Cryptosporidium

E-pharmacophore and deep learning based high throughput virtual screening for identification of CDPK1 inhibitors of Cryptosporidium parvum

Cryptosporidiosis, a prevalent gastrointestinal illness worldwide, is caused by the protozoan parasite Cryptosporidium parvum. Calcium-dependent protein kinase 1 (CpCDPK1), crucial for the parasite's life cycle, serves as a promising drug target due to its role in regulating invasion and egress from host cells. While potent Pyrazolopyrimidine analogs have been identified as candidate hit molecules, they exhibit limitations in inhibiting Cryptosporidium growth in cell culture, prompting exploration of alternative scaffolds. Leveraging the most potent compound, RM-1-95, co-crystallized with CpCDPK1, an E-pharmacophore model was generated and validated alongside a deep learning model trained on known CpCDPK1 compounds. These models facilitated screening Enamine's 2 million HTS compound library for novel CpCDPK1 inhibitors. Subsequent hierarchical docking prioritized hits, with final selections subjected to Quantum polarized docking for accurate ranking. Results from docking studies and MD simulations highlighted similarities in interactions between the cocrystallized ligand RM-1-95 and identified hit molecules, indicating comparable inhibitory potential against CpCDPK1. Furthermore, assessing metabolic stability through Cytochrome 450 site of metabolism prediction offered crucial insights for drug design, optimization, and regulatory approval processes.

A fractional perspective on the transmission dynamics of a parasitic infection, considering the impact of both strong and weak immunity

Infectious disease cryptosporidiosis is caused by the cryptosporidium parasite, a type of parasitic organism. It is spread through the ingestion of contaminated water, food, or fecal matter from infected animals or humans. The control becomes difficult because the parasite may remain in the environment for a long period. In this work, we constructed an epidemic model for the infection of cryptosporidiosis in a fractional framework with strong and weak immunity concepts. In our analysis, we utilize the well-known next-generation matrix technique to evaluate the reproduction number of the recommended model, indicated by [Formula: see text]. As [Formula: see text], our results show that the disease-free steady-state is locally asymptotically stable; in other cases, it becomes unstable. Our emphasis is on the dynamical behavior and the qualitative analysis of cryptosporidiosis. Moreover, the fixed point theorem of Schaefer and Banach has been utilized to investigate the existence and uniqueness of the solution. We identify suitable conditions for the Ulam-Hyers stability of the proposed model of the parasitic infection. The impact of the determinants on the sickness caused by cryptosporidiosis is highlighted by the examination of the solution pathways using a novel numerical technique. Numerical investigation is conducted on the solution pathways of the system while varying various input factors. Policymakers and health officials are informed of the crucial factors pertaining to the infection system to aid in its control.

Molecular Detection and Genotyping of Cryptosporidium spp. Isolates from Bats in Colombia

PURPOSE

Cryptosporidiosis is a zoonotic infectious disease caused by the protozoan parasite Cryptosporidium spp., frequently found in several animal species, including bats. Several Cryptosporidium genotypes have been described in bats worldwide, suggesting that bats are infected by host-specific Cryptosporidium spp. To date, there are no published reports about Cryptosporidium spp. in bats from Colombia. Therefore, this study aimed to determine the presence and molecular diversity of Cryptosporidium spp. in Colombian bats.

METHODS

A total of 63 gut samples from three bat species served for molecular detection of Cryptosporidium spp. 18S rDNA gene by qPCR. The sequenced amplicons were used in subsequent phylogenetic analyses to identify them as species or genotypes.

RESULTS

Cryptosporidium spp. qPCR detection occurred in 9.5% (6/63) of bat intestines, and four sequences represented two new genotypes, called Cryptosporidium bat genotypes XIX and XX, were identified.

CONCLUSIONS

This study describes the detection of two novel Cryptosporidium bat genotypes, in two species of bats from a region of Colombia, requiring further studies to determine the relationhip between Cryptosporidium and bats in Colombia.

Diarrhoeal pathogens in the stools of children living with HIV in Ibadan, Nigeria

Introduction

Diarrhoea can be debilitating in young children. Few aetiological investigations in Africans living with human immunodeficiency virus (HIV) have been performed since antiretrovirals became widely available.

Methods

Stool specimens from children with diarrhoea living with HIV, and HIV-uninfected controls, recruited at two hospitals in Ibadan, Nigeria, were screened for parasites and occult blood, and cultured for bacteria. Following biochemical identification of at least five colonies per specimen, diarrhoeagenic Escherichia coli and Salmonella were confirmed by PCR. Data were line-listed and comparisons were made using Fisher's Exact test.

Results

Only 10 children living with HIV could be enrolled during the 25-month study period and 55 HIV-uninfected children with diarrhoea were included for comparison. The most common pathogens overall were enteroaggregative E. coli (18/65, 27.7%), enteroinvasive E. coli (10/65, 15.4%), Cryptosporidium parvum (8/65, 12.3%) and Cyclospora cayetanensis (7/65, 10.8%). At least one pathogen was detected from seven of ten children living with HIV and 27 (49.1%) HIV-uninfected children. Parasite detection was associated with HIV positive status (p=0.03) with C. parvum specifically recovered more commonly from children living with HIV (p=0.01). Bacterial-parasite pathogen combinations were detected in specimens from four of ten children living with HIV but only 3(5.5%) HIV-uninfected children (p=0.009). Stools from five of ten children living with HIV and 7(12.7%) HIV-negative children (p = 0.014) contained occult blood.

Discussion

Even though children living with HIV present infrequently to Ibadan health facilities with diarrhoea, their greater propensity for mixed and potentially invasive infections justifies prioritizing laboratory diagnosis of their stools.

