This study has been conducted to estimate the occurrence of Cryptosporidium oocysts in water supplies in the Metropolitan area of Seoul, South Korea, for 10 years from 2000 to 2009. Water samples were collected quarterly at 6 intakes in the Han River and its largest stream and 6 conventional Water Treatment Plants (WTPs) serving drinking water for 10 million people of Seoul. Cryptosporidium oocysts were found in 22.5% of intake water samples and arithmetic mean was 0.65 oocysts/10 L (range 0-22 oocysts/10 L). Although the annual mean of oocyst number was as low as 0.04-1.90 oocysts/10 L, 3 peaks in 2004 and 2007 were observed and the pollution level was a little higher in winter. The lowest density was observed at Paldang intake and the pollution level increased at Kuui and Jayang intakes. At the end of the largest stream, oocysts were found in 70% of collected samples (mean 5.71 oocysts/10 L) and it seemed that its joining the Han River resulted in the increase at Kuui intake and downstream. Oocyst removal by physical process exceeded 2.0-2.3 log and then all finished water samples collected at 6 WTPs were negative for Cryptosporidium in each 100 L sample for 10 years. These results suggested that domestic wastewater from the urban region could be a source of Cryptosporidium pollution and separating sewage systems adjacent to the intakes could be meaningful for some intakes having weakness related to parasitological water quality.
Cryptosporidium/growth & development/*isolation & purification ; Fresh Water/*parasitology ; Oocysts/growth & development ; Republic of Korea ; Rivers/parasitology ; Water Supply/*analysis

Cryptosporidium parvum is known as one of the most highly resistant parasites to gamma irradiation. To morphologically have an insight on the radioresistance of this parasite, ultrastructural changes in C. parvum sporozoites were observed after gamma irradiation using various doses (1, 5, 10, and 25 kGy) following a range of post-irradiation incubation times (10 kGy for 6, 12, 24, 48, 72, and 96 hr). The ultrastructures of C. parvum oocysts changed remarkably after a 10-kGy irradiation. Nuclear membrane changes and degranulation of dense granules were observed with high doses over 10 kGy, and morphological changes in micronemes and rhoptries were observed with very high doses over 25 kGy. Oocyst walls were not affected by irradiation, whereas the internal structures of sporozoites degenerated completely 96 hr post-irradiation using a dose of 10 kGy. From this study, morphological evidence of radioresistance of C. parvum has been supplemented.
Animals ; Cryptosporidiosis/parasitology ; Cryptosporidium parvum/*growth & development/radiation effects/ultrastructure ; Female ; Gamma Rays ; Humans ; Mice ; Mice, Inbred C57BL ; Microscopy, Electron, Transmission ; Oocysts/growth & development/*radiation effects/*ultrastructure

From May to June 2012, a waterborne outbreak of 124 cases of cryptosporidiosis occurred in the plumbing systems of an older high-rise apartment complex in Seoul, Republic of Korea. The residents of this apartment complex had symptoms of watery diarrhea and vomiting. Tap water samples in the apartment complex and its adjacent buildings were collected and tested for 57 parameters under the Korean Drinking Water Standards and for additional 11 microbiological parameters. The microbiological parameters included total colony counts, Clostridium perfringens, Enterococcus, fecal streptococcus, Salmonella, Shigella, Pseudomonas aeruginosa, Cryptosporidium oocysts, Giardia cysts, total culturable viruses, and Norovirus. While the tap water samples of the adjacent buildings complied with the Korean Drinking Water Standards for all parameters, fecal bacteria and Cryptosporidium oocysts were detected in the tap water samples of the outbreak apartment complex. It turned out that the agent of the disease was Cryptosporidium parvum. The drinking water was polluted with sewage from a septic tank in the apartment complex. To remove C. parvum oocysts, we conducted physical processes of cleaning the water storage tanks, flushing the indoor pipes, and replacing old pipes with new ones. Finally we restored the clean drinking water to the apartment complex after identification of no oocysts.
Cryptosporidiosis/*epidemiology/*parasitology ; Cryptosporidium parvum/genetics/growth & development/*isolation & purification ; Disease Outbreaks ; Drinking Water/*parasitology ; Housing ; Humans ; Oocysts/growth & development ; Republic of Korea/epidemiology ; Water Supply/analysis

