Molecular detection of free-living amoebae from Namhangang (southern Han River) in Korea

The free-living amoebae Naegleria spp. and Acanthamoeba spp. exist in the natural environment and are sometimes causal agents of lethal primary amoebic meningoencephalitis (PAM), amoebic keratitis (AK) and granulomatous amebic encephalitis (GAE) in humans, respectively. To ascertain the existence of free-living amoebae in Korea, water samples were collected from the Korean hydrosphere, Namhangang (southern Han River), an active location for water skiing and recreation. Samples underwent two-step filtration and were cultured on non-nutrient agar medium with inactivated E. coli. The remaining samples were subjected to PCR for primarily the 18S small ribosomal RNA gene and gene sequencing. Similarities in 18S rDNA sequences, in comparison with various reference amoebae in GenBank, showed 86~99% homology with N. gruberi, N. philippinensis, N. clarki, A. polyphaga, A. castellannii, and Hartmannella (Vermamoeba) vermiformis. Therefore, this study will be useful for seasonal detection of free-living amoebae from various Korean hydrospheres in future studies.

Infection Status with Digenetic Trematode Metacercariae in Fishes from Coastal Lakes in Gangwon-do, Republic of Korea

The infection status of digenetic trematode metacercariae (DTM) was investigated in fishes from coastal lakes in Gangwon-do, the Republic of Korea (Korea). All fishes collected in 5 lakes were examined with the artificial digestion method. More than 10 species, i.e., Metagonimus spp., Pygidiopsis summa, Centrocestus armatus, Metorchis orientalis, M. taiwanensis, Clinostomum complanatum, Echinostoma spp., Stictodora spp., Diplostomum sp. and Diplostomid No. 1. by Morita (1960), of DTM were detected in fishes from 5 coastal lakes in Gangwon-do. Metagonimus spp. metacercariae were found in 52 (41.3%) out of 126 sea rundace, Tribolodon hakonensis, from 5 lakes, and their density was 14.6 per fish infected. P. summa metacercariae were detected in 48 (84.2%) out of 57 mullets from 5 lakes, and their density was 316 per fish infected. C. armatus metacercariae were detected in 7 (14.6%) T. hakonensis and 3 (15.0%) Tridentiger brevispinis from Hyang-ho, and 5 (19.2%) Acanthogobius flavimanus from Gyeongpo-ho. Stictodora spp. metacercariae were found in 4 fish species, i.e., Tridentiger obscurus, Tridentiger trigonocephalus, Chelon haematocheilus, and Acanthogobius lactipes, from Gyeongpo-ho. Total 15 C. complanatum metacercariae were detected in 2 (9.1%) crucian carp, Carassius auratus, from Songji-ho. M. taiwanensis metacercariae were found in T. hakonensis from Hyang-ho and Gyeongpo-ho and in Pseudorasbora parva from Gyeongpo-ho. Total 11 M. orientalis metacercariae were detected in 3 (6.3%) T. hakonensis from Hyang-ho. From the above results, it was confirmed that various species of DTM are infected in fishes from coastal lakes in Gangwon-do, Korea.

Annual Fluctuation in Chigger Mite Populations and Orientia Tsutsugamushi Infections in Scrub Typhus Endemic Regions of South Korea

Objectives

Chigger mites are vectors for scrub typhus. This study evaluated the annual fluctuations in chigger mite populations and Orientia tsutsugamushi infections in South Korea.

Methods

During 2006 and 2007, chigger mites were collected monthly from wild rodents in 4 scrub typhus endemic regions of South Korea. The chigger mites were classified based on morphological characteristics, and analyzed using nested PCR for the detection of Orientia tsutsugamushi.

Results

During the surveillance period, the overall trapping rate for wild rodents was 10.8%. In total, 17,457 chigger mites (representing 5 genera and 15 species) were collected, and the average chigger index (representing the number of chigger mites per rodent), was 31.7. The monthly chigger index was consistently high (> 30) in Spring (March to April) and Autumn (October to November). The mite species included Leptotrombidium pallidum (43.5%), L. orientale (18.9%), L. scutellare (18.1%), L. palpale (10.6%), and L. zetum (3.6%). L. scutellare and L. palpale populations, were relatively higher in Autumn. Monthly O. tsutsugamushi infection rates in wild rodents (average: 4.8%) and chigger mites (average: 0.7%) peaked in Spring and Autumn.

Conclusion

The findings demonstrated a bimodal pattern of the incidence of O. tsutsugamushi infections. Higher infection rates were observed in both wild rodents and chigger mites, in Spring and Autumn. However, this did not reflect the unimodal incidence of scrub typhus in Autumn. Further studies are needed to identify factors, such as human behavior and harvesting in Autumn that may explain this discordance.

