title: Comparative morphology of minute intestinal fluke eggs that can occur in human stools in the republic of Korea.
abstract: The egg morphology of minute intestinal flukes (MIF) that can occur as human infections in the Republic of Korea, i.e., Metagonimus yokogawai, M. miyatai, M. takahashii, Heterophyes nocens, Heterophyopsis continua, Stellantchasmus falcatus, Stictodora fuscata, Pygidiopsis summa, and Gymnophalloides seoi, was studied in comparison with Clonorchis sinensis. The adult worms were obtained from residents of endemic areas, and their intrauterine eggs were studied and measured using light microscopy; the length, width, length-width ratio (LWR), and Faust-Meleney index (FMI). Several specimens were processed for scanning electron microscopy (SEM), and before gold-coating, the uterine portion of each fluke was etched with a sharp pin in order to expose the eggs. The MIF eggs were ovoid, pyriform, or elliptical with a size range of 21-35×12-21 µm. S. fuscata eggs revealed the highest FMI (largest in the area) and lowest LWR, whereas P. summa eggs showed the lowest FMI and medium LWR. SEM revealed that G. seoi and S. fuscata had remarkably clean shell surface lacking the muskmelon-like structure which is prominent in C. sinensis eggs. In Metagonimus spp., H. continua, H. nocens, and S. falcatus eggs, minute surface ridges were recognizable though less prominent compared with C. sinensis. On the surface of P. summa eggs, thread-like curly structures were characteristically seen. The results revealed that important differential keys for MIF eggs include the length, width, area (FMI), shape of the eggs, and the extent of the muskmelon-like structure or ridges on their shell surface and operculum.
authors.affiliation: Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul National University Medical Research Center, Seoul, Korea.
authors.forename: Jin-Joo
authors.initials: JJ
authors.lastname: Lee
authors.forename: Bong-Kwang
authors.initials: BK
authors.lastname: Jung
authors.forename: Hyemi
authors.initials: H
authors.lastname: Lim
authors.forename: Mi Youn
authors.initials: MY
authors.lastname: Lee
authors.forename: Sung-Yil
authors.initials: SY
authors.lastname: Choi
authors.forename: Eun-Hee
authors.initials: EH
authors.lastname: Shin
authors.forename: Jong-Yil
authors.initials: JY
authors.lastname: Chai
mesh_terms: D000818:Animals; D005243:Feces / Q000469:parasitology*; D005260:Female; D008853:Microscopy; D056910:Republic of Korea; D014200:Trematoda / Q000145:classification* / Q000302:isolation & purification / Q000648:ultrastructure; D014599:Uterus / Q000166:cytology; D015053:Zygote / Q000145:classification / Q000648:ultrastructure