Drug treatment and novel drug target against Cryptosporidium

Herbal-based compounds: A review on treatments of cryptosporidiosis

Cryptosporidium, a monoxenous apicomplexan coccidia, is a prevalent diarrhetic and an opportunistic agent, mainly in immunocompromised individuals. As there are few chemotherapeutic compounds that have limited efficacy, we need to identify new compounds or specific parasite targets for designing more potent drugs to treat cryptosporidiosis. Herbal products with low toxicity, environmental compatibility, wide therapeutic potential, and abundant resources can be considered alternatives for treatment. The current review tried to summarize the studies on plants or herbal bioactive constituents with anti-cryptosporidial activities. Based on constituents, plants act via different mechanisms, and further investigations are needed to clarify the exact mechanisms by which they act on the developmental stages of the parasite or host-parasite relationships.

Efficacy of Lactobacillus taiwanensis S29 and Lactiplantibacillus plantarum S27 against tapeworm infection in Swiss Albino rats

Hymenolepis diminuta a zoonotic tapeworm infection in human remains an important cestode model for anthelmintic study as it display common clinical symptoms like other adult human tapeworms during heavy infestation. The use of Lactobacillus as a probiotic is an alternative to drugs which have increased in research and usage considerably during the last decade. The present study aims to determine the anthelmintic efficacy of two probiotics, L. taiwanensis strain S29 and L. plantarum strain S27 against H. diminuta in infected rat. Four groups of animals, each with six numbers were randomly chosen as the negative control (Group I), positive control (infected) (Group II) and the infected treated with two probiotics Group III and Group IV respectively. Another four groups (Group V-VIII) were selected and further subdivided into four sub-groups to investigate the development of larvae to adult during probiotics treatment. Worm burden, egg per gram were determined after treatment with these two probiotics. Furthermore, hematological assays and levels of biochemical markers were estimated, tissue damage was assayed through histological study and intestinal mitochondria detection was done. Worm sustainability reduced about 70-90% and EPG count decreased by 81-94% in probiotics treated groups. A significant level of unsuccessful establishment of larvae was observed in the developmental phase. Improvement in hematological parameter along with some biochemical parameters in the host were significantly observed after treatment with probiotics. The architecture damaged caused in the intestine and mitochondria density due to parasite infection improved significantly as that of control after probiotics treatment.

Evaluation of the therapeutic efficacy of some essential oils in experimentally immunosuppressed mice infected with Cryptosporidium parvum

Cryptosporidiosis is a serious intestinal disease affecting mal-nourished children and immunocompromised individuals with severe fatal diarrhea. Our present work was done to evaluate the possible curative effects of different essential oils (Mint, Thyme, Chamomile and Basil) on Cryptosporidium parvum (C. parvum) in vivo compared with nitazoxanide (NTZ). Seventy immunosuppressed white Albino male mice were allocated in 7 groups as follows: group I infected and not treated (Positive control), group II (GII) treated with NTZ, group III (GIII) treated with Mint essential oil, group IV (GIV) treated with Thyme essential oil, group V (GV) treated with Chamomile essential oil, group VI (GVI) treated with Basil essential oil and group VII (GVII) naïve not infected mice (Negative control). Evaluation was done using parasitological, histopatholgical, serological as well as biochemical methods. All study groups revealed significant reduction (P value < 0.01) in the mean number of C. parvum oocysts in stool. Results of GII were the best with 87.7% reduction in the oocysts count followed by GIII (77.9%), GIV (74.7%), GVI (68.2%) and lastly GV (67.2%). Improvement of the histopathological damage in the small intestine was shown in treated groups. All treated mice showed significant upregulation in the interferon gamma (IFN-γ) levels, significant reduction in the malondialdehyde (MDA) levels and increase in superoxide dismutase (SOD) levels (P value < 0.0001). It is concluded that Mint, Thyme, Chamomile and Basil oils showed promising anti-cryptosporidial, anti-inflammatory and antioxidant functions.

Cost-effective In Vivo and In Vitro Mouse Models for Evaluating Anticryptosporidial Drug Efficacy: Assessing Vorinostat, Docetaxel, and Baicalein

BACKGROUND

Cryptosporidiosis is a significant diarrheal disease in humans and animals. Immunodeficient mice are the primary small animal models, but their high costs and specialized breeding/housing requirements limit in vivo drug testing. Numerous anticryptosporidial lead compounds identified in vitro remain untested in vivo.

METHODS

Cryptosporidium tyzzeri, a natural mouse parasite closely related to Cryptosporidium parvum and Cryptosporidium hominis, was isolated to establish an infection model in immunocompetent mice. The model was validated using classic anticryptosporidial drugs (paromomycin and nitazoxanide) and then employed to assess the efficacy of 3 new leads (vorinostat, docetaxel, and baicalein). An in vitro culture of C. tyzzeri was also developed to complement the animal model.

RESULTS

Chronic C. tyzzeri infection was established in chemically immunosuppressed wild-type mice. Paromomycin (1000 mg/kg/d) and nitazoxanide (100 mg/kg/d) demonstrated efficacy against C. tyzzeri. Vorinostat (30 mg/kg/d), docetaxel (25 mg/kg/d), and baicalein (50 mg/kg/d) were highly effective against C. tyzzeri infection. In vitro, nitazoxanide, vorinostat, docetaxel, and baicalein exhibited low to submicromolar efficacy against C. tyzzeri.

CONCLUSIONS

Novel in vivo and in vitro models have been developed for cost-effective anticryptosporidial drug testing. Vorinostat, docetaxel, and baicalein show potential for repurposing and/or optimization for developing new anticryptosporidial drugs.

Therapeutic efficacy of proton pump inhibitor (omeprazole) on cryptosporidiosis parvum in immunosuppressed experimental mice

Cryptosporidiosis is one of the most frequent food and water-borne diseases. The disease might be life-threatening in immunosuppressed patients. Unfortunately, the only approved drug, nitazoxanide, is with variable efficacies, particularly in malnourished children and immunocompromised patients. Therefore, there is a need to discover an alternative treatment that could be achieved by targeting the metabolic pathways. One of the important enzymes in the glycolysis pathway of C. parvum is triosephosphate isomerase, which could be hindered by the proton pump inhibitor (PPI) omeprazole. In this study, omeprazole was repurposed against C. parvum infection in experimentally immunosuppressed mice. This study was conducted on five mice groups (n = 10). Group I (Normal Control), group II (Infected Control): Mice were infected orally with 1 × 105 C. parvum oocysts on the 15th day of DEX induced immunosuppression. Group III (NTZ-treated): infected and treated by NTZ. Group IV (Omeprazole-treated), and lastly, Group V (NTZ + Omeprazole-treated). The result obtained with omeprazole alone was better than nitazoxanide regarding oocyst shedding reduction percentages (84.9% & 56.1%, respectively). Also, it was better regarding restoration of histopathological and ultrastructural architectures, improvement of liver enzymes (alanine aminotransferase and aspartate aminotransferase) and renal functions (urea and creatinine), and the reduction of C. parvum triosephosphate isomerase (TIM) gene expression by RT-PCR. However, the best results were obtained with the combined treatment. Hence, omeprazole could be considered a novel drug option to treat this life-threatening parasitic infection either alone or combined with NTZ, especially in immunosuppressed patients.