Postpartum women’s experience of abuse in childhood, postnatal depression, and thoughts of self-harm

Background

Postnatal depression threatens the health of both mothers and babies. To improve maternal and child health in Seoul, South Korea, a nurse home visitation program for pregnant women and new mothers and babies has been implemented since 2013.

Methods

Cross-sectional data collected from 9,124 mothers while they were visiting a public health center for prenatal services or a nurse was visiting their home within 6 weeks after birth between 2014 and 2018 were analyzed. Mothers were asked whether they had experienced physical, emotional, or sexual abuse in their childhood. Postnatal depression and thoughts of self-harm were measured using the Edinburgh Postnatal Depression Scale (EPDS). Postnatal depression was defined as a total EPDS score of 13 or higher; thoughts of self-harm were defined as a response of “yes, quite often,” “sometimes,” or “hardly ever” to the corresponding item, excluding the response of “never".

Results

Overall, 3.2% of mothers had experienced child abuse; 8.1% experienced postnatal depression and 5.4% reported thoughts of self-harm. Postnatal depression was more common in mothers who had experienced child abuse than among those who had not (24.2% vs. 7.6%). A similar pattern was found for thoughts of self-harm (21.1% vs. 4.9%, respectively). When controlling for mothers’ age, economic status, history of receiving treatment for mental health problems, and other factors, having experienced child abuse was associated with a 2.73-fold increase in the odds of postnatal depression (odds ratio, 2.02-3.70) and a 3.58-fold increase in the odds of thoughts of self-harm (odds ratio, 2.58-4.96).

Conclusions

Mothers should be screened for having experienced child abuse when providing public health perinatal care to improve mothers’ mental health and parenting practices and to promote their children’s growth and development.

Key messages

Child abuse may have a lifelong negative effect on victims, and the effect extends to the next generation’s health and development. Public health policy and interventions to prevent child abuse are needed to tackle health inequality beginning in early childhood.

Molecular Prevalence and Genotypes of Cryptosporidium parvum and Giardia duodenalis in Patients with Acute Diarrhea in Korea, 2013-2016

Cryptosporidium parvum and Giardia duodenalis are the main diarrhea-causing parasitic pathogens; however, their prevalence in Korea is unknown. Here, we conducted a survey to determine the prevalence and genotype distribution of these 2 pathogens causing acute diarrhea in 8,571 patients hospitalized in 17 Regional Institute of Health Environment sites in Korea, during 2013–2016. C. parvum and G. duodenalis were detected and genotyped by nested PCR, and the isolate were molecularly characterized by sequencing the glycoprotein 60 (Gp60) and β-giardin genes, respectively. The overall prevalence of C. parvum and G. duodenalis was 0.37% (n=32) and 0.55% (n=47), respectively, and both pathogens were more prevalent in children under 9 years old. Molecular epidemiological analysis showed that the C. parvum isolates belonged to the IIa family and were subtyped as IIaA13G2R1, IIaA14G2R1, IIaA15G2R1, and IIaA18G3R1. Analysis of the β-giardin gene fragment from G. duodenalis showed that all positive strains belong to assemblage A. This is the first report on the molecular epidemiology and subtyping of C. parvum and G. duodenalis in such a large number of diarrheal patients in Korea. These results highlight the need for continuous monitoring of these zoonotic pathogens and provide a basis for implementing control and prevention strategies. Further, the results might be useful for epidemiological investigation of the source of outbreak.

Detection and characterization of an emerging type of Babesia sp. similar to Babesia motasi for the first case of human babesiosis and ticks in Korea

Babesiosis is a tick-transmitted intraerythrocytic zoonosis. In Korea, the first mortalities were reported in 2005 due to Babesia sp. detection in sheep; herein we report epidemiological and genetic characteristics of a second case of babesiosis. Microscopic analysis of patient blood revealed polymorphic merozoites. To detect Babesia spp., PCR was performed using Babesia specific primers for β-tubulin, 18S rDNA, COB, and COX3 gene fragments. 18S rDNA analysis for Babesia sp., showed 98% homology with ovine Babesia sp. and with Babesia infections in Korea in 2005. Moreover, phylogenetic analysis of 18S rDNA, COB, and COX3 revealed close associations with B. motasi. For identifying the infectious agent, Haemaphysalis longicornis (296) and Haemaphysalis flava (301) were collected around the previous residence of the babesiosis patient. Babesia genes were identified in three H. longicornis: one sample was identified as B. microti and two samples were 98% homologous to B. motasi. Our study is the first direct confirmation of the infectious agent for human babesiosis. This case most likely resulted from tick bites from ticks near the patient house of the babesiosis patient. H. longicornis has been implicated as a vector of B. microti and other Babesia sp. infections.

