and Zoonotic Significance

BACKGROUND

This systematic review and meta-analysis assessed the global prevalence, species/genotype distribution and zoonotic impact of Cryptosporidium in rabbits.

METHODS

A systematic search of PubMed, Scopus and Web of Science was performed for studies from 2000 to 25 October 2024 on Cryptosporidium spp. in rabbits. Data on publication/implementation years, prevalence rates, rabbit types, diagnostics, countries and species/genotypes were collected. A meta-analysis with random-effects models estimated overall prevalence and assessed heterogeneity using the I2 index. A sensitivity analysis evaluated the robustness of the results.

RESULTS

This systematic review included 26 studies with 6093 rabbits from 9 countries, revealing a pooled Cryptosporidium spp. prevalence of 9% (95% CI: 6%-13.4%). Three zoonotic species were found in rabbits: Cryptosporidium cuniculus in 18 studies and each of C. parvum and C. andersoni in 1 study. The isolates included 2 genotypes of C. cuniculus (Va, Vb) and 1 genotype of C. parvum (IIc), along with 18 subtypes of C. cuniculus (VaA16, VaA18, VaA31, VbA18, VbA19, VbA21, VbA22, VbA23, VbA24, VbA25, VbA26, VbA28, VbA29, VbA31, VbA32, VbA33, VbA35 and VbA36). Among these, 11 subtypes (VbA19, VbA22-VbA26, VbA28, VbA29 and VbA31-VbA33) are identified as zoonotic. Pet rabbits had the highest Cryptosporidium spp. pooled prevalence at 21.9% (95% CI: 14.7%-31.3%), followed by farmed rabbits at 9.7% (95% CI: 5.1%-17.8%), wild rabbits at 8.8% (95% CI: 4.8%-15.5%) and laboratory rabbits at 1% (95% CI: 0.3%-3.1%), with higher rates noted in Africa and the AFR WHO region.

CONCLUSIONS

This study assessed the global distribution of Cryptosporidium spp. in rabbits, highlighting its zoonotic implications. It serves as a key resource for researchers, veterinarians and public health officials for future studies and control strategies.

Meta-analysis of canine cryptosporidiosis in Africa and prevalence of clinical infection in Oyo, Ogun, and Kwara states, Nigeria

Cryptosporidium infection is a significant parasitic disease affecting both humans and animals worldwide. However, there is limited data on its prevalence in canine populations across Africa. This study was carried out between December 2021 and August 2022 to assess the burden of Cryptosporidium infection in dogs on the continent through a meta-analysis and a targeted survey of dogs presented at veterinary clinics in Nigeria. A systematic review and meta-analysis were conducted using available studies on Cryptosporidium prevalence in dogs from African countries to determine the pooled prevalence. Additionally, a survey was carried out to determine the prevalence of Cryptosporidium oocysts in 309 dogs presented at veterinary clinics across several Nigerian states using microscopy and the presence of Cryptosporidium DNA was confirmed using the nested PCR methods. Data suitable for meta-analysis were found from only three African countries - Nigeria, Zambia, and Mozambique - highlighting a significant research gap across the continent. The pooled estimates of Cryptosporidium infection in Africa was 13.7% (95% CI: 7.7, 22.9), with country-specific rates of 22% in Nigeria, 5.9% in Zambia, and 6.4% in Mozambique. The survey conducted in Nigeria revealed a low prevalence of Cryptosporidium oocysts (6.7%) in dogs presented at clinics, while PCR confirmed the presence of Cryptosporidium DNA in positive samples. The findings highlight the significance of Cryptosporidium as a health concern in African canine populations, with prevalence rates comparable to global figures. The low prevalence observed in clinical settings indicates that routine screening should still be prioritized to ensure early detection and treatment, given the potential zoonotic risk posed by C. canis (the dominant species in dogs). Further research is needed to address the geographic and diagnostic gaps identified and to explore the clinical and public health implications of Cryptosporidium infection in dogs across Africa.

P23-Specific IgY Significantly Reduces Diarrhea and Oocyst Shedding in Calves Experimentally Infected with Cryptosporidium parvum

BACKGROUND/OBJECTIVES

Cryptosporidium parvum is a zoonotic enteroparasite causing severe diarrhea in newborn calves, leading to significant economic losses in dairy and beef farming. This study aimed to evaluate whether C. parvum p23-specific IgY antibodies could control neonatal calf diarrhea caused by C. parvum.

METHODS

A recombinant immunogen comprising the p23 protein fused to the antigen-presenting cell homing (APCH) molecule was expressed using the baculovirus system. Hens were immunized with the APCH-p23 immunogen, and the resulting IgY was spray-dried for treatment use. Eight newborn calves were included in the study and received commercial colostrum within the first 12 h of life. Four calves were treated with 20 g of powdered egg containing IgY (p23-specific IgY titer of 256 in milk) twice daily for 7 days. The remaining four calves received regular non-supplemented milk. All calves were orally infected with 6 million oocysts and monitored for 21 days.

RESULTS

Calves treated with p23-specific IgY exhibited significantly reduced diarrhea duration (3.5 vs. 7.5 days; p = 0.0397) and oocyst shedding duration (6.50 vs. 12 days; p = 0.0089). In addition, the total number of excreted oocysts, as measured by the change of the area under the curve (AUC), was significantly reduced in the treated group (14.25 vs. 33.45; p = 0.0117). Although the onset of diarrhea was delayed (3.5 to 6.5 days post-infection; p = 0.1840), and diarrhea severity was reduced (24.25 to 17 AUC; p = 0.1236), both parameters were not statistically significant.

CONCLUSIONS

P23-specific IgY antibodies effectively reduced the C. parvum-induced duration of diarrhea in experimentally infected calves. These findings highlight the potential of this passive treatment as a promising strategy for controlling neonatal calf diarrhea.

Gut Microbial Signatures Associated with Cryptosporidiosis: A Case Series

Cryptosporidium spp. are zoonotic protozoan parasites with a global prevalence, with both gastrointestinal and pulmonary involvement. Though symptoms can often be relatively mild, they can become severe and even fatal in children under five, the elderly, and in immunocompromised individuals, making cryptosporidiosis a leading cause of morbidity and mortality in fragile populations. Furthermore, there is an urgent clinical need for alternative therapies against cryptosporidiosis, as currently available FDA-approved treatments are ineffective in the immunocompromised. Recent evidence in animal models suggests that the gut microbiota (GM) can influence both host and parasite biology to influence the course of Cryptosporidium infection. Here, we present GM profiles in five cases of cryptosporidiosis, associated with varying underlying pathologies. We found that moderate-severe cryptosporidiosis was characterized by a reduction in alpha-diversity and an enrichment of Enterococcus spp., while decreases in Bifidobacterium, Gemmiger, and Blautia were detectable in the milder manifestations of the disease. Our results suggest that severe cryptosporidiosis is associated with a stronger change on the GM than is age or underlying pathology. Together with previously published studies in animal models, we believe that these results suggest that the GM could be a potential therapeutic target for human patients as well, particularly in the immunocompromised for whom anti-Cryptosporidium treatment remains largely ineffective.

Molecular pathogenesis of Cryptosporidium and advancements in therapeutic interventions

Cryptosporidiosis, caused by a Cryptosporidium infection, is a serious gastrointestinal disease commonly leading to diarrhea in humans. This disease poses a particular threat to infants, young children, and those with weakened immune systems. The treatment of cryptosporidiosis is challenging due to the current lack of an effective treatment or vaccine. Ongoing research is focused on understanding the molecular pathogenesis of Cryptosporidium and developing pharmacological treatments. In this review, we examine the signaling pathways activated by Cryptosporidium infection within the host and their role in protecting host epithelial cells. Additionally, we also review the research progress of chemotherapeutic targets against cryptosporidia-specific enzymes and anti-Cryptosporidium drugs (including Chinese and Western medicinal drugs), aiming at the development of more effective treatments for cryptosporidiosis.

