Purpose: This study aimed to investigate whether proteins present in the molting membranes of third-stage (L3) Anisakis larvae could serve as potential risk factors for allergic reactions. Methods: Third-stage larvae (L3) of Anisakis spp. were primarily collected from mackerels and cultured in vitro to yield both molting membranes and fourth-stage (L4) larvae. Major soluble proteins in the molting membranes were identified using SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis). Crude antigens extracted from L3, L4, and the molting membranes were subsequently evaluated by western blotting using sera from Anisakis-infected rabbits and patients with eosinophilia. Results: Antigens derived from the molting membranes reacted with sera from Anisakis-infected rabbits as well as with sera from 7 patients with eosinophilia of unknown origin. These findings suggest that unidentified proteins in the molting membranes of Anisakis L3 may contribute to early allergic reactions, particularly in patients sensitized by specific molecular components. Conclusion Our results indicate that proteins present in the molting membranes of third-stage Anisakis spp. larvae may be associated with allergic responses. Further studies are required to confirm the correlation between these membranes and Anisakis-induced allergies.

Purpose: This study aimed to investigate whether proteins present in the molting membranes of third-stage (L3) Anisakis larvae could serve as potential risk factors for allergic reactions. Methods: Third-stage larvae (L3) of Anisakis spp. were primarily collected from mackerels and cultured in vitro to yield both molting membranes and fourth-stage (L4) larvae. Major soluble proteins in the molting membranes were identified using SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis). Crude antigens extracted from L3, L4, and the molting membranes were subsequently evaluated by western blotting using sera from Anisakis-infected rabbits and patients with eosinophilia. Results: Antigens derived from the molting membranes reacted with sera from Anisakis-infected rabbits as well as with sera from 7 patients with eosinophilia of unknown origin. These findings suggest that unidentified proteins in the molting membranes of Anisakis L3 may contribute to early allergic reactions, particularly in patients sensitized by specific molecular components. Conclusion Our results indicate that proteins present in the molting membranes of third-stage Anisakis spp. larvae may be associated with allergic responses. Further studies are required to confirm the correlation between these membranes and Anisakis-induced allergies.

Purpose: This study aimed to investigate whether proteins present in the molting membranes of third-stage (L3) Anisakis larvae could serve as potential risk factors for allergic reactions. Methods: Third-stage larvae (L3) of Anisakis spp. were primarily collected from mackerels and cultured in vitro to yield both molting membranes and fourth-stage (L4) larvae. Major soluble proteins in the molting membranes were identified using SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis). Crude antigens extracted from L3, L4, and the molting membranes were subsequently evaluated by western blotting using sera from Anisakis-infected rabbits and patients with eosinophilia. Results: Antigens derived from the molting membranes reacted with sera from Anisakis-infected rabbits as well as with sera from 7 patients with eosinophilia of unknown origin. These findings suggest that unidentified proteins in the molting membranes of Anisakis L3 may contribute to early allergic reactions, particularly in patients sensitized by specific molecular components. Conclusion Our results indicate that proteins present in the molting membranes of third-stage Anisakis spp. larvae may be associated with allergic responses. Further studies are required to confirm the correlation between these membranes and Anisakis-induced allergies.

Purpose: This study aimed to investigate whether proteins present in the molting membranes of third-stage (L3) Anisakis larvae could serve as potential risk factors for allergic reactions. Methods: Third-stage larvae (L3) of Anisakis spp. were primarily collected from mackerels and cultured in vitro to yield both molting membranes and fourth-stage (L4) larvae. Major soluble proteins in the molting membranes were identified using SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis). Crude antigens extracted from L3, L4, and the molting membranes were subsequently evaluated by western blotting using sera from Anisakis-infected rabbits and patients with eosinophilia. Results: Antigens derived from the molting membranes reacted with sera from Anisakis-infected rabbits as well as with sera from 7 patients with eosinophilia of unknown origin. These findings suggest that unidentified proteins in the molting membranes of Anisakis L3 may contribute to early allergic reactions, particularly in patients sensitized by specific molecular components. Conclusion Our results indicate that proteins present in the molting membranes of third-stage Anisakis spp. larvae may be associated with allergic responses. Further studies are required to confirm the correlation between these membranes and Anisakis-induced allergies.