Investigation of the prophylactic and therapeutic effectiveness of oral thyme extract in rats experimentally infected with cryptosporidium parvum

In this study, the prophylactic and therapeutic activities of thyme extract at different concentrations against experimental Cryptosporidium parvum infection in immunosuppressed rats were investigated. Thyme extract was prepared at four different concentrations (10%, 30%, 50%, and 100%) and administered as a single oral dose of 1 mL for evaluation of its prophylactic efficacy. Five consecutive days after infection was detected in all rats, therapeutic evaluations were also performed. According to the results obtained by daily counting of oocysts in stools, the prophylactic and therapeutic effects of thyme extract administration were significant in comparison to the control group (P˂0.01). Oocyst shedding continued in the control group at high numbers from the beginning to the end of the study, while oocyst counts in the prophylaxis groups remained low throughout the study. On the other hand, oocyst excretion rates were high in the therapeutic groups and decreased rapidly after thyme extract administration. At the end of the study, oocyst excretion had completely stopped for some rats administered thyme extract. There was no group in which oocyst shedding ceased for all rats. No significant differences were observed in the therapeutic or prophylaxis groups regarding the doses administered (P > 0.01). Renal and hepatic functions were monitored by measuring urea, creatinine, alanine transaminase, and aspartate transaminase levels ​​before and after thyme extract administration. As a result, it was concluded that oral thyme extract administration at the doses applied in this study is effective and safe in the prophylactic and therapeutic treatment of experimental cryptosporidiosis in rats.

The potential therapeutic effect of Nigella sativa and Zingiber officinale extracts versus Nitazoxanide drug against experimentally induced cryptosporidiosis in laboratory mice

In this study, the potential anti-cryptosporidial effect of Nigella sativa (black seeds) and Zingiber officinale (ginger) alcoholic extracts versus Nitazoxanide (NTZ) medication was investigated in immunosuppressed (IS) laboratory mice. Parasitological, histopathological studies were used to assess their therapeutic efficacy. Serum level and tissue expression percentage of IFN-γ was also used. Nigella extract succeeded to reduce the mean oocyst counts in the feces of immunosuppressed mice followed by NTZ. Ginger-treated ones showed the lowest reduction percentage. Nigella sativa showed the best results in terms of restoring the normal architecture of ileal epithelium in histopathological sections stained with H&E. NTZ treatment sub-groups showed mild improvement, followed by ginger-treated mice, which showed a slight improvement in small intestine microenvironment. A significant substantial rise in serum and intestinal tissue IFN-γ cytokine levels were recorded in Nigella subgroups compared to those of NTZ and ginger respectively. According to our findings Nigella sativa outperformed Nitazoxanide in terms of anti-cryptosporidial effectiveness and regeneration characteristics revealing a promising medication. When compared to the commonly used Nitazoxanide medication or Nigella extracts, the outcomes of ginger extract were suboptimal.

Therapeutic Potency of Ginger, Garlic, and Pomegranate Extracts Against Cryptosporidium parvum-Mediated Gastro-Splenic Damage in Mice

PURPOSE

Cryptosporidium parvum is a protozoan parasite infecting most mammalian hosts and causing major health issues. The present study investigated the efficacy of ginger (Zingiber officinale), garlic (Allium sativum), and pomegranate (Punica granatum) peel extracts on the development and progression of experimental cryptosporidiosis in mice.

METHODS

Eighty-two mice were assigned to 6 groups: control, infected non-treated, metronidazole (MTZ), ginger, garlic, and pomegranate. The control group topically received no treatments. The infected non-treated group was experimentally infected by 104 C. parvum oocysts per mouse using a stomach tube. The MTZ group was infected with C. parvum oocysts combined with MTZ (50 mg/kg b.w./day). The ginger, garlic, and pomegranate groups daily received different plant extracts at doses of 100 mg/kg BW, 50 mg/kg BW, and 3 gm/kg BW, respectively, followed by infection with C. parvum oocysts. All treatments were applied orally one day after the infection for continuous 30 days.

RESULTS

Histopathological and immunohistochemical examinations for P53 and caspase-3 expressions in stomach and spleen tissues showed that MTZ and garlic-treated mice had a more significant effect on infected mice.

CONCLUSION

The garlic extract was found to exert a more pronounced effect on infected mice compared with the other treatments as well as to improve health. Garlic extracts, therefore, represent an effective and natural therapeutic alternative for the treatment of cryptosporidiosis with low side effects and without drug resistance.

In vivo evaluation of anticryptosporidial effects of wheat germ extracts in immunocompromised mice

Cryptosporidium species is a prime cause of diarrheal disease in individuals with competent immunity. In patients with compromised immunity, infections are more severe particularly in developing countries. Wheat germ oil was described to have antiparasitic effect. This study was done to evaluate the possible role of wheat germ extracts in Cryptosporidium parvum (C. parvum) infected immunocompromised mice. Thirty white albino mice were classified into six groups as follow: four study groups, all immunosuppressed and infected with C. parvum oocysts. These four groups received treatments as follow: Group (I): treated with nitazoxanide. Group (II): treated with wheat germ oil. Group (III): treated with wheat germ extracted by hexane. Group (IV): treated with wheat germ extracted by ethanol. The remaining two groups were immunosuppressed control groups as follow: Group (V): only infected with C. parvum oocysts (Positive control). Group (VI): non-infected (Negative control). Stool samples were collected and examined to detect oocyst and the ileocecal region was subjected to histopathological and immunohistochemical examination. Wheat germ extracts showed a statistically significant effect against C. parvum specially wheat germ oil with P value: < 0.001, this effect was also confirmed by pathological and immunohistochemical examinations. C. parvum has an influence on human health by its effect in diarrheal disease. Wheat germ oil and its extracts has proved to be a reliable herb for C. parvum. treatment confirmed by different methodologies.

