Risk factors for Cryptosporidium contamination in Minnesota public supply wells.

In a recent monitoring study of Minnesota's public supply wells, Cryptosporidium was commonly detected with 40% of the wells having at least one detection. Risk factors for Cryptosporidium occurrence in drinking water supply wells, beyond surface water influence, remain poorly understood. To address this gap, physical and chemical factors were assessed as potential predictors of Cryptosporidium occurrence in 135 public supply wells in Minnesota. Univariable analysis, regression techniques, and classification trees were used to analyze the data. Many variables were identified as significant risk factors in univariable analysis and several remained significant throughout the succeeding analysis techniques. These factors fell into general categories of well use and construction, aquifer characteristics, and connectedness to the land surface, well capture zones, and land use therein, existence of potential contaminant sources within 200-feet of the well, and variability in the chemical and isotopic parameters measured during the study. These risk categories, and the specific variables and threshold values we have identified, can help guide future research on factors influencing Cryptosporidium contamination of wells and can be used by environmental health programs to develop risk-based sampling plans and design interventions that reduce associated health risks.

In vivo assessment of the antiparasitic effects of Allium sativum L. and Artemisia absinthium L. against gastrointestinal parasites in swine from low-input farms.

BACKGROUND: Ethno-veterinary practices could be used as a sustainable developmental tool by integrating traditional phytotherapy and husbandry. Phytotherapeutics are available and used worldwide. However, evidence of their antiparasitic efficacy is currently very limited. Parasitic diseases have a considerable effect on pig production, causing economic losses due to high morbidity and mortality. In this respect, especially smallholders and organic producers face severe challenges. Parasites, as disease causing agents, often outcompete other pathogens in such extensive production systems. A total of 720 faecal samples were collected in two farms from three age categories, i.e. weaners, fatteners, and sows. Flotation (Willis and McMaster method), modified Ziehl-Neelsen stained faecal smear, centrifugal sedimentation, modified Blagg technique, and faecal cultures were used to identify parasites and quantify the parasitic load. RESULTS: The examination confirmed the presence of infections with Eimeria spp., Cryptosporidium spp., Balantioides coli (syn. Balantidium coli), Ascaris suum, Oesophagostomum spp., Strongyloides ransomi, and Trichuris suis, distributed based on age category. A dose of 180 mg/kg bw/day of Allium sativum L. and 90 mg/kg bw/day of Artemisia absinthium L. powders, administered for 10 consecutive days, revealed a strong, taxonomy-based antiprotozoal and anthelmintic activity. CONCLUSIONS: The results highlighted the therapeutic potential of both A. sativum and A. absinthium against gastrointestinal parasites in pigs. Their therapeutic effectiveness may be attributed to the content in polyphenols, tocopherols, flavonoids, sterols, sesquiterpene lactones, and sulfoxide. Further research is required to establish the minimal effective dose of both plants against digestive parasites in pigs.

Estimation and evaluation of the risks of protozoa infections associated to the water from a treatment plant in southern Brazil using the Quantitative Microbiological Risk Assessment Methodology (QMRA).

In this study, the Quantitative Microbial Risk Assessment (QMRA) methodology was applied to estimate the annual risk of Giardia and Cryptosporidium infection associated with a water treatment plant in southern Brazil. The efficiency of the treatment plant in removing protozoa and the effectiveness of the Brazilian legislation on microbiological protection were evaluated, emphasizing the relevance of implementing the QMRA in this context. Two distinct approaches were employed to estimate the mechanical removal of protozoa: The definitions provided by the United States Environmental Protection Agency (USEPA), and the model proposed by Neminski and Ongerth. Although the raw water collected had a higher concentration of Giardia cysts than Cryptosporidium oocysts, the estimated values for the annual risk of infection were significantly higher for Cryptosporidium than for Giardia. From a general perspective, the risk values of protozoa infection were either below or very near the limit set by the World Health Organization (WHO). In contrast, all the risk values of Cryptosporidium infection exceeded the threshold established by the USEPA. Ultimately, it was concluded that the implementation of the QMRA methodology should be considered by the Brazilian authorities, as the requirements and guidelines provided by the Brazilian legislation proved to be insufficient to guarantee the microbiological safety of drinking water. In this context, the QMRA application can effectively contribute to the prevention and investigation of outbreaks of waterborne disease.