The existence of symbiotic relationships between Acanthamoeba and a variety of bacteria is well-documented. However, the ability of Acanthamoeba interacting with host bacterial pathogens has gained particular attention. Here, to understand the interactions of Escherichia coli K1 and E. coli K5 strains with Acanthamoeba castellanii trophozoites and cysts, association assay, invasion assay, survival assay, and the measurement of bacterial numbers from cysts were performed, and nonpathogenic E. coli K12 was also applied. The association ratio of E. coli K1 with A. castellanii was 4.3 cfu per amoeba for 1 hr but E. coli K5 with A. castellanii was 1 cfu per amoeba for 1 hr. By invasion and survival assays, E. coli K5 was recovered less than E. coli K1 but still alive inside A. castellanii. E. coli K1 and K5 survived and multiplied intracellularly in A. castellanii. The survival assay was performed under a favourable condition for 22 hr and 43 hr with the encystment of A. castellanii. Under the favourable condition for the transformation of trophozoites into cysts, E. coli K5 multiplied significantly. Moreover, the pathogenic potential of E. coli K1 from A. castellanii cysts exhibited no changes as compared with E. coli K1 from A. castellanii trophozoites. E. coli K5 was multiplied in A. castellanii trophozoites and survived in A. castellanii cysts. Therefore, this study suggests that E. coli K5 can use A. castellanii as a reservoir host or a vector for the bacterial transmission.
Acanthamoeba castellanii/*microbiology ; Animals ; Disease Reservoirs/*microbiology ; Disease Vectors ; Escherichia coli/growth & development/pathogenicity/*physiology ; Oocysts/microbiology ; Symbiosis/*physiology ; Trophozoites/microbiology

Brain-derived neurotrophic factor (BDNF) can promote developmental competence in mammalian oocytes during in vitro maturation (IVM), but the role of BDNF in oocyte maturation at cellular level is not still clear. In this study, mouse cumulus-enclosed oocytes subjected to IVM were fertilized and cultured to blastocyst stage. Meiotic spindle configuration and cortical granules distribution during oocyte maturation in vitro were assessed by using immunofluorescence and laser confocal microscopy. The results showed that BDNF contributed to the complete preimplantation development of mouse oocytes compared to the control oocytes (13.78% vs. 5.92%; P<0.05). Further, BDNF did not accelerate nuclear maturation of IVM oocytes. For the BDNF-treated oocytes at meiosis I, Meiotic spindle areas were significantly smaller and the number of cytoplasmic microtubule organizing centers was greater than that in the control, and the percentages of oocytes showed spindles positioned near the oolemma and a well-formed cortical granule-free domain were significantly higher than that of the control. These morphological characteristics of the BDNF-treated oocytes were much closer to the oocytes matured in vivo than those of the control oocytes. In conclusion, BDNF can promote the developmental competence of mouse IVM oocytes, by improving the meiotic spindle configuration and location and cortical granules distribution at meiosis 1.
Animals ; Blastomeres ; cytology ; Brain-Derived Neurotrophic Factor ; pharmacology ; Female ; Fertilization in Vitro ; In Vitro Oocyte Maturation Techniques ; methods ; Male ; Mice ; Oocysts ; growth & development