Application of Fourier transform infrared spectroscopy (FTIR) for protozoan analysis: A systematic review

Protozoa present in water for human consumption represent a significant public health risk to a greater extent in the most vulnerable populations. Identifying protozoa in a traditional way through microscopy or with more advanced technologies such as molecular biology may present limitations in sensitivity, specificity, time, and costs. Fourier Transform Infrared (FTIR) spectroscopy have potential as an alternative for the detection of protozoa in water used for human consumption. An exhaustive search was carried out in the databases, SCIELO, PubMed, SCOPUS and Google Scholar, with the search terms "protozoa," "protozoan," "parasite," "FTIR," "infrared spectroscopy." Only six articles met the inclusion criteria. FTIR spectroscopy can detect changes in biochemical composition but has not been used for the identification of parasites in human clinical or environmental samples. The present systematic review identified a lack of studies in this area and the need to conduct research aimed at developing standardized methods and creating spectral database banks of protozoan species that will allow for the precise identification of protozoa such as Cryptosporidium spp. and Giardia spp. in water for human consumption.

Long-term symptoms in children after a Cryptosporidium hominis outbreak in Sweden: a 10-year follow-up

In 2010, a Cryptosporidium hominis outbreak resulted in 27,000 clinical cryptosporidiosis cases (45% of the population) in Östersund, Sweden. Long-term abdominal and joint symptoms are common following cryptosporidiosis in adults, and it can affect the development of children in low-income countries. We investigated the potential consequences for children in a high-income setting. In 2011, we prospectively surveyed 600 randomly selected children aged 0-5 years from Östersund. Cases were defined as respondents reporting new episodes of diarrhoea during the outbreak. After 10 years, respondents received a follow-up questionnaire about long-term symptoms (n = 423). We used X2 and Mann-Whitney U tests to assess between-group differences in demographics and the mean number of symptoms. Logistic regressions adjusted for sex, age, and prior issues with loose stools were used to examine associations between case status and symptoms reported at follow-up. We retrieved data on healthcare visits from patient records. In total, 121 cases and 174 non-cases responded to the follow-up questionnaire (69.7%). Cases reported 1.74 (median 1.00, range 0-14) symptoms and non-cases 1.37 (median 0.00, range 0-11) symptoms (p = 0.029). Cases were more likely to report joint symptoms (aOR 4.0, CI 1.3-12.0) and fatigue (aOR 1.9, CI 1.1-3.4), but numbers were generally low. We found no between-group differences in abdominal symptoms, healthcare utilization, or disease diagnoses. Children aged 0-5 years from high-income countries may experience long-term symptoms after cryptosporidiosis, but may not be affected to the same extent as adults or their peers living in low-income countries.

First microscopic and molecular identification of Cryptosporidium spp. in fat sand rats (Psammomys obesus) in Egypt and their potential zoonotic implications

Introduction

Rodents, thriving in human-altered environments, pose significant public health risks due to their role as reservoirs for numerous zoonotic parasites. Among these, Cryptosporidium spp. are recognized globally as leading causes of waterborne and foodborne diarrheal illnesses in humans. The specific role of fat sand rats (Psammomys obesus) in the transmission of Cryptosporidium spp. in Egypt and the genotypic characteristics of the circulating species in these animals remain poorly understood.

Methods

In this study, a total of 150 individual fat sand rat stool samples were collected from the saline marsh periurban areas of Abu-Rawash, Giza, Egypt. The samples were initially screened for the presence of Cryptosporidium spp. using light and scanning electron microscopy to characterize the parasite's oocysts. Furthermore, molecular identification and characterization of the parasite were carried out on selected microscopy-positive samples (n = 30) using conventional polymerase chain reaction (PCR) targeting the Cryptosporidium oocyst wall protein (COWP) gene. A subset of these positive samples by PCR was subjected to sequencing, with the resulting sequences deposited in GenBank™ and analyzed through phylogenetic methods.

Results

Conventional microscopy revealed that 46.7% (70/150; 95% CI: 38.7-54.6) of the analyzed stool samples contained structures consistent with Cryptosporidium oocysts. Moreover, the molecular analysis confirmed Cryptosporidium species in DNA from all 30 stool samples previously identified as heavily infected through microscopy. Notably, the phylogenetic analysis identified Cryptosporidium parvum (C. parvum) in the sequenced samples, likely originating from the rats' native habitats. These identified species have been deposited in GenBank™ under the accession numbers OM817461 (C. parvum FSA-1), OM817462 (C. parvum FSA-2), and OM817463 (C. parvum FSA-3) and revealed closed genetic identity with those species reported from human and other animal species in the same geographic location.

Conclusion

Overall, this study represents the first morphological and genetic identification of C. parvum isolated from fecal samples of fat sand rats trapped from periurban areas in Egypt. These findings provide valuable insights into the potential zoonotic implications of rodents in disease transmission at the national level, offering crucial information for public health awareness campaigns and informing local authorities.

Coproantigen detection and molecular identification of Cryptosporidium species among newborn and adult farm animals

Cryptosporidium sp. is an obligatory intracellular apicomplexan protozoan parasite that causes a disease called cryptosporidiosis with substantial veterinary and medical importance. Therefore, this study aimed to evaluate an early diagnosis of cryptosporidiosis using the anti-Cryptosporidium parvum oocyst immunoglobulin IgG polyclonal antibodies (anti-C. parvum IgG PAbs)-based sandwich enzyme-linked immunosorbent assay (ELISA) for the detection of Cryptosporidium oocyst antigens in fecal samples of farm animals in Egypt. Further molecular identification and sequencing were performed for the detected isolates. Eight hundred and twenty fecal samples of farm animals; 102 buffalo calves, 120 cattle calves, 100 lambs and 98 goat kids, 80 buffaloes, 60 cattle, 160 sheep and 100 goats, collected from different small-scale farms and local holders were examined for cryptosporidiosis by Modified Ziehl-Neelsen (MZN) technique. The percentage of positivity was 45.1%, 50%, 20%, 18.4%, 31.25%, 38.3%, 18.8%, and 11% in buffalo calves, cattle calves, lambs, goat kids, adult buffaloes, adult cattle, sheep, and goats, respectively. Molecular identification of Cryptosporidium samples was performed based on COWP gene, revealing the isolates: GenBank: OQ121955.1, OR029973.1 and PP316107.1 which were identical to the C. parvum and GenBank: PP316108.1 and OR029972.1 which were identical to C. hominis and C. andersoni, respectively. Then, C. parvum oocysts were used for preparation of antigens and rabbit immunization. Anti-C. parvum IgG PAbs were purified and characterized by SDS-PAGE and then labeled with horseradish peroxidase (HRP). Anti-C. parvum IgG PAbs in-house sandwich ELISA was prepared, then tested this ELISA on 820 samples and compared results with MZN microscopical examination and a commercial sandwich ELISA kit. In this study, in-house sandwich ELISA scored higher sensitivity of 98%, 100% specificity, validity 99% and relative agreement 98.6% than (92%, 90%, 91% and 91.4%) of MZN and (96%, 95%, 95.5% and 95.7%) of coproantigen commercial sandwich ELISA kit, respectively. Moreover, we used PCR to evaluate the positivity of in-house sandwich ELISA results, and the total PCR positive samples were 263 out of 268 sandwich ELISA positive samples (98.13%). In conclusion, the prepared Anti-C. parvum IgG PAbs based sandwich ELISA offered a simple and accurate diagnostic method for cryptosporidiosis in the fecal samples of different species of farm animals in Egypt with high sensitivity (98%) and specificity (100%). Further studies on this Anti-C. parvum IgG PAbs may help also in the protection against cryptosporidiosis.

Iron‑sulfur cluster biogenesis and function in Apicomplexa parasites

Iron‑sulfur cluster are ubiquitous and ancient protein cofactors that support a wide array of essential cellular functions. In eukaryotes, their assembly requires specific and dedicated machineries in each subcellular compartment. Apicomplexans are parasitic protists that are collectively responsible for a significant burden on the health of humans and other animals, and most of them harbor two organelles of endosymbiotic origin: a mitochondrion, and a plastid of high metabolic importance called the apicoplast. Consequently, apicomplexan parasites have distinct iron‑sulfur cluster assembly machineries located to their endosymbiotic organelles, as well as a cytosolic pathway. Recent findings have not only shown the importance of iron‑sulfur cluster assembly for the fitness of these parasites, but also highlighted parasite-specific features that may be promising for the development of targeted anti-parasitic strategies.