[Prevalence and molecular detection of human Cryptosporidium infections: a review].

Cryptosporidium is an important intestinal parasite that is mainly transmitted through the fecal-oral route. Human infection may occur following ingestion of water and food contaminated by Cryptosporidium oocysts, and children and immunocompromised individuals are at a high risk of infections. The main symptoms of Cryptosporidium infections include diarrhea, vomiting, malnutrition, and even death. Because of high sensitivity and rapid procedures, molecular tests are helpful for the diagnosis of cryptosporidiosis and may reduce the public health risk of cryptosporidiosis. This review summarizes the advances in the latest prevalence and molecular detection of human Cryptosporidium infections during recent years.

Genetic characterizations of Cryptosporidium spp. from children with or without diarrhea in Wenzhou, China: high probability of zoonotic transmission.

BACKGROUND: Cryptosporidium is a highly pathogenic parasite responsible for diarrhea in children worldwide. Here, the epidemiological status and genetic characteristics of Cryptosporidium in children with or without diarrhea were investigated with tracking of potential sources in Wenzhou City, China. METHODS: A total of 1032 children were recruited, 684 of whom had diarrhea and 348 without, from Yuying Children's Hospital in Wenzhou, China. Samples of stool were collected from each participant, followed by extraction of DNA, genotyping, and molecular identification of Cryptosporidium species and subtypes. RESULTS: Twenty-two of the 1032 (2.1%) children were infected with Cryptosporidium spp. with 2.5% (17/684) and 1.4% (5/348) in diarrhoeic and asymptomatic children, respectively. Four Cryptosporidium species were identified, including C. parvum (68.2%; 15/22), C. felis (13.6%; 3/22), C. viatorum (9.1%; 2/22), and C. baileyi (9.1%; 2/22). Two C. parvum subtypes named IIdA19G1 (n = 14) and IInA10 (n = 1), and one each of C. felis (XIXa) and C. viatorum (XVaA3g) subtype was found as well. CONCLUSIONS: This is the first research that identified Cryptosporidium in children of Wenzhou, China, using PCR. Identification of zoonotic C. parvum, C. felis, C. viatorum, and their subtypes indicate potential cross-species transmission of Cryptosporidium between children and animals. Additionally, the presence of C. baileyi in children suggests that this species has a wider host range than previously believed and that it possesses the capacity to infect humans.

Molecular Targets of the 5-Amido-Carboxamide Bumped Kinase Inhibitor BKI-1748 in Cryptosporidium parvum and HCT-8 Host Cells.

Cryptosporidium parvum is an apicomplexan parasite causing persistent diarrhea in humans and animals. Issuing from target-based drug development, calcium-dependent protein kinase 1 inhibitors, collectively named bumped kinase inhibitors (BKIs), with excellent efficacies in vitro and in vivo have been generated. Some BKIs including BKI-1748 share a core structure with similarities to the first-generation antiprotozoal drug quinine, which is known to exert notorious side effects. Unlike quinine, BKI-1748 rapidly interfered with C. parvum proliferation in the human colon tumor (HCT) cell line HCT-8 cells and caused dramatic effects on the parasite ultrastructure. To identify putative BKI targets in C. parvum and in host cells, we performed differential affinity chromatography with cell-free extracts from non-infected and infected HCT-8 cells using BKI-1748 and quinine epoxy-activated sepharose columns followed by mass spectrometry. C. parvum proteins of interest were identified in eluates from columns coupled to BKI-1748, or in eluates from both BKI-1748 and quinine columns. However, no C. parvum proteins could be identified binding exclusively to BKI-1748. In contrast, 25 BKI-1748-specific binding proteins originating from HCT-8 cells were detected. Moreover, 29 C. parvum and 224 host cell proteins were identified in both BKI-1748 as well as in quinine eluates. In both C. parvum and host cells, the largest subset of binding proteins was involved in RNA binding and modification, with a focus on ribosomal proteins and proteins involved in RNA splicing. These findings extend previous results, showing that BKI-1748 interacts with putative targets involved in common, essential pathways such as translation and RNA processing.