Molecular evaluation of Cryptosporidium spp. among breeding calves of Lorestan province Western Iran

BACKGROUND

Cryptosporidium spp. are opportunistic intestinal protozoans with global distribution and are of great importance as zoonotic protozoans are common to humans and domestic animals, including cattle and calves. Identification and detection of parasite species using precise methods including molecular methods can be an effective step in treating and controlling parasites.

OBJECTIVES

This study aimed to investigate the prevalence of Cryptosporidium among breeding calves of Khorramabad city, Lorestan province, Western Iran, using PCR.

METHODS

The faecal samples were taken from 181 healthy and diarrhoeal calves and after the Ziehl Neelsen Acid-fast staining and microscopic evaluation, the genomic DNA was extracted for molecular evaluations. To detect Cryptosporidium species, specific primers targeting the SAM-1 gene of Cryptosporidium and a commercial master mix were used for PCR.

RESULTS

Out of 181 faecal samples of breeding calves in Khorramabad city, 9 samples (5%) were positive for Cryptosporidium spp. using the PCR method. Statistical analysis of the data showed that there was no significant statistical relationship between Cryptosporidium infection of the calves and variables of age, breed, type of water consumption, clinical signs of diarrhoea, and sampling location, while parasite infection had a significant relationship with calf gender so that all Cryptosporidium positive samples were from male calves (p ≤ 0.05).

CONCLUSIONS

Considering the presence of Cryptosporidium infection, the region's traditional grazing system, and the close relationship between livestock and humans, there is a possibility of human infection in the region. So preventive measures such as periodic animal testing with sensitive and accurate diagnostic techniques including PCR, pharmacological treatment of livestock, water hygiene and the use of industrial grazing instead of traditional grazing to improve the hygiene of food consumed by livestock are recommended.

Cryptosporidiosis: From Prevention to Treatment, a Narrative Review

Cryptosporidiosis is a water- and food-borne zoonotic disease caused by the protozoon parasite of the genus Cryptosporidium. C. hominis and C. parvum are the main two species causing infections in humans and animals. The disease can be transmitted by the fecal-oral route as well as the respiratory route. The infective stage (sporulated oocysts) is resistant to different disinfectants including chlorine. Currently, no effective therapeutic drugs or vaccines are available to treat and control Cryptosporidium infection. To prevent cryptosporidiosis in humans and animals, we need to understand better how the disease is spread and transmitted, and how to interrupt its transmission cycle. This review focuses on understanding cryptosporidiosis, including its infective stage, pathogenesis, life cycle, genomics, epidemiology, previous outbreaks, source of the infection, transmission dynamics, host spectrum, risk factors and high-risk groups, the disease in animals and humans, diagnosis, treatment and control, and the prospect of an effective anti-Cryptosporidium vaccine. It also focuses on the role of the One Health approach in managing cryptosporidiosis at the animal-human-environmental interface. The summarized data in this review will help to tackle future Cryptosporidium infections in humans and animals and reduce the disease occurrence.

Does each bead count? A reduced-cost approach for recovering waterborne protozoa from challenge water using immunomagnetic separation

Giardia duodenalis and Cryptosporidium spp. are two of the most prominent aetiological agents of waterborne diseases. Therefore, efficient and affordable methodologies for identifying and quantifying these parasites in water are increasingly necessary. USEPA Method 1623.1 is a widely used and validated protocol for detecting these parasites in water samples. It consists of a concentration step, followed by parasite purification and visualization by immunofluorescence microscopy. Although efficient, this method has a high cost particularly due to the immunomagnetic separation (IMS) step, which is most needed with complex and highly contaminated samples. Based on this, the present study aimed to determine whether it is possible to maintain the efficiency of Method 1623.1 while reducing the amount of beads per reaction, using as a matrix the challenge water recommended by the World Health Organization. As for Giardia cysts, a satisfactory recovery efficiency (RE) was obtained using 50% less IMS beads. This was evaluated both with a commercial cyst suspension (56.1% recovery) and an analytical quality assessment (47.5% recovery). Although RE rates obtained for Cryptosporidium parvum did not meet Method 1623.1 criteria in any of the experimental conditions tested, results presented in this paper indicated the relevance of the described adaptations, even in challenge water.

Meat-borne parasites in the Arab world: a review in a One Health perspective

Meat-borne parasitic zoonoses are generally not well-monitored, and so understanding extent and overall prevalence is problematic. Without sufficient attention, their prevalence can become unexpectedly and unacceptably high. This review sheds light on meat-borne parasites in the Arab world, which includes all the Arab countries situated in the continents of Asia and Africa, with more than 400 million inhabitants distributed in 22 countries. Meat-borne parasites can be divided into two main categories-helminths and protozoa. The main helminths included in this review are Taenia saginata, Taenia solium, Taenia asiatica, Echinococcus spp., Fasciola spp., and Trichinella spiralis, while the meat-borne protozoan parasites are Toxoplasma gondii, Cryptosporidium spp., and Sarcocystis spp. In addition, Linguatula serrata, which belongs to the class Pentastomida, was included. Among those, the genus Taenia is the most frequently reported in the Arab world, particularly T. saginata. Many parasitic infections that are mainly transmitted through pork, although widespread in many parts of the world, are rare in the Arab countries, primarily due to religious proscriptions. The majority of the publications concerning meat-borne parasites were from Egypt, which contains the largest population in the Arab world and the highest population density, in addition to various economic, social, and environmental reasons.

Importance of colostrum IgG antibodies level for prevention of infection with Cryptosporidium parvum in neonatal dairy calves

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C. parvum is commonly associated with neonatal calf diarrhea in dairy cattle farms.

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Anti-C. parvum antibodies transferred through colostrum protect the newborn calves.

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Colostrum management is an important preventive measure against cryptosporidiosis.