Infection Status with Clinostomum complanatum Metacercariae in Fish from Water Systems of Nakdong-gang (River) in Korea

The infection status of Clinostomum complanatum metacercariae (CcMc) was broadly surveyed in fishes from water systems of Nakdong-gang (River) in the Republic of Korea (Korea) for 5 years. All 4,468 fishes collected were individually examined by the artificial digestion methods. No CcMc were detected in fishes from Naeseongcheon in Yecheon-gun, Gigyecheon in Gyeongju-si, Gyeongsangbuk-do, and Hamancheon in Haman-gun, Gyeongsangnam-do. In fishes from Wicheon in Gunwi-gun, Gyeongsangbuk-do, CcMc were detected in 180 (15.4%) out of 1,168 fishes and their intensity was 5.8 per fish infected. The prevalences with CcMc in positive fish species from 3 other surveyed areas, i.e., Banbyeoncheon in Yeongyang-gun, Nakdong-gang in Sangju-si and Hoecheon in Goryeong-gun, in Gyeongsangbuk-do were 19.3%, 33.3%, and 19.0% and their intensities were 1.5, 17.6, and 2.6 per fish infected respectively. In fishes from Yangcheon in Sancheong-gun, Gyeongsangnam-do, CcMc were detected in 811 (45.6%) out of 1,779 fishes examined and their intensity was 9.8 per fish infected. The prevalence was most high in Squalidus spp. (97.7%) and followed by acheilognathinid fish (66.8%), Pungtungia herzi (52.0%), rasborinid fish (39.6%) and Hemibarbus spp. (25.9%) from Yangcheon. The intensity was also most high in Squalidus spp. (27.0). The endemicity with CcMc was very low in fishes from water systems of Nakdong-gang in the east coast of Korea. Conclusively, it is confirmed that various fish species act as the second intermediate hosts of C. complanatum, and the endemicities of CcMc are more or less different by the fish species and group from Yangcheon, in Sancheong-gun, Gyeongsangnam-do, Korea

Severe vivax malaria in the Republic of Korea during the period 2000 to 2016

BACKGROUND

There has been a marked increase in the reporting of confirmed vivax malaria cases in certain geographical areas. This study investigated cases of severe vivax malaria in the Republic of Korea.

METHODS

We retrospectively reviewed the medical records of adult patients diagnosed with vivax malaria in the Republic of Korea during the period 2000 to 2016. Diagnosis was made using the World Health Organization criteria, with the exception of parasite density.

RESULTS

Among 1366 malaria cases, 255 (18.7%) were classified as severe vivax malaria, and 46 (3.4%) required intensive care. None of patients died of malaria. Patients with severe vivax malaria were older and had more comorbidity. The enrollment periods were classified into three groups, 2000 to 2005 (506 cases), 2006 to 2010 (696 cases), and 2011 to 2016 (304 cases). Malaria cases decreased from 2011 to 2016, but severe malaria cases increased significantly over time (14.3%, 20.1%, and 22.8%, p = 0.003). Common severe manifestations were shock (45.6%) and jaundice (43.1%).

CONCLUSIONS

Cases of severe malaria increased, and shock and jaundice were the predominant findings of severe vivax malaria in the Republic of Korea.

Infection Status with Clonorchis sinensis Metacercariae in Fish from Yangcheon (Stream) in Sancheong-gun, Gyeongsangnam-do, Korea

The infection status with Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fishes from Yangcheon (a branch of Gyeongho-gang), which is located in Sancheong-gun, Gyeongsangnam-do, the Republic of Korea. Total 2,201 fishes in 26 species were examined by the artificial digestion method through 7 years. CsMc were detected in 1,171 (53.2%) fishes in 21 spp. (80.8%) and their density was 85 per fish infected. Total 532 (99.6%) out of 534 Pungtungia herzi (index fish) examined were infected with 147 CsMc per fish infected. Metacercarial densities in this fish were highest in 2015 (179 CsMc), followed by 2012 (168), 2013 (152), 2016 (145), 2014 (114), and 2017 (89) respectively. In the gobioninid fish group, i.e., P. herzi, Sarcocheilichthys spp., Squalidus spp., Pseudogobio esocinus, Hemibarbus longirostris, and Hemibarbus labeo, 841 (92.7%) fishes were infected with 117 CsMc per fish infected. Total 250 (54.7%) acheilognathinid fish (bitterlings), Acheilognathus spp. and Acanthorhodeus spp. were infected with 5.8 CsMc. In the rasborinid fish (chubs) group, i.e., Zacco platypus, Zacco temminckii, and Zacco koreanus, 77 (13.7%) out of 563 fish examined were infected with 2.4 CsMc in average. The susceptibility indices of CsMc were 49.09 in the overall positive fish group, 104.15 in the gobioninid group, 3.17 in the acheilognathinid group and 0.35 in the rasborinid fish group respectively. Only 1 CsMc was detected in 3 fish species, Coreoperca herzi, Channa argus, and Lepomis macrochirus, respectively. Conclusively, it was confirmed that CsMc are moderately prevalent in fishes from Yangcheon in Sancheon-gun, Gyeongsangnam-do, Korea.

