MiR-4521 affects the propagation of Cryptosporidium parvum in HCT-8 cells through targeting foxm1 by regulating cell apoptosis

Cryptosporidium parvum could regulate the expression of microRNAs of epithelial cells to facilitate its intracellular propagation. MiR-4521 has been reported to play an important role during the development and progression of tumors and infectious diseases by regulating cell proliferation, apoptosis, and autophagy. However, the implication of miR-4521 during C. parvum infection was still unknown. In this study, the expression of miR-4521 was found to be upregulated in HCT-8 cells infected with C. parvum from 8 h post-infection (pi) to 48 hpi, and its upregulation would be related with the TLR/NF-κB signal pathway during C. parvum infection. One potential target of miR-4521, foxm1, was down-regulated in HCT-8 cells from 24 hpi to 48 hpi, and the expression of foxm1 was negatively regulated by miR-4521. The target relationship between miR-4521 and foxm1 was further validated by using dual luciferase reporter assay. Further studies showed that miR-4521 promoted the propagation of C. parvum in HCT-8 cells through targeting foxm1 by regulating BCL2-mediating cell apoptosis. These results contribute to further understanding of the regulatory mechanisms of host miRNAs during Cryptosporidium infection.

Myeloperoxidase as a biomarker for intestinal-brain axis dysfunction induced by malnutrition and Cryptosporidium infection in weanling mice

Cryptosporidiosis is a waterborne protozoal infection that may cause life-threatening diarrhea in undernourished children living in unsanitary environments. The aim of this study is to identify new biomarkers that may be related to gut-brain axis dysfunction in children suffering from the malnutrition/infection vicious cycle, necessary for better intervention strategies. Myeloperoxidase (MPO) is a well-known neutrophil-related tissue factor released during enteropathy that could drive gut-derived brain inflammation. We utilized a model of environmental enteropathy in C57BL/6 weanling mice challenged by Cryptosporidium and undernutrition. Mice were fed a 2%-Protein Diet (dPD) for eight days and orally infected with 107-C. parvum oocysts. C. parvum oocyst shedding was assessed from fecal and ileal-extracted genomic DNA by qRT-PCR. Ileal histopathology scores were assessed for intestinal inflammation. Prefrontal cortex samples were snap-frozen for MPO ELISA assay and NF-kb immunostaining. Blood samples were drawn by cardiac puncture after anesthesia and sera were obtained for serum amyloid A (SAA) and MPO analysis. Brain samples were also obtained for Iba-1 prefrontal cortex immunostaining. C. parvum-infected mice showed sustained stool oocyst shedding for six days post-infection and increased fecal MPO and inflammation scores. dPD and cryptosporidiosis led to impaired growth and weight gain. C. parvum-infected dPD mice showed increased serum MPO and serum amyloid A (SAA) levels, markers of systemic inflammation. dPD-infected mice showed greater MPO, NF-kB expression, and Iba-1 immunolabeling in the prefrontal cortex, an important brain region involved in executive function. Our findings suggest MPO as a potential biomarker for intestinal-brain axis dysfunction due to environmental enteropathy.

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.

Cryptosporidium rhoptry effector protein ROP1 injected during invasion targets the host cytoskeletal modulator LMO7

The parasite Cryptosporidium invades and replicates in intestinal epithelial cells and is a leading cause of diarrheal disease and early childhood mortality. The molecular mechanisms that underlie infection and pathogenesis are largely unknown. Here, we delineate the events of host cell invasion and uncover a mechanism unique to Cryptosporidium. We developed a screen to identify parasite effectors, finding the injection of multiple parasite proteins into the host from the rhoptry organelle. These factors are targeted to diverse locations within the host cell and its interface with the parasite. One identified effector, rhoptry protein 1 (ROP1), accumulates in the terminal web of enterocytes through direct interaction with the host protein LIM domain only 7 (LMO7) an organizer of epithelial cell polarity and cell-cell adhesion. Genetic ablation of LMO7 or ROP1 in mice or parasites, respectively, impacts parasite burden in vivo in opposite ways. Taken together, these data provide molecular insight into how Cryptosporidium manipulates its intestinal host niche.

Respiratory cryptosporidiosis in Malawian children with diarrheal disease

Background

Respiratory cryptosporidiosis has been documented in children with diarrhea. We sought to describe the dynamics of respiratory involvement in children hospitalized with gastrointestinal (GI) diarrheal disease.

Methods

We conducted a prospective, observational longitudinal study of Malawian children 2–24 months hospitalized with diarrhea. Nasopharyngeal (NP) swabs, induced sputum and stool specimens were collected. Participants that were positive by Cryptosporidium PCR in any of the three compartments were followed up with fortnightly visits up to 8 weeks post-enrollment.

Results

Of the 162 children recruited, participants had mild-moderate malnutrition (mean HAZ -1.6 (SD 2.1)), 37 (21%) were PCR-positive for Cryptosporidium at enrollment (37 stool, 11 sputum, and 4 NP) and 27 completed the majority of follow-up visits (73%). Cryptosporidium was detected in all compartments over the 4 post-enrollment visits, most commonly in stool (100% at enrollment with mean cycle thresholds (Ct) of 28.8±4.3 to 44% at 8 weeks with Ct 29.9±4.1), followed by sputum (31% at enrollment with mean Ct 31.1±4.4 to 20% at 8 weeks with Ct 35.7±2.6), then NP (11% with mean Ct 33.5±1.0 to 8% with Ct 36.6±0.7). Participants with Cryptosporidium detection in both the respiratory and GI tract over the study period reported respiratory and GI symptoms in 81% and 62% of study visits, respectively, compared to 68% and 27%, respectively, for those with only GI detection, and had longer GI shedding (17.5±6.6 v. 15.9±2.9 days).

Conclusion

Cryptosporidium was detected in both respiratory and GI tracts throughout the 8 weeks post-enrollment. The development of therapeutics for Cryptosporidium in children should target the respiratory as well as GI tract.

We conducted a prospective, observational longitudinal study of Malawian children 2–24 months hospitalized with diarrhea. NP swabs, induced sputum and stool specimens were collected. Participants that were positive by Cryptosporidium PCR in any of the three compartments were followed up with fortnightly visits up to 8 weeks post-enrollment. Cryptosporidium was detected by PCR in 21%, 7% and 3% in stool, sputum and nasopharynx of children hospitalized with diarrhea. Of those positive at enrollment, detection was noted in 44%, 20%, and 8%, respectively, by 8 weeks post-enrollment.

Plasma histidine concentrations as a specific biomarker for intestinal mucosal damage in calves with cryptosporidiosis

Specific alterations in plasma histidine concentrations and diamine oxidase (DAO) activity were recently reported as a potential biomarker for intestinal mucosal damage in diarrheic calves. However, there are no data on the comparison of precision between histidine concentration and DAO activity in bovine plasma. The aim of the present study was to compare precision of histidine concentrations and DAO activities in plasma as a biomarker for the Cryptosporidium parvum (C. parvum)-associated intestinal mucosal damage in diarrheic calves. Thirty-two Holstein calves aged 12.2 ± 4.1 days old were enrolled in the present study; they were divided into C. parvum (n = 9), diarrhea (n = 11), and control (n = 12) groups based on the presence or absence of diarrhea and with or without C. parvum infection. Receiver operating characteristic (ROC) curves were used to characterize the sensitivity and specificity of each parameter for the C. parvum-associated intestinal mucosal damage. The proposed cut-off points for plasma histidine concentrations and plasma DAO activities for cryptosporidiosis in calves based on ROC analyses were < 55.8 nM and < 246.0 IU/ml, respectively. The sensitivities and specificities of the proposed diagnostic cut-offs were 88.9% and 82.6% for plasma histidine concentrations and 100.0% and 34.8% for plasma DAO activities, respectively. It was concluded that plasma histidine concentrations may be superior to plasma DAO activities as a specific biomarker for the C. parvum-associated intestinal mucosal damage in diarrheic calves.

