Cryptosporidium Parvum Oocysts Research Articles

Inactivation and surface interactions of MS-2 bacteriophage in a TiO 2 photoelectrocatalytic reactor

Inactivation of MS-2 bacteriophage in a TiO 2 photoelectrocatalytic system was evaluated, wherein TiO 2 particles were coated onto an indium tin oxide (ITO) electrode and an electrical potential was applied under black light blue (BLB) irradiation. MS-2 phage inactivation was greatly enhanced by anodic potential, whereas cathodic potential completely inhibited inactivation. Experiments performed with radical scavengers showed that inactivation was primarily caused by hydroxyl radicals, both in the bulk phase and on the TiO 2 surface. Application of positive potential to the electrode was found to result in two distinct beneficial effects: (i) electrostatic attraction between the negatively charged viral capsid and catalyst surface, causing improved usage of surface-bound hydroxyl radical, in comparison to conventional TiO 2 photocatalytic disinfection; and (ii) higher reactive oxygen species production. Results also suggest that inactivation of various microorganisms including Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Bacillus subtilis spores and Cryptosporidium parvum oocyst was enhanced via positive potential induction to TiO 2.

Quantitative comparison of different purification and detection methods for Cryptosporidium parvum oocysts

Cryptosporidium parvum ( C. parvum) is the causal agent of cryptosporidiosis in many animals, mainly cattle, and possesses a high zoonotic potential. It occurs worldwide and ubiquitously. Detection of C. parvum is mainly performed directly but purification of the oocysts is useful to increase sensitivity and to obtain oocyst material for further use. The study was designed to compare (a) three different direct diagnostic methods, namely modified Ziehl–Neelsen staining, carbol fuchsin staining and conventional PCR, and (b) three routine oocyst purification methods, in particular flotation with saturated sodium chloride solution, Sheather's sucrose solution and a Percoll ® gradient. During comparison of purification methods, special regard was paid to the ability to separate morphologically intact oocysts from the morphologically degenerated fraction or viable from non-viable oocysts, respectively. Results: (a) Diagnostic methods: Most effective in C. parvum oocysts detection in calf faeces was PCR; carbol fuchsin and modified Ziehl–Neelsen stainings achieved comparable results. (b) Purification methods: Oocyst flotation using sodium chloride solution showed to be superior to Percoll ® gradient centrifugation and sugar flotation in terms of purification quality, recovery efficacy (yield) and reduction of the proportion of degenerated or non-viable oocysts.

Risk factors associated with the occurrence of Cryptosporidium parvum infection in calves

Cryptosporidium parvum oocysts were detected in feces of dairy calves raised in Rio de Janeiro State and the risk factors involved in the infection were determined. A hundred calves aging up to 12-month-old from 13 dairy farms were sampled. Polymerase chain reaction was used to detect the presence of oocysts. The zoonotic C. parvum species was detected in 45% animals. Statistical risk factors analyses revealed an association between infection and animals raised in technical systems such as the use of milking equipment, milking cooler, and water trough(P<0.05)

A Comparison of Fecal Percent Dry Matter and Number of Cryptosporidium parvum Oocysts Shed to Observational Fecal Consistency Scoring in Dairy Calves

Evaluation of dairy calf feces is often used in research and for clinical decision making to assess severity of diarrhea. However, this has not been validated for agreement between dry matter content and observed fecal consistency. Therefore, a comparison of observed fecal consistency score to fecal percent dry matter and Cryptosporidium parvum oocyst shedding was performed to assess the accuracy of observational scoring as a measure of diarrhea and its association with number of oocysts shed. Fecal samples from 20 dairy calves experimentally infected with C. parvum oocysts were collected daily post-infection and scored on a scale from 1 to 4, with 1 being normal feces to 4 being severe diarrhea. An aliquot of each sample was analyzed for percent dry matter and Cryptosporidium oocyst counts by using immunofluorescent microscopy. Fecal consistency scores of 1, 2, 3, and 4 had median percent dry matter of 20.9, 16.3, 9.6, and 5.8, respectively. Using percent dry matter assessed by fecal consistency scoring were significantly different from each other (P < 0.001). A higher fecal consistency score also was associated with a greater number of Cryptosporidium oocysts shed (P < 0 .0001). Scores of 1, 2, 3, and 4 had median oocyst counts of 0, 0, 1.3 × 10⁶, and 2.8 × 10⁶, respectively. These results suggest that observational scoring is a useful proxy to assess diarrhea in dairy calves.