Garlic (Allium sativum Linnaeus) improved inflammation and reduced cryptosporidiosis burden in immunocompromised mice

ETHNOPHARMACOLOGICAL RELEVANCE

For thousands of years, garlic (Allium sativum Linnaeus) has been consumed in food and health by numerous civilizations. Cryptosporidium (C.) parvum is an apicomplexan parasite that causes a gastrointestinal disease, with the most common symptoms being watery diarrhea. Although several substances have been tried for its anti-cryptosporidial action, there is no effective treatment for Cryptosporidium disease, especially in immunocompromised individuals. The present study aimed firstly to characterize the bio-active compounds in Allium sativum L. and secondly to evaluate its efficacy as a therapy for cryptosporidiosis especially in immunocompromised mice.

MATERIALS AND METHODS

This was accomplished by evaluating the parasitological and histopathological parameters in the experimentally infected immunocompetent and immunocompromised mice. Also, the cytokine profile during the experimental time was recorded through the measuring of T helper (h)1, Th2 and Th17 cells cytokines. Immunosuppressed mice were given 0.25 μg/g per day of dexamethasone orally, before infection with Cryptosporidium parvum oocysts, for fourteen consecutive days. Starting 10 days post infection (PI), nitazoxanide (100 mg/kg per day) or Allium sativum (50 mg/kg per day) was given orally for fourteen consecutive days.

RESULTS

Our results showed that oocyst shedding, on the 32nd day PI, in immunocompromised infected group treated with Allium sativum (354.11, 99.35% PR) showed a significant decrease when compared to its corresponding group treated with nitazoxanide (4369.14, 92.05% PR). On the 32nd day PI, all cytokines levels have been decreased to levels that were similar to those of their uninfected corresponding control groups; also, the histopathological changes and the loss in animals' body weight had been improved. Treatment with nitazoxanide did not result in infection clearance or a reduction in the increased cytokines' levels.

CONCLUSION

Allium sativum L. displayed high efficacy as a potential therapeutic agent against Cryptosporidium, which supports its traditional usage in parasite diseases.

Efficacy of clofazimine and nitazoxanide combination in treating intestinal cryptosporidiosis and enhancing intestinal cellular regeneration in immunocompromised mice

Cryptosporidium is a widely distributed food and water-borne enteric protozoan that affects a wide range of vertebrates, resulting in life-threatening consequences, particularly in immunocompromised hosts. The lack of effective anti-cryptosporidial drugs may be related to the parasite's unique intestinal location, plus the lack of studies on the process by which the protozoan is able to impair intestinal cellular function. The present work aimed to assess the effect of clofazimine (CFZ), an FDA-approved drug for the treatment of leprosy, as an anti-cryptosporidial drug, using transmission electron microscopy (TEM) and an immunocompromised mouse model. The affected intestinal mucosa with parasitic stages in the infected non-treated group showed signs of severe cellular degeneration, including the loss of tight junctions, deformed and damaged microvilli and irregularly distributed nuclei with a severely vacuolated cytoplasm. Comparatively, nitazoxanide (NTZ) monotherapy showed the lowest efficacy as the drug was associated with the lowest rate of oocyst shedding. In addition, NTZ treatment failed to achieve the return of complete cellular function; abnormalities were evident in the microvilli, cytoplasmic organelles and nuclear features. Clofazimine demonstrated an improvement of the mucosal cellular components, including mitochondria and significantly reduced oocyst shedding. Combined treatment with low-dose CFZ and half-dose NTZ resulted in a significant improvement in the enterocyte cellular structures with an absence of intracellular parasitic stages. These results indicate that CFZ, a safe and readily prescribed drug, effectively reduces cryptosporidiosis when used in combination with only half the dose of NTZ. Used in combination, these drugs were shown to be efficient in regaining intestinal cellular activity following Cryptosporidium-induced functional damage in an immunocompromised mouse model.

A multi-epitope vaccine candidate developed from unique immunogenic epitopes against Cryptosporidium hominis by utilizing an immunoinformatics-driven approach

An immunoinformatics-based strategy is being investigated to identify prospective multi-subunit vaccine candidates against Cryptosporidium hominis (C. hominis). We used a systematic technique based on protein structure to create a competent multi-subunit vaccine candidate against C. hominis, with the likelihood of antigenicity, allergenicity, and transmembrane helices as the screening criteria. Using the suitable linkers, the best-screened epitopes such as B-cell epitopes (BCL), Helper T-lymphocytes (HTL), and cytotoxic T-lymphocytes (CTL) were linked together to intensify and develop the presentation and processing of the antigenic molecules. The greatest 3 D model of the component protein was created with the help of modeling software called Raptorax. The validation of the modeled protein was accomplished via the use of PROCHECK. Furthermore, using the ClusPro web server, the projected modeled structure was docked with known receptor TLR-4 to determine their interactions. A molecular dynamics (MD) simulation was used to investigate the stability of the multi-subunit vaccine bound with TLR-4 based on the docking score. Aside from that, the codon optimization and in silico expression demonstrate the possibility of high expression and simple purification of the vaccine product resulting from codon optimization. The overall findings indicated that the multi-subunit vaccine might be a viable vaccination candidate against C. hominis.Communicated by Ramaswamy H. Sarma.

Persistent Cryptosporidium parvum Infection Leads to the Development of the Tumor Microenvironment in an Experimental Mouse Model: Results of a Microarray Approach

Cryptosporidium spp. are enteric protozoa parasites that infect a variety of vertebrate hosts. These parasites are capable of inducing life-threatening gastrointestinal disease in immunocompromised individuals. With the rising epidemiological evidence of the occurrence of Cryptosporidium infections in humans with digestive cancer, the tumorigenic potential of the parasite has been speculated. In this regard, Cryptosporidium parvum has been reported to induce digestive adenocarcinoma in a rodent model of chronic cryptosporidiosis. However, the processes by which the parasite could induce this carcinogenesis are still unknown. Therefore, the transcriptomes of C. parvum infected ileo-cecal regions of mice developing tumors were analyzed in the current study. For the first time, downregulation of the expression of α-defensin, an anti-microbial target of the parasite in response to C. parvum infection was observed in the transformed tissues. This phenomenon has been speculated to be the result of resistance of C. parvum to the host defense through the upregulated expression of interferon γ-stimulated genes. The inflammatory response generated as result of attenuated expression of anti-microbial peptides highlights the role of immune evasion in the C. parvum-induced tumorigenesis. The study has also succeeded in the characterization of the tumor microenvironment (TME) which is characterized by the presence of cancer associated fibroblasts, myeloid-derived suppressor cells, tumor-associated macrophages and extracellular matrix components. Identification of immune suppressor cells and accumulation of pro-inflammatory mediators speculates that chronic inflammation induced by persistent C. parvum infection assists in development of an immunosuppressive tumor microenvironment.