Abstract P4-14-04: Time course changes in serum FSH, estradiol, and menstruation restoration in premenopausal patients with breast cancer taking adjuvant tamoxifen after completing chemotherapy: A report from the ASTRRA study

BACKGROUND

Assessment of restoration of ovarian function after chemotherapy is critical with respect to the initiation of different types of endocrine treatment in young high risk breast cancer patients

METHODS

In total, 1289 women who remained premenopausal or resumed premenopausal status after chemotherapy were randomized to receive 5 years of tamoxifen or 5 years of tamoxifen plus 2 years of ovarian suppression. The patients who did not resume menstruation were followed up for 2 years with tamoxifen treatment after finishing chemotherapy. Prospectively collected consecutive post-chemotherapy hormone and menstruation data were available for 705 breast cancer patients who enrolled tamoxifen-only treatment group or did not resume menstruation during follow up. This analysis evaluated the proportion of patients with pre-menopausal FSH levels (<30 mIU/ml), E2 levels (340 pg/ml), and menstruation at any time point during treatment with tamoxifen.

RESULTS

During 5 years of tamoxifen treatment after chemotherapy for premenopausal breast cancer patients, 62% of patients resumed menstruation. Menstruation returned in 92% of patients under 35 years old but only in 31% of patients over 45 years old. Ovarian function, defined by serum FSH and E2 levels, resumed in 94% and 65% of patients, respectively, over 5 years. Most patients achieved ovarian function restoration during the first 2 years after chemotherapy, with 47.1% resuming menstruation and 86.2% and 50.3% achieving pre-menopausal FSH and E2 levels, respectively, in the first 2 years. Clinical factors related to menstruation restoration were younger age (HR = 6.38, 95% CI 1.33-3.47), 6 month hormone profile after chemotherapy (FSH<30: HR=1.67, 95% CI 1.28-2.17; E2 >40: HR=2.96, 95% CI 2.25-3.89), and anthracycline without taxane chemotherapy (HR=1.63, 95% CI 1.25-2.13).

CONCLUSIONS

During 5 years of tamoxifen treatment after chemotherapy, half of patients experienced menstruation restoration, including most very young patients under 35 years. The majority of patients experienced menstruation restoration in the first 2 years of tamoxifen treatment.

Citation Format: Kim HJ, Noh WC, Nam SJ, Park B-w, Lee ES, Im SA, Jung YS, Yoon JH, Kang SS, Park KH, Lee S-J, Jung J, Lee MH, Cho SH, Kim SY, Kim H-A, Han S-H, Han W, Hur MH, Ahn SH. Time course changes in serum FSH, estradiol, and menstruation restoration in premenopausal patients with breast cancer taking adjuvant tamoxifen after completing chemotherapy: A report from the ASTRRA study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-04.

Incidence and Risk Factors of Immediate Hypersensitivity Reactions Associated With Low-Osmolar Iodinated Contrast Media: A Longitudinal Study Based on a Real-Time Monitoring System

OBJECTIVES

We investigated the incidence of immediate hypersensitivity reaction (HSR) caused by different types of low-osmolar contrast media (LOCM) and cumulative exposure to LOCM.

METHODS

This cohort study included all consecutive patients who underwent LOCM-enhanced computed tomography from 2012 through 2014. We assessed 5 LOCM (iobitridol, iohexol, iomeprol, iopamidol, and iopromide). All patients were monitored for adverse events, and new symptoms and signs were recorded in real time using the Contrast Safety Monitoring and Management System (CoSM2oS).

RESULTS

The overall incidence of immediate HSR to LOCM was 0.97% (2004 events resulting from 205 726 exposures). Incidence differed significantly depending on whether the patient had a previous history of HSR to LOCM (0.80% in patients with no history and 16.99% in patients with a positive history of HSR to LOCM, P=.001). The incidence of HSR to individual LOCM ranged from 0.72% (iohexol) to 1.34% (iomeprol), although there were no significant differences across the 5 LOCM. A longitudinal analysis demonstrated that the incidence of HSR increased gradually with more frequent previous exposure to LOCM (HR=2.006 [95%CI, 1.517-2.653], P<.001). However, this cumulative increase in risk was observed in patients who had experienced HSR to LOCM, but not in those who had not.

CONCLUSION

The incidence of HSR did not differ significantly across the 5 LOCM assessed in the study. Repeated exposure to LOCM did not increase the risk of HSR among patients who had never experienced HSR to LOCM.