Mouse Models for Use in Cryptosporidium Infection Studies and Quantification of Parasite Burden Using Flow Cytometry, qPCR, and Histopathology

Cryptosporidiosis threatens life of young children in developing countries and newborn calves around the world. No vaccine or therapy can prevent or cure this diarrhea-inducing enteric disease caused by Cryptosporidium spp. protozoan parasites. There is an essential need to discover new therapeutic drugs efficient in reducing parasite burden in infected individuals. Research therefore relies on reliable small animal models of cryptosporidiosis. Here, we present excellent mouse models which can efficiently mimic pathogenesis of human and bovine cryptosporidiosis. We also describe methods to purify C. parvum oocysts from stool and intestine of infected mice to facilitate oocyst quantification. Moreover, we present protocols using flow cytometry, quantitative polymerase chain reaction, and histopathology to accurately quantify parasite burden in stool or intestine samples.

Cryptosporidium parvum alters glucose transport mechanisms in infected enterocytes

The parasite Cryptosporidium parvum Tyzzer 1912 destroys parts of the intestinal brush border membrane which is important for the uptake of nutrients like glucose. In this study, glucose transport mechanisms of the host cells (IPEC-J2 cells) infected by C. parvum were investigated. The mRNA expression levels of glucose transporters (GLUT) 1 and 2 and Na⁺-coupled glucose transporter (SGLT) 1 were compared in infected and uninfected cells over an infection time of 24-96 h by RT-qPCR. Furthermore, the protein expression of SGLT 1 and GLUT 2 was quantified in western blot studies. While the protein expression of SGLT 1 was not altered in infected cells, mRNA expression of SGLT 1 and GLUT 1 was significantly increased 24 h p. i. and decreased 96 h p. i. The mRNA expression of GLUT 2 was significantly decreased 24 h, 72 h, and 96 h p. i. and also correlated significantly with the infection dose at 72 h p. i. In contrast to that, the protein expression of GLUT 2 was significantly increased 48 h p. i., associated with a significantly higher intracellular glucose level in infected cells compared with control cells at that time point of infection. This points to an adaptation of the host cells' glucose uptake taking place in the acute phase of the infection. A better understanding of these molecular mechanisms following a C. parvum infection may probably lead to an improvement of therapy strategies in the future.

Calf Clinical Model of Cryptosporidiosis for Efficacy Evaluation of Therapeutics

Cryptosporidiosis, caused by the apicomplexan parasite Cryptosporidium parvum, is a moderate-to-severe diarrheal disease now recognized as one of the leading causes of morbidity and mortality in livestock globally, and in humans living in resource-limited parts of the world, particularly those with AIDS or malnourished individuals. This recognition has fueled efforts for the discovery of effective therapeutics. While recent progress in drug discovery has been encouraging, there are presently no acceptably effective parasite-specific drugs for the disease. The urgent need for new drug discovery or drug repurposing has also increased the need for refined animal models of clinical disease for therapeutic efficacy evaluation. Here, we describe an acute model of cryptosporidiosis using newborn calves to evaluate well-defined clinical and parasitological parameter outcomes, including the effect on diarrhea severity and duration, oocyst numbers produced, and multiple measures of clinical health. The model is highly reproducible and provides unequivocal direct measures of treatment efficacy on diarrhea severity and parasite replication.

Novel lactate dehydrogenase inhibitors with in vivo efficacy against Cryptosporidium parvum

Cryptosporidium parvum is a highly prevalent zoonotic and anthroponotic protozoan parasite that causes a diarrheal syndrome in children and neonatal livestock, culminating in growth retardation and mortalities. Despite the high prevalence of C. parvum, there are no fully effective and safe drugs for treating infections, and there is no vaccine. We have previously reported that the bacterial-like C. parvum lactate dehydrogenase (CpLDH) enzyme is essential for survival, virulence and growth of C. parvum in vitro and in vivo. In the present study, we screened compound libraries and identified inhibitors against the enzymatic activity of recombinant CpLDH protein in vitro. We tested the inhibitors for anti-Cryptosporidium effect using in vitro infection assays of HCT-8 cells monolayers and identified compounds NSC158011 and NSC10447 that inhibited the proliferation of intracellular C. parvum in vitro, with IC₅₀ values of 14.88 and 72.65 μM, respectively. At doses tolerable in mice, we found that both NSC158011 and NSC10447 consistently significantly reduced the shedding of C. parvum oocysts in infected immunocompromised mice’s feces, and prevented intestinal villous atrophy as well as mucosal erosion due to C. parvum. Together, our findings have unveiled promising anti-Cryptosporidium drug candidates that can be explored further for the development of the much needed novel therapeutic agents against C. parvum infections.

Cryptosporidium parvum is a protozoan parasite that can cause a life-threatening gastrointestinal disease in children and in immunocompromised adults. The only approved drug for treatment of Cryptosporidium infections in humans is nitazoxanide, but it is not effective in immunocompromised individuals or in children with malnutrition. C. parvum possesses a unique lactate dehydrogenase (CpLDH) enzyme that it uses for generating metabolic energy (ATP) via the glycolytic pathway to fuel its growth and proliferation in the host. We have identified novel inhibitors for the enzymatic activity of CpLDH. Further, we have demonstrated that two of the CpLDH inhibitors effectively block the growth, proliferation and pathogenicity of C. parvum at tolerable doses in immunocompromised mice. Together, our findings have unveiled novel CpLDH inhibitors that can be explored for the development of efficacious therapeutic drugs against C. parvum infections.

Accounting for long-term manifestations of Cryptosporidium spp infection in burden of disease and cost-of-illness estimations, the Netherlands (2013-2017)

Background

Burden of disease (BoD) estimations are increasingly used to prioritize public health interventions. Previous Cryptosporidium BoD models accounted only for acute episodes, while there is increasing evidence of long-term manifestations. Our objective was to update Cryptosporidium BoD and cost-of-illness (COI) models and to estimate BoD and COI for the Netherlands in years 2013–2017.

Methods

We performed a scoping literature review and drew an outcome tree including long-term manifestations for which sufficient evidence was found, such as recurrent diarrhea and joint pain. We chose the Disability-Adjusted Life Year (DALY) metric to synthesize years of life lost due mortality (YLLs) and years lived with disability due to non-fatal outcomes (YLDs). For the costs, we adopted a societal perspective accounting for direct healthcare costs, patient costs and productivity losses. Uncertainty was managed using Latin Hypercube sampling (30,000 iterations).

Results

In the Netherlands in 2017, we estimated 50,000 Cryptosporidium cases (95% uncertainty interval (UI): 15,000–102,000), 7,000 GP visits, 300 hospitalizations and 3 deaths, resulting in 137 DALYs (95%UI: 54–255) and €19.2 million COI (95%UI: €7.2 million– €36.2 million). Estimates were highest for 2016 (218 DALYs and €31.1 million in COI), and lowest in 2013 (100 DALYs and €13.8 million in COI). Most of the BoD was attributable to YLD (≈80% of DALYs). The most important cost was productivity losses (≈90% of total COI). Long-term manifestations, including recurring diarrhea and joint pain, accounted for 9% of the total DALYs and 7% of the total COI.

Conclusion

Current evidence supports the inclusion of long-term manifestations in Cryptosporidium models, which contribute close to 10% of the total DALYs and costs. This may be an underestimation, as we were conservative in our assumptions. Cryptosporidium should be considered a priority organism with respect to public health surveillance, even in industrialized countries with high hygiene standards.