QSAR and deep learning model for virtual screening of potential inhibitors against Inosine 5' Monophosphate dehydrogenase (IMPDH) of Cryptosporidium parvum

Cryptosporidium parvum (Cp) causes a gastro-intestinal disease called Cryptosporidiosis. C. parvum Inosine 5' monophosphate dehydrogenase (CpIMPDH) is responsible for the production of guanine nucleotides. In the present study, 37 known urea-based congeneric compounds were used to build a 2D and 3D QSAR model against CpIMPDH. The built models were validated based on OECD principles. A deep learning model was adopted from a framework called Deep Purpose. The model was trained with 288 known active compounds and validated using a test set. From the training set of the 3D QSAR, a pharmacophore model was built and the best pharmacophore hypotheses were scored and sorted using a phase-hypo score. A phytochemical database was screened using both the pharmacophore model and a deep learning model. The screened compounds were considered for glide XP docking, followed by quantum polarized ligand docking. Finally, the best compound among them was considered for molecular dynamics simulation study.

The Efficacy of Citrus maxima Peels Aqueous Extract Against Cryptosporidiosis in Immunecompromised Mice

INTRODUCTION

 Cryptosporidiosis is an opportunistic globally distributed parasitic disease caused by protozoan Cryptosporidium where its development is closely related to the host's immune status. New therapeutic agents are a high priority as chemotherapeutics are impractical and vaccines are unavailable for young as well as immune-compromised patients or animals. The current study was designed to evaluate the therapeutic effect of the internal white (albedo) and external yellow (flavedo) peels of Citrus maxima (C. maxima) as an alternative medicinal plant. MATERIALS AND METHODS : Parasitological examination for oocysts in the stool was determined. Histopathological alterations and immunohistochemical expression of APC and cyclin D1 as well as an assessment of interferon-γ (IFN-γ) and interleukin 1β (IL-1β) in ileal tissues was carried out. In addition, the biochemical examination of serum albumin, globulin and liver enzymes were evaluated. Results revealed a significant decrease of oocysts count correlated with an amelioration of histopathological and immunohistochemical changes in ileal tissue with an enhancement of liver enzymes and inflammatory cytokines levels.

CONCLUSION

 It could be concluded that treatment with C. maxima peel extracts have a potential therapeutic and an immunoregulatory efficacy against Cryptosporidiosis. Obtained results showed that the white peel was found to have more immunological effect that could significantly enhance inflammatory cytokines response towards normal status. Hence, it can be used in the daily animal diet to give protective effects against infection.

Giardia and Cryptosporidium in Neo-Tropical Rodents and Marsupials: Is There Any Zoonotic Potential?

Cryptosporidiosis and giardiasis have been identified as emerging diseases in both developed and developing countries. Wildlife has been highlighted to play a major role in the spread of these diseases to humans. This review aims to highlight the research findings that relate to Cryptosporidium spp. and Giardia spp., with a focus on (1) parasitism of neo-tropical hystricomorphic rodents and marsupials from the genus Didelphis and (2) prevention and treatment strategies for humans and animals for the neo-tropical region. It was found that there are few studies conducted on neo-tropical rodent and marsupial species, but studies that were found illustrated the potential role these animals may play as zoonotic carriers of these two parasites for the neo-tropical region. Thus, it is recommended that further studies be done to assess the threat of protozoan parasites in neo-tropical wildlife to humans and domestic animals, and to further determine the most effective prophylaxis adapted for the unique conditions of the region.

The immunomodulatory activity of secnidazole-nitazoxanide in a murine cryptosporidiosis model

Introduction. Cryptosporidium parvum causes intestinal parasitic infections affecting both immunosuppressed and immunocompetent individuals.Gap statement. Given the absence of effective treatments for cryptosporidiosis, especially in immunodeficient patients, the present study was designed to assess the therapeutic efficacy of secnidazole (SEC) and its combination with nitazoxanide (NTZ) in comparison to single NTZ treatment in relation to the immune status of a murine model of C. parvum infection.Methodology. The infected groups were administered NTZ, SEC or NTZ-SEC for three or five successive doses. At days 10 and 12 post-infection (p.i.), the mice were sacrificed, and the efficacy of the applied drugs was evaluated by comparing the histopathological alterations in ileum and measuring the T helper Th1 (interferon gamma; IFN-γ), Th2 [interleukin (IL)-4 and IL-10] and Th17 (IL-17) cytokine profiles in serum.Results. The NTZ-SEC combination recorded the maximal reduction of C. parvum oocyst shedding, endogenous stages count and intestinal histopathology, regardless of the immune status of the infected mice. The efficacy of NTZ-SEC was dependent on the period of administration, as the 5 day-based treatment protocol was also more effective than the 3 day-based one in terms of immunocompetence and immunosuppression. The present treatment schedule induced an immunomodulatory effect from SEC that developed a protective immune response against C. parvum infection with reduced production of serum IL-17, IFN-γ, IL-4 and IL-10.Conclusions. Application of NTZ-SEC combined therapy may be useful in treatment of C. parvum, especially in cases involving immunosuppression.

Evaluation of possible prophylactic and therapeutic effect of mefloquine on experimental cryptosporidiosis in immunocompromised mice

Cryptosporidiosis is an imperative global health concern. Unfortunately, Nitazoxanide (NTZ) (the nowadays drug of choice) is not effective in treatment of immunocompromised patients. We aimed to assess the possible anti-cryptosporidial prophylactic and therapeutic effects of Mefloquine (MQ) on infected immunosuppressed murine models. Mice were divided into five groups; GI: received Mefloquine (400 mg/kg/day), GII: received NTZ (100 mg/kg/bid), GIII: received a combination, half dose regimen of both drugs, GIV: infected untreated and GV: non-infected untreated. Each treated group was divided into three subgroups; Ga prophylaxis (PX), thereafter infection, Gb first and Gc second treatment doses. Assessment was done by parasitological, histopathological and serological techniques. A significant oocyst clearance was detected in all prophylactically treated groups. GIa showed 77% reduction of the mean oocyst count in stool while GIb and GIIIc showed100% oocyst clearance. Histopathologically, the ileocecal sections from GIV showed loss of brush borders with marked villous atrophy. GIa induced a moderate improvement of those pathological changes. Moreover, the villi in GIb and GIIIc retained their normal appearance with minimal inflammatory cells. Serum interferon gamma levels showed highly significant increases in GI&GIII compared to GIV while a non-significant increase was observed in GIIa only. On the contrary, serum interleukin-17 levels showed a highly significant down-regulation in all treated groups in comparison to GIV. This study proved a marvelous effect of MQ-PX on cryptosporidiosis in immunosuppressed mice and thus it could be introduced as one of the most promising re-purposed prophylactic and therapeutic anti-cryptosporidial agents.