Pyroptosis Tuning in Intestinal Cryptosporidiosis via the Natural Histone Deacetylase Inhibitor Romidepsin.

Cryptosporidium is an opportunistic protozoan, with many species of cross-human infectivity. It causes life-threatening diarrhoea in children and CD4-defective patients. Despite its limited efficacy, nitazoxanide remains the primary anti-cryptosporidial drug. Cryptosporidium infects the intestinal brush border (intracellular-extracytoplasmic) and down-regulates pyroptosis to prevent expulsion. Romidepsin is a natural histone deacetylase inhibitor that triggers pyroptosis. Romidepsin's effect on cryptosporidiosis was assessed in immunocompromised mice via gasdermin-D (GSDM-D) immunohistochemical expression, IFN-γ, IL-1ß and IL-18 blood levels by ELISA, and via parasite scanning by modified Ziehl-Neelsen staining and scanning electron microscopy (SEM). Oocyst deformity and local cytokines were also assessed in ex vivo ileal explants. Following intraperitoneal injection of romidepsin, oocyst shedding significantly reduced at the 9th, 12th and 15th d.p.i. compared with infected-control and drug-control (nitazoxanide-treated) mice. H&E staining of intestinal sections from romidepsin-treated mice showed significantly low intestinal scoring with marked reduction in epithelial hyperplasia, villous blunting and cellular infiltrate. SEM revealed marked oocyst blebbing and paucity (in vivo and ex vivo) after romidepsin compared with nitazoxanide. Regarding pyroptosis, romidepsin triggered significantly higher intestinal GSDM-D expression in vivo, and higher serum/culture IFN-γ, IL-1ß and IL-18 levels in romidepsin-treated mice than in the control groups. Collectively, in cryptosporidiosis, romidepsin succeeded in enhancing pyroptosis in the oocysts and infected epithelium, reducing infection and shifting the brush border towards normalisation.

Identification of host protein ENO1 (alpha-enolase) interacting with Cryptosporidium parvum sporozoite surface protein, Cpgp40.

BACKGROUND: Cryptosporidium parvum is an apicomplexan zoonotic parasite causing the diarrheal illness cryptosporidiosis in humans and animals. To invade the host intestinal epithelial cells, parasitic proteins expressed on the surface of sporozoites interact with host cells to facilitate the formation of parasitophorous vacuole for the parasite to reside and develop. The gp40 of C. parvum, named Cpgp40 and located on the surface of sporozoites, was proven to participate in the process of host cell invasion. METHODS: We utilized the purified Cpgp40 as a bait to obtain host cell proteins interacting with Cpgp40 through the glutathione S-transferase (GST) pull-down method. In vitro analysis, through bimolecular fluorescence complementation assay (BiFC) and coimmunoprecipitation (Co-IP), confirmed the solid interaction between Cpgp40 and ENO1. In addition, by using protein mutation and parasite infection rate analysis, it was demonstrated that ENO1 plays an important role in the C. parvum invasion of HCT-8 cells. RESULTS: To illustrate the functional activity of Cpgp40 interacting with host cells, we identified the alpha-enolase protein (ENO1) from HCT-8 cells, which showed direct interaction with Cpgp40. The mRNA level of ENO1 gene was significantly decreased at 3 and 24 h after C. parvum infection. Antibodies and siRNA specific to ENO1 showed the ability to neutralize C. parvum infection in vitro, which indicated the participation of ENO1 during the parasite invasion of HCT-8 cells. In addition, we further demonstrated that ENO1 protein was involved in the regulation of cytoplasmic matrix of HCT-8 cells during C. parvum invasion. Functional study of the protein mutation illustrated that ENO1 was also required for the endogenous development of C. parvum. CONCLUSIONS: In this study, we utilized the purified Cpgp40 as a bait to obtain host cell proteins ENO1 interacting with Cpgp40. Functional studies illustrated that the host cell protein ENO1 was involved in the regulation of tight junction and adherent junction proteins during C. parvum invasion and was required for endogenous development of C. parvum.