Cryptosporidiosis is one of the most common zoonosis worldwide, causing intestinal infection to both humans and livestock. The purpose of this study was to assess whether the level of anti-C. parvum IgG antibodies transferred through colostrum from dams to newborn calves impacts the susceptibility to cryptosporidiosis. A number of 50 dams and their healthy newborns were included in the study. Colostrum samples were collected within 12 h after birth and anti-C. parvum IgG antibody levels were determined by single radial immunodiffusion. The health condition of the newborns was daily monitored, and fecal samples were collected at first diarrheic episode of a calf. In all dams, the anti-C. parvum IgG antibody concentration in colostrum varied between 570 and 4070 mg/dl; in dams who gave birth to calves with diarrhea and were C. parvum-positive, the antibody concentration in colostrum varied between 680 and 3680 mg/dl (Table 1). The point-biserial correlation showed a negative correlation between the levels of anti-C. parvum antibodies and manifestation of clinical cryptosporidiosis (r=-0.425). Our findings highlight the importance of IgG levels in colostrum received by neonatal calves during their first day of life for prevention of C. parvum infection.

Molecular Prevalence of Cryptosporidium spp. in Breeding Kennel Dogs

Cryptosporidium is a common intestinal protozoan that can lead to diarrhea in humans and dogs. The predominant species of infection are C. hominis and C. parvum in humans, and C. canis in dogs. However, C. canis can infect immunocompromised humans. Considering the close contact with humans, dogs have the potential to be reservoirs for human cryptosporidiosis. Breeding kennels are the major supply source of puppies for pet shops. The present study is to determine the molecular prevalence and characteristics of Cryptosporidium spp. found in breeding kennel dogs. A total of 314 fecal samples were collected from young and adult dogs kept in 5 breeding kennels. A polymerase chain reaction targeting the small subunit rRNA gene was employed for the detection of Cryptosporidium spp. To determine the species, the DNA sequences were compared to GenBank data. Overall, 21.0% of the fecal samples were positive for Cryptosporidium spp. infection. Cryptosporidium spp. was detected in all 5 facilities. A sequencing analysis demonstrated that all isolates shared 99–100% similarity with C. canis. The results suggest that Cryptosporidium spp. infection is present at a high-level in breeding kennel dogs. However, because dominant species in this survey was C. canis, the importance of breeding kennel dogs as reservoirs for Cryptosporidium spp. transmission to humans is likely to be low in Japan.

PREVALENCE OF CRYPTOSPORIDIUM SPP. AMONG ASYMPTOMATIC HEALTHY EXPATRIATE WORKERS IN SHARJAH, UNITED ARAB EMIRATES

Background:

Epidemiological data on Cryptosporidium infections in the United Arab Emirates (UAE) is scarce. Therefore, the main objective of this study was to determine the prevalence of Cryptosporidium species among a community of expatriates in Sharjah, UAE working in different sectors, including the food industry, house maids and other domestic occupations.

Materials and Methods:

One hundred and thirty four stool samples were collected from asymptomatic individuals presenting to the Sharjah Municipality Public Health Clinic (SMPHC) for screening of intestinal parasites for work permission purposes between 2009 and 2011. Demographic information such as age, sex, and country of origin was collected. Genomic DNA extracted from the stool samples were tested for Cryptosporidium species using real-time PCR (qPCR).

Results:

Twenty-six individuals (19.4%) were positive for Cryptosporidium sp. by PCR. The infection rate was found to be highest in Afghan nationals (33%; 3/9) compared with the rest of the study population; yet, no significant association existed between nationality and infection rate. Moreover, no association was observed between infection rate and gender (χ² = 2.439; P = 0.118), nor infection rate and age group (χ² = 1.219; P = 0.544).

Conclusion:

Infection by Cryptosporidium sp. was common in the study group, and further studies are needed within the native Emirati population before any conclusions can be made about foreigners potentially transmitting the parasite. Furthermore, data provided in this study could help determine its public and veterinary significance particularly in outbreaks in the country.

Molecular Analysis of the Enteric Protozoa Associated with Acute Diarrhea in Hospitalized Children

Pediatric diarrhea is a common cause of death among children under 5 years of age. In the current study, we investigated the frequency of intestinal parasites among 580 pediatric patients with chronic diarrhea. Parasitic protozoa (all species combined) were detected by molecular tools in 22.9% of the children and the most common parasite was Cryptosporidium spp. (15.1%). Blastocystis hominis was detected in 4.7%, Dientamoeba fragilis in 4%, Giardia duodenalis in 1.7%, and Entamoeba histolytica in 0.17%. Protozoan infections were observed among all regional groups, but prevalence was highest among Qatari subjects and during the winter season. Typing of Cryptosporidium spp. revealed a predominance of Cryptosporidium parvum in 92% of cases with mostly the IIdA20G1 subtype. Subtypes IIdA19G2, IIdA18G2, IIdA18G1, IIdA17G1, IIdA16G1, and IIdA14G1 were also detected. For Cryptosporidium hominis, IbA10G2 and IbA9G3 subtypes were identified. This study provides supplementary information for implementing prevention and control strategies to reduce the burden of these pediatric protozoan infections. Further analyses are required to better understand the local epidemiology and transmission of Cryptosporidium spp. in Qatar.