Toxoplasma replication is inhibited by MMV676477 without development of resistance

Protozoan parasites cause life-threatening infections in both humans and animals, including agriculturally significant livestock. Available treatments are typically narrow spectrum and are complicated by drug toxicity and the development of resistant parasites. Protozoan tubulin is an attractive target for the development of broad-spectrum antimitotic agents. The Medicines for Malaria Pathogen Box compound MMV676477 was previously shown to inhibit replication of kinetoplastid parasites, such as Leishmania amazonensis and Trypanosoma brucei, and the apicomplexan parasite Plasmodium falciparum by selectively stabilizing protozoan microtubules. In this report, we show that MMV676477 inhibits intracellular growth of the human apicomplexan pathogen Toxoplasma gondii with an EC50 value of ~50 nM. MMV676477 does not stabilize vertebrate microtubules or cause other toxic effects in human fibroblasts. The availability of tools for genetic studies makes Toxoplasma a useful model for studies of the cytoskeleton. We conducted a forward genetics screen for MMV676477 resistance, anticipating that missense mutations would delineate the binding site on protozoan tubulin. Unfortunately, we were unable to use genetics to dissect target interactions because no resistant parasites emerged. This outcome suggests that future drugs based on the MMV676477 scaffold would be less likely to be undermined by the emergence of drug resistance.

Molecular characterization of Cryptosporidium spp. in symptomatic children from Cape Verde

Cryptosporidiosis has been identified as one of the leading causes of diarrhea and diarrhea-associated deaths in young children in sub-Saharan Africa. In Cape Verde, available data on human infections caused by Cryptosporidium spp. are limited. The aim of the present study was to analyze the molecular epidemiology of Cryptosporidium spp. in Cape Verde. Stool samples were obtained from patients on the Santiago and Sal islands (Cape Verde); 10/105 (9.5 % CI: 4.7; 16.8) from the Santiago Island and 4/85 (4.7 % CI: 1.3; 11.6) from the Sal Island presented Cryptosporidium sp., and were analyzed by nested-PCR of the SSU rRNA gene and nested-PCR of the 60 kDa glycoprotein gene for subtyping. Two species, Cryptosporidium hominis and Cryptosporidium felis, were identified. In Santiago Island, only C. hominis was detected, while both species were found in Sal Island. Cryptosporidium hominis IfA 14G1R5 subtype was identified in children from Santiago and Sal. Although the consumption of non-bottled water is a risk factor for infection by Cryptosporidium spp. on Santiago Island, none of the factors analysed (age, gender, clinical symptoms, source of drinking water, presence of animals at home, attending kindergarten or school, and having a bathroom at home) were significantly related to the presence of Cryptosporidium spp. in Sal Island. Cryptosporidium hominis is the most commonly identified species associated with cryptosporidiosis in the studied population, indicating a predominance of anthroponotic transmission. This study provides the first data on C. hominis subtyping in Cape Verde and the first report of C. felis in humans from this region, demonstrating the possibility of zoonotic transmission. The obtained results highlight the need for further molecular and epidemiological studies of Cryptosporidium spp. infections in human and animals from Cape Verde, in order to investigate the transmission dynamics of cryptosporidiosis and develop effective control strategies to prevent the spread of the disease.

Occurrence and molecular characterization of Cryptosporidium oocysts in chickens from Egypt, and a meta-analysis for Cryptosporidium infections in chickens worldwide

Cryptosporidium is a leading cause of diarrhea in children and immunocompromised patients. Various animals and birds can also be infected with this protist, and Cryptosporidium zoonosis is common. A few reports have been published worldwide on Cryptosporidium infections in chickens. The present study surveyed Cryptosporidium infections in chickens from Dakahlia governorate, Egypt. Cryptosporidium oocysts were tested, using the Ziehl Neelsen modified acid-fast staining, in 884 chickens collected from various farms and live bird markets (LBMs) in Dakahlia governorate, Egypt. COWP (Cryptosporidium oocyst wall protein)-PCR testing coupled with isolate sequencing was conducted for 10 Cryptosporidium-positive samples. Intestinal contents of 58 (6.6 %) out of the surveyed chickens in Dakahlia, Egypt, had Cryptosporidium oocysts. The native breed (Balady) had a significantly higher prevalence than the commercial breeds. Oocysts of two different size ranges were detected; 4-5.5 × 4-5 μm and 6-7 × 5-6 μm. Two of the ten PCR-tested samples were successfully sequenced and identified as Cryptosporidium parvum. The present study conducted also the first meta-analysis describing the epidemiology, clinical disease, and species diversity of Cryptosporidium infecting chickens worldwide. The pooled Cryptosporidium prevalence in 18,579 chickens tested worldwide was 18.3 %, with insignificant geographical variations. The prevalence was two-fold higher (40.5 %) at the flock level. Chickens collected from LBMs (30.5 %) had significantly higher pooled prevalence than farmed chickens (14.4 %). Insignificant prevalence variations were detected according to the production type (broiler or layer), diagnostic method, or disease status. Three Cryptosporidium species common to infect birds were molecularly identified in 760 chickens tested worldwide: Cryptosporidium baileyi, Cryptosporidium meleagridis, and Cryptosporidium galli, with the former being the most frequently detected. Cryptosporidium parvum was detected in a few samples mostly from free-range chickens. In conclusion, potential C. parvum zoonosis from chickens is suggested in Egypt, where C. parvum is common among humans and various animals. Given that chicken has a substantial role in the global C. meleagridis zoonoses, and no bird-specific Cryptosporidium spp. were detected in the tested samples from Egypt, we do recommend a large-scale molecular survey to detect various species and genotypes infecting chickens throughout various Egyptian governorates.

Therapeutic potential of platelet rich plasma against experimental Cryptosporidium parvum infection: in vivo study in immunosuppressed mice

The present study was designed to assess the possible effects of platelet rich plasma (PRP) when used individually and in combination with nitazoxanide (NTZ) on experimental Cryptosporidium parvum (C. parvum) infection. It was conducted on 100 male albino mice, laboratory bred in Theodore Bilharz Research Institute. Starting from the 7th day post infection (p.i), therapeutics were given to immunosuppressed infected mice, which were divided as follows; oral NTZ treated group (0.2 mg/g/day for 6 consecutive days), six-PRP-treated groups (0.5 μl/g/week) to be administered intravenously (IV) in 1st, 2nd, 3rd week as PRP alone in (3 groups) and combined with oral NTZ (0.2 mg/g/day for 6 consecutive days) in (3 groups). Parasitological, histopathological and immunohistochemical assessments of therapeutics under study were done. Fecal pellets collected from groups at different intervals were stained using modified Ziehl-Neelsen and examined under microscope. Among PRP-treated groups, the highest significant percentage of oocyst reduction (89.96%) was observed in the group received 3 doses of PRP in combination with NTZ on the 35th day post infection. Likewise, the histopathological examination of small intestinal tissue sections showed improvement in villous architecture with mild to moderate stunting and moderate inflammatory infiltrates in lamina propria. Immunohistochemical staining of small intestinal tissue sections showed moderate increase in the expression of TGF-β1. Therefore, PRP can be a novel strategy in the treatment of cryptosporidiosis particularly when combined with NTZ.

Cryptosporidium species and subtypes in Norway: predominance of C. parvum and emergence of C. mortiferum

PCR-based diagnostics has revealed the previously largely unknown Cryptosporidium transmission and infections in high-income countries. This study aimed to determine domestic and imported subtypes of Cryptosporidium species in Norway, evaluate their demographic distribution, and identify potential small outbreaks. Cryptosporidium-positive human faecal samples were obtained from six medical microbiology laboratories between February 2022 and January 2024, together with 22 Cryptosporidium-positive animal samples. Species and subtypes were identified by sequencing PCR products from gp60 and SSU rRNA genes. Most cryptosporidiosis cases occurred during late summer/early autumn, primarily in children and young adults. Of 550 human samples, 359 were successfully characterized molecularly (65%), revealing infection with 10 different Cryptosporidium species. C. parvum occurred in 245 (68%) human isolates with IIa and IId being major allele families, with distinct regional distribution patterns of common subtypes. A kindergarten outbreak with 5 cases was due to C. parvum IIaA14G1R1. C. mortiferum was identified in 33 (9.2%) human cases of which 24 were known to be of domestic origin, making it the second most common species in human autochthonous cases in Norway. All C. mortiferum isolates were of the same genotype; XIVaA20G2T1, including 13 cases from a suspected small outbreak in Trøndelag. C. hominis occurred in 68 typed cases (19%), but mostly in infections acquired abroad, with allele families Ib and If occurring most often. In conclusion, this study of recent Cryptosporidium spp. and subtypes in Norway, highlights the predominance of C. parvum and the emergence of C. mortiferum among autochthonous cases.