Infectivity of Cryptosporidium parvum oocysts after storage of experimentally contaminated apples.

Irrigation water and washing water have been inferred to be associated with contamination of fresh fruits and vegetables with pathogenic microorganisms infectious for humans. The objective of the present study was to determine whether apples experimentally contaminated with Cryptosporidium oocysts represent a food safety concern. Laser scanning confocal microscopy revealed no morphological changes in Cryptosporidium parvum oocysts attached to apples after 6 weeks of cold storage, suggesting that oocysts might remain viable and possibly infectious during prolonged storage. Mice were fed apple peels from experimentally contaminated apples to determine whether oocysts had remained infectious on apples stored for 4 weeks. All mice developed cryptosporidiosis. To evaluate the strength of oocyst attachment to apples, washing methods that have been reported to be helpful for recovery of oocysts from various foodstuffs were evaluated, except that the intensity of washing was increased in the present study. None of the tested washing methods succeeded in completely removing oocysts from the apple peel. The most efficient removal (37.5%) was achieved by rigorous manual washing in water with a detergent and by agitation in an orbital shaker with Tris-sodium dodecyl sulfate buffer. Glycine and phosphate-buffered saline buffers had no effect on oocyst removal. Scanning electron microscopy revealed that some oocysts were attached in deep natural crevices in the apple exocarp and others were attached to the smooth surface of the peel. Some oocysts were closely associated with what appeared to be an amorphous substance with which they might have been attached to the apple surface.

Health Risk from the Use of Roof-Harvested Rainwater in Southeast Queensland, Australia, as Potable or Nonpotable Water, Determined Using Quantitative Microbial Risk Assessment

A total of 214 rainwater samples from 82 tanks were collected in urban Southeast Queensland (SEQ) in Australia and analyzed for the presence and numbers of zoonotic bacterial and protozoal pathogens using binary PCR and quantitative PCR (qPCR). Quantitative microbial risk assessment (QMRA) analysis was used to quantify the risk of infection associated with the exposure to potential pathogens from roof-harvested rainwater used as potable or nonpotable water. Of the 214 samples tested, 10.7%, 9.8%, 5.6%, and 0.4% were positive for the Salmonella invA, Giardia lamblia β-giardin, Legionella pneumophila mip, and Campylobacter jejuni mapA genes, respectively. Cryptosporidium parvum oocyst wall protein (COWP) could not be detected. The estimated numbers of Salmonella, G. lamblia, and L. pneumophila organisms ranged from 6.5 × 10¹ to 3.8 × 10² cells, 0.6 × 10⁰ to 3.6 × 10⁰ cysts, and 6.0 × 10¹ to 1.7 × 10² cells per 1,000 ml of water, respectively. Six risk scenarios were considered for exposure to Salmonella spp., G. lamblia, and L. pneumophila. For Salmonella spp. and G. lamblia, these scenarios were (i) liquid ingestion due to drinking of rainwater on a daily basis, (ii) accidental liquid ingestion due to hosing twice a week, (iii) aerosol ingestion due to showering on a daily basis, and (iv) aerosol ingestion due to hosing twice a week. For L. pneumophila, these scenarios were (i) aerosol inhalation due to showering on a daily basis and (ii) aerosol inhalation due to hosing twice a week. The risk of infection from Salmonella spp., G. lamblia, and L. pneumophila associated with the use of rainwater for showering and garden hosing was calculated to be well below the threshold value of one extra infection per 10,000 persons per year in urban SEQ. However, the risk of infection from ingesting Salmonella spp. and G. lamblia via drinking exceeded this threshold value and indicated that if undisinfected rainwater is ingested by drinking, then the incidences of the gastrointestinal diseases salmonellosis and giardiasis are expected to range from 9.8 × 10° to 5.4 × 10¹ (with a mean of 1.2 × 10¹ from Monte Carlo analysis) and from 1.0 × 10¹ to 6.5 × 10¹ cases (with a mean of 1.6 × 10¹ from Monte Carlo analysis) per 10,000 persons per year, respectively, in urban SEQ. Since this health risk seems higher than that expected from the reported incidences of gastroenteritis, the assumptions used to estimate these infection risks are critically examined. Nonetheless, it would seem prudent to disinfect rainwater for use as potable water.