Long-term sequelae of sporadic cryptosporidiosis: a follow-up study

To determine the frequency of occurrence of sequelae following cryptosporidiosis. A follow-up study was performed during a case-control study for sporadic cryptosporidiosis in the Netherlands (2013–2016). Cryptosporidiosis cases were invited to complete a follow-up questionnaire 4 months after diagnosis. Using a case-crossover study design, we compared the frequencies of reported symptoms 4 months after the acute phase to those reported 4 months before the onset of illness and during illness. Frequencies of symptoms in the pre- to post-infection phases were also compared with those of a population control group. Cryptosporidium species-specific effects were also studied. Logistic regression was used to calculate adjusted odds ratios (aOR) for symptoms occurrence. Of the 731 available cases, 443 (60%) responded and 308 (42%) could be included in the follow-up study. The median age was 26 years (range 1–80); 58% were female; 30% were infected with C. hominis and 70% with C. parvum. Compared to before illness, cases were significantly more likely to report dizziness (OR = 2.25), headache (OR = 2.15), fatigue (OR = 2.04), weight loss (OR = 1.82), diarrhoea (OR = 1.50), abdominal pain (OR = 1.38) or joint pain (OR = 1.84). However, symptoms of joint pain and headache occurred among cases after illness at a rate that was not significantly different from that observed in the general population. There were no significant differences in post-infection symptom occurrence between C. hominis and C. parvum. The disease burden of cryptosporidiosis extends beyond the acute phase of the infection, with cases reporting both intestinal and extra-intestinal symptoms up to 4 months following infection.

Report of fatal mixed infection with Cryptosporidium parvum and Giardia intestinalis in neonatal calves

In the production and management of beef and dairy cattle, controlling diarrhea is one of the important concerns. Pathogenic agents of the disease, protozoan parasites including Cryptosporidium spp., are difficult to control, making prevention, diagnoses, and treatment of diarrhea. In the present study, we investigated a farm with a history of calf deaths over a period of 10 years in order to determine the cause of disease and to clarify the detailed distribution of the pathogens. In four examined calves that were reared in calf pens, all were positive with Cryptosporidium and/or Giardia, while the other breeding stock and adult cattle were negative. Molecular analyses revealed that the isolates from calves were C. parvum subtype IIaA15G2R1 as a zoonotic and G. intestinalis assemblage E. Other pathogenic bacteria and diarrhea-causing viruses were not detected. After treating the calf pens with boiling water and milk of lime (Ca[OH]2), oocysts of C. parvum and cysts of G. intestinalis were not found and no additional calves died. This is the first report to describe the mixed infection of both parasites in Japan.

Morphological and Immunohistochemical Features of Cryptosporidium andersoni in Cattle

Light and electron microscopic features and immunohistochemical features of Cryptosporidium andersoni ( C. andersoni) and host reaction in the mucosa were studied. Although the affected cattle demonstrated no apparent clinical signs, a severe infection of C. andersoni was observed in the abomasum. C. andersoni were round in shape, measured 6-8 μm in size and were mainly observed to be freely located in the gastric pits, being attached in occasional cases to the surface of the abomasum epithelium. Frequent inflammatory cells had infiltrated the lamina propria of the affected mucosa, and frequent mitotic figures were observed in epithelial cells at the dilated isthmus. To access the cell kinetics, the number of epithelial cells infected with C. andersoni were counted and compared with noninfected cattle. The number of gastric pit cells in infected cattle was significantly higher than that in the controls. The number of proliferative cells determined by the Ki-67 antigen in C. andersoni infected cattle was also significantly higher than that in the controls. Transmission electron microscopy and scanning electron microscopy revealed that the morphology of the C. andersoni organism was common to those of other Cryptosporidium spp. immunohistochemically, several commercial antibodies against Cryptosporidium spp. showed positive reactions at the wall of these oocysts or parasitophorous vacuoles. This report is possibly the first to discuss the prominent hyperplasia of the abomasum mucosa, as well as morphologic features of C. andersoni in cattle.

THE EFFICACY OF THREE MEDICINAL PLANTS; GARLIC, GINGER AND MIRAZID AND A CHEMICAL DRUG METRONIDAZOLE AGAINST CRYPTOSPORIDIUM PARVUM: II-HISTOLOGICAL CHANGES

Cryptosporidiosis parvum is a zoonotic protozoan parasite infects intestinal epithelial cells of man and animals causing a major health problem. This study was oriented to evaluate the protective and curative capacity of garlic, ginger and mirazid in comparison with metronidazole drug (commercially known) against Cryptosporidium in experimental mice. Male Swiss Albino mice experimentally infected with C. parvum were treated with medicinal plants extracts (Ginger, Mirazid, and Garlic) as compared to chemical drug Metronidazole. Importantly, C. parvum-infected mice treated with ginger, Mirazid, garlic and metronidazole showed a complete elimination in shedding oocysts by 9th day PI. The reduction and elimination of shedding oocysts in response to the treatments might be attributable to a direct effect on parasite growth in intestines, sexual phases production and/or the formation of oocysts. The results were evaluated histopathological examination of ideum section of control mice (uninfected, untreated) displayed normal architecture of the villi. Examiination of infected mice ileum section (infected, untreated) displayed histopathological alterations from uninfected groups. Examination of ileum section prepared from mice treated with garlic, ginger, mirazid, and metronidazole displayed histopathological alterations from that of the control groups, and showed marked histologic correction in the pattern with the four regimes used in comparison to control mice. Garlic successfully eradicated oocysts of infected mice from stool and intestine. Supplementation of ginger to infected mice markedly corrected elevation in the inflammatory risk factors and implied its potential antioxidant, anti-inflammatory and immunomodulatory capabilities. Infected mice treated with ginger, mirazid, garlic and metronidazole showed significant symptomatic improvements during treatment.

Cryptosporidiosis: A Disease of Tropical and Remote Areas in Australia

Cryptosporidiosis causes gastroenteritis and is transmitted to humans via contaminated water and food, and contact with infected animals and people. We analyse long-term cryptosporidiosis patterns across Australia (2001–2012) and review published Australian studies and jurisdictional health bulletins to identify high risk populations and potential risk factors for disease. Using national data on reported cryptosporidiosis, the average annual rate of reported illness was 12.8 cases per 100 000 population, with cycles of high and low reporting years. Reports of illness peak in summer, similar to other infectious gastrointestinal diseases. States with high livestock densities like New South Wales and Queensland also record a spring peak in illnesses. Children aged less than four years have the highest rates of disease, along with adult females. Rates of reported cryptosporidiosis are highest in the warmer, remote regions and in Aboriginal and Torres Strait Islander populations. Our review of 34 published studies and seven health department reports on cryptosporidiosis in Australia highlights a lack of long term, non-outbreak studies in these regions and populations, with an emphasis on outbreaks and risk factors in urban areas. The high disease rates in remote, tropical and subtropical areas and in Aboriginal and Torres Strait Islander populations underscore the need to develop interventions that target the sources of infection, seasonal exposures and risk factors for cryptosporidiosis in these settings. Spatial epidemiology can provide an evidence base to identify priorities for intervention to prevent and control cryptosporidiosis in high risk populations.

The parasite Cryptosporidium is a common cause of gastroenteritis worldwide. Ineffectively focused interventions are partly why the disease remains a challenge to control. In this study, we describe the geographical, seasonal and demographic characteristics of reported cryptosporidiosis in Australia from 2001–2012. We combine this analysis of illnesses with evidence published in peer review articles and state health bulletins to identify high disease risk areas and populations. We find that rates of reported cryptosporidiosis are highest in warm, remote areas and in Aboriginal and Torres Strait Islander populations’ dominated regions. Our review of the published literature and health reports highlights a focus on short term outbreaks in metropolitan areas. This negligible overlap between areas with high disease rates and areas of public health focus is of concern. Public health interventions and promotion programs to prevent and control diarrhoea need to focus on remote and Indigenous dominated Australia to reduce the currently high rates in these regions and populations.

[Intestinal pathological changes of Kunming mice infected by Cryptosporidium and the therapeutic efficacy of spiramycin on infected mice]

OBJECTIVE

To observe the symptom, disease course of Crytosporidium-infected mice, and the therapeutic effect of spiramycin on infected mice.