Infection Status of Isthmiophora hortensis Metacercariae in Dark Sleepers, Odontobutis Species, from Some Water Systems of the Republic of Korea

Present study was performed to survey on infection status of Isthmiophora hortensis (formerly Echinostoma hortense) metacercariae (IhMc) in dark sleepers, Odontobutis spp., from some water systems of the Republic of Korea. A total of 237 Odontobutis spp. was collected in the water systems of 5 rivers, i.e., Mangyeong-gang (gang means river), Geum-gang, Tamjin-gang, Seomjin-gang, and Nakdong-gang. They were all examined with artificial digestion method for 5 years (2013-2017). A total of 137 (57.8%) Odontobutis spp. were infected with 14.8 IhMc in average. The prevalence was the highest in Nakdong-gang areas (62.9%) and followed by in Mangyeong-gang (57.1%), Geum-gang (56.3%), Tamjin-gang (54.8%), and Seomjin-gang (53.9%) areas. Metacercarial densities were 28.1 (Geum-gang), 13.9 (Mangyeong-gang), 13.3 (Nakdong-gang), 13.1 (Tamjin-gang), and 2.3 (Seomjin-gang) per infected fish. Especially, in case of Yugucheon (cheon means stream), a branch of Geum-gang, IhMc were detected in all fish (100%) examined and their density was about 48 per fish. By the present study, it was confirmed that the infection status of IhMc is more or less different by the surveyed areas and the dark sleepers, Odontobutis spp., are suitable fish hosts of I. hortensis.

Osseous versus Nonosseous Spinal Epidural Arteriovenous Fistulas: Experiences of 13 Patients

BACKGROUND AND PURPOSE

Spinal epidural arteriovenous fistulas are rare vascular malformations. We present 13 patients with spinal epidural arteriovenous fistulas, noting the various presenting symptom patterns, imaging findings related to bone involvement, and outcomes.

MATERIALS AND METHODS

Among 111 patients with spinal vascular malformations in the institutional data base from 1993 to 2017, thirteen patients (11.7%) had spinal epidural arteriovenous fistulas. We evaluated presenting symptoms and imaging findings, including bone involvement and mode of treatment. To assess the treatment outcome, we compared initial and follow-up clinical status using the modified Aminoff and Logue Scale of Disability and the modified Rankin Scale.

RESULTS

The presenting symptoms were lower back pain (n = 2), radiculopathy (n = 5), and myelopathy (n = 7). There is overlap of symptoms in 1 patient (No. 11). Distribution of spinal epidural arteriovenous fistulas was cervical (n = 3), thoracic (n = 2), lumbar (n = 6), and sacral (n = 2). Intradural venous reflux was identified in 7 patients with congestive venous myelopathy. The fistulas were successfully treated in all patients who underwent treatment (endovascular embolization, n = 10; operation, n = 1) except 2 patients who refused treatment due to tolerable symptoms. Transarterial glue (n = 7) was used in nonosseous types; and transvenous coils (n = 3), in osseous type. After 19 months of median follow-up, the patients showed symptom improvement after treatment.

CONCLUSIONS

Although presenting symptoms were diverse, myelopathy caused by intradural venous reflux was the main target of treatment. Endovascular treatment was considered via an arterial approach in nonosseous types and via a venous approach in osseous types.

A New Standard DNA Damage (SDD) Data Format

Our understanding of radiation-induced cellular damage has greatly improved over the past few decades. Despite this progress, there are still many obstacles to fully understand how radiation interacts with biologically relevant cellular components, such as DNA, to cause observable end points such as cell killing. Damage in DNA is identified as a major route of cell killing. One hurdle when modeling biological effects is the difficulty in directly comparing results generated by members of different research groups. Multiple Monte Carlo codes have been developed to simulate damage induction at the DNA scale, while at the same time various groups have developed models that describe DNA repair processes with varying levels of detail. These repair models are intrinsically linked to the damage model employed in their development, making it difficult to disentangle systematic effects in either part of the modeling chain. These modeling chains typically consist of track-structure Monte Carlo simulations of the physical interactions creating direct damages to DNA, followed by simulations of the production and initial reactions of chemical species causing so-called "indirect" damages. After the induction of DNA damage, DNA repair models combine the simulated damage patterns with biological models to determine the biological consequences of the damage. To date, the effect of the environment, such as molecular oxygen (normoxic vs. hypoxic), has been poorly considered. We propose a new standard DNA damage (SDD) data format to unify the interface between the simulation of damage induction in DNA and the biological modeling of DNA repair processes, and introduce the effect of the environment (molecular oxygen or other compounds) as a flexible parameter. Such a standard greatly facilitates inter-model comparisons, providing an ideal environment to tease out model assumptions and identify persistent, underlying mechanisms. Through inter-model comparisons, this unified standard has the potential to greatly advance our understanding of the underlying mechanisms of radiation-induced DNA damage and the resulting observable biological effects when radiation parameters and/or environmental conditions change.

A 21.6 kDa tegumental protein of Clonorchis sinensis induces a Th1/Th2 mixed immune response in mice

Introduction

Clonorchis sinensis is a major parasite affecting the Korea population. Despite the high infection rate and pathogenicity, very few studies have been conducted to investigate the immune responses against the proteins of C. sinensis.

