Development of a Normal Porcine Cell Line Growing in a Heme-Supplemented, Serum-Free Condition for Cultured Meat.

A key element for the cost-effective development of cultured meat is a cell line culturable in serum-free conditions to reduce production costs. Heme supplementation in cultured meat mimics the original meat flavor and color. This study introduced a bacterial extract generated from Corynebacterium that was selected for high-heme expression by directed evolution. A normal porcine cell line, PK15, was used to apply the bacterial heme extract as a supplement. Consistent with prior research, we observed the cytotoxicity of PK15 to the heme extract at 10 mM or higher. However, after long-term exposure, PK15 adapted to tolerate up to 40 mM of heme. An RNA-seq analysis of these heme-adapted PK15 cells (PK15H) revealed a set of altered genes, mainly involved in cell proliferation, metabolism, and inflammation. We found that cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1), lactoperoxidase (LPO), and glutathione peroxidase 5 (GPX5) were upregulated in the PK15H heme dose dependently. When we reduced serum serially from 2% to serum free, we derived the PK15H subpopulation that was transiently maintained with 5-10 mM heme extract. Altogether, our study reports a porcine cell culturable in high-heme media that can be maintained in serum-free conditions and proposes a marker gene that plays a critical role in this adaptation process.

Altered functional connectivity in children born very preterm at school age.

Children born very preterm are at significant risk of neurodevelopmental impairment. This study sought to identify differences in cognitive function in children born very preterm compared to term-born controls and investigate alteration in white matter microstructure and functional connectivity (FC) based on tract-based spatial statistics (TBSS) and resting-state functional MRI, respectively. At 6 years of age, 36 children born very preterm (< 32 weeks' gestation) without major neurological disabilities and 26 term-born controls were tested using the Wechsler Intelligence Scale for Children, 4th edition, and Child Behavior Checklist. Whole-brain deterministic tractography and FC measurements were performed in both groups. The very preterm group had significantly lower intelligence scores than the term-born controls. The TBSS revealed no significant differences between the two groups, whereas FC was significantly increased between the frontoparietal network and the language network and was significantly decreased between the right salience network nodes in the very preterm group. The altered FC patterns between specific regions of the higher-order networks may reflect underlying deficits in the functional network architecture associated with cognitive function. Further studies are needed to demonstrate a direct connection between FC in these regions and cognitive function.

Effects of a Neonatal Supportive Positioning Training Video Program for Preterm Infants on the Knowledge and Performance of Nurses in Neonatal Intensive Care Units.

PURPOSE: The purpose of this study is to develop and apply a neonatal supportive positioning (NSP) training video program for premature infants, using a position support mat for nurses in neonatal intensive care units (NICUs), and to verify its effect on nurses' performance. METHODS: Thirty-five NICU nurses were included in the study. For the pre-test, preliminary check-ups were conducted, questionnaires about NSP knowledge on preterm infants were distributed, and NSP performance using neonatal dolls were video recorded for each participant. PowerPoint presentations and videos were used to educate participants on NSP. Furthermore, a 20-minute one-on-one training session was conducted using an NPS kit. Two weeks after the training, we repeated the process of distributing questionnaires about NSP knowledge and recording nurses' performance videos using neonatal dolls. Questionnaires and videos collected before and after the training were compared. RESULTS: After NSP training, the mean knowledge score of the participants improved significantly from 23.71 ± 3.62 to 29.51 ± 2.29 (Z = -5.09, p < .001). The performance score for postural supportive positioning was 38.03 ± 7.46 before training and 80.06 ± 9.85 after receiving training, indicating a high-performance score after NSP training (Z = -5.16, p < .001). CONCLUSION: Our NSP training video program increased nurses' NSP knowledge and performance. Continuous training NICU nurses on NSP, using a standardized training video program, can help improve the care of premature infants.

Cerebellar Development in Preterm Infants at Term-Equivalent Age Is Impaired after Low-Grade Intraventricular Hemorrhage.