Purpose: This study aimed to investigate whether proteins present in the molting membranes of third-stage (L3) Anisakis larvae could serve as potential risk factors for allergic reactions. Methods: Third-stage larvae (L3) of Anisakis spp. were primarily collected from mackerels and cultured in vitro to yield both molting membranes and fourth-stage (L4) larvae. Major soluble proteins in the molting membranes were identified using SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis). Crude antigens extracted from L3, L4, and the molting membranes were subsequently evaluated by western blotting using sera from Anisakis-infected rabbits and patients with eosinophilia. Results: Antigens derived from the molting membranes reacted with sera from Anisakis-infected rabbits as well as with sera from 7 patients with eosinophilia of unknown origin. These findings suggest that unidentified proteins in the molting membranes of Anisakis L3 may contribute to early allergic reactions, particularly in patients sensitized by specific molecular components. Conclusion Our results indicate that proteins present in the molting membranes of third-stage Anisakis spp. larvae may be associated with allergic responses. Further studies are required to confirm the correlation between these membranes and Anisakis-induced allergies.

Background: A nationwide anti-parasite control program (1969–1995) successfully reduced soil-transmitted helminth infections; however, fish-borne trematode infections persisted in some areas. Since the 2012 National Parasite Infection Survey, information on the current status of intestinal helminth infections has not been updated. Analysis of the current trends in intestinal helminth infections is necessary to prevent and manage parasitic diseases in Korea. Methods: This retrospective study analyzed the prevalence of intestinal parasites in 1,211,799 individuals who visited 16 regional branches of the Korea Association of Health Promotion between 2011 and 2020. Examinations were performed using microscopy and Kato's method. The results were analyzed according to parasite species, year, sex, age, and region of origin. Results: Intestinal helminth infections remained above 2.0% from 2011 to 2014 but decreased to 1.0% by 2020. Clonorchis sinensis had the highest infection rate (1.3%), followed by Metagonimus yokogawai (0.3%) and Trichuris trichiura (0.2%). Men had a higher infection rate (2.4%) than that of women (1.2%). The infection rate was higher among those in their 50s (2.0%), 60s, and older (1.8%). The highest regional infection rates were observed in Gyeongnam (4.8%), Ulsan (3.1%), Gyeongbuk (2.5%), Busan (1.8%), and Jeonnam (1.6%). Conclusion These results provide valuable insights into the decreasing prevalence and epidemiological characteristics of intestinal helminth infections in the Korean population.Therefore, various control measures are needed to prevent intestinal helminth infections, and continuous monitoring is essential until they are eradicated.

Life cycle stages, including daughter sporocysts, cercariae, and metacercariae, of Parvatrema duboisi (Dollfus, 1923) Bartoli, 1974 (Digenea: Gymnophallidae) have been found in the Manila clam Ruditapes philippinarum from Aphaedo (Island), Shinan-gun, Jeollanam-do, Korea. The daughter sporocysts were elongated sac-like and 307-570 (av. 395) μm long and 101-213 (av. 157) μm wide. Most of the daughter sporocysts contained 15-20 furcocercous cercariae each. The cercariae measured 112-146 (av. 134) μm in total length and 35-46 (av. 40) μm in width, with 69-92 (av. 85) μm long body and 39-54 (av. 49) μm long tail. The metacercariae were 210-250 (av. 231) μm in length and 170-195 (av. 185) μm in width, and characterized by having a large oral sucker, genital pore some distance anterior to the ventral sucker, no ventral pit, and 1 compact or slightly lobed vitellarium, strongly suggesting P. duboisi. The metacercariae were experimentally infected to ICR mice, and adults were recovered at day 7 post-infection. The adult flukes were morphologically similar to the metacercariae except in the presence of up to 20 eggs in the uterus. The daughter sporocysts and metacercariae were molecularly (ITS1-5.8S rDNA-ITS2) analyzed to confirm the species, and the results showed 99.8-99.9% identity with P. duboisi reported from Kyushu, Japan and Gochang, Korea. These results confirmed the presence of various life cycle stages of P. duboisi in the Manila clam, R. philippinarum, playing the role of the first as well as the second intermediate host, on Aphae-do (Island), Shinan-gun, Korea.