The purpose of this study was to investigate whether sporulated Neospora caninum oocysts, which had been stored for 46 mo in a 2% sulfuric acid solution at 4 degrees C, remain morphologically viable and infective to gerbils (Meriones unguiculatus). Six gerbils were orally inoculated with doses of 400 or 1,200 oocysts. Two mo after inoculation, the animals did not show any clinical signs, had no histological lesions, and were seronegative for N. caninum at 1: 50 in an immunofluorescent antibody test. PCR using the brain from each gerbil did not reveal N. caninum specific DNA. We conclude that oocysts preserved for 46 mo are not infective, despite being morphologically intact.
Acids ; Animals ; Brain/parasitology/pathology ; Cattle/parasitology ; Coccidiosis/parasitology/pathology/*veterinary ; Feces/parasitology ; Female ; Gerbillinae/*parasitology ; Neospora/genetics/growth & development/*pathogenicity ; Oocysts/*growth & development ; Polymerase Chain Reaction/methods ; Refrigeration ; Virulence

In order to determine the distribution and prevalence of human cryptosporidiosis on western and southern coastal islands of Jeollanam-do (Province), fecal samples were collected from 2,541 people residing on 25 islands, 13 in the western coasts and 12 in the southern coasts, during July and August 2000. Fecal smears were prepared following formalin-ether sedimentation of the samples and stained by a modified acid-fast procedure. The presence of Cryptosporidium oocysts was determined by light microscopy. Cryptosporidium oocysts were detected in 38 specimens (1.5%). The oocyst positive rate varied (0-6.0%) according to island; the highest was detected on Oenarodo (6.0%), followed by Naenarodo (5.6%) and Nakwoldo (5.4%). The majority (35 persons, 94.6%) of Cryptosporidium-infected individuals were older than 50 years of age. Men (22/1,159; 1.9%) were infected at a higher rate than women (16/1,382; 1.2%). The results of the present survey indicate that human Cryptosporidium infections (due to Cryptosporidium hominis and/or C. parvum) are maintained at a relatively low prevalence on coastal islands of Jeollanam-do, Republic of Korea.
Sex Distribution ; Prevalence ; Oocysts ; Middle Aged ; Male ; Korea/epidemiology ; Infant, Newborn ; Infant ; Humans ; Female ; Feces/parasitology ; Cryptosporidium parvum/growth & development/*isolation & purification ; Cryptosporidium/growth & development/*isolation & purification ; Cryptosporidiosis/*epidemiology/parasitology ; Child, Preschool ; Child ; Animals ; Aged ; Age Distribution ; Adult ; Adolescent

The present study was undertaken to determine the viability and infectivity of oocysts of Cryptosporidium baileyi that had been stored from 1 to 40 months at 4 degrees C preserved in 2.5% potassium dichromate solution. Oocysts of C. baileyi were purified from the feces of experimentally infected chickens using discontinuous sucrose gradients. Subsequently, the purified oocysts were suspended in 2.5% potassium dichromate solution at a concentration of 1 x 10 (7) organism/ml, and their viabilities were assessed by nucleic acid staining, histologic examination, and infectivity to 2-day-old chickens. All chickens inoculated with oocysts that had been stored for 1-18 months developed patent infections, while chickens infected with older oocysts remained uninfected. Between 5.8% and 82.2% of the oocysts, stored at 4 degrees C in 2.5% potassium dichromate solution, were found to be viable, as determined by nucleic acid staining. Parasite colonization in the bursa of Fabricius was detected in the microvillus border of bursal epithelium. The finding that C. baileyi oocysts remain infective to chickens for at least 18 months offers important time-saving advantages to investigators who frequently require large numbers of oocysts.
Animals ; Bursa of Fabricius/parasitology ; Chickens/*parasitology ; Coloring Agents ; Cryptosporidiosis/parasitology/pathology/*veterinary ; Cryptosporidium/drug effects/*growth & development/pathogenicity ; Feces/parasitology ; Oocysts/drug effects/*growth & development/pathogenicity ; *Organic Chemicals ; *Potassium Dichromate/pharmacology ; Poultry Diseases/parasitology/pathology ; Preservation, Biological/*methods ; Staining and Labeling