OBJECTIVES: To investigate cerebellar development in preterm infants at term-equivalent age compared with healthy full-term infants and to examine the effect of a low-grade intraventricular hemorrhage (IVH) on cerebellar development. STUDY DESIGN: This study used 3T magnetic resonance and diffusion tensor imaging (DTI) at 36-41 weeks' postmenstrual age (PMA) in 72 preterm infants without severe brain injury and 16 full-term infants. Cerebellar volumes and DTI parameters of the cerebellar peduncles including fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity, and radial diffusivities were measured. Clinical variables that may affect brain development were collected. RESULTS: Compared with full-term infants, preterm infants showed smaller cerebellar volumes and a lower FA, greater ADC, and increased radial diffusivities in the cerebellar peduncles (all P < .05). This cerebellar impairment was associated significantly with PMA and IVH grade 2 but was independent of gestational age at birth. When we adjusted for clinical variables, an IVH grade 2 was related with 1.73 cm(3) reduction in cerebellar volumes and altered DTI parameters in the cerebellar peduncles, including decreased FA and increased radial diffusivities in the superior cerebellar peduncle and increases in ADC, axial diffusivity, and radial diffusivities of the middle cerebellar peduncle (all P < .05). Cerebellar hemispheric volumes were associated with both ipsilateral and contralateral IVH grade 2. CONCLUSION: Preterm infants without severe brain abnormalities showed impaired cerebellar development at term-equivalent age after we controlled for PMA at the time of the scan, and this is associated with IVH grade 2. These findings suggest that even a low-grade IVH has potential harmful effects on cerebellar development.

Hepatitis associated with Mycoplasma pneumoniae infection in Korean children: a prospective study.

PURPOSE: Mycoplasma pneumoniae (MP) infection is a major cause of respiratory infection in school-aged children. Extrapulmonary manifestations of MP infection are common, but liver involvement has been rarely reported. The aim of this study was to determine the clinical characteristics of MP-associated hepatitis. METHODS: This prospective study included 1,044 pediatric patients with MP infection diagnosed serologically with MP IgM at one medical center from January 2006 to December 2012. Eighty of these patients had elevated levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), each greater than 50 IU/L, without any other specific liver disorder and were compared with the 964 children without liver disorders. RESULTS: In total, 7.7% of patients with MP infection had a diagnosis of hepatitis, especially in fall and winter. The ratio of male to female patients was 1.7:1, and the mean age of the patients was 5 years and 5 months. The most common symptoms were cough, fever, and sputum. Anorexia was the most common gastrointestinal symptom, followed by nausea/vomiting, diarrhea, and abdominal pain. Mean levels of AST and ALT were 100.65 IU/L and 118.73 IU/L, respectively. Serum AST/ALT level was normalized within 7.5 days on average without complications. The mean duration of hospitalization (11.3 days) was longer for children with hepatitis than for those without hepatitis (P=0.034). CONCLUSION: MP-associated hepatitis is not uncommon and has a relatively good prognosis. Therefore, clinicians should be concerned about liver involvement in MP infection but avoid further unnecessary evaluation of hepatitis associated with MP.

Variation between residents and attending staff interpreting radiographs to verify placement of nutrition access devices in the neonatal intensive care unit.

INTRODUCTION: Although radiography is considered the standard for confirming the position of nutrition access devices, it is sometimes difficult to visualize their tips. The purpose of this study was to evaluate how well pediatric residents could confirm placement via radiography of feeding tubes and intravenous (IV) nutrition catheter support in a neonatal intensive care unit (NICU). METHODS: Seventy radiographs in a NICU during May 2013 were retrospectively evaluated. Eight pediatric residents (mean NICU experience, 5 months; range, 0-12 months) recorded the location of feeding tubes and IV nutrition catheters and marked their tips on computerized radiographs. Consensus review of radiographs by a radiologist and a NICU expert using a picture archiving communication system monitor in a reading room served as the reference standard. Detection rates and correct tip localization percentages were evaluated. RESULTS: Of the 70 neonates, 38 had nutrition access devices: orogastric tube (n = 36), oroduodenal tube (n = 4), or central venous catheter (CVC) (n = 8). Detection rates were 89.6% for orogastric tubes (range, 75.0%-100%), 90.6% for oroduodenal tubes (range, 50.0%-100%), and 46.9% for CVCs (range, 12.5%-75.0%). Percentage of correct tip localizations was 85.7% for orogastric tubes (range, 74.1%-100%), 86.2% for oroduodenal tubes (range, 25.0%-100%), and 70% for CVCs (range, 50.0%-100%). CONCLUSION: It is not easy for pediatrician residents to confirm the position of nutrition access devices in neonates by using radiographs. Reinforcement of radiology teaching, second opinions from radiologists or NICU experts, and other methods for verifying the positions of nutrition access devices are needed to minimize complications.

Serial diffusion tensor images during infancy and their relationship to neuromotor outcomes in preterm infants.