Human infection with Taenia asiatica or a hybrid between Taenia saginata and T. asiatica has not been reported in Cambodia. We detected for the first time a hybrid form between T. saginata and T. asiatica in Preah Vihear Province, Cambodia. An adult tapeworm specimen, i.e., 75 cm long strobila without scolex, was expelled from a 27-year-old man after praziquantel medication and purging. It was morphologically indistinguishable between T. saginata and T. asiatica. Several proglottids were molecularly analyzed to confirm the tapeworm species. The mitochondrial gene encoding cytochrome c oxidase subunit 1 (cox1) and nuclear genes encoding elongation factor-1α (ef1) and ezrin-radixin-moesin (ERM)-like protein (elp) were sequenced, and a single-allele analysis was performed to confirm the haploid genotype. The results revealed that our sample showed a discrepancy between the mitochondrial and 2 nuclear genes. It possessed homozygous sequences typical of T. saginata at cox1 and ef1 loci. However, it was heterozygous at the elp locus, with 1 allele in T. asiatica (elpA) and 1 in T. saginata (elpC), which indicates that it is a hybrid between T. saginata and T. asiatica. The present results confirmed the presence of a hybrid between T. saginata and T. asiatica in Cambodia and strongly suggest the existence of also ‘pure’ T. asiatica in Cambodia.

A 12-year nationwide survey (2008-2019) was performed to investigate the prevalence of Enterobius vermicularis infection among preschool children in Seoul, 4 large cites (Busan, Incheon, Daegu, and Ulsan), and 9 provinces (grouped into 5 localities) in the Republic of Korea (=Korea). The survey was carried out once a year by 16 regional offices of the Korea Association of Health Promotion. The cello-tape perianal swab method (1 smear per child) was applied to detect eggs of E. vermicularis and other helminths. According to the results, the egg positive rate of E. vermicularis infection in 2008-2009 was 1.8-2.0%, but it decreased gradually to 0.6% in 2019 (P<0.05). The prevalence was significantly higher in boys (0.7-5.0%, mean 1.8%) than in girls (0.5-2.8%, mean 1.3%) (P<0.05). The 2 most southern localities, Jejudo (Province) and Jeolla-do (inclusive of Jeollabuk-do and Jeollanam-do) and a mid-western province, Gyeonggi-do, revealed higher prevalences, whereas Seoul and Gangwon-do showed lower prevalences. The results indicate that a low-grade prevalence of E. vermicularis infection (less than 4%) has been maintained for the recent 12 years among preschool children in Korea. Continuous monitoring of enterobiasis in the child age group is necessary in Korea.

Acanthoparyphium shinanense n. sp. (Digenea: Echinostomatidae) is described from chicks experimentally infected with the metacercariae encysted in 2 brackish water clam species, Ruditapes philippinarum and Coecella chinensis, in the Republic of Korea. The metacercariae were round to oval, armed with 23 collar spines, and 0.216 (0.203-0.226) mm in diameter. From 5 chicks experimentally infected each with 200 metacercariae, 34 juvenile (5-day-old worms) and 104 adult flukes (7-day-old worms) were harvested from their small intestines, with the average worm recovery rate of 13.8%. The adult flukes were 3.18 (2.89-3.55) mm long and 0.68 (0.61-0.85) mm wide, with an elongated, posteriorly tapering body, and a prominent head collar armed with 23 collar spines arranged in a single uninterrupted row. The posterior testis of A. shinanense was longitudinally elongated, which is similar to Acanthoparyphium spinulosum Johnston, 1917 but unique from the other closely related species, including Acanthoparyphium tyosenense Yamaguti, 1939, Acanthoparyphium kurogamo Yamaguti, 1939, and Acanthoparyphium marilae Yamaguti, 1934. The eggs of A. shinanense were larger than those of A. spinulosum, and the anterior extent of 2 lateral groups of vitellaria was slightly more limited in A. shinanense than in A. spinulosum. Molecular analysis of nuclear and mitochondrial genes revealed low homology with A. spinulosum from USA (96.1% in 5.8S rRNA) and Ukraine (97.9% in 28S rRNA), Acanthoparyphium n. sp. from USA (98.0% in 28S rRNA), and Acanthoparyphium sp. from Australia, Kuwait, and New Zealand. Biological characteristics, including its first intermediate host and natural definitive hosts, as well as its zoonotic capability, should be elucidated.