Efficacy of chitosan, a natural polysaccharide, against Cryptosporidium parvum in vitro and in vivo in neonatal mice

Anticryptosporidial action mechanisms of Launaea spinosa extracts in Cryptosporidium parvum experimentally infected mice in relation to its UHPLC-MS metabolite profile and biochemometric tools

BACKGROUND

Cryptosporidium parvum, a leading cause of diarrhea, is responsible for millions of food and waterborne illnesses in humans and animals worldwide. Launaea spinosa (Asteraceae family) is a common herb found in the desert of the Mediterranean region, encompassing the peninsula of Sinai. Traditionally, it has been utilized for managing gastrointestinal issues and inflammation.

METHODS AND FINDINGS

The present study aimed to assess Launaea spinosa (LS) extracts viz. ethyl acetate (LS-EtOAc), ethanol (LS-EtOH), and n-butanol (LS-BuOH), of different polarities against C. parvum in experimentally infected mice based on immunological, biochemical, histo- and immunohistochemical assays. Extracts were characterized via UHPLC-ESI-LIT-Orbitrap-MS and metabolite profiles were subjected to correlation modeling with bioactivities via supervised Partial Least Square (PLS) to identify active agents. Most L. spinosa extracts reduced fecal C. parvum oocyst count and mucosal burden (P < 0.05) than untreated infected mice, with LS-BuOH (200 mg/kg) exerting the highest reduction percentage (97%). These extracts increased immunoglobulin G (IgG) levels in infected and treated mice at all examined days post treatment. Also, the highest Interferon-Gamma (IFN-γ) and Interleukin-15 (IL-15) levels were obtained after 10 days of post inoculation (dPI), which were restored to a healthy state after 21 days, concurrent with a decrease in Tumor Necrosis Factor-Alpha (TNF-α) (P < 0.001). The increased liver enzyme (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase) levels with infection were likewise reduced with extract administration. The LS extracts caused a significant increase in antioxidant glutathione peroxidase (GSH-Px) and catalase (P < 0.001). Examination of colon tissue revealed that infected-treated mice with LS extracts exhibited a reduction in the expression of cleaved caspase-3, damage score, and degenerative changes. Metabolite profiling of different L. spinosa extracts led to the identification of 86 components, primarily phenolic acids, flavonoids, triterpenoid saponins, and fatty acids, with the first report of sulfated triterpenoid saponins in Launaea genus. PLS regression analysis revealed that bioeffects were significantly positioned close to LS-BuOH extract (R2: 0.9) mostly attributed to triterpenoid saponins and flavonoid glycosides.

CONCLUSIONS

This study demonstrated potential anti-cryptosporidial effects of LS extracts, especially LS-BuOH, suggesting its potential for inclusion in future nutraceuticals aimed at C. parvum treatment.

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.

Recent progressions in biomedical and pharmaceutical applications of chitosan nanoparticles: A comprehensive review

Nowadays, the most common approaches in the prognosis, diagnosis, and treatment of diseases are along with undeniable limitations. Thus, the ever-increasing need for using biocompatible natural materials and novel practical modalities is required. Applying biomaterials, such as chitosan nanoparticles (CS NPs: FDA-approved long-chain polymer of N-acetyl-glucosamine and D-glucosamine for some pharmaceutical applications), can serve as an appropriate alternative to overcome these limitations. Recently, the biomedical applications of CS NPs have extensively been investigated. These NPs and their derivatives can not only prepare through different physical and chemical approaches but also modify with various molecules and bioactive materials. The potential properties of CS NPs, such as biocompatibility, biodegradability, serum stability, solubility, non-immunogenicity, anti-inflammatory properties, appropriate pharmacokinetics and pharmacodynamics, and so forth, have made them excellent candidates for biomedical applications. Therefore, CS NPs have efficiently applied for various biomedical applications, like regenerative medicine and tissue engineering, biosensors for the detection of microorganisms, and drug delivery systems (DDS) for the suppression of diseases. These NPs possess a high level of biosafety. In summary, CS NPs have the potential ability for biomedical and clinical applications, and it would be remarkably beneficial to develop new generations of CS-based material for the future of medicine.