Pyridopyrimidinones as a new chemotype of calcium dependent protein kinase 1 (CDPK1) inhibitors for Cryptosporidium

The protozoan protein kinase calcium-dependent protein kinase 1 (CDPK1) has emerged as a potential therapeutic target for the treatment of cryptosporidiosis. A focused screen of known kinase inhibitors identified a pyridopyrimidinone as a new chemotype of Cryptosporidium parvum (Cp) CDPK1 inhibitors. Structural comparison of CpCDPK1 to two representative human kinases, RIPK2 and Src, revealed differences in the positioning of the αC-helix that was used in the design of a potent pyridopyrimidinone-based CpCDPK1 inhibitor 7 (a.k.a. UH15-16, IC50 = 10 nM), which blocked the growth of three C. parvum strains (EC50 = 12-40 nM) as well as C. hominis (EC50 = 85 nM) in HCT-8 host cells. Pharmacokinetic and tissue distribution analyses indicated that 7 had low systemic exposure after oral administration, but high gastrointestinal concentration, as well as good Caco-2 cell permeability. Finally, 7 demonstrated partial efficacy in an IL-12 knock-out mouse model of acute cryptosporidiosis.

Cryptosporidium Species Infections Detected from Fecal Samples of Animal and Human Hosts in South Africa: Systematic Review and Meta-Analysis

This study presents a systematic review and meta-analysis approach of Cryptosporidium species prevalence studies in animal and human hosts published between 1980 and 2020 in South Africa. Extensive searches were conducted on three electronic databases including PubMed, ScienceDirect and Google Scholar. The findings indicated an overall pooled prevalence estimate (PPE) of Cryptosporidium spp. infections in animals and humans at 21.5% and 18.1%, respectively. The PCR-RFLP appeared to be the most sensitive diagnostic method with a PPE of 77.8% for the detection of Cryptosporidium spp. infections followed by ELISA (66.7%); LAMP (45.4%); PCR (25.3%); qPCR (20.7%); microscopy (10.1%); IFAT (8.4%); and RDT (7.9%). In animal hosts, C. parvum had the highest PPE of 3.7%, followed by C. andersoni (1.5%), C. ubiquitum (1.4%) and C. bovis (1.0%), while in humans, C. parvum also had the highest PPE of 18.3% followed by C. meleagridis at 0.4%. The data generated in this study indicated that Cryptosporidium spp. infections were highly prevalent in both animals and humans in South Africa, especially in the KwaZulu-Natal and North West provinces. However, we further observed that there was a lack of prevalence studies for both animals and humans in some of the provinces. This study highlights the necessity for a "One Health" strategic approach promoting public hygiene, animal husbandry and regular screening for Cryptosporidium spp. infections in both animals and humans.

Cryptosporidium spp. prevalence in the general population in Guinea: first large-scale screening study

Cryptosporidium is a leading cause of diarrheal mortality in children in Africa and Asia. Despite the public health significance of this parasite, its molecular epidemiology and circulation in Guinea remain poorly understood. Therefore, this study aimed to determine the prevalence and genotype distribution of Cryptosporidium in the Guinean general population. To achieve this, fecal samples were collected from 834 individuals, both with and without digestive disorders, at two hospitals in Conakry. The presence of the parasite in the stool samples was detected using nested PCR targeting the SSU rDNA gene, followed by sequencing of the PCR products for genotyping of the isolates. The PCR-based prevalence was 0.12% for the whole cohort, and 0.2% among adults. The low frequency of Cryptosporidium observed in the current study is thus consistent with the prevalence of this parasite already reported in certain other African countries. The species identified in the positive samples was Cryptosporidium hominis. This study is the first to report the prevalence of Cryptosporidium in the general population of Guinea. Given the potential of this parasite to cause life-threatening diarrhea, further studies are needed to clarify the epidemiology of Cryptosporidium in this country.

Cryptosporidiosis in a Zoonotic Gastrointestinal Disorder Perspective: Present Status, Risk Factors, Pathophysiology, and Treatment, Particularly in Immunocompromised Patients

Cryptosporidium infection is highly prevalent among immunocompromised patients with Acquired Immunodeficiency Syndrome, cancer, primary immunodeficiency, and organ transplant recipients. Comprehensive knowledge about Cryptosporidium infection provides the means for efficient diagnosis, treatment, and prevention. Therefore, with the objective of providing an in-depth analysis of Cryptosporidiosis in immunocompromised patients, this review presents a comprehensive understating of the prevalence, risk factors, pathophysiology of Cryptosporidium infection, clinical presentation in the immunocompromised, the immune response of the host, diagnostic methods performed in laboratory settings, possible treatments, and prevention methods, which can be used for further studies. Peer-reviewed, published, original articles on cryptosporidiosis in immunocompromised patients were searched using specific key-words on PubMed, ResearchGate, Google Scholar, and ScienceDirect databases. Articles which were accessible to the date of 18th of August 2023, were included in this comprehensive review. We analyzed reports on Cryptosporidium in immunocompromised patients with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), cancer, primary immunodeficiency, and organ transplant recipients. 134 Articles describing epidemiology, related risk factors, clinical presentation, diagnosis, and possible treatments in the light of pathogenesis, pathophysiology, and virulence factors of Cryptosporidium and immunology of the host are summarized in this study. Effective treatments to be administered, importance, and ways of prevention were identified. Cryptosporidium infection was found to be highly prevalent among immunocompromised in Asia, Africa, Europe, and North America. The immunity of the host and the decrease in CD4+ T-cell count were found to the main factors which decide the susceptibility and the severity of infection. Drugs that activate host immunity and suppress Cryptosporidium growth, along with supportive therapy, is an effective treatment. But prevention is the most effective strategy for immunocompromised patients; thus, a better understanding about the disease would lead to effective prevention.

A Pumpless and Tubeless Microfluidic Device Enables Extended In Vitro Development of Cryptosporidium parvum

Background

The enteric parasite Cryptosporidium remains a treatment challenge for drinking water utilities globally due to its resistance to chlorine disinfection. However, the lack of an in vitro culture system for Cryptosporidium that is both cost-effective and reliable remains a key bottleneck in Cryptosporidium research.

Methods

Here we report that the microfluidic culture of human ileocecal colorectal adenocarcinoma (HCT-8) cells under fluid shear stress enables the extended development of Cryptosporidium parvum. Specifically, the growth of C. parvum in a user-friendly pumpless microfluidic device was assessed using immunofluorescence assays, scanning electron microscopy, and quantitative polymerase chain reaction, which revealed that development continued for 10 days in total.

Results

Oocysts produced within the microfluidic device were infective to fresh HCT-8 monolayers; however, these oocysts were only present at low levels.

Conclusions

We anticipate that such microfluidic approaches will facilitate a wide range of in vitro studies on Cryptosporidium and may have the potential to be further developed as a routine infectivity assessment tool for the water industry.

Cryptosporidium PI(4)K inhibitor EDI048 is a gut-restricted parasiticidal agent to treat paediatric enteric cryptosporidiosis

Diarrhoeal disease caused by Cryptosporidium is a major cause of morbidity and mortality in young and malnourished children from low- and middle-income countries, with no vaccine or effective treatment. Here we describe the discovery of EDI048, a Cryptosporidium PI(4)K inhibitor, designed to be active at the infection site in the gastrointestinal tract and undergo rapid metabolism in the liver. By using mutational analysis and crystal structure, we show that EDI048 binds to highly conserved amino acid residues in the ATP-binding site. EDI048 is orally efficacious in an immunocompromised mouse model despite negligible circulating concentrations, thus demonstrating that gastrointestinal exposure is necessary and sufficient for efficacy. In neonatal calves, a clinical model of cryptosporidiosis, EDI048 treatment resulted in rapid resolution of diarrhoea and significant reduction in faecal oocyst shedding. Safety and pharmacological studies demonstrated predictable metabolism and low systemic exposure of EDI048, providing a substantial safety margin required for a paediatric indication. EDI048 is a promising clinical candidate for the treatment of life-threatening paediatric cryptosporidiosis.

