• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.248-288
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• 2022

The study on vascular plants of Gayasan National Park was conducted in 2016 over a period of 34 days from March to October 2016. As the study, a total of 768 taxa were recorded, including 118 families, 396 genera, 691 species, 15 subspecies, 51 varieties, and 11 forms. In the vascular plants, four endangered wild plants were recorded, Ponerorchis cucullata (L.) X.H.Jin, Trientalis europaea var. arctica (Fisch.) Ledeb., Cypripedium macranthos Sw., and Pedicularis hallaisanensis Hurus. Taxa of Least Concern (LC) or higher level on National Red List published by the Ministry of Environment of Korea were 21 taxa for example Tricyrtis macropoda Miq., and Lilium cernuum Kom. A total of 37 Korean endemic plants were investigated for example Abies koreana E.H.Wilson and Impatiens atrosanguinea (Nakai) B.U.Oh & Y.P.Hong. A total of 162 taxa of floristic regional indicators (3^rd to 5^th degree) were investigated including 9 taxa of V, 15 taxa of IV, 38 taxa of III, 45 taxa of II, and 53 taxa of I. Naturalized plants were recorded a total of 46 taxa with a Naturalization Index of 6.0%, the Urbanization Index was calculated to be 14.3% and 5 taxa of ecosystem disturbance plants were investigated such as Sicyos angulatus L., Rumex acetosella L., and Humulus scandens (Lour.) Merr. As the result of comparison with previous studies, in this study a total of 206 taxa were newly identified including 62 families, 144 genera, 184 species, 2 subspecies, 15 varieties, and 5 forms.

• Parasites, Hosts and Diseases
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• v.60 no.4
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• pp.241-246
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• 2022

Felids are the unique definitive host of Toxoplasma gondii. The intestine of felid is the only site for initiating Toxoplasma gondii sexual reproduction. T. gondii excretes millions of infectious oocysts from the intestine, which are the primary source of infection. There are many difficulties in developing vaccines and drugs to control oocyst excretion due to the lack of an appropriate experimental model. Here, we established an in vitro feline intestinal epithelial cell (IEC) infection system and an efficient animal model of T. gondii Chinese 1 genotype, Wh6 strain (TgCtwh6). The Kunming mice brain tissues containing TgCtwh6 cysts were harvested 42-day post-infection. The bradyzoites were co-cultured with cat IECs in vitro at a ratio of 1:10. Five 3-month-old domestic cats were orally inoculated with 600 cysts each. The oocysts were detected by daily observation of cat feces by microscopy and polymerase chain reaction. We found that the parasite adhered and invaded cat IECs in vitro, transformed into tachyzoites, and then divided to form rose-like structures. These parasites eventually destroyed host cells, escaped, and finished the asexual reproduction process. Schizonts associated with sexual reproduction have not been observed during development in vitro cultured cells. However, schizonts were detected in all infected cat intestinal epithelial cells, and oocysts were presented in all cat feces. Our study provides a feasible cell model and an efficient infection system for the following studies of T. gondii sexual reproduction, and also lays a foundation to develop drugs and vaccines for blocking excretion and transmission of oocysts.

• Parasites, Hosts and Diseases
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• v.60 no.1
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• pp.65-71
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• 2022

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a zoonotic, tick-borne RNA virus of the genus Bandavirus (Family Phenuiviridae), mainly reported in China, Japan, and the Republic of Korea (Korea). For the purpose of this study, a total of 3,898 adult and nymphal ticks of species Haemaphysalis longicornis (94.2%), Haemaphysalis flava (5.0%), Ixodes nipponensis (0.8%), and 1 specimen of Ixodes ovatus, were collected from the Deogyusan National Park, Korea, between April 2016 and June 2018. A single-step reverse transcriptase-nested PCR was performed, targeting the S segment of the SFTSV RNA. Total infection rate (IR) of SFTSV in individual ticks was found to be 6.0%. Based on developmental stages, IR was 5.3% in adults and 6.0% in nymphs. The S segment sequences obtained from PCR were divided into 17 haplotypes. All haplotypes were phylogenetically clustered into clades B-2 and B-3, with 92.7% sequences in B-2 and 7.3% in B-3. These observations indicate that the Korean SFTSV strains were closer to the Japanese than the Chinese strains. Further epidemiological studies are necessary to better understand the characteristics of the Korean SFTSV and its transmission cycle in the ecosystem.