BACKGROUND: Even preterm infants with normal magnetic resonance imaging (MRI) results are at greater risk for neuromotor dysfunction. OBJECTIVES: Our aim was to compare serial diffusion tensor imaging (DTI) data from preterm infants without apparent brain abnormalities on magnetic resonance imaging with those from term controls and to investigate the white matter (WM) region associated with neuromotor outcomes. METHODS: We obtained serial DTIs from 21 preterm infants at term-equivalent age (TEA) and 1 year of corrected age. As controls, 15 term neonates and 20 newly recruited term infants aged 1 year underwent DTI. Preterm and term infants at 1 year of age were assessed with the Bayley Scales of Infant Development, second edition. Tract-based spatial statistics and regions of interest were used for analysis. RESULTS: At TEA, the entire WM development was delayed in the preterm infants compared with the term controls, but at 1 year of age, the WM development, except for that of the corpus callosum (CC), had reached the development level of the term controls. The psychomotor developmental index was positively correlated with the fractional anisotropy (FA) in the CC (particularly in the body and splenium) at 1 year of age after correcting for gestational age, chronic lung disease, and postnatal infection. CONCLUSIONS: The CC of the preterm infants was consistently underdeveloped compared with that of the term controls. The FA in the CC, particularly in the body and splenium at 1 year of age, well reflected the degree of motor function in infants without apparent brain abnormalities.

Clinical Features of Symptomatic Meckel's Diverticulum in Children: Comparison of Scintigraphic and Non-scintigraphic Diagnosis.

PURPOSE: Meckel's diverticulum (MD) has various clinical manifestations, and diagnosis or selectection of proper diagnostic tools is not easy. This study was conducted in order to assess the clinical differences of MD diagnosed by scintigraphic and non-scintigraphic methods and to find the proper diagnostic tools. METHODS: We conducted a retrospective review ofthe clinical, surgical, radiologic, and pathologic findings of 34 children with symptomatic MD, who were admitted to Gachon University Gil Medical Center, Inha University Hospital, and The Catholic University of Korea, Incheon St. Mary's Hospital between January 2000 and December 2012. The patients were evaluated according to scintigraphic (12 cases; group 1) and non-scintigraphic (22 cases; group 2) diagnosis. RESULTS: The male to female ratio was 7.5: 1. The most frequent chief complaint was lower gastrointestinal (GI) bleeding in group 1 and nonspecific abdominal pain in group 2, respectively. The most frequent pre-operative diagnosis was MD in both groups. Red blood cell (RBC) index was significantly lower in group 1. MD was located at 7 cm to 85cm from the ileocecal valve. Four patients in group 1 had ectopic gastric tissues causing lower GI bleeding. The most frequent treatment modality was diverticulectomy in group 1 and ileal resection in group 2, respectively. CONCLUSION: To diagnose MD might be delayed unless proper diagnostic tools are considered. It is important to understand indications of scintigraphic and non-scintigraphic methods according to clinical and hematologic features of MD. Scintigraphy would be weighed in patients with anemia as well as GI symptoms.

Respiratory viruses in neonates hospitalized with acute lower respiratory tract infections.

BACKGROUND: The burden of respiratory syncytial virus (RSV) in neonates has not been clearly studied. The aims of this study were to determine the overall distribution of respiratory viruses in neonates hospitalized with acute lower respiratory tract infectiosns (ALRI) and to describe the clinical characteristics of RSV infections in these neonates. METHODS: From January 2009 through May 2010, neonates aged <1 month who were hospitalized with ALRI and did not have underlying disease were included in the study. Viruses were identified on multiplex reverse transcription polymerase chain reaction using nasal swab samples. Clinical variables were evaluated between the RSV and non-RSV infection groups. RESULTS: Of the 108 infants included in the study, 46 (42.6%) had RSV; human rhinovirus (18.5%), human parainfluenza virus 3 (7.5%), and human metapneumovirus (3.7%) were the next most common infections. Codetections accounted for 8.3% of the cases. Crowding increased the risk of RSV infection compared to the non-RSV group (OR, 16.5; P = 0.001). The RSV group had a greater incidence of dyspnea (P = 0.027), pneumonia (P < 0.001), requirement for oxygen (P < 0.001), and prolonged hospitalization (P = 0.011) than the non-RSV group. CONCLUSIONS: RSV was the most common viral etiology in neonates without underlying diseases who were hospitalized with ALRI. The disease severity of RSV infection was worse than that of other detected viral infections. Strict prevention strategies should be considered in overcrowded situations.