METHODS

Seventy Kunming mice were randomly divided into normal control group (A, n = 10) and 3 experimental groups (B, C, and D). Mice in groups B, C, and D (n = 20) were immunosuppressed with 5, 7.5, and 10 mg/L dexamethasone in drinking water for two weeks, respectively. The mice were observed and the number of oocysts in fecal sample was counted daily after immunosuppression. Two weeks post immunosuppression, 50% of mice in each group were sacrificed, and small intestine was removed for observation of parasitic site. The pathological changes of mucous membrane were observed under microscope, and sIgA level in intestinal fluid was determined. Immunosuppression was withdrawn in the rest mice, and after two weeks unrecovered mice were divided into treatment group (n = 6) and control group (n = 7). Mice in treatment group were each given 2 mg/d spiramycin for 10 d. Each mouse in control group was given same amount of normal saline. The mice were observed and the oocysts shedding in fecal pellets were counted after treatment.

RESULTS

On the 6th day post immunosuppression, Cryptosporidium sp. positive fecal samples were found in the experimental groups. The number of oocysts per gram of feces in groups D (70.3 +/- 4.0) and B (31.9 +/- 2.4) reached a peak on the 12th day and 10th day post immunosuppression, respectively (P < 0.05). The conspicuous enteron symptom was observed in each experimental group. Cryptosporidium parasitized mainly in upper jejunum. Pathological examination of intestinal mucous membrane showed that swollen mucous membrane and hemorrhages were observed in group D, and less inflammatory cell occurred in groups B and C. sIgA level in intestinal fluid of experiment mice descended, there was a statistical significance between groups D [(2.7 +/- 0.6) microg/ml], C [(3.2 +/- 0.8) microg/ml], B [(4.9 +/- 1.3) microg/ml] and A [(6.1 +/- 1.2) microg/ml] (P < 0.05). After withdrawal of immunosuppression, out of 30 positive mice, symptoms including diarrhea and loose stools improved in 17 mice. After treated with spiramycin, status of the mice got improved, and there was statistical significance in the level of oocyst shedding between treatment group (0) and control group (11.3 +/- 8.1) (P < 0.05).

CONCLUSION

The level of oocyst shedding, disease course, and pathological change of intestinal mucosa membrane are closely related to immune status of Cryptosporidium-infected mice. Spiramycin is effective in treating of Cryptosporidium infection.

[Changes in the heart of neonatal rats after cryptosporidial gastroenteritis of different degrees of severity]

Disturbances at the childhood age increase risk of the appearance of cardiovascular diseases decades later. The nature of this interconnection called ontogenetic programming is not completely understood. Valuable sources of knowledge about mechanisms of ontogenetic programming are data of interspecies study of biology of the body life cycles and of heart physiological capabilities. Taken into account the interspecies differences, these data allow finding the correct direction of experimental investigations. Results of studies of almost 100 homoiothermal species have shown the slow growth and a high loading on the heart at postnatal development to decrease its aerobic capability in adults. Basing on these data, we suggested that the neonatal gastroenteritis causing tachyarrhythmia, malabsorption, and the growth deceleration might lead to pathological changes in the heart. Our task was to evaluate the effect of cryptosporidial gastroenteritis of different degrees of severity on heart of the neonatal rats. By using methods of Real-Time PCR, immunocytochemistry, image analysis, and study of interatrial septum, we have established that a gradual increase of intensity of infestation with Cryptosporidium parvum oocytes causes sharp changes corresponding to the "all or nothing" response. At a weak infestation the interatrial septum was close (like in control), while significant changes in expression of isoforms of heavy chains of alpha- and beta-myosin were absent. At the intermediate and severe infestation, in the interatrial septum the foramen ovale was visualized and there were observed cardiac atrophy and a strong shift of ration of expression of myosin heavy chains toward the low-velocity beta chain. Thus, by disturbing the frequency-strength ratios and causing outflow of resources from the formed heart, the neonatal gastroenteritis produces pathological changes of the organ molecular and anatomical structures. Our results can be interest to evolutionary biologists and physicians, as they show importance of knowledge of evolutionary-comparative investigations for the search for novel risk factors of heart diseases and demonstrate interconnection between gastroenteritis, pathology of interatrial septum, and a change of composition of the main contractile proteins in cardiomyocytes.

[Threshold rat neonatal cardiomyocyte response to gradual cryptosporidial infection severity increase]

Infectious gastroenteritis is one of the common causes of tachyarrythmia, malabsorbtion and growth retardation in children. Our recent studies have indicated that neonatal.cryptosporidial gastroenteritis is associated with long-term cardiomyocyte abnormalities. The aim of the present study was to find out how neonatal cryptosporidiosis of various severities affects cardiac anatomy and cardiomyocyte polyploidization, remodeling and HIF-1α expression. Using real-time PCR, cytometry, immunohistochemistry, image analysis and interatrial septum visual examination, we revealed that gradual increase in cryptosporidial invasion was associated with threshold changes. At weak parasitic infection, interatrial septum was entire and there was no statistically significant change in cardiomyocytes. At moderate and severe infection, all changes in cardiac anatomy and cardiomyocytes were statistically significant and demonstrated approximately similar degree. Compared to control, heart were atrophied and elongated, interatrial septum contained a small window (patentforamrn ovale), and cardiomyocytes lost protein, became elongated, thin and accumulated additional genomes. Also we found HIF-1α mRNA hyperexpression. Notable, the threshold response to gradual stimulus is an important criterion of development programming since such a response is commonly a consequence of abnormal anatomic structure formation and cell differentiation failure. Our results can be interesting for physicians because they indicate that even moderate cryptosporidiosis can be dangerous for neonatal heart and can trigger neonatal programming of cardiovascular pathology. Also, our results for the first time demonstrate the association between gastroenteritis, patent foramen ovale and cardiomyocyte malfunction.

Effect of immunosuppression on the course of cryptosporidiosis experimentally

This study evaluated the effect of immunosuppression on experimental cryptosporidiosis, by parasitological and histopathological studies at different days post infection (p.i). A total of one hundred five clean laboratory bred male Wister rats were divided into four groups: normal control group (GI), infected group (GII), immunosuppressed control group (GIII) and immunosuppressed infected group (GIV). The infection was done by inoculation orally with 10(5) Cryptosporidium oocysts in 0.1 ml PBS. The immunosuppression was done by administration of cytotoxic drug (Endoxan) intraperitoneal in a dose of 5 mg/kg/d for 4 weeks. The results showed that in GII, most of animals attained its activities without apparent clinical symptoms except some of them had diarrhea while in GIV, all had diarrhea, loss of appetite, weakness, lethargy and hair loss. The death rate was (10%) in GII while in GIV was 51.4%. The infection rate among GII was 95% and GIV was 100%. The infection intensity was higher in GIV than in GIII and the greatest number of excreted oocysts was observed on day 15th post-infection (PI) in GIV and on day 11th PI in GII. The histopathological changes in the ileum were more advanced in GIV.

Chick embryo tracheal organ: a new and effective in vitro culture model for Cryptosporidium baileyi

In the present study, chick embryo tracheal organ (TOCs) was used to cultivate oocysts or sporozoites of Cryptosporidium baileyi. Approximately 5 × 10(4) sporozoites and oocysts mixture for group I; 5 × 10(5), 1 × 10(6), 2 × 10(6) purified sporozoites for group II, group III and group IV, respectively, were inoculated into respective chick embryo tracheal rings maintained in RPMI 1640 supplemented with 5% heat-inactivated FBS, and cultivated in each well of the 24-well culture plate at 40°C and 5% CO(2). The tracheal rings in four experimental groups (I-IV) were successfully infected with C. baileyi, and different stages of parasites were also observed under light and electron microscopy. Parasite infection and cytological alterations were noted as early as PI 72 h. The Cryptosporidium were seen attached to the edge of the tracheal epithelium, with more number of parasites in group I than that in group II, group III and group IV. The moderate nuclear swelling and chromatin margination were also detected, and the normal vertical orientation and basilar location of the nuclei of the epithelial cells were almost lost. C. baileyi that has been passed by TOCs exhibited similar immunity and molecular features with parasites before intratracheal inoculation. These results suggest that chick embryo tracheal organ is a new and effective in vitro culture model for C. baileyi and other respiratory pathogens.