Safe drinking water: to what extent are shallow wells reliable?

Our study investigated the presence of Cryptosporidium hominis-parvum-meleagridis and Giardia duodenalis in shallow wells used for drinking water (DW) in a rural area. Also, bovine feces were collected from their vicinity. Our findings highlight significant potential risks associated with these pathogens in DW sources. Due to the COVID-19 pandemic, samples were collected in two phases: September/2019 to March/2020 and October/2021 to April/2022. Water samples (n = 69) and feces (n = 13) were collected biweekly and analyzed using the USEPA 1623.1 method and molecular tools for species identification, and feces by direct DNA extraction. During the first phase, oocysts and cysts were detected at frequencies ranging from 9.1 to 41.7 and 27.3 to 83.3, respectively. In the second phase, oocyst frequencies ranged from not detected to 25%, while cyst ranged from 18.2 to 83.3%. Escherichia coli concentrations were significant at all collection points. C. hominis-parvum-meleagridis and G. duodenalis were notably detected in bovine feces. Our study revealed the presence of anthropogenic parasites and E. coli in DW sources intended for human consumption. These findings underscore the urgent need for preventive measures to ensure safe DW and prevent future contamination. Effective water quality surveillance is crucial in this regard.

Comparative efficacy and safety of anti-cryptosporidial agents: an in vitro study on nitazoxanide, halofuginone lactate, KDU731, and paromomycin against Cryptosporidium parvum

This study evaluated the in vitro effectiveness of anti-cryptosporidial agents nitazoxanide, halofuginone, the pyrazolopyridine analog KDU731, and paromomycin (PMC) in combating the significant zoonotic pathogen Cryptosporidium parvum. The study utilized HCT-8 host cells to culture C. parvum and fluorescent microscopy/quantitative PCR (qPCR) for detecting parasitic growth. The efficacy of the compounds was assessed by calculating their inhibitory concentrations (IC) against the total growth of C. parvum at 48 h post-infection. The study further investigated the impact of these compounds on early parasitophorous vacuole (PV) formation, merozoite egress, host cell viability, and cell growth cycle. KDU731 displayed the most promising profile, with low nanomolar (102 nM ± 2.28) activity and negligible host cell toxicity. This study offers new insights into the relative efficacy and safety of various anti-cryptosporidial compounds, highlighting their stage-specific effects on C. parvum and the consequential impacts on host cells. Identifying safe and effective anti-cryptosporidial agents contributes significantly to the One Health approach, which emphasizes the importance of integrated strategies in controlling zoonotic diseases.

Clinical Significance of Respiratory Involvement in Cryptosporidiosis: Cross-Sectional Study of Children with Diarrhea and Respiratory Symptoms in Uganda

Respiratory cryptosporidiosis is considered an occasional, late-stage complication of HIV/AIDS. This study aimed to assess the clinical importance of respiratory cryptosporidiosis in children with diarrhea and respiratory symptoms at Mulago Hospital, Kampala, Uganda. Children aged 9 to 36 months presenting with diarrhea and cough or unexplained tachypnea (N = 1,918) were screened for fecal Cryptosporidium using polymerase chain reaction (PCR). Children with positive stool samples were eligible for further diagnostic tests, including sputum induction. Sputum samples were subjected to PCR for Cryptosporidium, as well as routine microbiology (culture and gram stain) and auramine stain for tuberculosis. Regression analyses were used to investigate 1) factors associated with respiratory cryptosporidiosis and 2) whether respiratory cryptosporidiosis was independently associated with hospitalization. Prevalence of enteric cryptosporidiosis was 260/1,918 (13.6%) (>80% Cryptosporidium hominis). Of the 236 children who had sputum available for analysis, 62 (26.3%) had Cryptosporidium in the sputum, only two of whom had HIV infection. Children with Cryptosporidium in the sputum were more likely to have abnormal oxygen saturation at presentation (SpO2 <96%; P = 0.053); no other differences in frequency or severity of respiratory signs were noted. No alternative bacterial cause of respiratory symptoms was identified in 37.7% of children with respiratory cryptosporidiosis, compared with 23.6% of children without (P = 0.04). Sputum-positive children had twice the odds of hospitalization compared with children without Cryptosporidium infection at this site (adjusted odds ratio = 2.08, 95% confidence interval: 1.02-4.22; P = 0.043). Respiratory tract involvement is common in children with intestinal cryptosporidiosis who are experiencing respiratory symptoms. Such children may experience some degree of respiratory compromise and may be at increased risk for hospitalization.

Multiplex PCR for gastrointestinal parasites in stool: Benchmarking against direct microscopy and simplex PCR

PURPOSE

To develop and validate a multiplex conventional PCR assay to simultaneously detect Cryptosporidium spp., Entamoeba histolytica, and Giardia lamblia in diarrheal samples as a rapid, cost-effective, and sensitive diagnostic tool for prevalent co-infections for improved diagnostic accuracy and efficiency in resource-limited settings.

METHODS

Stool samples collected from patients with gastrointestinal symptoms after taking written consent, processed via wet mount, iodine mount, and PCR assays. Cohen's kappa statistical analysis was done to test agreement.

RESULT

Among 240 patients, 28.75% showed intestinal protozoa via Microscopy; Single-plex and multiplex PCR demonstrated 100% concordance, detecting 27.9%; confirmed by sequencing. Highest parasite positivity was observed in transplant and immunocompromised patients, with moderate to almost perfect agreement between microscopy and molecular methods.

CONCLUSION

Multiplex-conventional PCR offers superior sensitivity and specificity over microscopy and 100% concordance with single-plex PCR, enabling rapid, cost-effective diagnosis of multiple parasites from single stool sample. Its adoption could revolutionize parasitic infection management in routine diagnostics.

Exploring the impact of digestive physicochemical parameters of adults and infants on the pathophysiology of Cryptosporidium parvum using the dynamic TIM-1 gastrointestinal model

BACKGROUND

Human cryptosporidiosis is distributed worldwide, and it is recognised as a leading cause of acute diarrhoea and death in infants in low- and middle-income countries. Besides immune status, the higher incidence and severity of this gastrointestinal disease in young children could also be attributed to the digestive environment. For instance, human gastrointestinal physiology undergoes significant changes with age, however the role this variability plays in Cryptosporidium parvum pathogenesis is not known. In this study, we analysed for the first time the impact of digestive physicochemical parameters on C. parvum infection in a human and age-dependent context using a dynamic in vitro gastrointestinal model.

RESULTS

Our results showed that the parasite excystation, releasing sporozoites from oocysts, occurs in the duodenum compartment after one hour of digestion in both child (from 6 months to 2 years) and adult experimental conditions. In the child small intestine, slightly less sporozoites were released from excystation compared to adult, however they exhibited a higher luciferase activity, suggesting a better physiological state. Sporozoites collected from the child jejunum compartment also showed a higher ability to invade human intestinal epithelial cells compared to the adult condition. Global analysis of the parasite transcriptome through RNA-sequencing demonstrated a more pronounced modulation in ileal effluents compared to gastric ones, albeit showing less susceptibility to age-related digestive condition. Further analysis of gene expression and enriched pathways showed that oocysts are highly active in protein synthesis in the stomach compartment, whereas sporozoites released in the ileum showed downregulation of glycolysis as well as strong modulation of genes potentially related to gliding motility and secreted effectors.

CONCLUSIONS

Digestion in a sophisticated in vitro gastrointestinal model revealed that invasive sporozoite stages are released in the small intestine, and are highly abundant and active in the ileum compartment, supporting reported C. parvum tissue tropism. Our comparative analysis suggests that physicochemical parameters encountered in the child digestive environment can influence the amount, physiological state and possibly invasiveness of sporozoites released in the small intestine, thus potentially contributing to the higher susceptibility of young individuals to cryptosporidiosis.