Altered microstructure of white matter except the corpus callosum is independent of prematurity.

BACKGROUND: Diffusion tensor imaging (DTI) reflects the maturation of the brain microstructure. Although preterm infants are at significant risk for altered brain microstructure, it remains unclear whether this is affected by prematurity itself or other clinical factors. OBJECTIVES: To investigate DTI parameters in preterm infants at a term-equivalent age (TEA) compared with healthy term infants and to assess the associations between DTI parameters and clinical factors that may affect brain development. METHODS: We studied 34 preterm infants without apparent brain lesions and 12 healthy term infants using tract-based spatial statistics. Region-of-interest analysis was performed in the posterior and anterior limbs of the internal capsule (PLIC and ALIC), corpus callosum (CC), optic radiation, and cerebral peduncle. RESULTS: Preterm infants had significantly decreased fractional anisotropy (FA) in nearly the entire white matter (WM) compared with term infants (p < 0.01). Multiple regression analysis showed that FA in the PLIC, ALIC, optic radiation, and cerebral peduncle were positively associated with postmenstrual age (PMA) at imaging and that the apparent diffusion coefficient was negatively associated with PMA. Only FA in the CC was positively correlated with gestational age. Chronic lung disease (CLD) and postnatal infection were associated with decreased FA in the CC and PLIC, respectively. CONCLUSIONS: Preterm infants at TEA showed an altered microstructure of the WM compared with healthy term infants. The altered microstructure of the measured WM except the CC was independent of the degree of prematurity. Chronic lung disease and postnatal infection are related to localized WM alterations.

Clinical characteristics and genotypes of rotaviruses in a neonatal intensive care unit.

BACKGROUND: There are few reports on the symptoms of rotavirus infections in neonates. This study aims to describe clinical signs of rotavirus infections among neonates, with a particular focus on preterm infants, and to show the distribution of genotypes in a neonatal intensive care unit (NICU). METHODS: A prospective observational study was conducted at a regional NICU for 1 year. Stool specimens from every infant in the NICU were collected on admission, at weekly intervals, and from infants showing symptoms. Rotavirus antigens were detected by enzyme-linked immunosorbent assay (ELISA), and genotypes were confirmed by Reverse transcription-Polymerase chain reaction (RT-PCR). The infants were divided into three groups: symptomatic preterm infants with and without rotavirus-positive stools [Preterm(rota+) and Preterm(rota-), respectively] and symptomatic full- or near-term infants with rotavirus-positive stools [FT/NT(rota+)]. Demographic and outcome data were compared among these groups. RESULTS: A total of 702 infants were evaluated for rotaviruses and 131 infants were included in this study. The prevalence of rotavirus infections was 25.2%. Preterm(rota+) differed from Preterm(rota-) and FT/NT(rota+) with respect to frequent feeding difficulty (p = 0.047 and 0.034, respectively) and higher percentage of neutropenia (p = 0.008 and 0.011, respectively). G4P[6] was the exclusive strain in both the Preterm(rota+) (97.7%) and FT/NT(rota+) (90.2%), and it was the same for nosocomial, institutional infections, and infections acquired at home. CONCLUSION: Systemic illness signs such as feeding difficulty and neutropenia are specific for preterm infants with rotavirus infections. G4P[6] was exclusive, regardless of preterm birth or locations of infections. This study might be helpful in developing policies for management and prevention of rotavirus infections in NICUs.

Poor adherence and reasons for nonadherence to the asthma guidelines among pediatricians in Korea.

BACKGROUND: Information is limited regarding adherence to the asthma guidelines in Asia, especially for children. OBJECTIVE: The aim of the study was to estimate adherence to the asthma guidelines, and investigate reasons for nonadherence. METHODS: We conducted a cross-sectional questionnaire survey on the primary care pediatricians practicing in Incheon, Korea. RESULTS: Surveys were returned by 81 of 131 eligible primary care pediatricians for a response rate of 61.8%. Almost all respondents (98.8%) had heard of the asthma guidelines, and most (93.8%) had read or received education about them. The classification of asthma severity was well understood with the accuracy of 85.7%. Correct responses for treatments were 51.3% for intermittent, 68.5% for mild persistent and 56.9% for moderate persistent asthma. For severe persistent asthma, the accuracy was high (85.7%). Only 21.5% of the respondents reported routine use of office peak flow measurement for patients with moderate or severe persistent asthma for diagnosis, and fewer (10.3%) used spirometry. A written action plan was reported to be given to only 5.2% of patients with asthma. The principal barrier to adherence was the presence of external barriers (lack of time, equipment, supporting staff etc.). Different barriers were prominent for different types of guideline components. CONCLUSIONS: There is poor adherence to the asthma guidelines in several aspects of their recommendations. Tailored interventions that address the current state of barriers need to be designed and implemented.