Composition and Conformation of Cryptosporidium parvum Oocyst Wall Surface Macromolecules and Their Effect on Adhesion Kinetics of Oocysts on Quartz Surface

We characterized the composition and conformation of Cryptosporidium parvum ( C. parvum ) oocyst wall surface macromolecules and studied their effect on interactions between C. parvum oocyst and quartz surface. Proteinase K and mixed glycosidases were used to modify C. parvum oocyst surface macromolecules. The peptides released by proteinase K and carbohydrates hydrolyzed by mixed glycosidases were respectively analyzed with liquid chromatography/nanoelectrospray ionization tandem mass spectrometry (LC-MS/MS) and phenol-sulfuric acid assay to determine the composition of C. parvum oocyst wall surface macromolecules. Surface potential and polarity of the untreated and proteinase treated C. parvum oocysts revealed information about the conformation of oocyst wall surface macromolecules. The results illustrated that C. parvum oocyst wall is covered by a fluffy layer of glycoproteins. Adhesion kinetics of untreated and proteinase K treated C. parvum oocysts on quartz surface were studied in a radial stagnation point flow cell over a wide range of ionic strength to investigate the effect of C. parvum oocyst wall surface macromolecules on oocysts-quartz interactions. The adhesion rate coefficient of proteinase K treated C. parvum oocysts significantly decreased compared to that of untreated oocysts. This observation indicated that the fluffy layer on C. parvum oocysts wall leads to weaker van der Waals interaction and stronger steric repulsion.

Acute cryptosporidiosis as a cause of sudden recurrence of digestive symptoms in patients with Crohn's disease

Gastrointestinal symptoms occurring in patients with Crohn's disease (CD) can be related to disease activity or to intercurrent infection. Absence of appropriate stool work-up can lead to misdiagnosis and wrong treatment. We report here two cases of acute cryptosporidiosis in patients with CD. This microorganism can trigger IBD flare or cause severe infections in immunocompromised host. Adding specific search for oocysts of Cryptosporidium parvum using the Ziehl–Neelsen technique to the microbiologic work-up from stools in patients with Crohn's disease seeking medical intervention for sudden exacerbation of digestive symptoms seems to be recommended.

Environmental Monitoring of Opportunistic Protozoa in Rivers and Lakes in the Neotropics Based on Yearly Monitoring