Minimal zoonotic risk of cryptosporidiosis and giardiasis from frogs and reptiles.

The zoonotic potential of the protist parasites Cryptosporidium spp. and Giardia duodenalis in amphibians and reptiles raises public health concerns due to their growing popularity as pets. This review examines the prevalence and diversity of these parasites in wild and captive amphibians and reptiles to better understand the zoonotic risk. Research on Giardia in both groups is limited, and zoonotic forms of Cryptosporidium or Giardia have not been reported in amphibians. Host-adapted Cryptosporidium species dominate in reptiles, albeit some reptiles have been found to carry zoonotic (C. hominis and C. parvum) and rodent-associated (C. tyzzeri, C. muris and C. andersoni) species, primarily through mechanical carriage. Similarly, the limited reports of Giardia duodenalis (assemblages A, B and E) in reptiles may also be due to mechanical carriage. Thus, the available evidence indicates minimal zoonotic risk associated with these organisms in wild and captive frogs and reptiles. The exact transmission routes for these infections within reptile populations remain poorly understood, particularly regarding the importance of mechanical carriage. Although the risk appears minimal, continued research and surveillance efforts are necessary to gain a more comprehensive understanding of the transmission dynamics and ultimately improve our ability to safeguard human and animal health.

Parasitic contamination of fresh vegetables and fruits sold in open-air markets in peri-urban areas of Jimma City, Oromia, Ethiopia: A community-based cross-sectional study.

BACKGROUND: Consuming contaminated raw vegetables and fruits is one of the primary means of parasite transmission to humans. Periodic monitoring of parasitic contamination in these food items is a crucial step in preventing the spread of parasitic disease in the community. This study was aimed at detecting intestinal parasitic contamination caused by consuming raw vegetables and fruits sold in three open-air markets and its associated factors in peri-urban areas of Jimma City, Oromia, Ethiopia. METHODS: A cross-sectional study was conducted on fruits and vegetables collected from three peri-urban open-aired markets (namely; Hora Gibe, Bore and Jiren markets) in peri-urban areas of Jimma City between July and September 2021. A total of 187 fresh vegetable samples and 188 fruits were collected and examined for intestinal parasite contamination. About 200g of fruit and vegetable samples were processed and examined microscopically for parasite contamination, utilizing direct wet mount and modified Zeihl-Neelson staining methods in accordance with standard protocols. A structured questionnaire was used to collect data on the socio-demographic characteristics of vendors and risk factors for fruit and vegetable contamination. All data were analyzed using SPSS version 20.0. RESULT: Of the 187 fresh vegetable samples and 188 fresh vegetable samples, 105 (56.1%) and 68/188 (36.2%) of vegetables and fruit samples, respectively, were found contaminated with one or more intestinal parasites. Remarkably, high level of contamination in fresh vegetable samples was recorded both in Carrot (Daucus carota) 63.8% (30/46) and Lettuce (Lactuca sativa) 63.1% (29/46) while Green pepper (Capsicum spp.) is the least contaminated. In fruit samples, Avokado (Persea americana) 42.6% (20/47) and Banana (Musa acuminata) 14.9% (7/47) were the most and the least commonly contaminated items respectively. The identified helminthes and protozoans were Ascaris lumbricoides, Strongyloides stercoralis, Hymenolepis nana, Entamoeba histolytica/dispar, Giardia lamblia, Cryptosporidium spp., Toxocara spp. And Fasciola spp. The most predominant parasite encountered was A. lumbricoides 46(12.3%) whereas both Toxocara spp. 12(6.9) and Fasciola spp. 2(0.5) were the least detected parasites. It is worth-mentioned that the rate of contamination in Bore market (38.15%) was higher compared with Jiren market (34.7%) and Hora Gibe market (27%). However, the rate of contamination in vegetables and fruit obtained from the three district was non-significant (p = 0.19). Contamination was more common in vegetables than fruits (AOR = 5.78, p<0.001). It was also observed that decreased parasitic contamination was significantly associated with washing the products before displaying it for selling (p < 0.001). CONCLUSION: The study has identified a high rate of raw vegetables and fruits contaminated with intestinal helminthes and protozoan. Contaminated fresh vegetables and fruits in open-aired peri-urban markets of Jimma city, Ethiopia may play a significant role in transmission of intestinal parasitic infections to humans, particularly A. lumbricoides infection. Therefore, it is urgently needed for health authorities to educate the public on the proper handling of vegetables and fruits prior to consumption.