Genetic variation of G4P[6] rotaviruses: evidence for novel strains circulating between the hospital and community.

One hundred forty-six fecal specimens collected between 2007 and 2008 from infants with acute gastroenteritis were screened for rotavirus by ELISA with VP6-specific antibody. One hundred twenty-three of the samples (84.2%) were confirmed to be positive for group A rotavirus (community-acquired, n = 90 [73.2%] and nosocomial, n = 33 [26.8%]), and were typed subsequently using RT-PCR and sequence analysis methods. Determination of G- and P-type combinations showed that G4P[6] (78.9%) was the most common strain, followed by G3P[8] (7.3%), G1P[8] (6.5%), G2P[4] (0.8%), G2P[6] (0.8%), G1P[6] (0.8%), and G9P[8] (0.8%) strains. Of the 97 G4P[6] strains, 62 (63.8%) were responsible for community-acquired cases and 35 (36.1%) were hospital-acquired cases. Phylogenetic analysis of the VP7 gene from the G4P[6] strains revealed that both the community-acquired and nosocomial strains were segregated to the human rotaviruses circulating world-wide, including the prototype vaccinal strain, ST3, which constituted a novel sublineage in lineage 1. Owing to the recent emergence of G4P[6] rotaviruses within the hospital, as well as in the community, the findings from this study are important since they provide new information concerning the community and nosocomial spread of rotaviruses.

A single dose of anti-D immunoglobulin raises platelet count as efficiently as intravenous immunoglobulin in newly diagnosed immune thrombocytopenic purpura in Korean children.

OBJECTIVE: The aim of this study is to compare the efficacy and safety of a single dose of anti-D immunoglobulin (anti-D) at 50 mug/kg to intravenous immunoglobulin (IVIG) in Korean children with acute immune thrombocytopenic purpura (ITP). METHODS: We performed this study prospectively by randomly administering 2 consecutive doses of IVIG at a dose of 1.0 g/kg/dor a single dose of anti-D at 50 microg/kg to children upon initial diagnosis of acute ITP. The platelet count and adverse events, including hemoglobin concentration, were then serially evaluated, and the responses were compared. RESULTS: The likelihood of having a platelet count greater than 20x10/mm after 3 days of treatment in the IVIG and anti-D group was 93% and 92%, respectively. In addition, hemoglobin concentration in the anti-D group had declined more than that of the IVIG group (1.49 g/dL vs. 0.80 g/dL, P=0.014) 3 days after treatment. Fever, chills, and headache occurred less frequently in the anti-D group than the IVIG group, however, this difference was not statistically significant (25% vs. 45%, P=0.494). CONCLUSIONS: A single dose of 50 microg/kg of anti-D raised platelet count as efficiently as IVIG in newly diagnosed cases of ITP in Korean children. Although 50 microg/kg of anti-D had a greater effect on the hemoglobin concentration than IVIG, the adverse effects were found to be acceptable, and no serious events were observed.

Induction of early meconium evacuation promotes feeding tolerance in very low birth weight infants.

BACKGROUND: A delay in reaching full enteral feeding is linked to poorer outcome in preterm neonates. Meconium retention has been viewed as a cause of bowel dysfunction in very low birth weight infants (VLBWI). Thus, adequate evacuation of meconium could help to promote feeding tolerance. OBJECTIVES: Our goal was to determine the effect of the induction of early meconium evacuation on feeding tolerance in VLBWI. METHODS: An observational study involving two subsequent periods was performed in inborn infants with birth weights of <1,500 g, before (control) and after (study) the induction of early meconium evacuation by routine glycerin enema. The total duration of these periods was from January 2003 to December 2005. To evaluate feeding tolerance, we measured time to achieve full enteral feeding. Complications such as sepsis and necrotizing enterocolitis were compared. RESULTS: The study group achieved full enteral feeding significantly faster than the control group (hazard ratio (HR) = 2.9; 95% confidence interval (CI) = 1.8-4.8), and this effect was more definite in infants with a birth weight of <1,000 g (HR = 4.6; 95% CI = 1.9-11.1). The study group passed first meconium faster than the control group (median = 1.4 vs. 3.7 days; p < 0.001). Sepsis, especially as determined by positive culture in central venouscatheter, was significantly reduced in the study group (7.7 vs. 27.8%; p = 0.02). CONCLUSIONS: The induction of early meconium evacuation had a significantly positive effect on feeding tolerance and sepsis prevention in VLBWI.