Identification of potent anti-Cryptosporidium new drug leads by screening traditional Chinese medicines

Cryptosporidium spp. are gastrointestinal opportunistic protozoan parasites that infect humans, domestic animals, and wild animals all over the world. Cryptosporidiosis is the second leading infectious diarrheal disease in infants less than 5 years old. Cryptosporidiosis is a common zoonotic disease associated with diarrhea in infants and immunocompromised individuals. Consequently, cryptosporidiosis is considered a serious economic, veterinary, and medical concern. The treatment options for cryptosporidiosis are limited. To address this problem, we screened a natural product library containing 87 compounds of Traditional Chinese Medicines for anti-Cryptosporidium compounds that could serve as novel drug leads and therapeutic targets against C. parvum. To examine the anti-Cryptosporidium activity and half-maximal inhibitory doses (EC50) of these compounds, we performed in vitro assays (Cryptosporidium growth inhibition assay and host cell viability assay) and in vivo experiments in mice. In these assays, the C. parvum HNJ-1 strain was used. Four of the 87 compounds (alisol-A, alisol-B, atropine sulfate, and bufotalin) showed strong anti-Cryptosporidium activity in vitro (EC50 values = 122.9±6.7, 79.58±13.8, 253.5±30.3, and 63.43±18.7 nM, respectively), and minimum host cell cytotoxicity (cell survival > 95%). Furthermore, atropine sulfate (200 mg/kg) and bufotalin (0.1 mg/kg) also showed in vivo inhibitory effects. Our findings demonstrate that atropine sulfate and bufotalin are effective against C. parvum infection both in vitro and in vivo. These compounds may, therefore, represent promising novel anti-Cryptosporidium drug leads for future medications against cryptosporidiosis.

Chitosan Protects Immunosuppressed Mice Against Cryptosporidium parvum Infection Through TLR4/STAT1 Signaling Pathways and Gut Microbiota Modulation

Cryptosporidium parvum infection is very common in infants, immunocompromised patients, or in young ruminants, and chitosan supplementation exhibits beneficial effects against the infection caused by C. parvum. This study investigated whether chitosan supplementation modulates the gut microbiota and mediates the TLR4/STAT1 signaling pathways and related cytokines to attenuate C. parvum infection in immunosuppressed mice. Immunosuppressed C57BL/6 mice were divided into five treatment groups. The unchallenged mice received a basal diet (control), and three groups of mice challenged with 1 × 10⁶ C. parvum received a basal diet, a diet supplemented with 50 mg/kg/day paromomycin, and 1 mg/kg/day chitosan, and unchallenged mice treated with 1 mg/kg/day chitosan. Chitosan supplementation regulated serum biochemical indices and significantly (p < 0.01) reduced C. parvum oocyst excretion in infected mice treated with chitosan compared with the infected mice that received no treatment. Chitosan-fed infected mice showed significantly (p < 0.01) decreased mRNA expression levels of interferon-gamma (IFN-γ) and tumor necrosis factor-α (TNF-α) compared to infected mice that received no treatment. Chitosan significantly inhibited TLR4 and upregulated STAT1 protein expression (p < 0.01) in C. parvum-infected mice. 16S rRNA sequencing analysis revealed that chitosan supplementation increased the relative abundance of Bacteroidetes/Bacteroides, while that of Proteobacteria, Tenericutes, Defferribacteres, and Firmicutes decreased (p < 0.05). Overall, the findings revealed that chitosan supplementation can ameliorate C. parvum infection by remodeling the composition of the gut microbiota of mice, leading to mediated STAT1/TLR4 up- and downregulation and decreased production of IFN-γ and TNF-α, and these changes resulted in better resolution and control of C. parvum infection.

Advances in therapeutic and vaccine targets for Cryptosporidium: Challenges and possible mitigation strategies

Cryptosporidium is known to be the second most common diarrheal pathogen in children, causing potentially fatal diarrhea and associated with long-term growth stunting and cognitive deficits. The only Food and Drug Administration-approved treatment for cryptosporidiosis is nitazoxanide, but this drug has not shown potentially effective results in susceptible hosts. Therefore, a safe and effective drug for cryptosporidiosis is urgently needed. Cryptosporidium genome sequencing analysis may help develop an effective drug, but both in vitro and in vivo approaches to drug evaluation are not fully standardized. On the other hand, the development of partial immunity after exposure suggests the possibility of a successful and effective vaccine, but protective surrogates are not precise. In this review, we present our current perspectives on novel cryptosporidiosis therapies, vaccine targets and efficacies, as well as potential mitigation plans, recommendations and perceived challenges.

