• Journal of Veterinary Clinics
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• v.29 no.5
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• pp.377-383
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• 2012

Bovine diarrhea is a major economical burden to the bovine industry in Korea. Since multiple infectious agents can be involved in bovine diarrhea, differential diagnosis is essential for effective treatment. Therefore, a panel of two multiplex real-time PCR assays which can simultaneously detect six major bovine enteric pathogens [i.e., bovine viral diarrhea virus (BVDV), bovine coronavirus (BCoV), group A bovine rotavirus (BRV), Salmonella spp., Escherichia coli (E. coli) $K99^+$, and Cryptosporidium parvum] was developed and applied to test 97 fecal samples collected from cattle farms in Korea. In addition, microscopic examination was also preformed on the samples to detect Coccidium oocyst. The estimated sensitivity of the multiplex PCR was 0.1 $TCID_{50}$ for BVDV, BCoV and group A BRV, 5 and 0.5 CFU for E. coli $K99^+$ and Salmonella, respectively, and 50 oocysts for Cryptosporidium. The amplification efficiency of the multiplex PCR ranged between 0.97 and 0.99 for each pathogen. Among 97 samples, 36 samples were positive for at least one of the 6 major pathogens and 6 samples were simultaneously positive for 2 pathogens by the multiplex PCR assay. Coccidium oocysts were also detected in 48 samples, which were all collected from over 1 month old calves. In conclusion, the multiplex real-time PCR panel can be a useful tool for fast and accurate diagnosis of calf diarrhea associated with BVDV, BCoV, group A BRV, E. coli $K99^+$, Salmonella, and/or Cryptosporidium and Coccidium may be an important target which needs to be included in the multiplex PCR panel in the future.

• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.113-120
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• 2010

To understand protozoan, viral, and bacterial infections in diarrheal patients, we analyzed positivity and mixedinfection status with 3 protozoans, 4 viruses, and 10 bacteria in hospitalized diarrheal patients during 2004-2006 in the Republic of Korea. A total of 76,652 stool samples were collected from 96 hospitals across the nation. The positivity for protozoa, viruses, and bacteria was 129, 1,759, and 1,797 per 10,000 persons, respectively. Especially, Cryptosporidium parvum was highly mixed-infected with rotavirus among pediatric diarrheal patients (29.5 per 100 C. parvum positive cases), and Entamoeba histolytica was mixed-infected with Clostridium perfringens (10.3 per 100 E. histolytica positive cases) in protozoan-diarrheal patients. Those infected with rotavirus and C. perfringens constituted relatively high proportions among mixed infection cases from January to April. The positivity for rotavirus among viral infection for those aged $\leq$ 5 years was significantly higher, while C. perfringens among bacterial infection was higher for $\geq$ 50 years. The information for association of viral and bacterial infections with enteropathogenic protozoa in diarrheal patients may contribute to improvement of care for diarrhea as well as development of control strategies for diarrheal diseases in Korea.

• Parasites, Hosts and Diseases
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• v.44 no.4 s.140
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• pp.367-372
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• 2006

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 Cyptosporidium oocysts was determined by light microscopy. Cyptosporidium 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 Cyptosporidium infections (due to Cyptosporidium hominis and/or C. parvum) are maintained at a relatively low prevalence on coastal islands of Jeollanam-do, Republic of Korea.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.71-78
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• 2006

The removal of protozoa in the coagulation process was evaluated under the different pH and turbidity using the jar test after the addition of polyaluminium chloride (PAC) as a coagulant. Two well-known protozoa of Cryptosporidium parvum and Giardia lamblia were tested at the same time with turbidity, the critical water quality parameter of the water treatment process. Both protozoa were removed about 1log (and up to 2log) at the optimum injection of PAC. The source water turbidity and pH affected the removal of protozoa and turbidity. At neutral and alkaline pH, 1.3-1.7log removal of protozoa for low turbid water with 5NTU, and 1.6-2.3log removal for high turbid water with 30NTU were achieved. However, at acidic pH, maximum 0.8-1.0log and 1.1-1.2log were removed for low and high turbid water, respectively, at the optimum PAC injection of 15mg/L. The relation of protozoa and turbidity removals were expressed as the 1st order equation (significantly positive relation) in the most of the tested conditions. In addition, the relation of protozoan removals with residual turbidity were also expressed the 1st order equation (significantly negative relation), although the significance of the equations were reduced at acidic pH. Therefore, residual turbidity could be a good index of efficient protozoan removal in the coagulation process, probably except at the low pH condition.

• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.366-370
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• 1998

To determine the efficacy of immunotherapeutic agents, four female Holstein calves 7-day-old were inoculated per os with $1{\times}10^7$ C parvum oocysts (VRI-CN91). Each calf received twice daily oral dosage of 200-500ml of the immune bovine serum, immune bovine colostrum, mAb C6, and phosphate-buffered saline, respectively. Treatment was initiated 4 days postinfection and laster 3 days. The clinical sign of the calf treated with phosphate-buffered saline lasted 9 days after the initial treatment. The calves treated with those immunotherapeutic agents, however, showed decreased severity of diarrhea at day 3, 2, 5 after the initial administration, respectively. The calves treated with immunotherapeutic agents showed reduced parasite loads compared to control calf. These results suggest that oral passive immunotherapy with immune bovine colostrum and immune bovine serum may be a useful treatment approach.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.1
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• pp.85-92
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• 1999