Prevalence of Cryptosporidium infection and related risk factors in children in Awo and Iragberi, Nigeria

Cryptosporidiosis is an important major cause of enteric parasitic infection among infants and children in developing countries with morbidity and mortality especially among immune- deficient individuals. Poor performance of traditional diagnostic procedures in many laboratories can resulted in misdiagnosis and mistreatment, thereby probably promotes drug resistance. This study was carried out to determine the prevalence of enteric Cryptosporidiosis in children attending primary health centers in Egbedore local government area of Osun State, Nigeria between July-December 2014. Informed consent questionnaires were administered to collect demographic data and a total of 180 stool samples were collected to detect Cryptosporidium oocyst and antigen using Modified Ziehl Neelsen (MZN) and enzyme-linked immunosorbent assay (ELISA) methods, respectively. Prevalence of 38.3% (72/188) and 46.8% (88/188) was obtained by MZN and ELISA, respectively. The prevalence was higher in children between 1-2.5 years and lower in children above 2.5 years. There was significant association between diarrhea and prevalence rate (P = 0.006; P < 0.05) for ELISA and ZN, respectively. The present results show that cryptosporidiosis poses a public health challenge in children found in Egbedore. This study also warrants intensified effort towards awareness of the disease and proper diagnosis is needed most especially among immunocompromised individuals.

Cryptosporidium in children with diarrhea: a hospital-based Study

OBJECTIVE

To estimate the proportionate contribution of Cryptosporidium to diarrhea in under-five children, and to study its demographic and clinical associates.

METHODS

We collected stool specimens from children (age <5 yrs) suffering from diarrhea. The specimen was examined on the same day by Kinyouns acid-fast staining for the presence of Cryptosporidium parvum oocyst; rest of the sample was preserved for later cryptosporidium antigen detection by commercially available ELISA kit.

RESULTS

Out of 175 children with diarrhea, 48 (27.4%) had Cryptosporidium antigen in their stool specimen. Gender, history of contact with domestic animal, hydration status, breastfeeding and nutritional status were not significantly associated with cryptosporidium infection in children with diarrhea.

CONCLUSION

Cryptosporidium is present in a significant portion of children suffering from diarrhea in our setting. Antigen detection has much higher isolation rate than acid-fast staining.

Cryptosporidiosis: An under-recognized public health problem

Cryptosporidium spp. is under recognized as an important pathogen causing diarrhea in children and HIV-infected individuals with associated high morbidity and mortality. In endemic areas, most symptomatic infections are in childhood and in immunocompromised adults. The immune status of the host plays a critical role in determining the severity of cryptosporidiosis. Infection is self-limited in immunocompetent hosts, but can be severe and persistent in the immunocompromised such as AIDS patients or malnourished children. Cryptosporidiosis in developing countries is a major cause of acute and persistent diarrhea in children and is associated with subsequent impairment in growth, physical fitness, and cognitive function. Despite recognition of the importance of immune status, the correlates of protective immunity in cryptosporidiosis in humans are poorly understood, and treatment modalities are limited.

Prevalence of Cryptosporidium-like infection in one-humped camels (Camelus dromedarius) of northwestern Iran

Cryptosporidium is a ubiquitous enteropathogen protozoan infection affecting livestock worldwide. The present study was carried out to determine the prevalence of Cryptosporidium infection in different age groups of dromedary camels in northwestern Iran from November 2009 to July 2010. A total number of 170 fecal samples were collected and examined using modified Ziehl-Neelsen (MZN) staining under light microscope. Examination of stained fecal smears revealed that 17 camels (10%) were positive for Cryptosporidium-like. The prevalence of Cryptosporidium-like was significantly higher in camel calves (< 1 years old) (20%) than other age groups, in which the diarrhoeic calves had the prevalence of 16%. In adult camels the prevalence was 6.5%. There was no significant difference in the prevalence of Cryptosporidium-like between male and female camels. It is concluded that Cryptosporidium infection is a problem in camel husbandry and could be of public health concern in the region.

Parasites and malignancies, a review, with emphasis on digestive cancer induced by Cryptosporidium parvum (Alveolata: Apicomplexa)

The International Agency for Research on Cancer (IARC) identifies ten infectious agents (viruses, bacteria, parasites) able to induce cancer disease in humans. Among parasites, a carcinogenic role is currently recognized to the digenetic trematodes Schistosoma haematobium, leading to bladder cancer, and to Clonorchis sinensis or Opisthorchis viverrini, which cause cholangiocarcinoma. Furthermore, several reports suspected the potential association of other parasitic infections (due to Protozoan or Metazoan parasites) with the development of neoplastic changes in the host tissues. The present work shortly reviewed available data on the involvement of parasites in neoplastic processes in humans or animals, and especially focused on the carcinogenic power of Cryptosporidium parvum infection. On the whole, infection seems to play a crucial role in the etiology of cancer.

CONTROLE DE QUALIDADE ANALÍTICA DOS MÉTODOS UTILIZADOS PARA A DETECÇÃO DE PROTOZOÁRIOS PATOGÊNICOS EM AMOSTRAS DE ÁGUA

RESUMO As espécies de protozoários patogênicos de veiculação hídrica Giardia spp. e Cryptosporidium spp. foram responsáveis por cerca 90% dos surtos de gastroenterite ocorridos nos últimos 25 anos, em vários países. Critérios de avaliação das etapas referentes à detecção destes agentes em amostras de água, tais como: precisão inicial, inoculação nas amostras em água bruta e, diagnóstico e localização de erros estão abordados neste trabalho. Estes critérios devem ser correntemente aplicados e constantemente avaliados pelos laboratórios, a fim de assegurar a confiabilidade dos resultados obtidos durante um monitoramento e, assim, fornecer subsídios para uma avaliação do risco de surtos.