FIVE YEARS OF PARTULA SNAIL PRE-EXPORT HEALTH SCREENING.

Between 2015 and 2019, a health screening was carried out annually on captive-bred Partula snails prior to export for reintroduction as part of an international effort to repopulate areas of French Polynesia, where the snails were extinct or critically endangered. In total, 129 separate tank populations of 12 different species were screened at ZSL London Zoo. Wet mounts and smears stained with modified Ziehl-Neelsen (MZN) of 535 fecal samples were examined, and 45% contained flagellated protozoa, and 35.5% had MZN-positive oocysts, measuring 3-5 µm in diameter. Smaller (2 µm) presumptive spores, MZN-positive bacilli, ciliated protozoa and nematodes were recorded less frequently. Fecal bacterial culture yielded mixed species, with a clear predominance of Myroides species (88.9% of samples). The MZN-positive oocysts (3-5 µm) were present in 6.5% of impression smears from the apices of 432 snails examined postmortem, plus acid-fast bacilli in a few cases, but no 2 µm spores. Mixed bacteria were cultured from coelomic swabs, with Myroides species again the most common (63.5%). Histologic examination was carried out on 292 snails. Autolysis affected almost 90% of those found dead but only 3.4% of euthanized snails. Histology commonly identified microsporidial sporocysts in the digestive gland and midgut epithelium of all but two species. Intracellular, extracytoplasmic Cryptosporidium-like organisms were also common in the midgut but were only observed when snails were fixed in 10% formalin (2017-2019), not ethanol. There were no clear pathologic changes associated with either organism. Pigmented hemocytic nodules were commonly observed, most frequently in the foot process; these were either age related or evidence of prior chronic inflammatory reaction and of low clinical significance. With no evidence of poor health and no significant organisms found, a total of 4,978 individuals representing 12 species were exported for reintroduction.

Quercetin as a Promising Antiprotozoan Phytochemical: Current Knowledge and Future Research Avenues.

Despite tremendous advances in the prevention and treatment of infectious diseases, only few antiparasitic drugs have been developed to date. Protozoan infections such as malaria, leishmaniasis, and trypanosomiasis continue to exact an enormous toll on public health worldwide, underscoring the need to discover novel antiprotozoan drugs. Recently, there has been an explosion of research into the antiprotozoan properties of quercetin, one of the most abundant flavonoids in the human diet. In this review, we tried to consolidate the current knowledge on the antiprotozoal effects of quercetin and to provide the most fruitful avenues for future research. Quercetin exerts potent antiprotozoan activity against a broad spectrum of pathogens such as Leishmania spp., Trypanosoma spp., Plasmodium spp., Cryptosporidium spp., Trichomonas spp., and Toxoplasma gondii. In addition to its immunomodulatory roles, quercetin disrupts mitochondrial function, induces apoptotic/necrotic cell death, impairs iron uptake, inhibits multiple enzymes involved in fatty acid synthesis and the glycolytic pathways, suppresses the activity of DNA topoisomerases, and downregulates the expression of various heat shock proteins in these pathogens. In vivo studies also show that quercetin is effective in reducing parasitic loads, histopathological damage, and mortality in animals. Future research should focus on designing effective drug delivery systems to increase the oral bioavailability of quercetin. Incorporating quercetin into various nanocarrier systems would be a promising approach to manage localized cutaneous infections. Nevertheless, clinical trials are needed to validate the efficacy of quercetin in treating various protozoan infections.