• Journal of Naturopathy
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• v.8 no.2
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• pp.78-87
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• 2019

Purpose: The aim was to collect and classify the Cordyceps parasitized in cicadas from July to October every year from 1990 to 2016 in Korea. And they were frequently collected in Nepal, Vietnam, Japan, China, and Thailand. Methods: Cordyceps parasitizing cicadas collected in mountains and fields. Results: A total of 1,104 specimens were collected that belonged to 10 different species under nine genera. The highest number of samples belonged to Ophiocordyceps (563 specimens), followed by Isaria (361 specimens), Polycephalomyces (73 specimens), Cordyceps (70 specimens), Beauveria (25 specimens), Perennicordyceps (8 specimens), Metarhizium (2 specimens) and Purpureocillium (2 ones). Among Ophiocordyceps spp. O. longissima was most frequently collected with a total of 426 samples out of 563, followed by O. heteropoda with 120 ones and O. sobolifera with 17 specimens. The species mainly collected in Korea, but C. ishikariensis was collected in Nepal only. The new characteristic was that Isaria cicada-like synnemata were found growing together with C. ishikariensis stromata on the same host. In Korea, the collected 691 specimens in total out of 1,104 were found in Mt. Halla in Jeju Island. Other mountains in Korea where the samples were collected were Mountains Daeryong, Jiri, Yongmoon, Samag, Seolag, Gujeol, Duryun, Baegam, Chilgap, Chundeung, Naejang, Welchul, and Daeryong. The three samples were not identified. Conclusions: A total of 1,104 specimens belonged to 10 different species under nine genera, and the collected 691 samples were found in Mt. Halla in Jeju Island.

• Parasites, Hosts and Diseases
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• v.59 no.6
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• pp.615-623
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• 2021

Human sparganosis is a food-borne parasitic disease caused by the plerocercoids of Spirometra species. Clinical diagnosis of sparganosis is crucial for effective treatment, thus it is important to identify sensitive and specific antigens of plerocercoids. The aim of the current study was to identify and characterize the immunogenic proteins of Spirometra erinaceieuropaei plerocercoids that were recognized by patient sera. Crude soluble extract of the plerocercoids were separated using 2-dimensional gel electrophoresis coupled with immunoblot and mass spectrometry analysis. Based on immunoblotting patterns and mass spectrometry results, 8 antigenic proteins were identified from the plerocercoid. Among the proteins, cysteine protease protein might be developed as an antigen for diagnosis of sparganosis.

• Parasites, Hosts and Diseases
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• v.59 no.6
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• pp.625-634
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• 2021

Based on the field investigations in 91 investigation sites (counties) in southwest China between 2001 and 2019, the present paper reported the chigger mites on A. agrarius mice in southwest China for the first time by using a series of statistical methods. From 715 striped field mice captured in 28 of 91 investigated sites, only 255 chiggers were collected, and they were identified as 14 species, 6 genera in 3 subfamilies under 2 families. Of 715 A. agrarius mice, only 24 of them were infested with chigger mites with low overall prevalence (P_M=3.4%), overall mean abundance (M_A=0.36 mites/host) and overall mean intensity (M_I=10.63 mites/host). The species diversity and infestation of chiggers on A. agrarius were much lower than those previously reported on some other rodents in southwest China. On a certain species of rodent, A. agrarius mouse in southwest China seems to have a very low susceptibility to chigger infestations than in other geographical regions. Of 14 chigger species, there were 3 dominant species, Leptotrombidium sialkotense, L. rupestre and Schoengastiella novoconfuciana, which were of aggregated distribution among different individuals of A. agrarius hosts. L. sialkotense, one of 6 main vectors of scrub typhus in China, was the first dominant on A. agrarius. The species similarity of chigger mites on male and female hosts was low with C_SS=0.25, and this reflects the sex-bias of different genders of A. agrarius mice in harboring different chigger species.

• Parasites, Hosts and Diseases
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• v.60 no.1
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• pp.39-43
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• 2022

Plasmodium vivax exhibits dormant liver-stage parasites, called hypnozoites, which can cause relapse of malaria. The only drug currently used for eliminating hypnozoites is primaquine. The antimalarial properties of primaquine are dependent on the production of oxidized metabolites by the cytochrome P450 isoenzyme 2D6 (CYP2D6). Reduced primaquine metabolism may be related to P. vivax relapses. We describe a case of 4 episodes of recurrence of vivax malaria in a patient with decreased CYP2D6 function. The patient was 52-year-old male with body weight of 52 kg. He received total gastrectomy and splenectomy 7 months before the first episode and was under chemotherapy for the gastric cancer. The first episode occurred in March 2019 and each episode had intervals of 34, 41, and 97 days, respectively. At the first and second episodes, primaquine was administered as 15 mg for 14 days. The primaquine dose was increased with 30 mg for 14 days at the third and fourth episodes. Seven gene sequences of P. vivax were analyzed and revealed totally identical for all the 4 samples. The CYP2D6 genotype was analyzed and intermediate metabolizer phenotype with decreased function was identified.