The goal of this study was to standardise and use parasitological and molecular techniques in the analysis and seasonal monitoring of opportunistic protozoa in water from fluvial systems for human usage in the municipality of Goiânia, the capital of the state of Goias, in the mid- western region of Brazil. We focused on Cryptosporidium sp. Cyclospora cayetanensis, Isopora belli, Microsporidia and Giardia lamblia. Water samples were collected monthly from February 2006 to January 2007 and concentrated using vacuum filtration and a positively charged membrane. Sev- eral methods were used to identify the different protozoa of interest. To detect coccidia (Cryptosporidium sp., Isospora belli, and Cyclospora cayetanensis), we used a Kinyoun hot- staining method and a modified Ziehl-Neelsen technique. Enteral microsporidia were detected by a hot-chromotrope technique while a MERIFLUOR ® Cryptosporidium kit was used to confirm the presence of Cryptosporidium sp. Finally, we used PCR to detect Cryptosporidium parvum/hominis. Water is of vital importance to living beings; however, due to anthropic action, several microorganisms are disseminated into aquatic environments. Among them are opportunistic protozoa that infect mainly immunodepressed and immuno- suppressed individuals, children and elderly people. These protozoa pose a significant health hazard. Nevertheless, the presence of these pathogens is underestimated because they are not considered during routine environmental monitor- ing. In our study, we were able to observe the presence of Giardia cysts, Cryptosporidium sp. and Cryptosporidium parvum oocysts in the bodies of water monitored in this re- search.

Report of cryptosporidiosis in gray brocket deer (Mazama gouazoupira) in southern Brazil

The aim of this study was to report the occurrence of cryptosporidiosis in gray brocket deer in Brazil. Fecal samples of a male and a female Mazama gouazoupira kept in captivity in southern Brazil were evaluated. Samples collected at 10-d intervals were analyzed by the centrifugal flotation technique and stained by the modified Ziehl–Neelsen and by the Kinyoun staining methods. The first analysis showed a high number of Cryptosporidium parvum oocysts in the feces, associated with the presence of diarrhea in both animals. However, even without drug therapy, the number of oocysts of the protozoan decreased and the feces returned to normal after 10 days. This is the first report of cryptosporidiosis in M. gouazoupira.

Comparison of transport and attachment behaviors of Cryptosporidium parvum oocysts and oocyst-sized microspheres being advected through three minerologically different granular porous media

In order to gain more information about the fate of Cryptosporidium parvum oocysts in tropical volcanic soils, the transport and attachment behaviors of oocysts and oocyst-sized polystyrene microspheres were studied in the presence of two soils. These soils were chosen because of their differing chemical and physical properties, i.e., an organic-rich (43–46% by mass) volcanic ash-derived soil from the island of Hawaii, and a red, iron (22–29% by mass), aluminum (29–45% by mass), and clay-rich (68–76% by mass) volcanic soil from the island of Oahu. A third agricultural soil, an organic- (13% by mass) and quartz-rich (40% by mass) soil from Illinois, was included for reference. In 10-cm long flow-through columns, oocysts and microspheres advecting through the red volcanic soil were almost completely (98% and 99%) immobilized. The modest breakthrough resulted from preferential flow-path structure inadvertently created by soil-particle aggregation during the re-wetting process. Although a high (99%) removal of oocysts and microsphere within the volcanic ash soil occurred initially, further examination revealed that transport was merely retarded because of highly reversible interactions with grain surfaces. Judging from the slope of the substantive and protracted tail of the breakthrough curve for the 1.8-μm microspheres, almost all (>99%) predictably would be recovered within ∼4000 pore volumes. This suggests that once contaminated, the volcanic ash soil could serve as a reservoir for subsequent contamination of groundwater, at least for pathogens of similar size or smaller. Because of the highly reversible nature of organic colloid immobilization in this soil type, C. parvum could contaminate surface water should overland flow during heavy precipitation events pick up near-surface grains to which they are attached. Surprisingly, oocyst and microsphere attachment to the reference soil from Illinois appeared to be at least as sensitive to changes in pH as was observed for the red, metal-oxide rich soil from Oahu. In contrast, colloidal attachment in the organic-rich, volcanic ash soil was relatively insensitive to changes in pH in spite of the high iron content. Given the fundamental differences in transport behavior of oocyst-sized colloids within the two volcanic soils of similar origin, agricultural practices modified to lessen C. parvum contamination of ground or surface water would necessitate taking the individual soil properties into account.