Antiparasitic Effects of Sulfated Polysaccharides from Marine Hydrobionts

This review presents materials characterizing sulfated polysaccharides (SPS) of marine hydrobionts (algae and invertebrates) as potential means for the prevention and treatment of protozoa and helminthiasis. The authors have summarized the literature on the pathogenetic targets of protozoa on the host cells and on the antiparasitic potential of polysaccharides from red, brown and green algae as well as certain marine invertebrates. Information about the mechanisms of action of these unique compounds in diseases caused by protozoa has also been summarized. SPS is distinguished by high antiparasitic activity, good solubility and an almost complete absence of toxicity. In the long term, this allows for the consideration of these compounds as effective and attractive candidates on which to base drugs, biologically active food additives and functional food products with antiparasitic activity.

Effect of sex and genotype of the host on the anthelmintic efficacy of albendazole microcrystals, in the CBi-IGE Trichinella infection murine model

Albendazole (ABZ) is an anthelmintic pharmaceutical commonly used in the treatment of nematode infections. It is a Class II drug poorly water-soluble, with very low bioavailability, a feature particularly limiting to treat the trichinellosis chronic phase. Microcrystals obtained by controlled precipitation using hydroxyethyl cellulose and chitosan have previously been shown to improve ABZ biopharmaceutical properties. This investigation aimed to test the systems' in vivo efficacy in the CBi-IGE murine model of Trichinella spiralis infection in the infection's different phases and parasite’ stages. Treatment in the enteral phase led to a 90% decrease in the larval muscle load, probably due to its effect on T. spiralis female fecundity. Both microcrystal systems given in the migratory phase halved muscle load in males, a response not observed in females. The chitosan-based microcrystals proved to be the best when administered in the chronic phase of the infection – an increased proportion of L1 dead larvae was found compared to controls, except in CBi+-treated females. Males and females from the highly susceptible CBi+ line presented a significantly different treatment response in this phase. In vivo efficacy depended on the host genotype and sex and was related to the parasite cycle stage in which the formulations were administered.

Assessment of chitosan nanoparticles in improving the efficacy of nitazoxanide on cryptosporidiosis in immunosuppressed and immunocompetent murine models

Cryptosporidiosis is one of the major causes of diarrhea in immunocompetent and immunocompromised patients. It is self-limited in immunocompetent individuals. However, in the immunocompromised it can cause life-threatening diarrhea and results in chronic malabsorption of fluids, vitamins and electrolytes resulting in wasting. Our study is concerned with assessing and comparing the efficacy of nitazoxanide (NTZ) alone and NTZ loaded chitosan nanoparticles (NTZ loaded CS NPs) in the treatment of experimental cryptosporidiosis using parasitological and histopathological parameters. One hundred mice were divided into 5 groups (20 mice each). Each group was divided into 2 subgroups according to the immune status [a-immunocompetent, b-immunosuppressed]. group 1: control (healthy), group 2: control infected by Cryptosporidium oocysts, group 3: infected treated by NTZ, group 4: infected then treated by NTZ loaded CS NPs and group 5: infected then treated by chitosan nanoparticles (CS NPs) alone. Treatment of Cryptosporidium infected mice with NTZ loaded on CS NPs resulted in the highest significant reduction in oocysts shedding in both immunocompetent and immunosuppressed groups followed by treatment with NTZ form then by treatment with CS NPs alone. The treatment with NTZ loaded CS NPs displayed a remarkable improvement of the histopathological changes of the intestine, liver and lung while NTZ treated group showed some improvement. Treatment with NTZ loaded CS NPs in murine cryptosporidiosis gave the best results as it caused marked reduction in fecal oocysts counts and improvement of histopathological changes in immunocompetent and immunosuppressed groups.