Effects of octreotide on jejunal hypersensitivity triggered by Cryptosporidium parvum intestinal infection in an immunocompetent suckling rat model

BACKGROUND

Similar to other bacterial or protozoan infections, human cryptosporidiosis may trigger postinfectious irritable bowel syndrome (IBS)-like symptoms, a condition in which enhanced visceral perception of pain during intestinal distension plays a pivotal role. In an immunocompetent suckling rat model which mimicks features of postinfectious IBS, Cryptosporidium parvum infection induces long-lasting jejunal hypersensitivity to distension in association with intestinal activated mast cell accumulation. The aim of the present study was to explore in this model whether octreotide, a somatostatin agonist analog, could prevent the development of jejunal hypersensitivity and intestinal mast cell/nerve fiber accumulation.

METHODS

Five-day-old Sprague-Dawley rats were infected with C. parvum and treated 10 days later with octreotide (50 g kg(-1) day(-1), i.p.) for 7 days.

KEY RESULTS

Compared with untreated infected rats, octreotide treatment of infected rats resulted in increased weight gain [day 23 postinfection (PI)], decreased food intake (day 16 PI), and a reduction in jejunal villus alterations (day 14 PI), CD3(+) IEL (day 37 PI) and mast cell (days 37 and 50 PI) accumulations, nerve fiber densities (day 50 PI), and hypersensitivity to distension (day 120 PI). In uninfected rats, the effects of octreotide treatment were limited to higher weight gain (days 16 and 23 PI) and decreased food intake (day 23 PI) compared with uninfected-untreated rats.

CONCLUSIONS & INFERENCES

Data confirms the relevance of the present rat model to postinfectious IBS studies and prompt further investigation of somatostatin-dependent regulatory interactions in cryptosporidiosis.

Cryptosporidium and Giardia associated with reduced lamb carcase productivity

On two extensive sheep farms in southern Western Australia, 111 (Farm A) and 124 (Farm B) female crossbred lambs (2-6 weeks old) were randomly selected and individually identified using ear tags (a numbered tag and radio-frequency tag) at marking. On five separate occasions, faecal samples were collected and live weight, body condition score (BCS), faecal consistency score (FCS), breech fleece faecal soiling score and faecal dry matter percentage (DM%) were recorded. Lamb hot carcase weight (HCW) and dressing percentage were measured at slaughter. Faecal samples were screened by PCR for Cryptosporidium (18S rRNA, actin and 60 kDa glycoprotein [gp60] loci), Giardia duodenalis (glutamate dehydrogenase [gdh] and triosephosphate isomerise [tpi]) and Campylobacter jejuni (16S rRNA). Observation of Eimeria oocysts and faecal worm egg counts (WECs) were performed using a modified McMaster technique. The WECs were adjusted for FCS for analyses. Faecal samples were screened for patent strongylid infections using PCR (specifically ITS-2 nuclear ribosomal DNA for Teladorsagia circumcincta, Trichostrongylus spp. and Haemonchus contortus). Lambs positive for Cryptosporidium at least once had lighter HCWs by 1.25 kg (6.6%) (P=0.029) and 1.46 kg (9.7%) (P<0.001) compared to lambs never positive for Cryptosporidium for Farms A and B respectively. Similarly, dressing percentages were 1.7% (P=0.022) and 1.9% (P<0.001) lower in Cryptosporidium-positive lambs on Farms A and B respectively. Lambs positive for Giardia at least once had 0.69 kg (P<0.001) lighter HCWs and 1.7% (P<0.001) lower dressing percentages compared to lambs never positive for Giardia on Farm B only. Cryptosporidium-positive lambs at the second sampling were 4.72 (P=0.010) and 3.84 (P=0.002) times more likely to have non-pelleted faeces compared to Cryptosporidium-negative lambs for Farms A and B respectively. Breech fleece faecal soiling scores of Cryptosporidium-positive lambs were 3.36 (P=0.026) and 2.96 (P=0.047) times more likely to be moderate to severe (scores 3-5), compared to negative lambs at the second sampling for Farms A and B respectively. Live weight, growth rate and BCS were inconsistently associated with protozoa detection across different samplings and farms. Adjusted WEC was correlated positively with FCS and negatively with faecal DM%, differing between sampling occasions and farms. Campylobacter jejuni prevalence was very low (<1%). Adjusted WEC were not correlated with carcase attributes, growth rates or live weights. This study is the first to quantify productivity consequences of naturally acquired protozoa infections in lambs managed under extensive farming conditions.

Cryptosporidium and Giardia associated with reduced lamb carcase productivity

On two extensive sheep farms in southern Western Australia, 111 (Farm A) and 124 (Farm B) female crossbred lambs (2-6 weeks old) were randomly selected and individually identified using ear tags (a numbered tag and radio-frequency tag) at marking. On five separate occasions, faecal samples were collected and live weight, body condition score (BCS), faecal consistency score (FCS), breech fleece faecal soiling score and faecal dry matter percentage (DM%) were recorded. Lamb hot carcase weight (HCW) and dressing percentage were measured at slaughter. Faecal samples were screened by PCR for Cryptosporidium (18S rRNA, actin and 60 kDa glycoprotein [gp60] loci), Giardia duodenalis (glutamate dehydrogenase [gdh] and triosephosphate isomerise [tpi]) and Campylobacter jejuni (16S rRNA). Observation of Eimeria oocysts and faecal worm egg counts (WECs) were performed using a modified McMaster technique. The WECs were adjusted for FCS for analyses. Faecal samples were screened for patent strongylid infections using PCR (specifically ITS-2 nuclear ribosomal DNA for Teladorsagia circumcincta, Trichostrongylus spp. and Haemonchus contortus). Lambs positive for Cryptosporidium at least once had lighter HCWs by 1.25 kg (6.6%) (P=0.029) and 1.46 kg (9.7%) (P<0.001) compared to lambs never positive for Cryptosporidium for Farms A and B respectively. Similarly, dressing percentages were 1.7% (P=0.022) and 1.9% (P<0.001) lower in Cryptosporidium-positive lambs on Farms A and B respectively. Lambs positive for Giardia at least once had 0.69 kg (P<0.001) lighter HCWs and 1.7% (P<0.001) lower dressing percentages compared to lambs never positive for Giardia on Farm B only. Cryptosporidium-positive lambs at the second sampling were 4.72 (P=0.010) and 3.84 (P=0.002) times more likely to have non-pelleted faeces compared to Cryptosporidium-negative lambs for Farms A and B respectively. Breech fleece faecal soiling scores of Cryptosporidium-positive lambs were 3.36 (P=0.026) and 2.96 (P=0.047) times more likely to be moderate to severe (scores 3-5), compared to negative lambs at the second sampling for Farms A and B respectively. Live weight, growth rate and BCS were inconsistently associated with protozoa detection across different samplings and farms. Adjusted WEC was correlated positively with FCS and negatively with faecal DM%, differing between sampling occasions and farms. Campylobacter jejuni prevalence was very low (<1%). Adjusted WEC were not correlated with carcase attributes, growth rates or live weights. This study is the first to quantify productivity consequences of naturally acquired protozoa infections in lambs managed under extensive farming conditions.

Cryptosporidiosis and its potential risk factors in children and calves in Babol, north of Iran

This study was carried out during April-August 2009 to determine the prevalence of Cryptosporidium spp. and its potential risk factors in children and calves in Babol, north of Iran. A total of 150 faecal samples were taken directly from the rectums of calves which were no more than two months old. Information about age, breeding conditions, consistency of faeces (as diarrhoeic or normal) and contact with human were recorded. At the same time, 150 stool samples were taken from children aged one month to 6 years old in Amir Kola children hospital (Babol, north of Iran). All samples were stained with modified Ziehl-Neelsen's acid-fast and Auramine O techniques to detect for the presence of Cryptosporidium oocysts. Results revealed that the prevalence of Cryptosporidium in children and calves were 16% and 7.33% (Auramine O stain), and 10.67% and 4% (Modified Acid-fast stain), respectively. The prevalence of the infection according to age groups and consistency of faeces were found to be statistically significant with Auramine O stain. The prevalence of infection in urban and rural children was similar, but prevalence of Cryptosporidium was more in calves with native breeding. The young calves and children and type of animal breeding represent important risk factors for transmission of cryptosporidiosis. Moreover, there was no relationship between infection of Cryptosporidium in children and calves. Our finding revealed that clinical cryptosporidiosis cases exist in north of Iran and the most important infection route for Cryptosporidium spp. is anthroponotic transmission.