Implications of faecal indicator bacteria for the microbiological assessment of roof-harvested rainwater quality in southeast Queensland, Australia

The study aimed to evaluate the suitability of Escherichia coli, enterococci, and Clostridium perfringens for assessing the microbiological quality of roof-harvested rainwater and assessing whether the concentrations of these faecal indicators can be used to predict the presence or absence of specific zoonotic bacterial or protozoan pathogens. From a total of 100 samples tested, 58%, 83%, and 46% of samples were found to be positive for, respectively, E. coli, enterococci, and Clostridium perfringens spores, as determined by traditional culture-based methods. Additionally, in the samples tested, 7%, 19%, 1%, 8%, 17%, and 15% were PCR positive for Aeromonas hydrophila lip, Campylobacter coli ceuE, Campylobacter jejuni mapA, Legionella pneumophila mip, Salmonella invA, and Giardia lamblia beta-giardin genes, respectively. However, none of the samples was positive for E. coli O157 lipopolysaccharide, verocytotoxin 1, and verocytotoxin 2 and Cryptosporidium parvum oocyst wall protein genes. The presence or absence of these potential pathogens did not correlate with any of the faecal indicator bacterial concentrations as determined by a binary logistic regression model. The roof-harvested rainwater samples tested in this study appeared to be of poor microbiological quality, and no significant correlation was found between the concentration of faecal indicators and pathogenic microorganisms. The use of faecal indicator bacteria raises questions regarding their reliability in assessing the microbiological quality of water and particularly their poor correlation with pathogenic microorganisms. The presence of one or more zoonotic pathogens suggests that the microbiological analysis of water should be performed and that appropriate treatment measures should be undertaken, especially in tanks where the water is used for drinking.

Role of Divalent Cations on Deposition of Cryptosporidium parvum Oocysts on Natural Organic Matter Surfaces

A Radial Stagnation Point Flow (RSPF) system coupled with a microscope was used to study deposition of Cryptosporidium parvum oocysts on quartz and Suwannee River Natural Organic Matter (SRNOM)-coated surfaces in solutions with different Ca(2+) or Mg(2+) concentrations. Both untreated and proteinase K-treated oocysts were used. Deposition of oocysts on a SRNOM surface in Ca(2+) solution was higher than in Mg(2+) solution, even though the energy barriers calculated from Derjaguin-Landau-Verwey-Overbeek (DLVO) theory for Ca(2+) solution were higher than for Mg(2+) solution. On the other hand, the attachment of oocysts on a quartz surface was the same in both Ca(2+) and Mg(2+) solution and in qualitative agreement with the DLVO energy profiles. Inductive coupled plasma (ICP) was employed to measure the free divalent cation concentration in solutions containing oocysts. ICP data showed more Ca(2+) bound to oocyst surface than Mg(2+). Moreover, proteinase K treatment of oocysts led to a significant decrease in deposition rate due to less binding of Ca(2+) to the surface of the treated oocysts as shown by the ICP data. The deposition and ICP results suggested that inner-sphere complexation of Ca(2+) with carboxylate groups on both SRNOM and oocyst surfaces enhanced deposition of oocysts on a SRNOM surface.

A Novel Family of Cyst Proteins with Epidermal Growth Factor Repeats in Giardia lamblia