Establishment of a Newborn Lamb Gut-Loop Model to Evaluate New Methods of Enteric Disease Control and Reduce Experimental Animal Use

Enteric infectious diseases are not all well controlled, which leads to animal suffering and sometimes death in the most severe cases, in addition to economic losses for farmers. Typical symptoms of enteric infections include watery diarrhea, stomach cramps or pain, dehydration, nausea, vomiting, fever and weight loss. Evaluation of new control methods against enteric infections requires the use of many animals. We aimed to develop a new method for an initial in vivo screen of promising compounds against neonatal diseases such as cryptosporidiosis while limiting experimental animal use. We therefore adapted an in vivo method of multiple consecutive but independent intestinal loops to newborn lambs delivered by cesarean section, in which endotoxin responsiveness is retained. This new method allowed for the screening of natural yeast fractions for their ability to stimulate immune responses and to limit early Cryptosporidium parvum development. This model may also be used to investigate host–pathogen interactions and immune responses in a neonatal controlled environment.

Anti-protozoal activity of Thymol and a Thymol ester against Cryptosporidium parvum in cell culture

Cryptosporidium parvum is a protozoan parasite that infects intestinal epithelial cells causing malabsorption and severe diarrhea. The monoterpene thymol has been reported to have antifungal and antibacterial properties but less is known about the antiparasitic effect of this compound. Terpenes are sometimes unsuitable for therapeutic and food applications because of their instability. Esterification of terpenes eliminates this disadvantage. The present study evaluates the effects of thymol (Th) and a thymol ester, thymol octanoate (TO), against C. parvum infectivity in vitro. The cytotoxicity IC50 value for TO after 24 h of treatment was 309.6 μg/mL, significantly higher than that of Th (122.5 μg/mL) in a human adenocarcinoma cell line (HCT-8). In the same way, following 48 h of treatment, the cytotoxicity IC50 value for TO was significantly higher (139 μg/mL) than that of Th (75.5 μg/mL). These results indicate that esterification significantly reduces Th cytotoxicity. Dose-dependent effects were observed for TO and Th when both parasite invasion and parasite growth assays were evaluated. When evaluated for their activity against C. parvum growth cultured in vitro in HCT-8 cells, the anti-cryptosporidial IC50 values were 35.5 and 7.5 μg/mL, for TO and Th, respectively. Together, these findings indicate that esterified thymol has anti-cryptosporidial effect comparable with its parental compound thymol, but with improved safety margins in mammalian cells and better physicochemical properties that could make it more suitable for diverse applications as an antiparasitic agent.

Albalawi A, Alanazi AD, Baharvand P, Moghaddam A, Mahmoudvand H. Chitosan-Based Nanomaterials as Valuable Sources of Anti-Leishmanial Agents: A Systematic Review

BACKGROUND

The current chemotherapy agents against various forms of leishmaniasis have some problems and side effects, including high toxicity, high cost, and the emergence of resistant strains. Here, we aimed to review the preclinical studies (in vitro and in vivo) on the anti-leishmanial activity of chitosan and chitosan-based particles against Leishmania spp.

METHODS

This study was conducted based on the 06-PRISMA guidelines and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. Various English databases such as PubMed, Google Scholar, Web of Science, EBSCO, ScienceDirect, and Scopus were used to find the publications related to the anti-leishmanial effects of chitosan and its derivatives and other pharmaceutical formulations, without a date limitation, to find all the published articles. The keywords included "chitosan", "chitosan nanoparticles", "anti-leishmanial", "Leishmania", "leishmaniasis", "cutaneous leishmaniasis", "visceral leishmaniasis", "in vitro", and "in vivo". The language for data collection were limited to English.

RESULTS

Of 2669 papers, 25 papers, including 7 in vitro (28.0%), 7 in vivo (28.0%), and 11 in vitro/in vivo (44.0%) studies conducted up to 2020 met the inclusion criteria for discussion in this systematic review. The most common species of Leishmania used in these studies were L. major (12, 48.0%), L. donovani (7, 28.0%), and L. amazonensis (4, 16.80%). In vivo, the most used animals were BALB/c mice (11, 61.1%) followed by hamsters (6, 33.3%) and Wistar rats (1, 5.5%), respectively. In vitro, the most used Leishmania form was amastigote (8, 44.4%), followed by promastigote (4, 22.2%), and both forms promastigote/amastigote (6, 33.3%).