Methods

In this study, in vitro immune response induced by a recombinant 21.6 kDa tegumental protein derived from C. sinensis (rCsTegu21.6) was confirmed in murine dendritic cells and T cells. For the in vivo analysis, each mouse was immunized three times. Total serum IgG and T cell cytokine production were determined by ELISA, while T cell proliferation was detected by a WST (Water‐Soluble Tetrazolium salt)‐1 assay.

Results

In vitro tests indicated that rCsTegu21.6 treatment increased the expression of surface molecules, such as CD40 (77%), CD80 (52%) and CD86 (46%), on murine dendritic cells and the secretion of cytokines (TNF‐α, IL‐6, IL‐1β, IL‐10, and IL‐12p70). Moreover, co‐culturing dendritic cells activated by rCsTegu21.6 with allogenic T cells induced T cell proliferation over time. rCsTegu21.6 also stimulated specific antibody production and cytokine secretion [IL‐2, IL‐4, and interferon (IFN)‐γ)] from T cells following immunization in vivo. Notably, rCsTegu21.6 predominantly induced IgG1 production and secretion of the Th2 cytokine IL‐4, regardless of the type of adjuvant used.

Conclusion

These results serve as a foundation for the development of tegumental protein‐based vaccines against C. sinensis.

Development of Molecular Diagnosis Using Multiplex Real-Time PCR and T4 Phage Internal Control to Simultaneously Detect Cryptosporidium parvum, Giardia lamblia, and Cyclospora cayetanensis from Human Stool Samples

This study aimed to develop a new multiplex real-time PCR detection method for 3 species of waterborne protozoan parasites (Cryptosporidium parvum, Giardia lamblia, and Cyclospora cayetanensis) identified as major causes of traveler's diarrhea. Three target genes were specifically and simultaneously detected by the TaqMan probe method for multiple parasitic infection cases, including Cryptosporidium oocyst wall protein for C. parvum, glutamate dehydrogenase for G. lamblia, and internal transcribed spacer 1 for C. cayetanensis. Gene product 21 for bacteriophage T4 was used as an internal control DNA target for monitoring human stool DNA amplification. TaqMan probes were prepared using 4 fluorescent dyes, FAMTM, HEXTM, Cy5TM, and CAL Fluor Red® 610 on C. parvum, G. lamblia, C. cayetanensis, and bacteriophage T4, respectively. We developed a novel primer-probe set for each parasite, a primer-probe cocktail (a mixture of primers and probes for the parasites and the internal control) for multiplex real-time PCR analysis, and a protocol for this detection method. Multiplex real-time PCR with the primer-probe cocktail successfully and specifically detected the target genes of C. parvum, G. lamblia, and C. cayetanensis in the mixed spiked human stool sample. The limit of detection for our assay was 2×10 copies for C. parvum and for C. cayetanensis, while it was 2×103 copies for G. lamblia. We propose that the multiplex real-time PCR detection method developed here is a useful method for simultaneously diagnosing the most common causative protozoa in traveler's diarrhea.

Prevention and Control Strategies for Parasitic Infections in the Korea Centers for Disease Control and Prevention

Korea is successfully controlled intestinal parasitic infections owing to economic development and high health consciousness. The Division of Vectors and Parasitic Diseases (formerly the Division of Malaria and Parasitology) is in the Center for Laboratory Control of Infectious Diseases of the Korea Centers for Disease Control and Prevention. It has been the governmental agency responsible for controlling and leading scientific research on parasitic diseases. The Division of Vectors and Parasitic Diseases has conducted and funded basic research and disseminated the research results to various medical fields, ultimately promoting public health in Korea. Among the noteworthy achievements of this division are the national surveillance of healthcare-associated parasitic infections, prevention and control for parasitic infections, and the elimination of lymphatic filariasis from Korea. On a broader scale, the division's research programs and academic supports were influential in preventing and treating infectious parasitic diseases through public policies and laws. In this review, we summarize the past and present role of the Division of Vectors and Parasitic Diseases in preventing and treating infectious parasitic diseases in Korea.

Early development of de novo hepatocellular carcinoma after direct-acting agent therapy: Comparison with pegylated interferon-based therapy in chronic hepatitis C patients