S-Methylcysteine (SMC) Ameliorates Intestinal, Hepatic, and Splenic Damage Induced by Cryptosporidium parvum Infection Via Targeting Inflammatory Modulators and Oxidative Stress in Swiss Albino Mice

Cryptosporidiosis has been proposed to be one of the major causes of diarrhoeal disease in humans worldwide that possesses zoonotic concern. Thereby, this study investigated the potential effects of s-Methylcysteine (SMC) on the parasite in vivo followed by the measurement of cytokines, oxidative stress parameters, and an investigation of the major histopathological changes. Sixty male Swiss albino mice weighing 20-25 g were allocated equally into five groups and orally administered saline only (control), SMC only (SMC50) (50 mg/kg b.w.), and 10⁴Cryptosporidium parvum oocysts per mouse via an esophageal tube (C + ve untreated). The fourth and fifth groups (C + SMC25, C + SMC50) administrated 10⁴C. parvum oocysts combined with SMC25 (low dose) and 50 (high dose) mg/kg b.w., respectively. At days 7 and 14 post-infection (PI), the feces was collected from each group in order to count C. parvum oocysts. After two weeks of treatment, the animals were euthanized and the serum was collected for biochemical analysis. Next, the intestinal, spleen, and liver sections were dissected for histopathological examination. The results revealed lower oocyst numbers in the C + SMC25 and C + SMC50 groups compared to the infected untreated group. Moreover, higher doses of SMC treatment significantly reduced the enteritis induced by C. parvum in a dose-dependent manner. The hepatic lesions were also mitigated as demonstrated in C + SMC25 and C + SMC50 groups unlike the infected group via lowering the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) enzymes and increasing albumin and globulin serum levels. SMC administration also reduced cytokines production (SAP, TNF-α, IL-6, and IFN-γ) mediated by Cryptosporidium infection in contrast to the infected untreated group. There were marked lymphoid depletion and amyloidosis observed in the infected untreated group, while the treated groups showed obvious increase in the lymphoid elements. Moreover, the scoring of intestinal parasites, hepatic, and splenic lesions in the SMC-treated groups exhibited significantly lower pathological lesions in different organs in a dose-dependent manner, compared to the infected untreated group. Our results also revealed a significant change in the malondialdehyde content with an elevation of glutathione and superoxide dismutase in the intestines collected from C + SMC25 and C + SMC50 mice relative to the untreated group. Taken together, our results indicated that SMC could be a promising effective compound for treating and declining C. parvum infestation via restoring structural alterations in different tissues, enhancing antioxidant enzymes, and suppressing the cytokines liberation.

Potential therapeutic and prophylactic effects of Asafoetida in murine cryptosporidiosis

Cryptosporidium parvum is an important coccidian parasite that could infect the intestine, respiratory and biliary tracts of man and animals. This study aims to test the potential therapeutic and prophylactic effects of a natural herbal agent (Asafoetida) versus the nowadays drug of choice (Nitazoxanide). Fifty bred female, white Albino mice of CDI strain were divided into 5 groups; group I (GI): immunosuppressed, infected with C. parvum and treated with Asafoetida, group II (GII): immunosuppressed, prophylactically treated with Asafoetida for 7 days prior to infection, group III (GIII): immunosuppressed, infected and treated with Nitazoxanide, group IV (GIV): immunosuppressed and infected (Positive control), group V (GV): immunosuppressed and non infected (Negative control). Parasitological and histopatholgical examinations of the stool, ileocaecal and liver specimens were performed for the study groups. GI showed reduction of the mean oocyst count in stool with improvement of the pathological changes at the ileocaecal region with preservation of hepatic architecture. Results of GI were better than GII and GIV but not as good as GIII. GII showed the least improvement among the test groups. GIII showed the best response between the test groups. GIV show no statistical significant difference between the mean oocyst count in the mice stool at the time of infection and 7 days after infection. It was therefore concluded that Asafoetida is a promising natural therapeutic and prophylactic agent against cryptosporidiosis while, Nitazoxanide is the best chemotherapeutic agent against cryptosporidiosis.

Limitations in the screening of potentially anti-cryptosporidial agents using laboratory rodents with gastric cryptosporidiosis

The emergence of cryptosporidiosis, a zoonotic disease of the gastrointestinal and respiratory tract caused by Cryptosporidium Tyzzer, 1907, triggered numerous screening studies of various compounds for potential anti-cryptosporidial activity, the majority of which proved ineffective. Extracts of Indonesian plants, Piper betle and Diospyros sumatrana, were tested for potential anti-cryptosporidial activity using Mastomys coucha (Smith), experimentally inoculated with Cryptosporidium proliferans Kváč, Havrdová, Hlásková, Daňková, Kanděra, Ježková, Vítovec, Sak, Ortega, Xiao, Modrý, Chelladurai, Prantlová et McEvoy, 2016. None of the plant extracts tested showed significant activity against cryptosporidia; however, the results indicate that the following issues should be addressed in similar experimental studies. The monitoring of oocyst shedding during the entire experimental trial, supplemented with histological examination of affected gastric tissue at the time of treatment termination, revealed that similar studies are generally unreliable if evaluations of drug efficacy are based exclusively on oocyst shedding. Moreover, the reduction of oocyst shedding did not guarantee the eradication of cryptosporidia in treated individuals. For treatment trials performed on experimentally inoculated laboratory rodents, only animals in the advanced phase of cryptosporidiosis should be used for the correct interpretation of pathological alterations observed in affected tissue. All the solvents used (methanol, methanol-tetrahydrofuran and dimethylsulfoxid) were shown to be suitable for these studies, i.e. they did not exhibit negative effects on the subjects. The halofuginone lactate, routinely administered in intestinal cryptosporidiosis in calves, was shown to be ineffective against gastric cryptosporidiosis in mice caused by C. proliferans. In contrast, the control application of extract Arabidopsis thaliana, from which we had expected a neutral effect, turned out to have some positive impact on affected gastric tissue.