CONCLUSION

According to the literature, different types of drugs based on chitosan and their derivatives demonstrated considerable in vitro and in vivo anti-leishmanial activity against various Leishmania spp. Based on the findings of this review study, chitosan and its derivatives could be considered as an alternative and complementary source of valuable components against leishmaniasis with a high safety index. Nevertheless, more investigations are required to elaborate on this result, mainly in clinical settings.

Chitin and Chitosan Derivatives as Biomaterial Resources for Biological and Biomedical Applications

Chitin is a long-chain polymer of N-acetyl-glucosamine, which is regularly found in the exoskeleton of arthropods including insects, shellfish and the cell wall of fungi. It has been known that chitin can be used for biological and biomedical applications, especially as a biomaterial for tissue repairing, encapsulating drug for drug delivery. However, chitin has been postulated as an inducer of proinflammatory cytokines and certain diseases including asthma. Likewise, chitosan, a long-chain polymer of N-acetyl-glucosamine and d-glucosamine derived from chitin deacetylation, and chitosan oligosaccharide, a short chain polymer, have been known for their potential therapeutic effects, including anti-inflammatory, antioxidant, antidiarrheal, and anti-Alzheimer effects. This review summarizes potential utilization and limitation of chitin, chitosan and chitosan oligosaccharide in a variety of diseases. Furthermore, future direction of research and development of chitin, chitosan, and chitosan oligosaccharide for biomedical applications is discussed.

Effect of chitosan on Toxoplasma gondii infection: A systematic review

Background

The preferred treatment for management of toxoplasmosis is the combined use of pyrimethamine and sulfadiazine. However, there are a wide number of adverse side effects with these medications. Recent research has focused on the use of chitosan for the treatment of Toxoplasma gondii infections. This review was performed to obtain a better understanding of the in vivo and in vitro effects of chitosan on T. gondii strains.

Methods

The current study was carried out according to the PRISMA guideline and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-analysis Facility (SyRF) database. The search was performed in five scientific databases, including Scopus, PubMed, Web of Science, EMBASE, and Google Scholar, with date limits of 1992 to December 2019. The search was restricted to articles published in the English language. The words and terms searched were "Toxoplasma gondii", "Chitosan", "nanoparticles" and "anti-toxoplasmosis" with AND or OR.

Results

Of 2500 manuscripts, 9 met the eligibility criteria for review. All studies used the RH strain of T. gondii, with Me49 and PRU each included in one study. Five studies (56%) were performed in vivo, one study in vitro and 3 studies included in vivo and in vitro tests.

Conclusion

Considering the low toxicity and the high inhibitory potency of chitosan against T. gondii, chitosan nanoparticles show potential as an alternative treatment for T. gondii infections.

Cryptosporidium parvum Infection Depletes Butyrate Producer Bacteria in Goat Kid Microbiome

Cryptosporidium parvum is an important apicomplexan parasite infecting ruminants and humans. We characterized the impact of C. parvum infection on the goat kid microbiome. C. parvum was orally administered to parasite-naïve goats, and infection was monitored for 26 days in fecal samples using immunofluorescence assay and qPCR tests. Age-matched goats served as uninfected controls. A reduction in body weight gain, diarrhea, and dehydration were observed in infected goats compared to the uninfected controls. Infection decreased the bacterial diversity 5 days post-infection (dpi), but this parameter recovered at 15 dpi. The infection altered the relative abundance of several taxa. A total of 38 taxa displayed significant differences in abundance between control and infected goats at both 5 and 15 dpi. Co-occurrence network analysis revealed that the infection resulted in a differential pattern of taxa interactions and that C. parvum infection increased the relative abundance of specific taxa. The 16S data set was used for metagenome predictions using the software package PICRUSt2. As many as 34 and 40 MetaCyc pathways (from 387 total) were significantly affected by the infection at 5 and 15 dpi, respectively. Notably, C. parvum decreased the abundance of butyrate-producing pathways in bacteria. Low levels of butyrate may increase mucosal inflammation and tissue repair. Our results suggest that the gut inflammation induced by C. parvum infection is associated with the reduction of butyrate-producing bacteria. This insight could be the basis for the development of novel control strategies to improve animal health.