Patients with chronic hepatitis C who achieve a sustained viral response after pegylated interferon therapy have a reduced risk of hepatocellular carcinoma, but the risk after treatment with direct-acting antivirals is unclear. We compared the rates of early development of hepatocellular carcinoma after direct-acting antivirals and after pegylated interferon therapy. We retrospectively analysed 785 patients with chronic hepatitis C who had no history of hepatocellular carcinoma (211 treated with pegylated interferon, 574 with direct-acting antivirals) and were followed up for at least 24 weeks after antiviral treatment. De novo hepatocellular carcinoma developed in 6 of 574 patients receiving direct-acting antivirals and in 1 of 211 patients receiving pegylated interferon. The cumulative incidence of early hepatocellular carcinoma development did not differ between the treatment groups either for the whole cohort (1.05% vs 0.47%, P = .298) or for those patients with Child-Pugh Class A cirrhosis (3.73% vs 2.94%, P = .827). Multivariate analysis indicated that alpha-fetoprotein level >9.5 ng/mL at the time of end-of-treatment response was the only independent risk factor for early development of hepatocellular carcinoma in all patients (P < .0001, hazard ratio 176.174, 95% confidence interval 10.768-2882.473) and in patients treated with direct-acting agents (P < .0001, hazard ratio 128.402, 95% confidence interval 8.417-1958.680). In conclusion, the rate of early development of hepatocellular carcinoma did not differ between patients treated with pegylated interferon and those treated with direct-acting antivirals and was associated with the serum alpha-fetoprotein level at the time of end-of-treatment response.

Infections with Centrocestus armatus Metacercariae in Fishes from Water Systems of Major Rivers in Republic of Korea

The infection status of Centrocestus armatus metacercariae (CaMc) was broadly surveyed in freshwater fishes from major river systems in the Republic of Korea (Korea) during 2008–2017. A total of 14,977 fishes was caught and examined by the artificial digestion method. CaMc were detected in 3,818 (97.1%) (2,114 Z. platypus: 96.1% and 1,704 Z. temminckii: 98.4%) out of 3,932 Zacco spp. examined and their density was 1,867 (2,109 in Z. platypus and 1,567 in Z. temminckii) per fish infected. The prevalences with CaMc were high, 93.7–100%, in Zacco spp. from all surveyed areas. However, their densities were more or less different by the surveyed areas and fish species. They were most high in Nakdong-gang in Gyeongsangnam-do (4,201 in average), and followed by Geum-gang (2,343), Nakdong-gang in Gyeongsangbuk-do (1,623), Han-gang (1,564), Tamjin-gang and Yeongsan-gang (1,540), streams in the east coast (1,028), Seomjin-gang (488) and Mangyeong-gang (170). In another species of rasborinid fish, Opsariichthys uncirostris amurensis, CaMc were detected in 222 (74.8%) out of 297 ones examined and their density was 278 (1–4,480) per fish infected. CaMc were also detected in total 41 fish species except for the rasborinid fish, Z. platypus, Z. temminckii and O. uncirostris amurensis. Conclusively, it was confirmed that among the 3 species of rasborinid fish, Z. platypus and Z. temminckii are highly prevalent and O. uncirostris amurensis is moderately prevalent with CaMc. Additionally, we could know that variety of fish species act as the second intermediate hosts of C. armatus in Korea.

Infection Status with Metagonimus spp. Metacercariae in Fishes from Seomjin-gang and Tamjin-gang in Republic of Korea

To grasp the infection status of Metagonimus spp. metacercariae (MsMc), the freshwater fishes were surveyed from Seomjin-gang (river) and Tamjin-gang in the Republic of Korea. Total 1,604 fishes from 7 local sites of Seomjin-gang and 1,649 fishes from 2 sites of Tamjin-gang were examined for 6 years (2012–2017) by the artificial digestion method. MsMc were detected in fishes from 7 sites, i.e., Osucheon in Imsil-gun (36.3% fish in 6 spp.), Seomjin-gang in Sunchanggun (49.8% in 18 spp.), Songdaecheon in Namwon-si (64.5% in 8 spp.), Seomjin-gang in Gokseong-gun (72.4% in 14 spp.) and in Gurye-gun (78.8% in 17 spp.), Hoengcheon (75.9% in 11 spp.) and Namsancheon (58.9% in 7 spp.) in Hadong-gun. Their average densities were 4.2, 86.8, 39.9, 43.1, 246.5, 173.6 and 67.5 per fish infected respectively. Prevalence with MsMc in rasborinid fish from Seomjin-gang was 89.2% and their intensity was 73.6 per fish infected. Endemicities of MsMc in rasborinid fish from Seomjin-gang were significantly higher in fishes from the lower reaches (prevalence: 98.7%; density: 137) rather than in fishes from the middle (93.5%; 38) and upper (72.4%; 13) reaches. MsMc were also detected in 56.1% and 66.4% fishes from 2 surveyed areas, i.e., the middle reaches in Jangheung-gun and the lower reaches in Gangjin-gun, of Tamjin-gang, and their densities were 147 and 121 per fish infected. In susceptible fishes from Tamjin-gang, the prevalence was 84.1% and density was 227 per fish infected. By the present study, it was confirmed that MsMc is highly prevalent in the fishes from Seomjin-gang and Tamjin-gang in Korea.