Cryptosporidiosis is an intestinal disease caused by the protozoan Cryptosporidium parvum. The most common manifestation in human is enteric symptoms, which in immunocompetent hosts are self-limiting but can be life threatening in immunocompromised hosts, characterized by profuse watery diarrhea, abdominal pain, severe weight loss. It's prevalence rate in immunocompetent host is variable by geographic locations (3~11%) but up to 15~40% in AIDS patients. Now it is considered as one of the important enteropathogens causing diarrhea not only in immunocompromised but also in immunocompetent hosts, especially in children. We experienced two cases of cryptosporidiosis in a 15 year old boy who was admitted due to diarrhea, abdominal pain and fever and in a 8 year old boy who was admitted due to watery diarrhea and vomiting. These are the first clinical cases of cryptosporidiosis confirmed by electron microscopy of the colonic mucosa among immunocompetent children in Korea.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.864-871
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• 2021

Infectious calf diarrhea is one of the most significant diseases of neonatal calves. This study is conducted to identify the prevalence of pathogens in calf diarrhea for 2 years. A total of 544 feces samples from Korean native beef calves were obtained to investigate selected seven pathogens causing calf diarrhea: bovine rotavirus, bovine coronavirus, Cryptosporidium parvum, bovine viral diarrhea virus, Eimeria species, Escherichia coli K99, and Salmonella species. The presence of diarrhea, the number and species of detected pathogens, and the calves' ages were analyzed using various statistical methods depending on the case. Of the 544 calves, 340 calves (62.5%) had normal feces and 204 calves (37.5%) had diarrhea. The presence of pathogens was significantly associated with diarrhea (p < 0.01) and fecal scores and the number of detected pathogens showed a significant linear trend (p < 0.001). Of the 7 target pathogens, 6 were detected in samples, but only C. parvum (p = 0.001) and bovine rotavirus (p < 0.001) were found at significantly higher rates in diarrheic calves than in non-diarrheic calves. Only Eimeria spp. showed a significant linear trend between the detection rate of the pathogen and the age groups (p < 0.05).

• Korean Journal of Veterinary Research
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• v.54 no.4
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• pp.257-260
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• 2014

A calf suffering from diarrhea was admitted to the Animal and Plant Quarantine Agency for diagnostic evaluation. Postmortem examination revealed that the mesenteric lymph node was enlarged and small intestine wall was thin. Microscopically, a large number of small round organisms were attached to the small intestine villi. Villous atrophy and proprial neutrophil infiltration were also observed. Based on modified Ziehl-Neelsen staining, electron microscopy, and ELISA results, the calf was diagnosed with fatal cryptosporidiosis.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.534-539
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• 2006

In the ozone disinfection unit process of a piston type batch reactor with continuous ozone analysis using a flow injection analysis (FIA) system, the CT values for 1 log inactivation of Cryptosporidium parvum by viability assays of DAPI/PI and excystation were $1.8{\sim}2.2\;mg/L{\cdot}min$ at $25^{\circ}C$ and $9.1mg/L{\cdot}min$ at $5^{\circ}C$, respectively. At the low temperature, ozone requirement rises $4{\sim}5$ times higher in order to achieve the same level of disinfection at room temperature. In a 40 L scale pilot plant with continuous flow and constant 5 minutes retention time, disinfection effects were evaluated using excystation, DAPI/PI, and cell infection method at the same time. About 0.2 log inactivation of Cryptosporidium by DAPI/PI and excystation assay, and 1.2 log inactivation by cell infectivity assay were estimated, respectively, at the CT value of about $8mg/L{\cdot}min$. The difference between DAPI/PI and excystation assay was not significant in evaluating CT values of Cryptosporidium by ozone in both experiment of the piston and the pilot reactors. However, there was significant difference between viability assay based on the intact cell wall structure and function and infectivity assay based on the developing oocysts to sporozoites and merozoites in the pilot study. The stage of development should be more sensitive to ozone oxidation than cell wall intactness of oocysts. The difference of CT values estimated by viability assay between two studies may partly come from underestimation of the residual ozone concentration due to the manual monitoring in the pilot study, or the difference of the reactor scale (50 mL vs 40 L) and types (batch vs continuous). Adequate If value to disinfect 1 and 2 log scale of Cryptosporidium in UV irradiation process was 25 $mWs/cm^2$ and 50 $mWs/cm^2$, respectively, at $25^{\circ}C$ by DAPI/PI. At $5^{\circ}C$, 40 $mWs/cm^2$ was required for disinfecting 1 log Cryptosporidium, and 80 $mWs/cm^2$ for disinfecting 2 log Cryptosporidium. It was thought that about 60% increase of If value requirement to compensate for the $20^{\circ}C$ decrease in temperature was due to the low voltage low output lamp letting weaker UV rays occur at lower temperatures.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.645-650
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• 2019

Despite differences in virulence between strains of Toxoplasma gondii, rapid and accurate genotyping methods are lacking. In this study, a method was developed to detect and genotype T. gondii in food and environmental samples using PCR and a novel peptide nucleic acid (PNA) melting array. An alignment of genome sequences for T. gondii type I, II, and III obtained from NCBI was generated, and a single nucleotide polymorphism analysis was performed to identify targets for PCR amplification and a PNA melting array. Prior to the PNA melting array, conventional PCR was used to amplify GRA6 of T. gondii. After amplification, the PNA melting array was performed using two different PNA hybridization probes with fluorescent labels (FAM and HEX) and quenchers. Melting curves for each probe were used to determine genotypes and identify mutations. A 214-bp region of the GRA6 gene of T. gondii was successfully amplified by PCR. For all T. gondii strains (type I, II, and III) used to evaluate specificity, the correct genotypes were determined by the PNA melting array. Non-T. gondii strains, including 14 foodborne pathogens and 3 protozoan parasites, such as Giardia lamblia, Cryptosporidium parvum, and Entamoeba histolytica, showed no signal, suggesting that the assay has a high specificity. Although this is only a proof-of-concept study, the assay is promising for the fast and reliable genotyping of T. gondii from food and environmental samples.