Development of Cryptosporidium parvum-induced gastrointestinal neoplasia in severe combined immunodeficiency (SCID) mice: severity of lesions is correlated with infection intensity

We reported previously that Cryptosporidium parvum was able to induce intestinal tumors in severe combined immunodeficiency (SCID) mice treated with corticoids. To further characterize this Cryptosporidium-induced cell transformation, SCID mice treated with dexamethasone were challenged with C. parvum oocysts, and euthanatized sequentially after infection for histologic examination. Ki-67 was used as a marker of cellular proliferation. Our previous results were confirmed, and it was also found that mice receiving higher inocula (10(6)-10(7)) experienced more severe neoplastic development. Additionally, neoplastic changes were observed not only in the caecum but also in the stomach and duodenum of some animals. Interestingly, SCID mice (6/6) inoculated with 10(5)-10(7) oocysts showed high grade intraepithelial neoplasia or adenomas with high grade dysplasia in the caecum after Day 46 post-infection (PI). Immunohistochemistry for Ki-67 staining indicated the neoplastic process associated to cryptosporidiosis, and evidenced the first immunohistochemical alterations at early stages of the process, even at 3 weeks PI.

Sensitivity analysis of the pressure-based direct integrity test for membranes used in drinking water treatment

We conducted a sensitivity analysis of the commonly employed pressure-based direct integrity test (DIT), the most sensitive test for defects in low-pressure hollow fiber (LPHF) microfiltration and ultrafiltration systems used in drinking water treatment. Incorporating uncertainty to assess the practice of DIT, we find the resolution in some tests may be insufficient to verify the presence of a barrier to oocysts of Cryptosporidium. Applying distributions and boundaries derived from literature and practice, we solved for the defect size resolution (DSR) using Monte Carlo and Probability Bounds Analysis for five commercial membrane designs. Surface tension was modeled using annual temperature profiles from three rivers. Contact angle measurement error and variability were derived from literature, respectively, as a standard deviation of 5.7 degrees and +/- 9.6 degrees median change due to natural organic matter (NOM) fouling. These measures of contact angle uncertainty and variability were combined in a normal distribution with the discrete values currently applied. Additionally we considered model uncertainty, applying the maximum bubble pressure method, an established method of surface tension measurement in liquids in which the maximum air pressure in a submerged capillary is developed after the contact angle becomes zero prior to bubble formation. Where the DSR exceeds 3 microm the test design is not compliant with applicable drinking water regulations. Implications include uncertain and variable log-removal values (LRV) as determined by DIT due to the possible emergence of defects large enough to allow oocysts to pass without detection by the DIT. Specifically, we found the DSR may exceed 3 microm and may be as large as 8 microm. With the variable contact angle model, all lower bound possibilities are compliant, whereas the upper bound is over 80% noncompliant for three of five commercial designs. Using the Maximum Bubble Pressure Method, the lower bounds in three designs start to exceed 3 microm for between 50 and 100% of the produced water, whereas the upper bounds of the DSR completely exceed 3 microm for four of five commercial designs examined.

Array lead zirconate titanate/glass piezoelectric microcantilevers for real-time detection of Bacillus anthracis with 10 spores/ml sensitivity and 1/1000 selectivity in bacterial mixtures

An array of three identical piezoelectric microcantilever sensors (PEMSs) consisting of a lead zirconate titanate layer bonded to a glass layer was fabricated and examined for simultaneous, in situ, real-time, all-electrical detection of Bacillus anthracis (BA) spores in an aqueous suspension using the first longitudinal extension mode of resonance. With anti-BA antibody immobilized on the sensor surfaces all three PEMS exhibited identical BA detection resonance frequency shifts at all tested concentrations, 10-10(7) spores/ml with a standard deviation of less than 10%. The detection concentration limit of 10 spores/ml was about two orders of magnitude lower than would be permitted by flexural peaks. In blinded-sample testing, the array PEMS detected BA in three samples containing BA: (1) 3.3x10(3) spores/ml, (2) a mixture of 3.3x10(3) spores/ml and 3.3x10(5) S. aureus (SA) and P. aeruginosa (PA) per ml, and (3) a mixture of 3.3x10(3) spores/ml with 3.3x10(6) SA+PA/ml. There was no response to a sample containing only 3.3x10(6) SA+PA/ml. These results illustrate the sensitivity, specificity, reusability, and reliability of array PEMS for in situ, real-time detection of BA spores.

Molecular characterization of Cryptosporidium spp. from HIV infected patients from an urban area of Brazil

Cryptosporidium spp. are important cause of enteric disease in humans, but may also infect animals. This study describes the relative frequency of several Cryptosporidium species found in human specimens from HIV infected patients in the São Paulo municipality obtained from January to July 2007. Sequence analysis of the products of nested-PCR based on small subunit rRNA and Cryptosporidium oocyst wall protein coding genes revealed 17 (63.0%) isolates of C. hominis, four (14.8%) C. parvum, five (18.5%) C. felis and one (3.7%) C. canis. These findings suggest that, in urban environments of Brazil, the cat adapted C. felis may play a potential role in the zoonotic transmission of cryptosporidiosis whereas the anthroponotic transmission of cryptosporidiosis caused by C. hominis seems to predominate.

Simultaneous detection of serum immunoglobulin G antibodies to Cryptosporidium parvum by multiplex microbead immunoassay using 3 recognized specific recombinant C. parvum antigens

Cryptosporidiosis is a significant diarrheal disease in both humans and other mammals worldwide. In the present study, we established and validated a multiplex microbead immunoassay (MIA) for surveillance of Cryptosporidium parvum infections. In the multiplex MIA, 3 specific recombinant proteins, CP23, SA35, and SA40, were used as the capture antigens simultaneously. The antibody directed against CP23 is an index of historic infection, and those against SA35 and SA40 are indices of recent infection. The multiplex MIA yielded essentially identical results with that of monoplex MIA using these 3 recombinant proteins, and the reproducibility of the multiplex MIA results was high when standardized with a calibration curve. With multiplex MIA, we detected that the pediatric population showed a higher percentage of recent infections (seropositive rates of antibodies directed against CP23, SA35, and SA40 were 6.28%, 23.19%, and 22.71%, respectively, n = 207), whereas the adult population showed a higher percentage of historic infections (seropositive rates of antibodies directed against CP23, SA35, and SA40 were 24.40%, 11.48%, and 16.75%, respectively, n = 209).