[Cardiomyocyte myosin heavy chain composition change after cryptosporidial gastroenteritis]

Cardiovascular diseases are the most common case of human death in developed countries. Thus, the discovering of their new risk factors is of primary importance. Based on epidemiology studies, vertebrate life-history traits comparison and cross-species cardiomyocyte transcriptome analysis, we suggest that one of these factors could be infectious gastroenteritis. This disease outflows recourses from cardio-vascular system and triggers pathological stimuli, like tachyarrhythmia, inflammation, malapsorption and energy depletion thereby disturbing cardiomyocyte metabolism and function. To test this hypothesis, we challenged gastroenteritis in neonatal rats with widespread human parasite Cryptosporidium parvum (Apicomplexa, Sporozoa). The results obtained by the methods of immunocytochemistry, quantitative morphometry and real-time PCR, indicate that moderate cryptosporidiosis lasting four days induces dramatic shift in myosin isoform expression ration toward isoform beta (with low ATPase activity) both at mRNA (by 1.7-4.5 folds) and protein (by 2.5-6 folds) levels. Antithetical manner of this shift and coherence between changes in mRNA and protein suggest that cryptosporidiosis affects all main steps of a complex myosin heavy chain regulatory network. Since the overexpression of myosin heavy chain beta (showing several times lower ATPase activity than myosin heavy chain alfa) is a generally accepted marker of human cardiac failure, we can consider cryptosporidial gastroenteritis as a new risk factor of cardiac contractile ability impairment. Our data can be interesting for clinicians.

Cryptosporidiosis: environmental, therapeutic, and preventive challenges

Cryptosporidium spp. are responsible for endemic and epidemic disease worldwide. Clinical manifestations may include acute, persistent, or chronic diarrhea, biliary, and pulmonary disease. Disease severity ranges from asymptomatic or mild to severe, intractable diarrhea with wasting depending on immune status, nutrition, and age. Transmission is fecal-oral with both human and animal reservoirs. Disease is often self limited in healthy individuals, but therapy remains a challenge in the immune-compromised. Prevention currently depends on appropriate hygiene and proper water management and treatment.

Pathological studies of different genotypes of human Cryptosporidium Egyptian isolates in experimentally mice

The genotyping of cryptosporidium clinical isolates obtained from 36 gastrointestinal symptomatic patients were identified by nested PCR for amplification of 18S rRNA followed by RFLP analysis using Ssp1 and Vsp1, and then pathological changes between different cryptosporidium genotypes were evaluated in experimentally infected mice. Cryptosporidium genotypes (C. parvum, C. hominis & C. melegridies) were detected (66.7%, 27.7% & 5.6%) respectively in human isolates. Different degrees of pathological changes were found among infected mice by different Cryptosporidium genotypes. Moderate and severe degrees of pathological changes with infection score ranging from 2 to 4 were found in all infected mice with C. parvum (except one isolate), while mild degree of pathological changes with infection score of 2 was found in all mice with C. melegridies. The results showed statistically significant relation between genotype and pathological degrees. There were no differences in the average number of oocysts per smear in Group II and Group III while in Group I, there was no oocysts shedding.

An outbreak of disease associated with cryptosporidia on a red-legged partridge (Alectoris rufa) game farm

An outbreak of disease associated with cryptosporidia on a red-legged partridge (Alectoris rufa) game farm is described. Morbidity (diarrhoea and cough) was between 60% and 70% during the first weeks of life (4 to 25 days) and mortality was higher than 50%. The results of bacteriological and virological analyses were negative. Histological examination and antigenic diagnosis by enzyme-linked immunosorbent analysis revealed the presence of Cryptosporidium spp. in respiratory and intestinal tracts. The application of polymerase chain reaction-restriction fragment length polymorphism techniques and sequencing of a Cryptosporidium oocyst wall protein gene fragment confirmed the existence of Cryptosporidium meleagridis in faecal samples. The results obtained suggest that avian cryptosporidiosis should be included among respiratory and enteric diseases routinely tested for in farmed birds.

Prevalence of Cryptosporidium sp. infection in diarrheic and non-diarrheic humans in Iran

For evaluation of the prevalence of Cryptosporidium sp. infection in diarrheic and non-diarrheic humans in Iran, fecal specimens from diarrheic (n = 129) and non-diarrheic humans (n = 271) were collected and examined for the presence of Cryptosporidium sp. oocysts. The presence of Cryptosporidium sp. oocysts was determined by Ziehl- Neelsen acid-fast staining. Humans were grouped according to their age as follows: younger than 15, 16-25, 26-35, 36-50, and over 51 years. The results showed that the overall prevalence of infection in all 400 samples was 10.8%, but the prevalence (25.6%) in diarrheic humans was higher than that (3.7%) in non-diarrheic humans. Oocysts of Cryptosporidium sp. were detected in the feces of 21.4%, 9.3%, 8.8%, 6.7% and 5.7% of different age groups, respectively. The intensity of oocysts was significantly higher in diarrheic humans than in non-diarrheic ones. There was a significant association between Cryptosporidium sp. infection and occurrence of diarrhea (P < 0.05). The results indicate that Cryptosporidium sp. infection is prevalent in diarrheic humans in Iran.

Molecular characterisation of Cryptosporidium: an emerging parasite

PURPOSE

The aim of the present study was to determine the prevalence of Crytposporidium in local population and to understand its epidemiology by molecular methods.

METHODS

Faecal samples from 681 children and 804 adults, admitted to tertiary care hospitals in twin cities of Hyderabad and Secunderabad with complaints of diarrhoea; and six calves with diarrhoea, were screened for Cryptosporidium oocysts by microscopy and enzyme linked immunosorbent assay (ELISA). Polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) based identification of Cryptosporidium species in positive specimens was done to elucidate epidemiology of Cryptosporidium.

RESULTS

Cryptosporidium was found in 52 (7.6%) children and 7(0.9%) adults and 1(16.6%) calf with diarrhoea. The prevalence of Cryptosporidium in children below five years of age was 8.2% and 14.3% in children in the age group of six months to one year. Of the 42 samples genotyped 29 (69%) were C. hominis and 8 (19%) were C. parvum and 5 (11.9%) were mixed infection with the two species.

CONCLUSIONS

Children in the age group of six months to one year were found to be the most vulnerable. The occurrence of C. parvum, in nearly one third of cases in the present series indicates that the zoonotic transmission is of considerable significance in the epidemiology of Cryptosporidiosis in the study area.

Differences in clinical manifestations among Cryptosporidium species and subtypes in HIV-infected persons

We performed a cross-sectional study to determine the epidemiology of Cryptosporidium in human immunodeficiency virus (HIV)-infected persons at 3 diagnostic levels: microscopy, genotypes of Cryptosporidium, and subtype families of C. hominis and C. parvum. The study enrolled 2,490 HIV-infected persons in Lima, Peru, and 230 were microscopy positive for Cryptosporidium infection. Specimens from 193 participants were available for genotyping. They had C. hominis (141 persons), C. parvum (22 persons), C. meleagridis (17 persons), C. canis (6 persons), C. felis (6 persons), and C. suis (1 person) infection. Although microscopy results showed that Cryptosporidium infections were associated with diarrhea, only infections with C. canis, C. felis, and subtype family Id of C. hominis were associated with diarrhea, and infection with C. parvum was associated with chronic diarrhea and vomiting. These results demonstrate that different Cryptosporidium genotypes and subtype families are linked to different clinical manifestations.