• Parasites, Hosts and Diseases
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• v.61 no.3
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• pp.282-291
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• 2023

Despite the recent progress in public health measures, malaria remains a troublesome disease that needs to be eradicated. It is essential to develop new antimalarial medications that are reliable and secure. This report evaluated the pharmacokinetics and antimalarial activity of 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) using the rodent malaria parasite Plasmodium berghei in vivo. After a single oral dose (75 mg /kg) of N-89, its pharmacokinetic parameters were measured, and t_1/2 was 0.97 h, T_max was 0.75 h, and bioavailability was 7.01%. A plasma concentration of 8.1 ng/ml of N-89 was maintained for 8 h but could not be detected at 10 h. The dose inhibiting 50% of parasite growth (ED₅₀) and ED₉₀ values of oral N-89 obtained following a 4-day suppressive test were 20 and 40 mg/kg, respectively. Based on the plasma concentration of N-89, we evaluated the antimalarial activity and cure effects of oral N-89 at a dose of 75 mg/kg 3 times daily for 3 consecutive days in mice harboring more than 0.5% parasitemia. In all the N-89-treated groups, the parasites were eliminated on day 5 post-treatment, and all mice recovered without a parasite recurrence for 30 days. Additionally, administering oral N-89 at a low dose of 50 mg/kg was sufficient to cure mice from day 6 without parasite recurrence. This work was the first to investigate the pharmacokinetic characteristics and antimalarial activity of N-89 as an oral drug. In the future, the following steps should be focused on developing N-89 for malaria treatments; its administration schedule and metabolic pathways should be investigated.

• Parasites, Hosts and Diseases
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• v.61 no.3
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• pp.317-324
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• 2023

Standard- and large-sized eggs of Trichuris trichiura were found in the feces of schoolchildren in Yangon, Myanmar during epidemiological surveys and mass deworming with albendazole in 2017-2019. The standard-sized eggs were identified as those of T. trichiura, but it was necessary to exclude the possibility of the large-sized eggs belonging to Trichuris vulpis, a dog whipworm. We conducted morphological and molecular studies to determine the species of the 2 types of Trichuris eggs. Individual eggs of both sizes were isolated from Kato-Katz fecal smears (n=20) and mechanically destroyed using a 23G injection needle. Nuclear DNA was extracted, and the 18S rRNA region was sequenced in 15 standard-sized eggs and 15 large-sized eggs. The average size of standard-sized eggs (T. trichiura) was 55.2×26.1 ㎛ (range: 51.7-57.6×21.3-28.0 ㎛; n=97), whereas the size of large-sized eggs was 69.3×32.0 ㎛ (range: 65.1-76.4×30.1-34.5 ㎛; n=20), slightly smaller than the known size of T. vulpis. Regarding standard-sized eggs, the 18S rRNA nucleotide sequences exhibited 100% homology with T. trichiura deposited in GenBank and 88.6-90.5% homology with T. vulpis. Regarding large-sized eggs, the nucleotide sequences showed 99.8-100% homology with T. trichiura in GenBank and 89.6-90.7% homology with T. vulpis. Both standard- and large-sized eggs of Trichuris spp. found in Myanmar schoolchildren during 2017-2019 were morphologically and molecularly confirmed to belong to T. trichiura. The conversion of eggs from smaller to large sizes might be due to anthelmintic treatments with albendazole.

• Parasites, Hosts and Diseases
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• v.61 no.3
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• pp.272-281
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• 2023

Chigger mites are the vector of scrub typhus. This study estimates the infestation status and ecological characteristics of chiggers on the chestnut white-bellied rat Niviventer fulvescens in Southwest China between 2001 and 2019. Chiggers were identified under the microscope, and infestation indices were calculated. The Preston's log-normal model was used to fit the curve of species abundance distribution. A total of 6,557 chiggers were collected in 136 of 342 N. fulvescens rats, showing high overall infestation indices (prevalence=39.8%, mean abundance=19.2, mean intensity=48.2) and high species diversity (S=100, H'=3.0). Leptotrombidium cangjiangense, Neotrombicula japonica, and Ascoschoengastia sifanga were the three dominant chigger species (constituent ratio=42.9%; 2,736/6,384) and exhibited an aggregated distribution among different rat individuals. We identified 100 chigger species, with 3 of them (Leptotrombidium scutellare, Leptotrombidium wenense, and Leptotrombidium deliense) as the main vectors of scrub typhus in China and nine species as potential vectors of this disease. Disease vector occurrence on N. fulvescens may increase the risk of spreading scrub typhus from rats to humans. Chigger infestation on N. fulvescens varied significantly in different environments. The species abundance distribution showed a log-normal distribution pattern. The estimated number of chigger species on N. fulvescens was 126 species.