Host and environmental risk factors associated with Cryptosporidium scophthalmi (Apicomplexa) infection in cultured turbot, Psetta maxima (L.) (Pisces, Teleostei)

An epidemiological cohort study of Cryptosporidium scophthalmi in cultured turbot Psetta maxima L. of Northwestern Spain was conducted along a four-year period. Four different ongrowing cohorts were monitored monthly from introduction into the ongrowing tanks (10-50 g) until reaching market size (400-1400 g). The association of host and environmental factors with five categories of parasite abundance was assessed using a multivariable regression framework. Epidemiological factors assessed here were water temperature, weight, length, month of collection, season, age, origin, condition factor, water filtration, and status to the myxozoan Enteromyxum scophthalmi infection. E. scophthalmi was included into the analysis because it targets the same organ than C. scophthalmi and it was prevalent in the studied population. The multivariable analysis demonstrated the statistically significant association between several factors and parasite abundance. C. scophthalmi abundance was associated (P<0.05) with age, condition factor, season, and status to E. scophthalmi infection. Young animals, with poor condition factor, during spring or summer, and not infected with the myxozoan were most likely to be highly infected by C. scophthalmi. Inclusion of these four variables significantly (P<0.05) improved the model, compared to the model that did not include any of these epidemiological factors. Increasing levels of C. scophthalmi abundance were associated (P<0.01) with higher severity of C. scophthalmi-compatible lesions. The frequency of distribution of C. scophthalmi abundance was clearly right-skewed and fitted a negative binomial distribution, whereas the intensity of infection fitted a Poisson distribution. The quantification of the variance-to-mean ratio stratified by age demonstrated overdispersion for 8-16 months old fish, although this bivariate association is likely affected by several other factors, as suggested by the results of the multivariable analysis. The negative relation between C. scophthalmi abundance and status to E. scophthalmi infection suggests differences in the transmission, onset, and course of both infections. The coarse filtration used in some cohorts did not significantly affect the levels of infection. C. scophthalmi was probably introduced into the ongrowing tanks mainly with carrier fish, though the involvement of infective oocysts from the water supply cannot be disregarded. Infection prevalence and mean intensity decreased with fish age and a seasonal distribution was found. Results presented here will help to understand the epidemiology of C. scophthalmi in turbot, to estimate the expected levels of infection associated with presence or absence of epidemiological factors, and to quantify the impact that the disease may have on susceptible turbot populations. The multivariable model used here is more powerful than the visual inspection of graphics for exploring associations in cooperative processes and can be easily extended to the assessment of epidemiological associations in other population and parasitic diseases.

Genetic polymorphism in Cryptosporidium species: an update

Cryptosporidia, widely distributed protozoan parasites of vertebrates, have attracted increasing interest due to several serious waterborne outbreaks, the life-threatening nature of infection in immunocompromised patients, and the realization of economic losses caused by these pathogens in livestock. Genetic polymorphism within Cryptosporidium species is being detected at a continuously growing rate, owing to the widespread use of modern molecular techniques. The aim of this paper is to review the current status of taxonomy, genotyping and molecular phylogeny of Cryptosporidium species. To this date, 20 Cryptosporidium species have been recognized. Two named species of Cryptosporidium have been found in fish, 1 in amphibians, 2 in reptiles, 3 in birds, and 12 in mammals. Nearly 61 Cryptosporidium genotypes with uncertain species status have been found based on SSUrRNA sequences. The gp-60 gene showed a high degree of sequence polymorphism among isolates of Cryptosporidium species and several subtype groups and subgenotypes have been identified, of which the Cryptosporidium parvum IIa and IId subtype groups were found to be zoonotic. This review describes considerable progress in the identification, genetic characterization, and strain differentiation of Cryptosporidium over the last 20 years. All the valid species, genotypes and zoonotic subtypes of Cryptosporidium reported in the international literature are included in this paper with respect to the taxonomy, epidemiology, transmission and morphologic-genetic information for each species.

Detection and surveillance of waterborne protozoan parasites

The majority of the world's population still live without access to healthy water and the contamination of drinking water with protozoan pathogens poses a serious threat to millions of people in the developing world. Even in the developed world periodic outbreaks of diarrhoeal diseases are caused by the protozoan parasites Cryptosporidium sp., Giardia duodenalis and Entamoeba histolytica. Thus, surveillance of drinking water is imperative to minimize such contaminations and ensure continuous supplies of healthy water world-wide. This article reviews the progress in technology for detection and surveillance of these important waterborne parasites.

Genotypic identification of Cryptosporidium spp. isolated from HIV-infected patients and immunocompetent children of São Paulo, Brazil

Cryptosporidium isolates identified in fourteen stool samples, collected from five HIV-infected patients and nine immunocompetent children, living in the State of São Paulo, Brazil, were submitted to a molecular analysis using a nested PCR followed of restriction fragment length polymorphism (RFLP), for genetic characterization. The analysis was based on digestion with RsaI restriction enzyme of a DNA fragment amplified from the Cryptosporidium oocyst wall protein (COWP) gene. Based on this analysis, four samples were identified as Cryptosporidium parvum, eight as Cryptosporidium hominis and two presented a profile that corresponded to Cryptosporidium meleagridis when compared to the standards used in the analysis. The use of molecular methods can be helpful to identify source of infections and risk factors related to Cryptosporidium infection in our communities.