First identification of Cryptosporidium parvum zoonotic subtype IIaA15G2R1 in diarrheal lambs in France

To date, no information is available about the presence of Cryptosporidium spp. in French sheep, nor their potential role as zoonotic reservoirs. A total of 23 fecal samples were collected from diarrheic lambs (<11 days old) from seven randomly selected farms. Cryptosporidium-oocysts were detected microscopically with Direct Immunofluorescence Assays (DFA) in 23/23 (100%) of fecal samples. PCR-RFLP of the 18S rRNA gene was used to determine species in all samples, and only Cryptosporidium parvum was identified. Isolates were subtyped by sequencing the 60 kDa glycoprotein (gp60) gene. Two zoonotic subtypes within the IIa subtype family were identified, including IIaA15G2R1 (22/23) and IIaA16G3R1 (1/23). This study reports for the first time the identification and genotyping of zoonotic C. parvum subtypes from lambs in France. Sheep could thus play an important role as potential reservoirs for this zoonotic protist.

The determination of treatment effect of chitosan oligosaccharide in lambs with experimentally cryptosporidiosis

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Chitosan oligosaccharide contributes to clinical improvement in lambs with experimentally cryptosporidiosis.

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Chitosan oligosaccharide reduces C. parvum oocysts.

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Chitosan oligosaccharide can be used in the treatment of cryptosporidiosis.

In this study, it was aimed to investigate the efficacy of chitosan oligosaccharide administrations in different doses of experimental infected lambs with Cryptosporidium parvum. 32 male lambs were used in the study and the lambs were divided into 4 groups with 8 lambs in each group. Groups 1, 2 and 3, twice a day, were administered chitosan oligosaccharide at a dose of 100, 500, and 1000 mg/kg for 7 days, respectively, with milk replacer. In group 4, lambs with cryptosporidiosis were subjected to normal feeding as control without drug administration. Clinical examinations of lambs were made before treatment (day 0) and on days 1, 3, 5 and 7 after treatment and 5 ml of blood was collected from vena jugularis for blood analysis of all lambs. Weight changes of lambs were recorded at 0, 7, 14, and 21 days. Stool specimens were collected pre-treatment (day 0) and on days 1, 3, 5, 7, 14 and 21 post-treatment to determine oocyst excretion of lambs with cryptosporidiosis. Lambs with a mean oocyte counts >10 after stool examination were included to the treatment. Changes in clinical hematology, blood gases and biochemical parameters were observed during the course of treatment, but these changes were limited. Weight loss was observed at 7th day according to 0th day the lambs with experimental cryptosporidiosis but gradually weight increase was observed at 14th and 21st days and these changes were similar in all groups. Oocyst excretion decreased in all groups during treatment. According to 0th day, there was a significant (p < 0.05) decrease in oocyte excretions in the third day in group 1 and 2, and in day 5 in the group 3 and 4. Significant changes (p < 0.05) were observed in oocyst excretions on the third and fifth days among the groups. As a result, in lambs with experimental cryptosporidiosis, chitosan oligosaccharide improved in clinical signs and stool character shorter than the positive control group and the administration of chitosan oligosaccharide at doses of 100, 500 and 1000 mg/kg for 7 days significantly reduced oocyst excretion but not enough to remove cryptosporidiosis completely.

Molecular characterization of Cryptosporidium isolates from diarrheal dairy calves in France