Increase of interleukin-6 in tracheal aspirate at birth: a predictor of subsequent bronchopulmonary dysplasia in preterm infants.

AIM: We tested whether interleukin-6 (IL-6) in tracheal aspirate (TA) at birth, as a marker of fetal pulmonary inflammation, can be a predictor of bronchopulmonary dysplasia (BPD) in preterm infants. METHODS: A total of 75 preterm (< or = 32 wk) infants who were intubated in the delivery room were prospectively enrolled. Multivariate logistic regression analysis was done to determine whether IL-6 in TA at birth is an independent risk factor for BPD, and a receiver-operating characteristic curve was constructed to determine the accuracy of IL-6 in TA for predicting the risk of BPD. RESULTS: IL-6 in TA at birth was an independent risk factor for BPD. Fetal pulmonary inflammation defined as IL-6 in TA at birth > or = 316 pg/ml together with patent ductus arteriosus (PDA) additively predicted the risk of BPD. The sensitivity, specificity, and positive and negative predictive values of fetal pulmonary inflammation for the identification of BPD were 73%, 71%, 58% and 83%, respectively. CONCLUSION: IL-6 in TA at birth can be used as a predictor of BPD in combination with the presence of PDA.

Low birth weight,very low birth weight rates and gestational age-specific birth weight distribution of korean newborn infants.

To obtain the low birth weight (LBW) rate, the very low birth weight (VLBW) rate, and gestational age (GA)-specific birth weight distribution based on a large population in Korea, we collected and analyzed the birth data of 108,486 live births with GA greater than 23 weeks for 1 yr from 1 January to 31 December 2001, from 75 hospitals and clinics located in Korea. These data included birth weight, GA, gender of the infants, delivery type, maternal age, and the presence of multiple pregnancy. The mean birth weight and GA of a crude population are 3,188 +/-518 g and 38.7+/-2.1 weeks, respectively. The LBW and the VLBW rates are 7.2% and 1.4%, respectively. The preterm birth rate (less than 37 completed weeks of gestation) is 8.4% and the very preterm birth rate (less than 32 completed weeks of gestation) is 0.7%. The mean birth weights for female infants, multiple births, and births delivered by cesarean section were lower than those for male, singletons, and births delivered vaginally. The risk of delivering LBW or VLBW infant was higher for the teenagers and the older women (aged 35 yr and more). We have also obtained the percentile distribution of GA-specific birth weight in infants over 23 weeks of gestation.

[Metacercariae of Echinochasmus japonicus encysted in a fresh water fish, Pseudorasbora parva, and their development in experimental mice]

The echinostomatid metacercariae encysted in the gill of the fresh water fish, Pseudorasbora parva were identified through obtaining adult worms after experimental infection to mice. In addition, a brief course of worm development and maturation was observed in this experimental host. The results were as follows: The echinostomatid metacercariae were elliptical, golden yellow, 0.073~0.078 mm long and 0.054-0.065 mm wide. Their head portions were characterized by the presence of a head crown armed with collar spines of total 24 in number and interrupted at the mid-dorsal side of the oral sucker. The average rate of worm recovery from 12 mice (on the 1-21th postinfection days) was 19.4 percent and the rate revealed no decrease in accordance with the increase of infection duration. The worms were collected chiefly from the lower part of the small intestine. After the infection, their sexual maturation was attained in 5 days and their growth in size nearly completed in 7 days. The early growth curve of genital organs was S shape while that of nongenital organs was C form. In 5 day old worms, l or 2 eggs were found from their uteri and the stools of mice revealed echinostomatid eggs from the 5-6th postinfection day. The 7 day old adult worms were ovoid in shape, 0.54-0.69 mm long and 0.29-0.34 mm wide, and characterized by a well developed head crown with 24 collar spines and vitelline follicles distributed from the acetabular level down to the posterior end of body. Based on these characters they were identified to be Echinochasmus japonicus Tanabe, 1926. From these results, it is verified that P. parva is one of the second intermediate hosts of E. japonicus in Korea.