• Parasites, Hosts and Diseases
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• 제45권3호
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• pp.225-228
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• 2007

We observed the time gap between oocyst shedding and antibody responses in mice (3-week-old C57BL/6J females) infected with Cryptosporidium parvum. Oocyst shedding was verified by modified acid-fast staining. The individually collected mouse sera were assessed for C. parvum IgM and IgG antibodies by enzyme-linked immunosorbent assay from 5 to 25 weeks after infection. The results showed that C. parvum oocysts were shed from day 5 to 51 post-infection (PI). The IgM antibody titers to C. parvum peaked at week 5 PI, whereas the IgG antibody titers achieved maximum levels at week 25 PI. The results revealed that IgM responses to C. parvum infection occurred during the early stage of infection and overlapped with the oocyst shedding period, whereas IgG responses occurred during the late stage and was not correlated with oocyst shedding. Hence, IgM antibody detection may prove helpful for the diagnosis of acute cryptosporidiosis, and IgG antibody detection may prove effective for the detection of past infection and endemicity.

• Parasites, Hosts and Diseases
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• 제39권2호
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• pp.201-203
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• 2001

The present study was undertaken to know the infection status of Cryptosporidium parvum among the residents of Chorwon-gun, Kangwon-do in 1993. Total 461 fecal samples were collected from the inhabitants residing in Chorwon-gun during the period of August 12 to September 14, 1993. Fecal smears were prepared by formalin-ether sedimentation, and examined after modified acid fast staining. Of the 461 fecal samples,9 (1.9%) were positive for C. parvum oocysts. The positive cases were limited to thirties (4) patients, forties (3), and sixties (2) , and no oocyst was detected in other age groups. The oocyst positive rate for male was 1.4% and that of female was 2.6%.

• 대한수의학회지
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• 제51권2호
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• pp.101-105
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• 2011

We investigate the resistance of Cryptosporidium (C.) parvum oocysts to commercial bleach treatment. The viability and infectivity of C. parvum oocysts suspended in 100, 50, 25, 12.5, 6.3 or 3.2% aqueous commercial bleach for 10, 30, 60, 120 or 180 min at room temperature were assessed by nucleic acid Syto-9 staining, histologic examination of ileum and infectivity to immunosuppressed neonatal C57BL/6N mice. Although the viability was decreased compared with normal oocysts, all oocysts in contact with serially diluted commercial bleach for 180 min were alive by nucleic acid dye Syto-9 staining. And, microscopic examination of ileum sections revealed developmental stages of C. parvum in all mice. The oocyst shedding patterns between mice infected with oocysts contacted with commercial bleach and normal control mice were not significantly different each other. Although commercial bleach is widely used as a bacterial and viral disinfectant, the present findings indicate that it is not an effective disinfectant for C. parvum oocysts under practical conditions. Authors conclude that, therefore, it is undesirable to recommend commercial bleach as a disinfectant for C. parvum oocysts.

• Parasites, Hosts and Diseases
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• 제30권4호
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• pp.259-262
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• 1992

국내 마우스에서 분리하여 계대중인 Cryptosporidium parvum 원충이 송아지에 감염되는지 알아보기 위하여 25일령의 한우 송아지에 1×106개의 오오시스트를 감염시킨 결과 점종 후 4일 째부터 분변 내에 오오시스트를 배출하였다. 오오시스트의 배설은 8일간 지속되었고, 그 수는 인충 점종 후 6일째에 가장 많았다(분변 gram당 4.9×105개 오오시스트). 감염된 송아지의 분변 내로 오오시스트가 배출되는 동안 분변의 성상은 정상이었다. 이상의 결과로 볼 때 국내 마우스에서 분리된 C. parvum은 송아지에게도 교차감염이 이루어져 숙주특이성이 없음을 알 수 있었다.

• 한국미생물·생명공학회지
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• 제17권5호
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• pp.494-498
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• 1989

AIDS 환자의 치명적인 2차 감염을 유발하는 Cryptosporidium parvum 의 Infective stage 인 sporozoites의 단일군 항체를 분리하였다. Oocysts를 효소처리하여 sporozoites를 excystation시킨 후 Isopycnic percoll gradients를 이용하여 sporozoites를 순수분리한 후 단일군 항체 생산을 위한 항원으로 사용하였다. 두 달된 BALB/c 쥐를 immunize한 후 splenocytes와 P3-X63-Ag8 myeloma cells를 융합시킨 후 hybridoma 기술을 이용해 Kor1(IgGl), Ea2(Ig2a) 두 clones을 분리하였으며 정제된 sporozoites를 SDS-PAGE로 분리한 후 Western blot을 이용하여 단일군 항체 Kor1과 Ea2는 20,000 daltons 크기의 항원을 인식하였다. Immunofluorescent assay에서 단일군 항체가 sporozoites 표면에 반응하는 것으로 보아 20-kDa 단백질 항원은 sporozoites 표면에 위치하는 항원으로 밝혀졌으며 C. parvum에 감염되었을 때 항체생성에 관여하는 중요 항원 중 하나일 것으로 추정되었다.