Prevalence of Parasitic Disease Burden in the Adult Population Presenting With Persistent or Chronic Diarrhea

Introduction Parasitic infection is an overlooked cause of diarrhea in adults. It can cause persistent or chronic diarrhea that contributes to a significant burden on the overall morbidity of the population. Stool sampling would aid in the diagnosis of parasitic infection in adults presenting with diarrhea. Methods A cross-sectional study was conducted from January to June 2024 at Medical Teaching Institution (MTI)-Hayatabad Medical Complex, Peshawar, Pakistan. A total of 500 stool samples were collected using non-probability consecutive sampling. All the patients presenting with complaints of persistent or chronic diarrhea to the medical outpatient department or admitted to the medical units were included in the study. Patients with bloody diarrhea and those less than 13 years of age were excluded from the study. Verbal and written informed consent was obtained from all the patients included in the study. The stool samples of all the patients were collected, reported, and verified by the microbiology department. Results Out of 500 stool samples of the patients with persistent or chronic diarrhea, 174 (34.8%) were found to be infected with cysts or trophozoites of parasites. Gender distribution of parasitic infections showed that 89 out of 245 females (36.3%) and 85 out of 255 males (33.3%) were affected. The comparison between genders yielded a p-value of 0.482. All the patients showed mono parasitism. The most common isolate was Giardia lamblia in 90 (51.72%) cases, followed by H-Nana in 49 (28.17%) isolates, Entamoeba histolytica in 16 (9.20%), Ascaris lumbricoides in 14 (8.04%), Trichuris trichura in two (1.15%), Taenia saginata in two (1.15%), and Cryptosporidium in one (0.6%) infected patient.  Conclusion Parasitic intestinal infections, particularly Giardia and H-Nana, are prevalent yet overlooked causes of persistent and chronic diarrhea in adults. These findings underscore the importance of routine stool examination as a cost-effective diagnostic tool, potentially improving patient outcomes and reducing unnecessary medical interventions.​​​​​​​​​.

Emerging therapeutic avenues against Cryptosporidium: A comprehensive review

Cryptosporidium is among the top causes of life-threatening diarrheal infection in public health and livestock sectors. Despite its high prevalence and economic importance, currently, there is no vaccine. Control of this protozoan is difficult due to the excretion of many resistant oocysts in the feces of the infected host, which contaminate the environment. Paromomycin shows inconsistent results and isn't considered a reliable therapy for cryptosporidiosis. Nitazoxanide (NTZ), the only FDA-approved drug against this parasite, is less productive in impoverished children and PLWHA (people living with HIV/AIDS). The absence of mitochondria and apicoplast, its unique location inside enterocytes separated by parasitophorous vacuole, and, most importantly, challenges in its genetic manipulations are some hurdles to the drug-discovery process. A library of compounds has been tested against Cryptosporidium during in vitro and in vivo trials. However, there has still not been sufficient success in finding the drug of choice against this parasite. Recent genome editing technologies based on CRISPR/Cas-9 have explored the functions of the vital genes by producing transgenic parasites that help to screen a collection of compounds to find target-specific drugs, provided the sufficient availability of in vitro culturing platforms, efficient transfection methods, and analytic techniques. The use of herbal remedies against Cryptosporidium is also an emerging area of interest with sufficient clinical success due to enhanced concern regarding anthelmintic resistance. Here, we highlighted present treatment options with their associated limitations, the use of genetic tools and natural products against it to find safe, effective, and inexpensive drugs to control the ever-increasing global burden of this disease.

Identification of potent and orally efficacious phosphodiesterase inhibitors in Cryptosporidium parvum-infected immunocompromised male mice

Cryptosporidium parvum and C. hominis are parasites that cause life-threatening diarrhea in children and immunocompromised people. There is only one approved treatment that is modestly effective for children and ineffective for AIDS patients. Here, screening 278 compounds from the Merck KGaA, Darmstadt, Germany collection and accelerated follow-up enabled by prior investigation of the compounds identifies a series of pyrazolopyrimidine human phosphodiesterase (PDE)-V (hPDE-V) inhibitors with potent anticryptosporidial activity and efficacy following oral administration in C. parvum-infected male mice. The lead compounds affect parasite host cell egress, inhibit both C. parvum and C. hominis, work rapidly, and have minimal off-target effects in a safety screening panel. Interestingly, the hPDE-V inhibitors sildenafil and the 4-aminoquinoline compound 7a do not affect Cryptosporidium. C. parvum expresses one PDE (CpPDE1) continuously during asexual growth, the inhibited life stage. According to homology modeling and docking, the lead compounds interact with CpPDE1. Bulkier amino acids (Val900 and His884) in the CpPDE1 active site replace alanines in hPDE-V and block sildenafil binding. Supporting this, sildenafil kills a CRISPR-engineered Cryptosporidium CpPDE1 V900A mutant. The CpPDE1 mutation also alters parasite susceptibility to pyrazolopyrimidines. CpPDE1 is therefore a validated pyrazolopyrimidine molecular target to exploit for target-based optimization for improved anticryptosporidial development.

γ-tubulin complex controls the nucleation of tubulin-based structures in Apicomplexa

Apicomplexan parasites rely on tubulin structures throughout their cell and life cycles, particularly in the polymerization of spindle microtubules to separate the replicated nucleus into daughter cells. Additionally, tubulin structures, including conoid and subpellicular microtubules, provide the necessary rigidity and structure for dissemination and host cell invasion. However, it is unclear whether these tubulin structures are nucleated via a highly conserved γ-tubulin complex or through a specific process unique to apicomplexans. This study demonstrates that Toxoplasma γ-tubulin is responsible for nucleating spindle microtubules, akin to higher eukaryotes, facilitating nucleus division in newly formed parasites. Interestingly, γ-tubulin colocalizes with nascent conoid and subpellicular microtubules during division, potentially nucleating these structures as well. Loss of γ-tubulin results in significant morphological defects due to impaired nucleus scission and the loss of conoid and subpellicular microtubule nucleation, crucial for parasite shape and rigidity. Additionally, the nucleation process of tubulin structures involves a concerted action of γ-tubulin and Gamma Tubulin Complex proteins (GCPs), recapitulating the localization and phenotype of γ-tubulin. This study also introduces new molecular markers for cytoskeletal structures and applies iterative expansion microscopy to reveal microtubule-based architecture in Cryptosporidium parvum sporozoites, further demonstrating the conserved localization and probable function of γ-tubulin in Cryptosporidium.

Domesticated animal reservoirs of Cryptosporidium and Giardia in agricultural farms in Laguna and Quezon provinces, Philippines

Cryptosporidium and Giardia are recognized as significant etiological agents of diarrheal outbreaks in humans as these parasites may be transmitted through the ingestion of water and food contaminated with feces of human or animal origin. However, surveillance studies on the role of animal reservoirs in the transmission of Cryptosporidium and Giardia are deemed insufficient and the complete dimension of the problem contributing to contamination in an agricultural setting is unknown. This study aimed to assess the presence of Cryptosporidium and Giardia in domesticated animals from selected farms in the agricultural provinces of Laguna and Quezon in Southern Luzon, Philippines. Using immunofluorescence assay, an overall 85.7% incidence of protozoan infection was recorded among the animals (N = 161). Of these, 77.0 and 73.9% were positive for Cryptosporidium and Giardia, respectively. Highest incidence (95.83%) of Cryptosporidium was documented in swine and the highest incidence (89.47%) of Giardia was observed in ruminants. Analyses revealed significant differences in the incidence of the protozoan parasites among animals with different containment status, water source, age group, and sex. On the other hand, farm workers' knowledge on parasite transmission was negatively correlated (p = 0.001) to parasite incidence. With the scarcity of data about Cryptosporidium and Giardia in farm-raised animals in the Philippines, the information obtained from this study will be vital for protozoan source tracking and further control interventions against Cryptosporidium and Giardia infections.

Prevalence and associated risk factors of Cryptosporidium infection in calves and hospitalized humans in Libo Kemkem, North Western Ethiopia

BACKGROUND

Cryptosporidium infection is one of the major causes of acute gastroenteritis and diarrhoea caused by a protozoan parasite affecting vertebrates and humans. The disease is prevalent in cases of immunocompromised individuals. Despite the impact of the diseases in calf and hospitalized humans, well-documented studies are not available in the study area.

