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.

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.

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.

Taenia saginata infection has seldom been reported in Cambodia. In this study, we performed a survey of intestinal parasites in 1,156 residents of Preah Vihear and Stung Treng Provinces in 2018. The results revealed that 26 (2.4%) cases were positive for Taenia spp. eggs. In order to obtain the strobilae of the tapeworms, 2 patients in Preah Vihear were treated with praziquantel and purged with magnesium salts. The proglottids expelled after the medication were morphologically and molecularly analyzed to determine the species. The main uterine lateral braches in gravid proglottids were >15 in number suggesting that they are either T. saginata or Taenia asiatica. The sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and 2 nuclear loci, elongation factor-1 alpha (ef1) and ezrin-radixin-moesin-like protein (elp), were identical to the sequences of T. saginata available in GenBank but distant from Taenia solium, T. asiatica, and T. saginata-T. asiatica hybrid. This is the first report of the presence of T. saginata in the northern part of Cambodia bordering Lao PDR based on a molecular confirmation.

Gymnophallid metacercariae found in the Manila clam Ruditapes philippinarum (‘Banjirak’ in Korean) from Gochang-gun, Jeollabuk-do, Korea were morphologically and molecularly confirmed to be Parvatrema duboisi (Dollfus, 1923) Bartoli, 1974. The metacercariae were morphologically characterized by having a large oral sucker, small ventral sucker, genital pore some distance anterior to the ventral sucker, no ventral pit, and 1 compact or slightly lobed vitellarium, which were all compatible with P. duboisi. Some of the metacercariae were experimentally fed to mice, and adult flukes were recovered at day 7 post-infection. The morphology of the adult flukes was basically the same as that of the metacercariae except for the presence of uterine eggs; the uterus was filled with up to 40 eggs. The nucleotide sequences (1,193 bp) from ITS regions (ITS1, 5.8S rDNA, and ITS2) of the metacercariae showed 99.7% identity with P. duboisi and 75.7% identity with Gymnophalloides seoi deposited in GenBank. These results confirmed the presence of P. duboisi metacercariae in the Manila clam R. philippinarum in an estuary region of Gochang-gun, Korea.

The Chinese edible frogs, Hoplobatrachus rugulosus (n=20), and the striped snakehead fish, Channa striata (n=34), were purchased from local markets in 3 administrative regions of Cambodia (Phnom Penh, Pursat, and Takeo Provinces) from May 2017 to April 2019, and their infection status with Gnathostoma sp. larvae was investigated. The frogs and fish were transported to the laboratory with ice and examined using the artificial digestion method. Advanced 3rd-stage larvae (AdL3) of Gnathostoma spinigerum, 24 in total number (1-6 larvae/frog), were detected from 6 (60.0%) out of 10 frogs purchased from Phnom Penh. No gnathostome larvae were detected in 10 frogs purchased from Takeo Province and 34 snakeheads from Phnom Penh, Pursat, and Takeo Provinces. AdL3 isolated from the frogs were 2.55- 3.90 mm long and 0.31-0.36 mm wide. They had a characteristic head bulb (0.081×0.191 mm in average size) with 4 rows of hooklets, a muscular long esophagus (0.950-1.230 mm long), and 2 pairs of cervical sacs (0.530-0.890 mm long). The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. These features were consistent with G. spinigerum AdL3. By the present study, it has been first confirmed that the Chinese edible frog, H. rugulosus, from Phnom Penh serves as a second intermediate host for G. spinigerum, although their intensity of infection was not so high compared to other previously reported localities.