• Parasites, Hosts and Diseases
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• 제49권1호
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• pp.25-31
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• 2011

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.

• Parasites, Hosts and Diseases
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• 제46권2호
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• pp.71-75
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• 2008

The diagnosis of cryptosporidiosis has been carried out using coprologic techniques in the Republic of Korea. However, antibody responses to Cryptosporidium have rarely been studied. Serum antibodies from HIV-positive/oocyst-positive Korean patients recognized significantly 31 and 27 kDa antigens, and HIV-negative/oocyst-positive individuals clearly reacted to 15/17 kDa antigens. Compared with oocyst-positive cases, 18.7% and 75.8% of sera from HIV-positive patients reacted to 31 and 27 kDa antigens. Only 11.1% of HIV-negative individuals reacted to 15/17 kDa. Based on these findings, serum antibody responses were different between HIV-positive and HIV-negative individuals infected with Cryptosporidium, and it is suggested that HIV-positive patients are more frequently exposed to C. parvum compared to HIV-negative individuals.

• Parasites, Hosts and Diseases
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• 제47권3호
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• pp.293-297
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• 2009

Improved methods for detection of Cryptosporidium oocysts in environmental and clinical samples are urgently needed to improve detection of cryptosporidiosis. We compared the sensitivity of 7 PCR primer sets for detection of Cryptosporidium parvum. Each target gene was amplified by PCR or nested PCR with serially diluted DNA extracted from purified C. parvum oocysts. The target genes included Cryptosporidium oocyst wall protein (COWP), small subunit ribosomal RNA (SSU rRNA), and random amplified polymorphic DNA. The detection limit of the PCR method ranged from $10^3$ to $10^4$ oocysts, and the nested PCR method was able to detect $10^0$ to $10^2$ oocysts. A second-round amplification of target genes showed that the nested primer set specific for the COWP gene proved to be the most sensitive one compared to the other primer sets tested in this study and would therefore be useful for the detection of C. parvum.

• Parasites, Hosts and Diseases
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• 제54권5호
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• pp.631-636
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• 2016

This study aimed to develop a multiplex-touchdown PCR method to simultaneously detect 3 species of protozoan parasites, i.e., Cryptosporidium parvum, Giardia lamblia, and Cyclospora cayetanensis, the major causes of traveler's diarrhea and are resistant to standard antimicrobial treatments. The target genes included the Cryptosporidium oocyst wall protein for C. parvum, Glutamate dehydrogenase for G. lamblia, and 18S ribosomal RNA (18S rRNA) for C. cayetanensis. The sizes of the amplified fragments were 555, 188, and 400 bps, respectively. The multiplex-touchdown PCR protocol using a primer mixture simultaneously detected protozoa in human stools, and the amplified gene was detected in > $1{\times}10^3$ oocysts for C. parvum, > $1{\times}10^4$ cysts for G. lamblia, and > 1 copy of the 18S rRNA gene for C. cayetanensis. Taken together, our protocol convincingly demonstrated the ability to simultaneously detect C. parvum, G. lamblia, and C. cayetanenesis in stool samples.

• Environmental Engineering Research
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• 제14권4호
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• pp.244-249
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• 2009

Designing an ozone contactor is complicated because the residual ozone, log C. parvum inactivation, and bromate formation should be optimized with fluctuating water quality. OCM software was developed to assist a plant designer or an operator to fulfill the sophisticated optimization required in the design or operation of a new or an existing plant. In this article, numerical simulations were carried out using the OCM software for the design of a new ozone contactor under diverse design factors (i.e., three pHs, three temperatures, low and high dispersion numbers, and four and ten cells with complete mixing) with kinetic parameters obtained from the sand-filter effluent of a water treatment plant treating water from the Paldang impoundment. The results of the simulation suggested that a high residual ozone concentration at low pH and low temperature would be challenging, and PFR-like hydrodynamics could lower the residual ozone concentration. The inactivation of C. parvum oocysts increased at a lower pH. A lower dispersion number and more cell division increased the inactivation efficiency. Bromate was instantaneously formed during the initial ozonation stage. The effluent concentration was much lower than the regulatory levels imposed by the USEPA because of the low bromide level in raw water.