OBJECTIVES

The objectives of this study were to determine the prevalence of Cryptosporidium infection in calves and hospitalized humans and assess the major associated risk factors associated with Cryptosporidium infection in calves and hospitalized humans.

METHOD

A cross-sectional study was conducted from November 2020 to March 2021 on calf and human Cryptosporidium infection in Libo Kemkem District, North West Ethiopia. A total of 193 calves and 122 human stool samples admitted to the hospital were used for this study. Three kebeles were selected purposely, and individual calves were selected using a simple random sampling method. A number of sampled calves were allocated proportionally to the selected kebeles. Human samples were collected using a systematic random sampling method. Faecal and stool samples were examined using a modified Ziehl-Neelsen staining method.

RESULT

The overall prevalence of calf and human Cryptosporidium infection found in this study was 15.5% and 11.5%, respectively. Age of calf, breed, body condition, water source, faecal consistency and hygienic condition were found significantly (p < 0.05) associated with Cryptosporidium infection in the calf. Similarly, the source of potable water, immunocompromisation and contact with domestic animals were found to be significantly (p < 0.05) associated with Cryptosporidium infection in humans.

CONCLUSION

There was a higher prevalence of Cryptosporidium infection in calves and humans in Libo Kemkem District. Therefore, the implementation of proper prevention methods of zoonotic Cryptosporidium infection between calf and human beings through significant risk factors is mandatory. Furthermore, additional studies to investigate the levels of economic importance of the disease should be conducted.

Cryptosporidium impacts epithelial turnover and is resistant to induced death of the host cell

Infection with the apicomplexan parasite Cryptosporidium is a leading cause of diarrheal disease. Cryptosporidiosis is of particular importance in infants and shows a strong association with malnutrition, both as a risk factor and as a consequence. Cryptosporidium invades and replicates within the small intestine epithelial cells. This is a highly dynamic tissue that is developmentally stratified along the villus axis. New cells emerge from a stem cell niche in the crypt and differentiate into mature epithelial cells while moving toward the villus tip, where they are ultimately shed. Here, we studied the impact of Cryptosporidium infection on this dynamic architecture. Tracing DNA synthesis in pulse-chase experiments in vivo, we quantified the genesis and migration of epithelial cells along the villus. We found proliferation and epithelial migration to be elevated in response to Cryptosporidium infection. Infection also resulted in significant cell loss documented by imaging and molecular assays. Consistent with these observations, single-cell RNA sequencing of infected intestines showed a gain of young and a loss of mature cells. Interestingly, enhanced epithelial cell loss was not a function of enhanced apoptosis of infected cells. To the contrary, Cryptosporidium-infected cells were less likely to be apoptotic than bystanders, and experiments in tissue culture demonstrated that infection provided enhanced resistance to chemically induced apoptosis to the host but not bystander cells. Overall, this study suggests that Cryptosporidium may modulate cell apoptosis and documents pronounced changes in tissue homeostasis due to parasite infection, which may contribute to its long-term impact on the developmental and nutritional state of children.

IMPORTANCE

The intestine must balance its roles in digestion and nutrient absorption with the maintenance of an effective barrier to colonization and breach by numerous potential pathogens. An important component of this balance is its constant turnover, which is modulated by a gain of cells due to proliferation and loss due to death or extrusion. Here, we report that Cryptosporidium infection changes the dynamics of this process increasing both gain and loss of enterocytes speeding up the villus elevator. This leads to a much more immature epithelium and a reduction of the number of those cells typically found toward the villus apex best equipped to take up key nutrients including carbohydrates and lipids. These changes in the cellular architecture and physiology of the small intestine may be linked to the profound association between cryptosporidiosis and malnutrition.

Treating cryptosporidiosis: A review on drug discovery strategies

Despite several decades of research on therapeutics, cryptosporidiosis remains a major concern for human and animal health. Even though this field of research to assess antiparasitic drug activity is highly active and competitive, only one molecule is authorized to be used in humans. However, this molecule was not efficacious in immunocompromised people and the lack of animal therapeutics remains a cause of concern. Indeed, the therapeutic arsenal needs to be developed for both humans and animals. Our work aims to clarify research strategies that historically were diffuse and poorly directed. This paper reviews in vitro and in vivo methodologies to assess the activity of future therapeutic compounds by screening drug libraries or through drug repurposing. It focuses on High Throughput Screening methodologies (HTS) and discusses the lack of knowledge of target mechanisms. In addition, an overview of several specific metabolic pathways and enzymatic activities used as targets against Cryptosporidium is provided. These metabolic processes include glycolytic pathways, fatty acid production, kinase activities, tRNA elaboration, nucleotide synthesis, gene expression and mRNA maturation. As a conclusion, we highlight emerging future strategies for screening natural compounds and assessing drug resistance issues.

Lower micromolar activity of the antifungal imidazoles on the bacterial-type bifunctional aldehyde/alcohol dehydrogenase (AdhE) in Cryptosporidium parvum and in vitro efficacy against the zoonotic parasite

Cryptosporidium parvum is a waterborne and foodborne zoonotic protozoan parasite, a causative agent of moderate to severe diarrheal diseases in humans and animals. However, fully effective treatments are unavailable for medical and veterinary uses. There is a need to explore new drug targets for potential development of new therapeutics. Because C. parvum relies on anaerobic metabolism to produce ATP, fermentative enzymes in this parasite are attractive targets for exploration. In this study, we investigated the ethanol-fermentation in the parasite and characterized the basic biochemical features of a bacterial-type bifunctional aldehyde/alcohol dehydrogenase, namely CpAdhE. We also screened 3892 chemical entries from three libraries and identified 14 compounds showing >50% inhibition on the enzyme activity of CpAdhE. Intriguingly, antifungal imidazoles and unsaturated fatty acids are the two major chemical groups among the top hits. We further characterized the inhibitory kinetics of selected imidazoles and unsaturated fatty acids on CpAdhE. These compounds displayed lower micromolar activities on CpAdhE (i.e., IC50 values ranging from 0.88 to 11.02 μM for imidazoles and 8.93 to 35.33 μM for unsaturated fatty acids). Finally, we evaluated the in vitro anti-cryptosporidial efficacies and cytotoxicity of three imidazoles (i.e., tioconazole, miconazole and isoconazole). The three antifungal imidazoles exhibited lower micromolar efficacies against the growth of C. parvum in vitro (EC50 values ranging from 4.85 to 10.41 μM and selectivity indices ranging from 5.19 to 10.95). The results provide a proof-of-concept data to support that imidazoles are worth being further investigated for potential development of anti-cryptosporidial therapeutics.

Comparative genomics of Cryptosporidium parvum reveals the emergence of an outbreak-associated population in Europe and its spread to the United States

The zoonotic parasite Cryptosporidium parvum is a global cause of gastrointestinal disease in humans and ruminants. Sequence analysis of the highly polymorphic gp60 gene enabled the classification of C. parvum isolates into multiple groups (e.g., IIa, IIc, Id) and a large number of subtypes. In Europe, subtype IIaA15G2R1 is largely predominant and has been associated with many water- and food-borne outbreaks. In this study, we generated new whole-genome sequence (WGS) data from 123 human- and ruminant-derived isolates collected in 13 European countries and included other available WGS data from Europe, Egypt, China, and the United States (n = 72) in the largest comparative genomics study to date. We applied rigorous filters to exclude mixed infections and analyzed a data set from 141 isolates from the zoonotic groups IIa (n = 119) and IId (n = 22). Based on 28,047 high-quality, biallelic genomic SNPs, we identified three distinct and strongly supported populations: Isolates from China (IId) and Egypt (IIa and IId) formed population 1; a minority of European isolates (IIa and IId) formed population 2; and the majority of European (IIa, including all IIaA15G2R1 isolates) and all isolates from the United States (IIa) clustered in population 3. Based on analyses of the population structure, population genetics, and recombination, we show that population 3 has recently emerged and expanded throughout Europe to then, possibly from the United Kingdom, reach the United States, where it also expanded. The reason(s) for the successful spread of population 3 remain elusive, although genes under selective pressure uniquely in this population were identified.