Impact of neonatal cryptosporidial gastroenteritis on epigenetic programming of rat hepatocytes

Inflammation, malnutrition and growth retardation during critical time-windows of development play a powerful role in ontogenetic programming of the life-long risk to many adult diseases (including metabolic syndrome, obesity and diabetes). Cellular mechanisms and the accurate timing and duration of critical periods for the liver remain obscure. To resolve this problem, we developed a postnatal suckling-weanling rat model of mild, moderate, and acute gastroenteritis challenged by a protozoan parasitic spread throughout the whole world, namely Cryptosporidium parvum. The physiological state of the liver was evaluated by hepatocyte ploidy and protein content that were measured by cytophotometry and image analysis on isolated cells. Hepatocyte ploidy is known to irreversibly increase after stress and is associated with the decrease in liver physiological capacity. Hepatocyte hypertrophy reflects cell functional loading. From our results, cryptosporidiosis is able to provoke a burst in premature hepatocyte polyploidization and hypertrophy (in proportion to parasitic load), and thus plays an important role in epigenetic programming of hepatocyte structure and function. We revealed two sensitive periods in liver growth. The first period (the less sensitive) covers the time before the establishment of homoiothermy, i.e. 6-9 days after birth. The second period (the more sensitive) covers the time of weaning when the change of type of nutrition and the peak of hepatocyte polyploidization and differentiation occurs. Thus, our data provide direct evidence that phenomenon of ontogenetic programming is reflected at the cellular level.

Characterization of a Cryptosporidium muris infection and reinfection in CF-1 mice

To establish control values for circulating cells and immune associated organs over the course of a self-limiting Cryptosporidium muris infection and rechallenge infection, mice were sacrificed at intervals starting before oral inoculation and ending after oocyst shedding had ceased. These values were used in other experiments to evaluate changes in these parameters induced by a single dose glucocorticoid immunosuppression model and in other immunosuppression studies. Flow cytometry counts of circulating T-lymphocytes and neutrophils, differential leukocyte counts, leukocyte morphology, spleen and thymus changes, and oocyst shedding were evaluated. Immediately after C. muris oocyst inoculation and up to the start of oocyst production (day 0 to day 7), the circulating blood profile showed a 50% drop in all leukocytes, including both large and small lymphocytes and CD3, CD4 and CD8 T-lymphocytes. There was an initial slight rise in circulating mature neutrophils after oocyst inoculation but numbers promptly dropped below normal and remaineded below normal. In the differential cell counts, monocytes with a fat, oval morphology increased by 60% at 24 h and remained high through oocyst shedding and beyond (day 8 through day 36). During oocyst shedding and continuing past the end of shedding, T-lymphocytes increased 100%. Monocytes with a flat, angular morphology increased in a similar manner. Immediately after oocyst inoculation the spleen contracted by 29%, but became 92% larger than its pre-inoculation size by day 14 when heavy oocyst shedding began. It remained enlarged through the end of oocyst shedding (day 29) and beyond (day 36). Spleen volume decreased and increased similar to changes in T-cell numbers. Throughout the C. muris infection the thymus remained largely unchanged. The transit of an oocyst bolus was followed from the stomach through the gut to the colon. No oocysts could be found in the stomach, caecum or feces of mice one half hour after oocyst inoculation. Likewise, an oral bolus of India ink passed from the stomach entirely into the colon after 3 h; therefore, no oocysts from the inoculum passed completely through the intestine and out into the feces. Recovered mice rechallenged with C. muris showed increased B-lymphocyte numbers; however, T-lymphocyte numbers remained level. The large lymphocytes increased after rechallenge, peaking on day 3, then decreased through day 10. B-cell numbers followed a pattern similar to the large lymphocytes. On day 10 of infection monocytes with a fat oval morphology rose sharply while B-cells fell in number. In both the initial infection and the rechallenge there was no unique blood profile which could definitely indicate a protozoal disease or identify a specific point during the course of the disease. There was no increase in the number of either small or large lymphocytes prior to increases in fat or flat monocytes.

Involvement of intestinal epithelial cells in dendritic cell recruitment during C. parvum infection

Dendritic cells (DCs) play a key role in activating and orientating immune responses. Little is currently known about DC recruitment during Cryptosporidium parvum infection. In the intestine, epithelial cells act as sensors, providing the first signals in response to infection by enteric pathogens. We analyzed the contribution of these cells to the recruitment of DCs during cryptosporidiosis. We found that intestinal epithelial cells produced a broad range of DC-attracting chemokines in vitro in response to C. parvum infection. The supernatant of the infected cells induced the migration of both bone marrow-derived DCs (BMDC) and the SRDC lymphoid dendritic cell line. Chemokine neutralization abolished DC migration in these assays. We next analyzed chemokine mRNA expression in the mucosa of C. parvum-infected neonatal mice and recruitment of the various subsets of DCs. Myeloid (CD11c+ CD11b+) and double-negative DCs (CD11c+ CD11b- CD8alpha-) were the main subsets recruited in the ileum during C. parvum infection, via a mechanism involving IFNgamma. DCs were also recruited and activated in the draining lymph nodes during C. parvum infection, as shown by the upregulation of expression of MHC II and of the costimulation molecules CD40 and CD86.

The suppressive effect of Mekabu fucoidan on an attachment of Cryptosporidium parvum oocysts to the intestinal epithelial cells in neonatal mice

The present study was done to investigate the effects of fucoidan and de-sulfated fucoidan isolated from the sporophyll of Undaria pinnatifida on the C. parvum adhesion to the cultured human intestinal cells and on the C. parvum infection in neonatal mice. The C. parvum adhesion to human Intestinal 407 cells was significantly suppressed by a low dose (1 micro g/ml) of Mekabu fucoidan (1 micro g/ml) (approx. 20.5 oocysts, p<0.0001), but not by de-sulfated fucoidan (approx. 138.2 oocysts), as compared with that (approx. 121.0 oocysts) of phosphate-buffered saline (PBS). The in vivo experiments presented here revealed that C. parvum oocysts in the fucoidan-treated mice was reduced nearly one fifth (approx. 5.4x10(4) oocysts, p<0.02) of the total number of oocysts (approx. 3.0x10(5)) in mice treated with PBS, but no significant effect of de-sulfated fucoidan was observed. These results show that (i) fucoidan effectively inhibits the growth of C. parvum in mice; and (ii) the ester sulfate of fucoidan is an active site to prevent the adhesion of C. parvum to the intestinal epithelial cells. Finally, we concluded that fucoidan might inhibit cryptosporidiosis through the direct binding of fucoidan to the C. parvum-derived functional mediators in the intestinal epithelial cells in neonatal mice.

Neutrophils do not mediate the pathophysiological sequelae of Cryptosporidium parvum infection in neonatal piglets

Cryptosporidium parvum is a minimally invasive protozoal pathogen of intestinal epithelium that results in villus atrophy, mucosal lipid peroxidation, diarrhea, and diminished barrier function. Influx of neutrophils is a consistent feature of human and animal cryptosporidiosis, and yet their contribution to the pathological sequelae of infection has not been investigated. Accordingly, we used an established neonatal piglet model of C. parvum infection to examine the role of neutrophils in disease pathogenesis by inhibiting their recruitment and activation in vivo using a monoclonal anti-CD18 antibody. Infected piglets were treated daily with anti-CD18 or isotype control immunoglobulin G and euthanized at peak infection, at which time neutrophil infiltrates, lipid peroxidation, severity of infection, and intestinal barrier function were quantified. C. parvum infection resulted in a significant increase in mucosal neutrophil myeloperoxidase activity that was prevented by treatment of piglets with anti-CD18 antibody. Neutrophil recruitment was dependent on mucosal superoxide formation (prevented by treatment of infected piglets with superoxide dismutase). Neutrophils did not contribute to peroxynitrite formation or peroxidative injury of C. parvum-infected mucosa and had no impact on the severity of epithelial infection, villus atrophy, or diarrhea. The presence of neutrophils in C. parvum-infected mucosa was associated with enhanced barrier function that could not be attributed to mucosal elaboration of prostaglandins or stimulation of their synthesis. These studies are the first to demonstrate that neutrophilic inflammation arising in response to infection by a noninvasive epithelial pathogen results in physiologic rather than pathological effects in vivo.