The Anti-parasitic Effect of Probiotic Bacteria via Limiting the Fecundity of Trichinella Spiralis Female Adults

A potential protective effect of probiotic strains against zoonotic Trichinella spiralis infection was investigated in the framework of a new therapeutic strategy aimed at using probiotics to control parasitic zoonoses. The study was focused on the impact of six selected probiotic (bacteriocinogenic) strains on the intensity of T. spiralis infection and female fecundity ex vivo and in vitro. Bacterial strains of different origin (Enterococcus faecium EF55, Enterococcus faecium 2019 = CCM7420, Enterococcus faecium AL41 = CCM8558, Enterococcus durans ED26E/7, Lactobacillus fermentum AD1 = CCM7421, Lactobacillus plantarum 17L/1) were administered daily in a dose of 109 CFU/ml in 100 μl, and mice were infected with 400 T. spiralis larvae on day 7 of treatment. Female adults of T. spiralis were isolated on day 5 post infection (p.i.) and subsequently were used in fecundity test ex vivo. E. faecium CCM8558, E. faecium CCM7420 and E. durans ED26E/7 strains significantly reduced the number of adults in the intestine. The application of L. fermentum CCM7421, L. plantarum 17L/1, E. faecium CCM8558 and E. durans ED26E/7 caused a significant decrease in the number of muscle larvae. The treatment with E. faecium CCM8558 and E. durans ED26E/7 showed the highest inhibitory effect on female fecundity (94 %). The number of newborn larvae (NBL) was also significantly decreased after administration of L. fermentum CCM7421 and L. plantarum 17L/1 (80 %). A direct impact of probiotic strains on female reproductive capacity was examined in vitro in females isolated from untreated infected mice on day 5 p.i. A correlation was found between the inhibitory effect and the concentration of probiotic strains. The reduction effects of the strains manifested as follows: L. fermentum CCM7421 (93 %), E. faecium CCM8558, L. plantarum 17L/1, E. faecium EF55 (about 80 %), E. faecium CCM7420 and E. durans ED26E/7 (about 60 %).

Cryptosporidiosis: A zoonotic disease concern

Cryptosporidiosis is considered to be a crucial zoonotic disease caused by worldwide distributing parasitic protozoa called Cryptosporidium spp. Cryptosporidiosis becomes a major public health and veterinary concern by affecting in human and various host range species of animals. Essentially, its importance of infection is increasing because of the high incidence in young children, immunocompromised persons, or immunodeficiency syndrome patients, especially in HIV/AIDS, and it is also one of the most causes of mortality in those patients who infected with Cryptosporidium spp. as well as young animals. All domestic animal, livestock, wildlife, and human can be potential reservoirs that contribute Cryptosporidium spp. to food and surface waters and transmitted to other hosts through fecal-oral route. The oocyst stage of Cryptosporidium spp. can remain infective and resistant to various environmental exposure and also resistant to many general disinfecting agents including chlorination which normally used in water treatment. Therefore, the understanding of these zoonotic pathogens is very essential in both animal and human health. This review focuses on the biology, life cycle, transmission, diagnosis, treatment, prevention, and control of this protozoan infection to emphasize and remind as the significant One Health problem.

Effect of oregano essential oil and carvacrol on Cryptosporidium parvum infectivity in HCT-8 cells

Cryptosporidium parvum is the second leading cause of persistent diarrhea among children in low-resource settings. This study examined the effect of oregano essential oil (OEO) and carvacrol (CV) on inhibition of C. parvum infectivity in vitro. HCT-8 cells were seeded (1×10⁶) in 96-well microtiter plates until confluency. Cell viability and infectivity were assessed by seeding HCT-8 cell monolayers with C. parvum oocysts (1×10⁴) in two modalities: 1) 4h co-culture with bioactive (0-250μg/mL) followed by washing and incubation (48h, 37°C, 5% CO₂) in bioactive-free media; and 2) 4h co-culture of C. parvum oocysts followed by washing and treatment with bioactive (0-250μg/mL) during 48-h incubation. Cell viability was tested using Live/Dead™ assay whereas infectivity was measured using C. parvum-specific antibody staining via immunofluorescence detection. Loss of cell viability was observed starting at 125μg/mL and 60μg/mL for OEO and CV, respectively. Neither OEO nor CV modulated the invasion of C. parvum sporozoites in HCT-8 cells. Treatment with bioactive after invasion reduced relative C. parvum infectivity in a dose-dependent manner to 55.6±10.4% and 45.8±4.1% at 60 and 30μg/mL of OEO and CV, respectively. OEO and CV are potential bioactives to counteract C. parvum infection in children.

Cryptosporidium canis in Two Mexican Toddlers

Cryptosporidium canis is reported for the first time in 2 toddlers in Northwestern Mexico. The 2 toddlers (33 and 34 months old) were symptomatic at diagnosis, presenting diarrhea and fever, and 1 case presented chronic malnutrition. Both toddlers were HIV-negative. C. canis was identified by SspI and VspI restriction enzyme digestion of the 18S rRNA polymerase chain reaction products and confirmed by sequence analysis.

Antiprotozoal Nitazoxanide Derivatives: Synthesis, Bioassays and QSAR Study Combined with Docking for Mechanistic Insight

In view of the serious health problems concerning infectious diseases in heavily populated areas, we followed the strategy of lead compound diversification to evaluate the near-by chemical space for new organic compounds. To this end, twenty derivatives of nitazoxanide (NTZ) were synthesized and tested for activity against Entamoeba histolytica parasites. To ensure drug-likeliness and activity relatedness of the new compounds, the synthetic work was assisted by a quantitative structure-activity relationships study (QSAR). Many of the inherent downsides – well-known to QSAR practitioners – we circumvented thanks to workarounds which we proposed in prior QSAR publication. To gain further mechanistic insight on a molecular level, ligand-enzyme docking simulations were carried out since NTZ is known to inhibit the protozoal pyruvate ferredoxin oxidoreductase (PFOR) enzyme as its biomolecular target.

Public health significance of zoonotic Cryptosporidium species in wildlife: Critical insights into better drinking water management

Cryptosporidium is an enteric parasite that is transmitted via the faecal-oral route, water and food. Humans, wildlife and domestic livestock all potentially contribute Cryptosporidium to surface waters. Human encroachment into natural ecosystems has led to an increase in interactions between humans, domestic animals and wildlife populations. Increasing numbers of zoonotic diseases and spill over/back of zoonotic pathogens is a consequence of this anthropogenic disturbance. Drinking water catchments and water reservoir areas have been at the front line of this conflict as they can be easily contaminated by zoonotic waterborne pathogens. Therefore, the epidemiology of zoonotic species of Cryptosporidium in free-ranging and captive wildlife is of increasing importance. This review focuses on zoonotic Cryptosporidium species reported in global wildlife populations to date, and highlights their significance for public health and the water industry.