Drinking water sources, quality, and associated health outcomes in Appalachian Virginia: A risk characterization study in two counties

OBJECTIVES

In the US, violations of drinking water regulations are highest in lower-income rural areas overall, and particularly in Central Appalachia. However, data on drinking water use, quality, and associated health outcomes in rural Appalachia are limited. We sought to assess public and private drinking water sources and associated risk factors for waterborne pathogen exposures for individuals living in rural regions of Appalachian Virginia.

METHODS

We administered surveys and collected tap water, bottled water, and saliva samples in lower-income households in two adjacent rural counties in southwest Virginia (bordering Kentucky and Tennessee). Water samples were tested for pH, temperature, conductivity, total coliforms, E. coli, free chlorine, nitrate, fluoride, heavy metals, and specific pathogen targets. Saliva samples were analyzed for antibody responses to potentially waterborne infections. We also shared water analysis results with households.

RESULTS

We enrolled 33 households (83 individuals), 82% (n = 27) with utility-supplied water and 18% with private wells (n = 3) or springs (n = 3). 58% (n = 19) reported household incomes of <$20,000/year. Total coliforms were detected in water samples from 33% (n = 11) of homes, E. coli in 12%, all with wells or springs (n = 4), and Aeromonas, Campylobacter, and Enterobacter in 9%, all spring water (n = 3). Diarrhea was reported for 10% of individuals (n = 8), but was not associated with E. coli detection. 34% (n = 15) of saliva samples had detectable antibody responses for Cryptosporidium spp., C. jejuni, and Hepatitis E. After controlling for covariates and clustering, individuals in households with septic systems and straight pipes had significantly higher likelihoods of antibody detection (risk ratios = 3.28, 95%CI = 1.01-10.65).

CONCLUSIONS

To our knowledge, this is the first study to collect and analyze drinking water samples, saliva samples, and reported health outcome data from low-income households in Central Appalachia. Our findings indicate that utility-supplied water in this region was generally safe, and individuals in low-income households without utility-supplied water or sewerage have higher exposures to waterborne pathogens.

Intestinal cDC1s provide cues required for CD4+ T cell-mediated resistance to Cryptosporidium

Cryptosporidium is an enteric pathogen and a prominent cause of diarrheal disease worldwide. Control of Cryptosporidium requires CD4+ T cells, but how protective CD4+ T cell responses are generated is poorly understood. Here, Cryptosporidium parasites that express MHCII-restricted model antigens were generated to understand the basis for CD4+ T cell priming and effector function. These studies revealed that parasite-specific CD4+ T cells are primed in the draining mesenteric lymph node but differentiate into Th1 cells in the gut to provide local parasite control. Although type 1 conventional dendritic cells (cDC1s) were dispensable for CD4+ T cell priming, they were required for CD4+ T cell gut homing and were a source of IL-12 at the site of infection that promoted local production of IFN-γ. Thus, cDC1s have distinct roles in shaping CD4+ T cell responses to an enteric infection: first, to promote gut homing from the mesLN, and second, to drive effector responses in the intestine.

The Cryptosporidium signaling kinase CDPK5 plays an important role in male gametogenesis and parasite virulence

The protozoan parasite Cryptosporidium is a leading cause of diarrhea in young children. The parasite's life cycle involves a coordinated and timely progression from asexual to sexual stages, leading to the formation of the transmissible oocyst. Underlying molecular signaling mechanisms orchestrating sexual development are not known. Here, we describe the function of a signaling kinase in Cryptosporidium male gametogenesis. We reveal the expression of Cryptosporidium parvum calcium-dependent protein kinase 5 (CDPK5) during male gamete development and its important role in the egress of mature gametes. Genetic ablation of this kinase results in viable parasites, indicating that this gene is dispensable for parasite survival. Interestingly, cdpk5 deletion decreases parasite virulence and impacts oocyst shedding in immunocompromised mice. Using phosphoproteomics, we identify possible CDPK5 substrates and biological processes regulated by this kinase. Collectively, these findings illuminate parasite cell biology by revealing a mechanism controlling male gamete production and a potential target to block disease transmission.

Mechanism of oxymatrine in the treatment of cryptosporidiosis through TNF/NF-κB signaling pathway based on network pharmacology and experimental validation

Cryptosporidiosis is a worldwide zoonotic disease. Oxymatrine, an alkaloid extracted and isolated from the plant bitter ginseng, has been reported to have therapeutic effects on cryptosporidiosis. However, the underlying mechanism of its action remains unclear. In this study, we utilized network pharmacology and experimental validation to investigate the mechanism of oxymatrine in the treatment of cryptosporidiosis. First, the potential targets of drugs and diseases were predicted by TCMSP, Gene Cards, and other databases. Following the intersection of drug-disease targets, the DAVID database was used to implement the enrichment analysis of GO functions and KEGG pathways, and then the network diagram of "intersected target-KEGG" relationship was constructed. Autodock 4.2.6 software was used to carry out the molecular docking of core targets to drug components. Based on the establishment of a mouse model of cryptosporidiosis, the validity of the targets in the TNF/NF-κB signaling pathway was confirmed using Western blot analysis and Quantitative Rea-ltime-PCR. A total of 41 intersectional targets of oxymatrine and Cryptosporidium were generated from the results, and five core targets were screened out by network analysis, including RELA, AKT1, ESR1, TNF, and CASP3. The enrichment analysis showed that oxymatrine could regulate multiple gene targets, mediate TNF, Apoptpsis, IL-17, NF-κB and other signaling pathways. Molecular docking experiments revealed that oxymatrine was tightly bound to core targets with stable conformation. Furthermore, we found through animal experiments that oxymatrine could regulate the mRNA and protein expression of IL-6, NF-κB, and TNF-α in the intestinal tissues of post-infected mice through the TNF/NF-κB signaling pathway. Therefore, it can be concluded that oxymatrine can regulate the inflammatory factors TNF-α, NF-κB, and IL-6 through the TNF/NF-κB signaling pathway for the treatment of cryptosporidiosis. This prediction has also been validated by network pharmacology and animal experiments.

Evaluation of molecular-based methods for the detection and quantification of Cryptosporidium spp. in wastewater

Cryptosporidium poses significant public health risks as a cause of waterborne disease worldwide. Clinical surveillance of cryptosporidiosis is largely underreported due to the asymptomatic and mildly symptomatic infections, clinical misdiagnoses, and barriers to access testing. Wastewater surveillance overcomes these limitations and could serve as an effective tool for identifying cryptosporidiosis at the population level. Despite its potential, the lack of standardized wastewater surveillance methods for Cryptosporidium spp. challenges implementation design and the comparability between studies. Thus, this study compared and contrasted Cryptosporidium wastewater surveillance methods for concentrating wastewater oocysts, extracting oocyst DNA, and detecting Cryptosporidium genetic markers. The evaluated concentration methods included electronegative membrane filtration, Envirocheck HV capsule filtration, centrifugation, and Nanotrap Microbiome Particles, with and without additional immunomagnetic separation purification (except for the Nanotrap Microbiome Particles). Oocyst DNA extraction by either the DNeasy Powersoil Pro kit and the QIAamp DNA Mini kit were evaluated and the impact of bead beating and freeze-thaw pretreatments on DNA recoveries was assessed. Genetic detection via qPCR assays targeting either the Cryptosporidium 18S rRNA gene or the Cryptosporidium oocyst wall protein gene were tested. Oocyst recovery percentages were highest for centrifugation (39-77 %), followed by the Nanotrap Microbiome Particles (24 %), electronegative filtration with a PBST elution (22 %), and Envirocheck HV capsule filtration (13 %). Immunomagnetic separation purification was found to be unsuitable due to interference from the wastewater matrix. Bead-beating pretreatment enhanced DNA recoveries from both the DNeasy Powersoil Pro kit (314 gc/μL DNA) and the QIAamp DNA Mini kit (238 gc/μL DNA). In contrast, freeze-thaw pretreatment reduced DNA recoveries to under 92 gc/μL DNA, likely through DNA degradation. Finally, while both qPCR assays were specific to Cryptosporidium spp., the 18S rRNA assay had a 5-fold lower detection limit and could detect a wider range of Cryptosporidium spp. than the Cryptosporidium oocyst wall protein assay.