Pulmonary cryptosporidiosis: role of COX2 and NF-kB

In the present study we investigated whether the pathological changes induced by Cryptosporidium in the lungs are mediated through the activation of COX-2, and whether the pathway employed for this activation involves NF-kB. 70 albino rats were submitted for this work. They were categorized into 3 groups: 30 immunocompetent (IC) rats infected with Cryptosporidium oocysts, 30 immunosuppressed (IS) rats infected with Cryptosporidium oocysts, and 10 IC, non-infected rats. Immunohistochemical expression of COX2 and NF-kB in lung tissues of the rats was examined. 43.3% of IC rats showed chronic pneumonia and fibrosis, 40% COX2 positivity, and 36.67% NF-kB positivity. 96.7% of IS rats showed chronic pneumonia and fibrosis, 56.7% non-caseating granuloma with Cryptosporidium oocysts, and 66.7% positivity for both COX2 and NF-kB. Density of inflammatory infiltration was statistically correlated with quickscore of both COX2 and NF-kB in both IC and IS groups. An association between quickscores of COX2 and NF-kB was found in our studied material. These data could demonstrate that Cryptosporidium infection induces upregulation of COX2 possibly through the NF-kB pathway, which suggests the events that contribute to the pathogenesis of Cryptosporidium. These findings could indicate potential therapeutic pharmacological target-mediating treatment of lesions caused by Cryptosporidium.

Infectivity and pathogenicity of Cryptosporidium andersoni to a novel host, southern multimammate mouse (Mastomys coucha)

The infectivity and pathogenicity of Cryptosporidium andersoni (bovine isolate) for neonatal and adult southern multimammate mice (Mastomys coucha) was studied using transmission experiments. C. andersoni isolate used in this study was not infective for BALB/c mice, but experimental infection proved susceptibility of neonatal and adult M. coucha to the infection. The prepatent period was 20-24 days, the patent period varied between 46 and 59 days. No signs of clinical illness or macroscopic findings were detected in infected animals. Cryptosporidium developmental stages were detected only in the glandular part of the stomach of M. coucha in histological sections stained with Wolbach's modification of Giemsa and using immunofluorecence. Histopathological changes were characterized by dilatation and epithelial metaplasia of infected gastric glands without inflammatory response in the lamina propria. Neonatal M. coucha were more susceptible to C. andersoni infection than adults. M. coucha seems to be a useful laboratory model for study of C. andersoni infection.

Observations and immunohistochemical detection of Coronavirus, Cryptosporidium parvum and Giardia intestinalis in neonatal diarrhoea in lambs and kids

In this study, clinical, parasitological, macroscopical, histopathological and immunohistochemical examinations were performed on 19 kids and 11 lambs (30 animals) with neonatal diarrhoea to detect the presence of Coronavirus, Cryptosporidium parvum and Giardia intestinalis. Clinically, severe dehydration, yellowish-green to brown coloured diarrhoea and death were observed. Mortality rates were 10-30% in the examined flocks. The most common agent was C. parvum diagnosed in 20 animals as a single causative agent, whereas G. intestinalis was found in 5 of 30 animals. These two protozoa were detected together in 4 animals upon faeces examination. Fifteen of 24 cases of C. parvum and 3 of 11 cases of G. intestinalis were also confirmed histopathologically. Following immunohistochemical examination, all cryptosporidiosis cases were confirmed by positive immunostaining of intestinal sections. Two additional Giardiosis cases with negative results upon parasitological and histopathological examinations were diagnosed by means of immunohistochemical examination. Coronavirus was detected immunohistochemically in one kid with neonatal enteritis. Following diagnosis, herds were treated with Trimethoprim + Sulfodoxine and multivitamin complexes. Intravenous and intramuscular administrations of these drugs were effective for both treatment and prevention of neonatal diarrhoea in lambs and kids.

Intestinal Cryptosporidiosis in Turkeys in Iran

Naturally occurring cryptosporidiosis is reported in turkey poults suffering from diarrhoea and unthriftness in Iran. Histological and ultrastructural studies revealed high number of Cryptosporidium developmental stages mainly located in the mid and terminal portions of small intestine of the poults. Other portions of the intestinal tract were less frequently infected. Oocyst shedding was detected only in 29% of the histologically positive birds. Based on host species, clinical signs, pathology and tissue location of the parasites, Cryptosporidium meleagridis was most likely responsible for these infections. This parasite was also reported recently in a child with diarrhoea in Iran.

Prevalence and Pathogenicity of Cryptosporidium suis in Pre- and Post-weaned Pigs

A total of 4338 faecal samples, 135 of sows, 3368 of pre-weaned and 835 of post-weaned piglets from eight farms in South Bohemia, Czech Republic were collected and examined for Cryptosporidium infection. No sow, but 5.7% pre-weaned and 24.1% post-weaned piglets were positive for Cryptosporidium infection. No relationship was found between diarrhoea and Cryptosporidium infection in any of the different age groups (pre- and post-weaned piglets). Four piglets, which were sporadically shedding cryptosporidia in faeces, were necropsied. Neither clinical signs of diarrhoea nor macroscopical changes were found. Histologically, a moderate infection of cryptosporidia was detected in the glandular epithelium along the large intestine, with predisposition to the ansa centralis of the colon. No inflammatory response in the lamina propria was observed. Cryptosporidia were also commonly found in the glandular epithelium of submucosal lymphoglandular complexes in the colon. Cryptosporidium isolates from all farms were identified as Cryptosporidium suis using molecular markers (SSU rRNA). All of the C. suis strains obtained were larger [6.2 (6.0-6.8) x 5.5 (5.3-5.7) microm] than any isolate described so far [4.6 (4.4-4.9) x 4.2 (4.0-4.3) microm] and did not appear to be infective for neonatal BALB/c mice.

Experimental study of the effects of probiotics on Cryptosporidium parvum infection in neonatal rats

To date, there is no efficient treatment for cryptosporidiosis and parasite eradication relies on innate and acquired immunity. In this study, we investigated the effect of administration of probiotic bacteria on the development and progression of the experimental infection in suckling rats. Rats were fed daily with 2.10(7) CFU of Lactobacillus casei-containing mixture, starting 2 days before the infection until the spontaneous clearance of the parasite. Effects on weight gain, parasite burden, mucosal histology and production of mucosal cytokines (IFNgamma, IL10 and TNFalpha) were studied. Although a trend to a more rapid clearance of parasites was noted in rats treated with probiotics, no significant effect of probiotics administration was observed in terms of weight gain, parasite burden, mucosal damage, or kinetics of mucosal cytokines during the course of infection. Overall, our results showed that the daily administration of L. casei-containing mixtures was unable to eradicate the parasite in our model.

Mucosal cytokine and antigen-specific responses to Cryptosporidium parvum in IL-12p40 KO mice

Studies of cellular immune responses to Cryptosporidium parvum have been limited in part by lack of suitable animal models. IL-12p40(-/-)mice are susceptible to initial infection with C. parvum but recover within 2 weeks, rendering the animals resistant to reinfection. Because the host responses that determine duration and severity of primary infection are not yet understood, we studied the cellular immune response to primary infection with C. parvum in IL-12p40(-/-)mice and also explored possible mechanisms for this response. Female IL-12p40(-/-)mice were inoculated with 10,000 oocysts. Uninfected age-matched mice served as controls. At different time intervals following exposure to oocysts, mice were sacrificed and their intestine, spleen, and mesenteric lymph node tissues were harvested. Cellular immune responses to C. parvum were characterized. Infection of IL-12p40(-/-)mice induced changes in the gene expression of the cytokines IFN-gamma, IL-4, IL-15, IL-18, TNF-alpha and TGF-beta during primary infection. There was also a significant increase in total numbers of lymphocytes and CD19/CD62L-expressing cells in mesenteric lymph nodes. These MLN cells exhibited increased antigen-specific proliferation and cytokine production (IL-6 and IFN-gamma) levels when stimulated in vitro. These observations delineate the cellular immune responses during acute C. parvum infection of the IL-12p40(-/-)mouse model.