Fecal microbiota impacts development of Cryptosporidium parvum in the mouse.

The dependence of Cryptosporidium parasites on host cell metabolites suggests that the development of nutritional interventions to limit parasite proliferation should be feasible. Based on this concept, we are testing dietary interventions to affect the enterocytes' metabolism in a manner that limits intracellular multiplication of the parasite. We hypothesize that changes in the metabolic pathways encoded by the gastro-intestinal tract microbiota may restrict parasite proliferation. To identify taxonomic and metabolic features of the microbiota associated with severity of cryptosporidiosis, as determined by estimating oocyst output, we characterized the fecal microbiota from mice experimentally infected with Cryptosporidium parvum. To eliminate the confounding effect of the interaction between co-housed mice, as well as facilitate the identification of microbiota markers associated with severity of cryptosporidiosis, fecal microbiota from individually caged mice were analyzed. Variation partitioning analysis applied to 16S sequence data from 25 mice belonging to four experiments shows that experiment was by far the biggest source of microbiota variation. Severity of cryptosporidiosis explained a smaller, though significant, fraction of microbiota variation. Notably, this effect was significant in the pre-patent phase of the infection, before mice excreted oocysts. These results are consistent with the pre-patent intestinal microbiota having a modest, but measurable, effect on cryptosporidiosis.

Genetic diversity of Cryptosporidium spp., Encephalitozoon spp. and Enterocytozoon bieneusi in feral and captive pigeons in Central Europe.

Cryptosporidium spp., Enterocytozoon bieneusi and Encephalitozoon spp. are the most common protistan parasites of vertebrates. The results show that pigeon populations in Central Europe are parasitised by different species of Cryptosporidium and genotypes of microsporidia of the genera Enterocytozoon and Encephalitozoon. A total of 634 and 306 faecal samples of captive and feral pigeons (Columba livia f. domestica) from 44 locations in the Czech Republic, Slovakia and Poland were analysed for the presence of parasites by microscopy and PCR/sequence analysis of small subunit ribosomal RNA (18S rDNA), 60 kDa glycoprotein (gp60) and internal transcribed spacer (ITS) of SSU rDNA. Phylogenetic analyses revealed the presence of C. meleagridis, C. baileyi, C. parvum, C. andersoni, C. muris, C. galli and C. ornithophilus, E. hellem genotype 1A and 2B, E. cuniculi genotype I and II and E. bieneusi genotype Peru 6, CHN-F1, D, Peru 8, Type IV, ZY37, E, CHN4, SCF2 and WR4. Captive pigeons were significantly more frequently parasitised with screened parasite than feral pigeons. Cryptosporidium meleagridis IIIa and a new subtype IIIl have been described, the oocysts of which are not infectious to immunodeficient mice, whereas chickens are susceptible. This investigation demonstrates that pigeons can be hosts to numerous species, genotypes and subtypes of the studied parasites. Consequently, they represent a potential source of infection for both livestock and humans.

Outcome of parasitological examinations in dogs in Germany: a retrospective survey.