Background Giardia lamblia parasitizes the human small intestine to cause diarrhea and malabsorption. It undergoes differentiation from a pathogenic trophozoite form into a resistant walled cyst form. Few cyst proteins have been identified to date, including three cyst wall proteins (CWPs) and one High Cysteine Non-variant Cyst protein (HCNCp). They are highly expressed during encystation and are mainly targeted to the cyst wall.Methodology and Principal FindingsTo identify new cyst wall proteins, we searched the G. lamblia genome data base with the sequence of the Cryptosporidium parvum oocyst wall protein as a query and found an Epidermal Growth Factor (EGF)-like Cyst Protein (EGFCP1). Sequence analysis revealed that the EGF-like repeats of the EGFCP1 are similar to those of the tenascin family of extracellular matrix glycoproteins. EGFCP1 and HCNCp have a higher percentage of cysteine than CWPs, but EGFCP1 has no C-terminal transmembrane region found in HCNCp. Like CWPs and HCNCp, the EGFCP1 protein (but not transcript) was expressed at higher levels during encystation and it was localized to encystation-specific vesicles in encysting trophozoites. Like HCNCp, EGFCP1 was localized to the encystation-specific vesicles, cyst wall and cell body of cysts, suggesting that they may share a common trafficking pathway. Interestingly, overexpression of EGFCP1 induced cyst formation and deletion of the signal peptide from EGFCP1 reduced its protein levels and cyst formation, suggesting that EGFCP1 may help mediate cyst wall synthesis. We also found that five other putative EGFCPs have similar expression profiles and similar locations and that the cyst formation was induced upon their overexpression.Conclusions and SignificanceOur results suggest that EGFCPs may function like cyst wall proteins, involved in differentiation of G. lamblia trophozoites into cysts. The results lead to greater understanding of parasite cyst walls and provide valuable information that helps develop ways to interrupt the G. lamblia life cycle.

Detection of Cryptosporidium parvum in buffer and in complex matrix using PEMC sensors at 5 oocysts mL −1

We show for the first time that a piezoelectric-excited millimeter-sized cantilever (PEMC) sensor can detect five Cryptosporidium parvum oocysts in 25% milk in PBS background in a flow format (1 mL min −1). To improve sensitivity, a secondary antibody (murine IgM) was used to confirm the attachment of oocysts to the sensor. PEMC sensor is a resonant-mode cantilever sensor whose resonant frequency decreases when target analyte binds to its surface. The sensor was functionalized with Protein G, and then immobilized with goat polyclonal IgG anti- C. parvum for oocysts detection. In the dynamic range of 50–10,000 oocysts mL −1 the sensor response is characterized by a semi-log relationship between resonant frequency response and C. parvum oocysts concentration. In 25% milk background, binding kinetics was slower and total sensor response was lower (∼45%) than in water-like buffer.

A Method for the Detection of Cryptosporidium parvum Oocysts in Milk Based on Microfiltration and Real-Time Polymerase Chain Reaction

A method for the detection of Cryptosporidium parvum oocysts in milk was developed on the basis of optimizing microfiltration and elution of the material from the filter, and using a previously developed highly sensitive downstream detection by real-time polymerase chain reaction. The method involves heating of milk to 40°C, microfiltration through a membrane microfilter made of a mixture of cellulose acetate and cellulose nitrate (pore size, 3.0 μm), elution of the material from the filter by a solution containing sodium pyrophosphate and Tween 80 in a shaker, rapid DNA extraction using a Chelex-based agent, and single-tube nested real-time PCR. The detection limit of the method is 10 C. parvum oocysts per 100 ml of milk. The developed method may be useful for specific and sensitive control of contamination of milk by C. parvum oocysts.

A New Duplex Reverse Transcription PCR for Simultaneous Detection of Viable Cryptosporidium parvum Oocysts and Giardia duodenalis Cysts

To simultaneously detect viable Cryptosporidium parvum oocysts and Giardia duodenalis cysts for the purpose of reducing time and cost spent. A duplex reverse transcription polymerase chain reaction (RT-PCR) method was newly developed. Using duplex RT-PCR method for the hsp70 gene, viable (oo)cyst concentrations of 10(1) and 10(3) (oo)cysts/100 microL could be detected for C. parvum and G duodenalis, respectively. However, after heat-shock stimulation the expression of hsp70 mRNAs was detectable at 10(0) and 10(1) (oo)cysts/100 microL concentrations of C. parvum and G duodenalis, respectively. Thus, the detection sensitivity was significantly increased when the viable (oo)cysts were exposed to heat shock. This study describes a new duplex RT-PCR method for hsp70 gene to detect the viable (oo)cysts of the C. parvum and G duodenalis with less time consumed and at a lower cost. This newly developed duplex RT-PCR method may be used to detect these parasites not only in aquatic environments but also in clinical samples.