Parasitic diarrheal disease: drug development and targets

Diarrhea is the manifestation of gastrointestinal infection and is one of the major causes of mortality and morbidity specifically among the children of less than 5 years age worldwide. Moreover, in recent years there has been a rise in the number of reports of intestinal infections continuously in the industrialized world. These are largely related to waterborne and food borne outbreaks. These occur by the pathogenesis of both prokaryotic and eukaryotic organisms like bacteria and parasites. The parasitic intestinal infection has remained mostly unexplored and under assessed in terms of therapeutic development. The lack of new drugs and the risk of resistance have led us to carry out this review on drug development for parasitic diarrheal diseases. The major focus has been depicted on commercially available drugs, currently synthesized active heterocyclic compounds and unique drug targets, that are vital for the existence and growth of the parasites and can be further exploited for the search of therapeutically active anti-parasitic agents.

Target validation of the inosine monophosphate dehydrogenase (IMPDH) gene in Cryptosporidium using Phylomer(®) peptides

Cryptosporidiosis, a gastroenteric disease characterised mainly by diarrheal illnesses in humans and mammals is caused by infection with the protozoan parasite Cryptosporidium. Treatment options for cryptosporidiosis are limited, with the current therapeutic nitazoxanide, only partly efficacious in immunocompetent individuals. The parasite lacks de novo purine synthesis, and is exclusively dependant on purine salvage from its host. Inhibition of the inosine 5' monophosphate dehydrogenase (IMPDH), a purine salvage enzyme that is essential for DNA synthesis, thereby offers a potential drug target against this parasite. In the present study, a yeast-two-hybrid system was used to identify Phylomer peptides within a library constructed from the genomes of 25 phylogenetically diverse bacteria that targeted the IMPDH of Cryptosporidium parvum (IMPcp) and Cryptosporidium hominis (IMPch). We identified 38 unique interacting Phylomers, of which, 12 were synthesised and screened against C. parvum in vitro. Two Phylomers exhibited significant growth inhibition (81.2-83.8% inhibition; P < 0.05), one of which consistently exhibited positive interactions with IMPcp and IMPch during primary and recapitulation yeast two-hybrid screening and did not interact with either of the human IMPDH proteins. The present study highlightsthe potential of Phylomer peptides as target validation tools for Cryptosporidium and other organisms and diseases because of their ability to bind with high affinity to target proteins and disrupt function.

Cryptosporidium parvum has an active hypusine biosynthesis pathway

The protozoan parasite Cryptosporidium parvum causes severe enteric infection and diarrheal disease with substantial morbidity and mortality in untreated AIDS patients and children in developing or resource-limited countries. No fully effective treatment is available. Hypusination of eIF5A is an important post-translational modification essential for cell proliferation. This modification occurs in a two step process catalyzed by deoxyhypusine synthase (DHS) followed by deoxyhypusine hydroxylase. An ORF of 1086bp was identified in the C. parvum (Cp) genome which encodes for a putative polypeptide of 362 amino acids. The recombinant CpDHS protein was purified to homogeneity and used to probe the enzyme's mechanism, structure, and inhibition profile in a series of kinetic experiments. Sequence analysis and structural modeling of CpDHS were performed to probe differences with respect to the DHS of other species. Unlike Leishmania, Trypanosomes and Entamoeba, Cryptosporidium contains only a single gene for DHS. Phylogenetic analysis shows that CpDHS is more closely related to apicomplexan DHS than kinetoplastid DHS. Important residues that are essential for the functioning of the enzyme including NAD(+) binding residues, spermidine binding residues and the active site lysine are conserved between CpDHS and human DHS. N(1)-guanyl-1,7-diaminoheptane (GC7), a potent inhibitor of DHS caused an effective inhibition of infection and growth of C. parvum in HCT-8 cells.

CDPKs of Cryptosporidium parvum--stage-specific expression in vitro

Cryptosporidium parvum is a zoonotic agent that bears a high risk for the health of particularly immunocompromised humans and animals. As currently available drugs and therapies against cryptosporidiosis do not turn out satisfactory, more intensive research on the control of this parasite is necessary. The genus Cryptosporidium is unique within the phylum Apicomplexa as its localisation is intracellular but extracytoplasmatic. Infection of host cells is initially a parasite-driven process, but the signalling events and their downstream actions within Cryptosporidium are poorly understood. Calcium-dependent protein kinases (CDPKs) are probably involved in the regulation of invasion and egress. Previously described in plants, algae and other Apicomplexa, CDPKs are not found in vertebrates. They are thus promising targets for pharmaceutical intervention. While CDPK1 is well characterised in Toxoplasma gondii (TgCDPK1) and Plasmodium falciparum (PfCDPK1), only little information exists about the expression and function of CDPK in C. parvum. Here, we describe results of the in silico analysis of seven CpCDPKs. Five CpCDPKs contain potential sites for N-myristoylation and N-palmitoylation. In a nested 3' rapid amplification of cDNA ends (RACE)-PCR, expression of six CpCDPKs resulted in distinct bands in infected cell cultures and extracts of freshly excysted sporozoites. The length of the 3' untranslated region (3' UTR) is described as well. Our results indicate CDPK expression to be stage specific on the mRNA level.

An evaluation of the potential use of Cryptosporidium species as agents for deliberate release

INTRODUCTION

We evaluated the potential of Cryptosporidium spp. for intentional transmission as a terrorist tactic in asymmetric conflicts in terms of the recognised optimum conditions for biological warfare.

METHODS

Published and widely accepted criteria regarding the optimum conditions for the success of biological warfare based on experience from passive biological warfare research were applied to hypothetical intentional Cryptosporidium spp. transmission.

RESULT

The feasibility of the use of Cryptosporidium spp. transmission for terrorist purposes was established. Particularly on tropical deployments with poor hygiene conditions, such attacks might have a good chance of remaining undetected as a deliberate terrorist attack.

CONCLUSIONS

Intentional transmission should be suspected in cases of sudden outbreaks of cryptosporidiosis, particularly where adequate food and drinking water hygiene precautions are being enforced. Appropriate diagnostic procedures should be available so that the diagnosis is not missed.