Dog faecal samples examined from January 2019 to December 2019 were retrospectively analysed for frequency of endoparasites. The examinations were performed with several different methods: 29,219 samples were examined by flotation method and sodium acetate-acetic acid-formalin concentration (SAFC) technique, 1,330 samples by Baermann-Wetzel migration technique, 12,221 samples using a Giardia coproantigen enzyme-linked-immunosorbent assay (ELISA), 1,180 samples using a Cryptosporidium coproantigen ELISA, 1,671 samples by polymerase chain reaction (PCR) testing for Giardia duodenalis and 447 samples by PCR testing for Cryptosporidium spp.. A total of 7.1% of the samples were positive for parasites in the microscopical examination using the flotation method and SAFC technique. The parasites found included Cystoisospora spp. (2.8%), Giardia duodenalis (2.3%), Ancylostomatidae (1.8%), Toxocara canis (1.6%), Trichuris vulpis (0.7%), Toxascaris leonina (0.5%), Capillaria spp. (0.2%), Angiostrongylus vasorum (0.2%), Crenosoma vulpis (0.1%), Taeniidae (0.1%), Sarcocystis spp. (0.03%), Dipylidium caninum (0.01%), Diphyllobothrium latum (< 0.01%), Spirurida (< 0.01%) and Opisthorchiidae (< 0.01%). Using the Baermann-Wetzel migration technique, Angiostrongylus vasorum was found in 0.75% and Crenosoma vulpis in 0.3% of the samples. ELISAs for Giardia duodenalis and Cryptosporidium spp. revealed 13.9% and 1.0% positive faecal samples, and Giardia duodenalis and Cryptosporidium spp. PCRs 19.4% and 2.0%, respectively. Dogs in the first year of life were more frequently infected with parasites than older animals. In the microscopic examination using flotation method and SAFC technique, the significantly highest detection rates were found in dogs up to six months of age (p < 0.001).

Molecular characterization and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in humans and domestic animals in Heilongjiang Province, China.

BACKGROUND: Cryptosporidiosis and giardiasis are significant parasitic diseases shared between humans and domestic animals. Due to the close contact between humans and domestic animals in rural areas, it is important to consider the potential transmission of zoonotic parasites from infected domestic animals to humans. This investigation aimed to determine the prevalence and molecular characteristics of Cryptosporidium spp. and Giardia duodenalis in domestic animals and villagers. METHODS: A total of 116 fecal samples from villagers and 686 fecal samples from domestic animals in Heilongjiang Province, China, were analyzed for two parasites using nested polymerase chain reaction (PCR) targeting various genetic loci and DNA sequence analysis of the PCR products. RESULTS: By sequence analysis of the SSU rRNA gene, the prevalence of Cryptosporidium in humans was 0.9% (1/116), with one species of C. parvum (n = 1) detected; among domestic animals, the prevalence was 2.6% (18/686), with five species identified: C. suis (n = 7) and C. scrofarum (n = 7) in pigs, C. meleagridis (n = 1) in chickens, C. andersoni (n = 1) in cattle, and C. canis (n = 2) in foxes. C. parvum and C. canis were further subtyped as IIdA19G1 and XXa4 on the basis of gp60 gene. Regarding G. duodenalis, based on the SSU rRNA, bg, gdh, and tpi genes, the prevalence in domestic animals was 5.1% (31/608), with three assemblages identified: A (n = 1) in pigs, D (n = 1) in foxes, and E (n = 27) in geese, cattle, pigs, ducks, and sheep, along with mixed infection of A + E (n = 1) in one pig and B + E (n = 1) in one sheep. No G. duodenalis was detected in humans (0/116). CONCLUSIONS: The present results show that no overlap of subtypes between animals and villagers was found in Cryptosporidium spp. and G. duodenalis, indicating a minor role of domestic animals in infecting humans in this population. However, the presence of zoonotic protozoa in domestic animals highlights the need for special attention to high-risk individuals during close contact with domestic animals.

Unlocking the mystery of the feeder organelle and versatile energy metabolism in Cryptosporidium parvum.

Xu and colleagues recently revealed the critical role of Cryptosporidium's feeder organelle in nutrient uptake, showcasing the parasite's ability to harness glucose and glucose-6-phosphate from host cells. This illuminates the sophisticated energy metabolism and survival strategies of the parasite, highlighting potential therapeutic targets.

Cryptosporidium parvum infection alters the intestinal mucosa transcriptome in neonatal calves: implications for immune function.