Survival of Cryptosporidium parvum oocysts in the presence of hydrated lime

To investigate the effects of hydrated lime on the survival of Cryptosporidium oocysts, the percentage viability of oocysts was assessed using fluorescent in situ hybridisation. In the absence of lime...

Cryptosporidium parvum Oocyst Shedding in Neonatal Calf Diarrhea Syndrome in Southern Taiwan

The objective of this study was to investigate the relationship between oocyst shedding of Cryptosporidium parvum and diarrhea in dairy calves in southern Taiwan. A total of 48 neonatal calves from six different farms known to be positive for Cryptosporidium parvum bovine genotype were included in this study. Feces were collected from each calf every three days during their first month of life. The consistency of each fecal sample was noted, and the number of oocysts per gram (OPG) of feces was calculated using modified Ziehel-Neelsen stain (MZN). In addition, a commercial antigen-based ELISA diagnostic kits for C, parvum, rotavirus, coronavirus and E. coil F5 was employed to identify the presence of common enteropathogenic agents in 66 randomly selected diarrheic samples. The results were as the following: Oocysts were detected in the feces of 79.2% (38/48) calves within the first month of life. Oocysts were first detected in 60.5% (23/38) of positive calves at 4 days of age (the time of the second sampling). The highest oocyst detection rate (71.1-78.9%) occurred between 7 and 16 days of age (the third to the sixth sampling). The oocystexcretion period varied from the first to the eighth sampling. Of the 66 diarrhea samples analyzed for the enteropathogenic agents, 6 (9.1%) and 1 (1.5%) were found to have the single pathogen C, parvum and 1 E, coil F5, respectively, and 59 (89.4%) were C, parvum association with rotavirus, coronavirus and/or E, coil. The ratio of diarrheic feces was significantly (P＜0.05) higher on the oocyst initial excretion day compared to oocyst pre-excretion period or oocyst-disappearance period. In addition, more calves became diarrhea during the periods of elevated OPGs, and the occurrence of diarrhea rapidly decreased after the oocyst disappearance in the feces. Based on these findings, we concluded that C. parvum infection plays an important pathogenic role in neonatal calf diarrhea syndrome in southern Taiwan.

English

&nbsp; Cryptosporidium&nbsp;species are minute, coccidian protozoan parasites that have been associated with enterocolitis. It has worldwide distribution and has emerged as an important cause of diarrhea, particularly in children less than 5 years of age and in immunocompromised individuals. Waterborne transmission is particularly troublesome because&nbsp;Cryptosporidium parvum&nbsp;oocysts are not eliminated by chlorination or domestic disinfectants. In the present study, single stool specimens from young children (&lt; 5 years) presented with diarrhea were collected in Khyber teaching hospital, Peshawar, Pakistan. Wet mount preparation and modified Ziehl-Neelsen staining were used for identification of oocysts in stool specimens.Cryptosporidium&nbsp;oocysts were found in 18 (9.0%) out of 200 children suffering from diarrhea. Infection was common in children between 1 - 24 months of age and associated with abdominal cramps (50%), vomiting (61.1%) and prolonged duration of diarrhea (88.9%). Direct and indirect contact with animals was present in most ofC. parvum&nbsp;infected children (83.3%). Most of&nbsp;C. parvum&nbsp;infected children were consumers of well water (77.8%).&nbsp;Cryptosporidium&nbsp;spp. are highly infectious causes of diarrheal illness around the world. It is an important cause of diarrhea in children. Clinician and laboratories should be encouraged to include&nbsp;C. parvumdiagnostic techniques while dealing with diarrheal stool samples of young children. &nbsp; Key words:&nbsp;Cryptosporidium parvum,&nbsp;cryptosporidiosis, modified Ziehl-Neelsen staining, immunocompromised, immunocompetent, diarrhea, Pakistan.