Infectivity of Cryptosporidium andersoni and Cryptosporidium muris to normal and immunosuppressive cynomolgus monkeys

Cryptosporidium andersoni and Cryptosporidium muris infections have been found in the mice and/or cattle. The oocysts of C. andersoni and C. muris have been sporadically detected in human feces, but the infectious capacity and features have been unknown, because of the scarcity of reports involving human infections. To assess the infectivity and the clinical and pathological features of C. andersoni and C. muris in primates, an experimental infectious study was conducted using cynomolgus monkeys. The monkeys were orally inoculated with oocysts of two different C. andersoni Kawatabi types and C. muris RN-66 under normal and immunosuppressive conditions. The feces of the monkeys were monitored for about 40 days after the administration of oocysts using the flotation method, but no shedding oocysts were observed under either both normal or immunosuppressive conditions. Gross and histopathological examinations were performed on the immunosuppressive monkeys, but these revealed no evidence of Cryptosporidium infections, even though the monkeys were subjected to immunosuppressive conditions. It is hypothesized that C. andersoni and C. muris pose little danger of infection in primates even under immunosuppressive conditions.

Effect of nitaxozanide and pyrimethamine on astrocytes infected by Toxoplasma gondii in vitro

BACKGROUND AND AIMS

T. gondii is a causal agent of encephalitis in immunocompromised patients. Pyrimethamine (PYR) has been the treatment of choice for toxoplasmosis. The aim of this study was to analyze the effect of nitazoxanide and pyrimethamine on astrocytes infected with T. gondii in vitro.

METHODS

Rat astrocytes were cultured and infected with T. gondii. The effect of nitazoxanide (10, 20 and 30 μg/mL) and pyrimethamine (7, 10 and 13 μg/mL) on astrocytes infected was evaluated at 24 and 48 h post-infection. Tachyzoites and astrocytes were detected by the immunocytochemical method. T. gondii viability in astrocytes infected and treated with NTZ and PYR as well as NTZ and PYR cytotoxicity on astrocytes in vitro were evaluated by the MTT assay.

RESULTS

The number of parasites in astrocytes treated with the drugs was significantly reduced when compared to control (p <0.001) at 24 and 48 h. Nitazoxanide produced 97% T. gondii death in a concentration of 10 μg/mL in 48 h infected astrocytes. At 48 h, the death rate of T. gondii was higher when treated with nitazoxanide than with pyrimethamine. A higher toxicity rate in astrocyte was observed when using pyrimethamine at 40 μg/mL.

CONCLUSIONS

Nitazoxanide reduced T. gondii infection more efficiently than pyrimethamine and is not cytotoxic to astrocytes at the administered dose.

Nitazoxanide suppresses IL-6 production in LPS-stimulated mouse macrophages and TG-injected mice

Suppression of interleukin (IL)-6 production has beneficial effects against various inflammatory diseases. Through a rapid screening system, we found that nitazoxanide, or 2-acetyloxy-N-(5-nitro-2-thiazolyl) benzamide, which is a well-known antiparasitic agent, suppressed lipopolysaccharide (LPS)-induced production of IL-6 from RAW 264.7 cells and mouse peritoneal macrophages, with 50% inhibitory concentrations (IC(50)s) of 1.54 mM and 0.17 mM, respectively. Nitazoxanide also inhibited the LPS-induced expression of IL-6 mRNA in RAW 264.7 cells. To investigate the effects of nitazoxanide in vivo, we orally administered nitazoxanide at a dose of 100mg/kg to mice 2h before a 1-mL intraperitoneal injection of 4% thioglycollate (TG). Six hours after TG injection, plasma IL-6 levels were markedly lower (by 90%) than the levels in vehicle-treated mice. These data suggest that nitazoxanide could be a promising lead compound for agents against various diseases associated with overproduction of IL-6.

Probiotics for the control of parasites: an overview

Probiotics are defined as live organisms, which confer benefits to the host. Their efficiency was demonstrated for the treatment of gastrointestinal disorders, respiratory infections, and allergic symptoms, but their use is mostly limited to bacterial and viral diseases. During the last decade, probiotics as means for the control of parasite infections were reported covering mainly intestinal diseases but also some nongut infections, that are all of human and veterinary importance. In most cases, evidence for a beneficial effect was obtained by studies using animal models. In a few cases, cellular interactions between probiotics and pathogens or relevant host cells were also investigated using in vitro culture systems. However, molecular mechanisms mediating the beneficial effects are as yet poorly understood. These studies indicate that probiotics might indeed provide a strain-specific protection against parasites, probably through multiple mechanisms. But more unravelling studies are needed to justify probiotic utilisation in therapeutics.

Structure of triosephosphate isomerase from Cryptosporidium parvum

Cryptosporidium parvum is one of several Cryptosporidium spp. that cause the parasitic infection cryptosporidiosis. Cryptosporidiosis is a diarrheal infection that is spread via the fecal-oral route and is commonly caused by contaminated drinking water. Triosephosphate isomerase is an enzyme that is ubiquitous to all organisms that perform glycolysis. Triosephosphate isomerase catalyzes the formation of glyceraldehyde 3-phosphate from dihydroxyacetone phosphate, which is a critical step to ensure the maximum ATP production per glucose molecule. In this paper, the 1.55 Å resolution crystal structure of the open-loop form of triosephosphate isomerase from C. parvum Iowa II is presented. An unidentified electron density was found in the active site.

The loading of labelled antibody-engineered nanoparticles with Indinavir increases its in vitro efficacy against Cryptosporidium parvum

There is much evidence to indicate the ability of Indinavir (IND) to reduce Cryptosporidium parvum infection in both in vitro and in vivo models. However, there are limitations to the administration of IND as such, due to its renal toxicity and the high rate of metabolism and degradation. We aimed to encapsulate IND in biodegradable poly (D,L-lactide-co-glycolide) nanoparticles (Np) and to engineer their surface by conjugation with an anti-Cryptosporidium IgG polyclonal antibody (Ab). Tetramethylrhodamine-labelled Np were loaded with IND and modified by conjugation with an Ab. The IND-loaded modified Np (Ab-TMR-IND-Np) did not show any change, as demonstrated by chemical analysis studies. Simultaneous addition of 50μM Ab-TMR-IND-Np and excysted oocysts to the cell culture resulted in complete inhibition of the infection. In C. parvum-infected cells, the extent to which the infection decreased depended on the duration of treatment with the Ab-TMR-IND-Np. The antibody-engineered Np loaded with IND were able to target C. parvum in infected cells and therefore might represent a novel therapeutic strategy against Cryptosporidium sp. infection. Moreover, the use of Np as an IND delivery device, allows the development of a more appropriate dose formulation thereby reducing the IND side effects.