Infections with Zoonotic Trematode Metacercariae in Yellowfin Goby, Acanthogobius flavimanus, from Coastal Areas of Republic of Korea

To investigate the infection status of zoonotic trematode metacercariae in yellowfin goby, Acanthogobius flavimanus, from coastal areas of the Republic of Korea (Korea), we examined total 344 gobies from 21 localities with an artificial digestion method from 2013 to 2017. The metacercariae of Stictodora lari were most frequently detected in 45.3% goby from 7 localities, i.e., Taean-gun (Chungcheongnam-do), Gochang-gun (Jeollabuk-do), Muan-gun, Shinan-gun, Haenam-gun (Jeollanam-do), Hadong-gun and Goseong-gun (Gyeongsangnam-do). Their infection rates were 90.0%, 66.7%, 46.7%, 8.0%, 3.3%, 26.7%, and 86.7% and intensities were 1,090, 6.2, 1.6 1.0, 2.0, 2.0, and 7.2 metacercariae per fish infected respectively. Heterophyopsis continua metacercariae were found in 38.2% goby from 6 localities, i.e., Gochang-gun, Muan-gun, Shinan-gun, Gangjin-gun, Boseong-gun (Jeollanam-do) and Goseong-gun, and their intensities were relatively low, 1–21 metacercariae. Stictodora fuscata metacercariae were detected in 61.3% goby from 4 localities, i.e., Taean-gun, Gochang-gun, Hadong-gun and Goseong-gun. Their infection rates were 90.0%, 53.3%, 5.9%, and 73.3% and intensities were 1,081, 3.1, 3.0, and 10.2 metacercariae per fish infected respectively. Heterophyes nocens metacercariae were found in 55.0% goby from Muan-gun and Shinan-gun. Total 3 metacercariae of Isthmiophora hortensis were detected in 2 (8.0%) gobies from Shinan-gun. Total 15 metacercariae of Centrocestus armatus were detected in 5 gobies (33.3%) from Gyeongpo-ho (ho means lake) in Gangneung-si, Gangwon-do. The present study suggests that yellowfin goby, A. flavimanus, acts as the infection sources of zoonotic intestinal flukes in western and southern coastal areas than in eastern coastal areas of Korea.

Venom allergen-like protein 28 in Clonorchis sinensis: four epitopes on its surface and the potential role of Cys124 for its conformational stability

Venom allergen-like (VAL) proteins are important to host-parasite interactions. We previously demonstrated that a Clonorchis sinensis VAL (CsVAL) protein-derived synthetic peptide suppresses allergic and inflammatory responses. However, little is known regarding the physicochemical and antigenic properties of CsVAL proteins. Here, we identified a novel 194 amino acid VAL protein, named C. sinensis VAL 28 (CsVAL28), and characterized its functional motifs and structural details as a new member of the CAP superfamily. Unlike members of the Schistosoma mansoni VAL (SmVAL) family, CsVAL28 has a single CAP1 motif and six highly conserved disulfide bond-forming cysteines. Tertiary models of wild-type CsVAL28 and mutants were built using SmVAL4 as template via homology modeling. Normal mode analysis predicted that disulfide bond breaking by mutation of cysteine 124 to serine would greatly affect protein mobility. Four major immunoreactive linear epitopes were identified in the surface-exposed region or its vicinity via epitope mapping, using sera from clonorchiasis patients and healthy controls. Our findings provide in-depth knowledge on the structure-function properties of VAL proteins and may help determine highly antigenic regions for developing new diagnostic approaches.

Infection Status with Clonorchis sinensis Metacercariae in Fish from Tamjin-gang (River) in Jeollanam-do, Republic of Korea

The present study was performed to investigate the infection status with Clonorchis sinensis metacercariae (CsMc) in fishes from 2 sites, the middle and lower reaches, of Tamjin-gang (River) in Jeollanam-do, the Republic of Korea. Total 1,132 fishes in 22 species were collected from the middle reaches in Jangheung-gun for 4 years (2014–2017) and 517 fishes in 17 species were also collected from the lower reaches in Gangjin-gun in 2014 and 2017. They were all individually examined with the artificial digestion method in our laboratory. CsMc were detected in 322 (28.5%) out of 1,132 fishes from Jangheung-gun, and in 161 (31.1%) out of 517 fishes from Gangjin-gun, and their densities were 51 and 57 per fish infected each. In the fish species with CsMc, positive rates were 61.5% in Jangheung-gun and 62.7% in Gangjin-gun. A total of 222 Pungtungia herzi were examined and they were all infected with CsMc. The average intensity was 103 CsMc in the index fish, P. herzi (95 in Jangheung-gun and 121 in Gangjin-gun). In P. herzi bimonthly examined in 2017, the intensity was commonly most higher in March in 2 surveyed sites, however the significant seasonal endemicity was not showed. Conclusively, it was confirmed that CsMc is more or less prevalent in fishes from Tamjin-gang and their endemicity is higher in fish from the lower reaches in Gangjin-gun than the middle reaches in Jangheung-gun in Jeollanam-do, Korea.