Label-free flow-enhanced specific detection of Bacillus anthracis using a piezoelectric microcantilever sensor

Differentiation between species of similar biological structure is of critical importance in biosensing applications. Here, we report specific detection of Bacillus anthracis (BA) spores from that of close relatives, such as B. thuringiensis (BT), B. cereus (BC), and B. subtilis (BS) by varying the flow speed of the sampling liquid over the surface of a piezoelectric microcantilever sensor (PEMS). Spore binding to the anti-BA spore IgG coated PEMS surface is determined by monitoring the resonance frequency change in the sensor's impedance vs. frequency spectrum. Flow increases the resonance frequency shift at lower flow rates until the impingement force from the flow overcomes the binding strength of the antigen and decreases the resonance frequency shift at higher flow rates. We showed that the change from increasing to decreasing resonance frequency shift occurred at a lower fluid flow speed for BT, BC, and BS spores than for BA spores. This trend reduces the cross reactivity ratio of BC, BS, and BT to the anti-BA spore IgG immobilized PEMS from around 0.4 at low flow velocities to less than 0.05 at 3.8 mm s(-1). This cross reactivity ratio of 0.05 was essentially negligible considering the experimental uncertainty. The use of the same flow that is used for detection to further distinguish the specific binding (BA to anti-BA spore antibody) from nonspecific binding (BT, BC, and BS to anti-BA spore antibody) is unique and has great potential in the detection of general biological species.

Cryptosporidium parvum, a potential cause of colic adenocarcinoma

Background

Cryptosporidiosis represents a major public health problem. This infection has been reported worldwide as a frequent cause of diarrhoea. Particularly, it remains a clinically significant opportunistic infection among immunocompromised patients, causing potentially life-threatening diarrhoea in HIV-infected persons. However, the understanding about different aspects of this infection such as invasion, transmission and pathogenesis is problematic. Additionally, it has been difficult to find suitable animal models for propagation of this parasite. Efforts are needed to develop reproducible animal models allowing both the routine passage of different species and approaching unclear aspects of Cryptosporidium infection, especially in the pathophysiology field.

Results

We developed a model using adult severe combined immunodeficiency (SCID) mice inoculated with Cryptosporidium parvum or Cryptosporidium muris while treated or not with Dexamethasone (Dex) in order to investigate divergences in prepatent period, oocyst shedding or clinical and histopathological manifestations. C. muris-infected mice showed high levels of oocysts excretion, whatever the chemical immunosuppression status. Pre-patent periods were 11 days and 9.7 days in average in Dex treated and untreated mice, respectively. Parasite infection was restricted to the stomach, and had a clear preferential colonization for fundic area in both groups. Among C. parvum-infected mice, Dex-treated SCID mice became chronic shedders with a prepatent period of 6.2 days in average. C. parvum-inoculated mice treated with Dex developed glandular cystic polyps with areas of intraepithelial neoplasia, and also with the presence of intramucosal adenocarcinoma.

Conclusion

For the first time C. parvum is associated with the formation of polyps and adenocarcinoma lesions in the gut of Dex-treated SCID mice. Additionally, we have developed a model to compare chronic muris and parvum cryptosporidiosis using SCID mice treated with corticoids. This reproducible model has facilitated the evaluation of clinical signs, oocyst shedding, location of the infection, pathogenicity, and histopathological changes in the gastrointestinal tract, indicating divergent effects of Dex according to Cryptosporidium species causing infection.

Human waterborne trematode and protozoan infections

Waterborne trematode and protozoan infections inflict considerable morbidity on healthy, i.e., immunocompetent people, and may cause life-threatening diseases among immunocompromised and immunosuppressed populations. These infections are common, easily transmissible, and maintain a worldwide distribution, although waterborne trematode infections remain predominantly confined to the developing countries. Waterborne transmission of trematodes is enhanced by cultural practices of eating raw or inadequately cooked food, socio-economical factors, and wide zoonotic and sylvatic reservoirs of these helminths. Waterborne protozoan infections remain common in both developed and developing countries (although better statistics exist for developed countries), and their transmission is facilitated via contacts with recreational and surface waters, or via consumption of contaminated drinking water. The transmissive stages of human protozoan parasites are small, shed in large numbers in feces of infected people or animals, resistant to environmental stressors while in the environment, and few are (e.g., Cryptosporidium oocysts) able to resist standard disinfection applied to drinking water.

Effectiveness of standard UV depuration at inactivating Cryptosporidium parvum recovered from spiked Pacific oysters (Crassostrea gigas)

When filter-feeding shellfish are consumed raw, because of their ability to concentrate and store waterborne pathogens, they are being increasingly associated with human gastroenteritis and have become recognized as important pathogen vectors. In the shellfish industry, UV depuration procedures are mandatory to reduce pathogen levels prior to human consumption. However, these guidelines are based around more susceptible fecal coliforms and Salmonella spp. and do not consider Cryptosporidium spp., which have significant resistance to environmental stresses. Thus, there is an urgent need to evaluate the efficiency of standard UV depuration against the survival of Cryptosporidium recovered from shellfish. Our study found that in industrial-scale shellfish depuration treatment tanks, standard UV treatment resulted in a 13-fold inactivation of recovered, viable C. parvum oocysts from spiked (1 x 10(6) oocysts liter (-1)) Pacific oysters. Depuration at half power also significantly reduced (P < 0.05; ninefold) the number of viable oocysts recovered from oysters. While UV treatment resulted in significant reductions of recovered viable oocysts, low numbers of viable oocysts were still recovered from oysters after depuration, making their consumption when raw a public health risk. Our study highlights the need for increased periodic monitoring programs for shellfish harvesting sites, improved depuration procedures, and revised microbial quality control parameters, including Cryptosporidium assessment, to minimize the risk of cryptosporidiosis.