One of the leading causes of infectious diarrhea in newborn calves is the apicomplexan protozoan Cryptosporidium parvum (C. parvum). However, little is known about its immunopathogenesis. Using next generation sequencing, this study investigated the immune transcriptional response to C. parvum infection in neonatal calves. Neonatal male Holstein-Friesian calves were either orally infected (N = 5) or not (CTRL group, N = 5) with C. parvum oocysts (gp60 subtype IIaA15G2R1) at day 1 of life and slaughtered on day 7 after infection. Total RNA was extracted from the jejunal mucosa for short read. Differentially expressed genes (DEGs) between infected and CTRL groups were assessed using DESeq2 at a false discovery rate < 0.05. Infection did not affect plasma immunohematological parameters, including neutrophil, lymphocyte, monocyte, leucocyte, thrombocyte, and erythrocyte counts as well as hematocrit and hemoglobin concentration on day 7 post infection. The immune-related DEGs were selected according to the UniProt immune system process database and were used for gene ontology (GO) and pathway enrichment analysis using Cytoscape (v3.9.1). Based on GO analysis, DEGs annotated to mucosal immunity, recognizing and presenting antigens, chemotaxis of neutrophils, eosinophils, natural killer cells, B and T cells mediated by signaling pathways including toll like receptors, interleukins, tumor necrosis factor, T cell receptor, and NF-KB were upregulated, while markers of macrophages chemotaxis and cytosolic pattern recognition were downregulated. This study provides a holistic snapshot of immune-related pathways induced by C. parvum in calves, including novel and detailed feedback and feedforward regulatory mechanisms establishing the crosstalk between innate and adaptive immune response in neonate calves, which could be utilized further to develop new therapeutic strategies.

Genomic and virulence analysis of in vitro cultured Cryptosporidium parvum.

Recent advances in the in vitro cultivation of Cryptosporidium parvum using hollow fiber bioreactor technology (HFB) have permitted continuous growth of parasites that complete all life cycle stages. The method provides access to all stages of the parasite and provides a method for non-animal production of oocysts for use in clinical trials. Here we examined the effect of long-term (>20 months) in vitro culture on virulence-factors, genome conservation, and in vivo pathogenicity of the host by in vitro cultured parasites. We find low-level sequence variation that is consistent with that observed in calf-passaged parasites. Further using a calf model infection, oocysts obtained from the HFB caused diarrhea of the same volume, duration and oocyst shedding intensity as in vivo passaged parasites.

Rabbits as reservoirs: An updated perspective of the zoonotic risk from Cryptosporidium and Giardia.

Rabbits are highly abundant in many countries and can serve as reservoirs of diseases for a diversity of pathogens including the enteric protozoan parasites, Cryptosporidium and Giardia. Both parasites shed environmentally robust environmental stages (oo/cysts) and have been responsible for numerous waterborne outbreaks of diseases. Cryptosporidium hominis and C. parvum are responsible for most infections in humans, while Giardia duodenalis assemblages A and B, cause most human cases of giardiasis. Cryptosporidium cuniculus, the dominant species infecting rabbits, is the only spceies other than C. hominis and C. parvum to have caused a waterborne outbreak of gastritis, which occurred in the United Kingdom in 2008. This review examines the prevalence of Cryptosporidium and Giardia species in rabbits to better understand the public health risks of contamination of water sources with Cryptosporidium and Giardia oo/cysts from rabbits. Despite the abundance of C. cuniculus in rabbits, reports in humans are relatively rare, with the exception of the United Kingdom and New Zealand, and reports of C. cuniculus in humans from the United Kingdom have declined substantially since the 2008 outbreak. Subtyping of C. cuniculus has supported the potential for zoonotic transmission. Relatively few studies have been conducted on Giardia, but assemblage B dominates. However, improved typing methods are required to better understand the transmission dynamics of Giardia assemblages in rabbits. Similarly, it is not well understood if pet rabbits or contaminated water are the main source of C. cuniculus infections in humans. Well-planned studies using high-resolution typing tools are required to understand the transmission dynamics better and quantify the public health risk of Cryptosporidium and Giardia from rabbits.