Cryptosporidium is an obligate intracellular protist parasite infecting a wide range of vertebrate hosts and causes significant intestinal disease in both animals and humans, as some species are zoonotic. Cattle and especially calves have been identified as one of the most common reservoirs of this protist. However, little is known about the genetics of Cryptosporidium in calves in some regions of France. The aim of this study was to detect and isolate Cryptosporidium spp. in faecal samples from naturally infected pre-weaned calves (≤45 days-old) in France. A total of 35 diarrhoeic pre-weaned calf faecal samples were collected from 26 dairy cattle farms in six departments (French administrative provinces). Cryptosporidium presence was established by microscopically screening samples for oocystes with an immunofluorescent (DFA) staining method. DFA-positive samples were then analysed by PCR-RFLP and 18S rRNA gene sequencing to determine species. Cryptosporidium parvum-positive samples were subtyped via nested PCR analysis of a partial fragment of the 60 kDa glycoprotein (gp60) gene product. Data were then integrated into phylogenetic tree analysis. DFA revealed the presence of Cryptosporidium oocysts in 31 out of 35 (88%) samples. Combined with 18S rRNA gene analysis results, C. parvum was detected in 30 samples. Subtyping analysis in 27/30 samples (90%) of the C. parvum isolates revealed two zoonotic subtype families, IIa (24/27) and IId (3/27). Four subtypes were recognised within the subtype family IIa, including the hypertransmissible IIaA15G2R1 subtype that is the most frequently reported worldwide (21/27), IIaA17G3R1 (1/27), IIaA17G1R1 (1/27), and IIaA19G1R1 (1/27). Two subtypes were recognised within the IId subtype family including IIdA22G1 (2/27) and IIdA27G1 (1/27). These findings illustrate the high occurrence of Cryptosporidium in calves in dairy herds and increase the diversity of molecularly characterised C. parvum isolates with the first description of IIaA17G3R1, IIaA19G1R1, and IId subtypes in France. The presence of zoonotic C. parvum subtype families (IIa, IId) in this study suggests that pre-weaned calves are likely to be a significant reservoir of zoonotic C. parvum, and highlights the importance of animal to human cryptosporidiosis transmission risk. Further molecular studies in calves and small ruminants from other French regions are required to better understand the epidemiology of cryptosporidiosis in France.

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Faecal samples from pre-weaned diarrheal calves were analysed

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Cryptosporidium spp. was detected in 30 samples out of 35.

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C. parvum was the only species identified

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Two zoonotic subtype families were identified: IIa and IId

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The hyper-transmissible IIaA15G2R1 was the dominant C. parvum subtype

Inhibitory activity of chitosan nanoparticles against Cryptosporidium parvum oocysts

Cryptosporidium is a ubiquitous harsh protozoan parasite that resists many disinfectants. It remains viable and infective for a long time in water and food causing global outbreaks. Chitosan (the deacetylated chitin molecule) was used in its nanosuspension form to evaluate its effect against Cryptosporidium parvum. The experiments were performed in vitro in serial concentrations and confirmed in mice in vivo infectivity assay. Chitosan nanoparticles (Cs NPs) were toxic to Cryptosporidium oocysts. The effect appeared to decrease the number of Cryptosporidium oocysts and altered their content. The destruction rate of oocysts was dependent on the dose of chitosan and the time of exposure (P < 0.05). Higher doses of Cs NPs over a prolonged period exhibited a significantly higher destruction rate. Using staining and light microscopy, remarkable destructive changes were observed in the oocysts' morphology. The minimal lethal dose for > 90% of oocysts was 3000 μg/ml, no mice infections in vivo were observed. The results in this study elucidate Cs NPs as an effective anti-cryptosporidial agent.

Cryptosporidium parvum-Infected Neonatal Mice Show Gut Microbiota Remodelling Using High-Throughput Sequencing Analysis: Preliminary Results

BACKGROUND

During the last decade, the scientific community has begun to investigate the composition and role of gut microbiota in normal health and disease. These studies have provided crucial information on the relationship between gut microflora composition and intestinal parasitic infection, and have demonstrated that many enteric pathogen infections are associated with altered gut microflora composition. In this study, we investigated the effects of Cryptosporidium parvum infection (zoonotic protozoan affecting a large range of vertebrates) on both qualitative and quantitative composition of gut microbiota in a CD-1 neonatal mouse model.

METHODS

5-day-old neonate mice were experimentally infected with 10⁵Cryptosporidium parvum Iowa oocysts by oesophageal gavage. The intestinal microbiota of both infected (Cp+) and uninfected (Cp-) mice groups was examined by high-throughput sequencing of the bacterial 16S rDNA gene V3-V4 hypervariable region.

RESULTS

The most consistent change in the microbiota composition of Cp+ mice was the increased proportion of bacterial communities belonging to the Phylum Bacteroidetes. In contrast, the microbiota of Cp- mice was associated with increased proportions of several Firmicutes and Actinobacteria phyla members.

CONCLUSION

For the first time, our study provides evidence of an association between cryptosporidial infection and gut dysbiosis, thus contributing valuable knowledge to the as-yet little-explored field of Cryptosporidium-microbiota interactions in a neonatal mouse model.