An evaluation of primers amplifying DNA targets for the detection of Cryptosporidium spp. using C. parvum HNJ-1 Japanese isolate in water samples

The performance of polymerase chain reaction (PCR) procedures for the detection of Cryptosporidium parvum HNJ-1 strain (genotype II) oocysts purified from mice using published protocols was evaluated. Oocysts were concentrated from fecal samples of infected severe combined immunodeficiency (SCID) mice by sucrose flotation and were then purified by immunomagnetic separation method. The genotype of C. parvum was established as type II by restriction fragment length polymorphism (RFLP) analysis. Water samples were spiked with different numbers of oocysts, determined by limiting dilution. Genomic DNA was extracted and used for PCR assays targeting various Cryptosporidium species genes (Beta-Tubulin, COWP, 70 kDa HSP, SSU rRNA, ITS1, TRAP-C1 and TRAP-C2 gene). DNA from oocyst numbers of more than 1 x 10(4) was detected using each of the primers. However, when using lower oocyst numbers, the tools based on 9 of the 16 different primer assays gave sufficient results. Assays using the remaining seven primers gave less than satisfactory results. A new primer set, named VKSS-F1/2 and VKSS-R1/2, that target the 18 SSU rRNA gene of C. parvum was constructed and applied. The VKSS-F1/2 and VKSS-R1/2 assays amplified DNA isolated from spiked samples in 206 of 211 trials (97.6%). This illustrates the difficulty of detecting low numbers of Cryptosporidium spp. oocysts by molecular methods when working with environmental samples.

Discrimination of Cryptosporidium species by denaturing gradient gel electrophoresis

Denaturing gradient gel electrophoresis (DGGE) was used for the discrimination of three species and one genotype of the protozoan parasite Cryptosporidium: the C. parvum, C. andersoni, C. muris, and C. muris Japanese field mouse genotype. A set of primers specific for the 18S rRNA gene of Cryptosporidium was used in the DGGE; consequently, the four strains showed different banding patterns. This is a potentially convenient and precise method for the discrimination of Cryptosporidium spp.

In situ detection of Bacillus anthracis spores using fully submersible, self-exciting, self-sensing PMN-PT/Sn piezoelectric microcantilevers

In this study, we have demonstrated in situ, all-electrical detection of Bacillus anthracis (BA) spores using lead magnesium niobate-lead titanate/tin (PMN-PT/Sn) piezoelectric microcantilever sensors (PEMS) fabricated from PMN-PT freestanding films and electrically insulated with methyltrimethoxysilane (MTMS) coatings on the tin surface. Antibody specific to BA spore surface antigen was immobilized on the platinum electrode of the PMN-PT layer. In phosphate-buffered saline (PBS) solution, the PMN-PT/Sn PEMS exhibited quality (Q) values ranging from 50 to 75. The detection was carried out in a closed-loop flow cell with a liquid volume of 0.8 ml and a flow rate of 1 ml min(-1). It was shown that one sensor, "PEMS-A" (500 microm long, 800 microm wide, with a 22 microm thick PMN-PT layer, a 20 microm thick tin layer and a 1 +/- 0.5 x 10(-12) g Hz(-1) mass detection sensitivity) exhibited resonance frequency shifts of 2100 +/- 200, 1100 +/- 100 and 700 +/- 100 Hz at concentrations of 20,000, 2000, and 200 spores ml(-1) or 16,000, 1600, and 160 total spores, respectively. Additionally, "PEMS-B" (350 microm long, 800 microm wide, with an 8 microm thick PMN-PT layer, a 6 microm thick tin layer and a 2 +/- 1 x 10(-13) g Hz(-1) mass detection sensitivity) exhibited resonance frequency shifts of 2400 +/- 200, 1500 +/- 200, 500 +/- 150 and 200 +/- 100 Hz at concentrations of 20,000, 2000, 100, and 45 spores ml(-1) or 16,000, 1600, 80, and 36 total spores, respectively.

Molecular characterization of Cryptosporidium isolates from humans and animals in Iran

Isolates of Cryptosporidium spp. from human and animal hosts in Iran were characterized on the basis of both the 18S rRNA gene and the Laxer locus. Three Cryptosporidium species, C. hominis, C. parvum, and C. meleagridis, were recognized, and zoonotically transmitted C. parvum was the predominant species found in humans.

Proteomics analysis and protein expression during sporozoite excystation of Cryptosporidium parvum (Coccidia, Apicomplexa)

Cryptosporidiosis, caused by coccidian parasites of the genus Cryptosporidium, is a major cause of human gastrointestinal infections and poses a significant health risk especially to immunocompromised patients. Despite intensive efforts for more than 20 years, there is currently no effective drug treatment against these protozoa. This study examined the zoonotic species Cryptosporidium parvum at two important stages of its life cycle: the non-excysted (transmissive) and excysted (infective) forms. To increase our understanding of the molecular basis of sporozoite excystation, LC-MS/MS coupling with a stable isotope N-terminal labeling strategy using iTRAQ reagents was used on soluble fractions of both non-excysted and excysted sporozoites, i.e. sporozoites both inside and outside oocysts were examined. Sporozoites are the infective stage that penetrates small intestinal enterocytes. Also to increase our knowledge of the C. parvum proteome, shotgun sequencing was performed on insoluble fractions from both non-excysted and excysted sporozoites. In total 303 C. parvum proteins were identified, 56 of which, hitherto described as being only hypothetical proteins, are expressed in both excysted and non-excysted sporozoites. Importantly we demonstrated that the expression of 26 proteins increases significantly during excystation. These excystation-induced proteins included ribosomal proteins, metabolic enzymes, and heat shock proteins. Interestingly three Apicomplexa-specific proteins and five Cryptosporidium-specific proteins augmented in excysted invasive sporozoites. These eight proteins represent promising targets for developing vaccines or chemotherapies that could block parasite entry into host cells.