Prevalence of sparganum in the frog (Rana nigromaculata) was surveyed in Dae-jeon city and in suburbs of the city, Chungnam Do. 39 (3.9 per cent) out of 1,011 frogs were infected with the worm, and the highest prevalence rate of sparganum was found the frogs from Shintanjin area(11.3 per cent). Infection rates of sparganum were observed due to the body weight and sex of frogs. The highest infection rate of frogs, the body weight of 50 gms or more, showed 30.3 per cent(female: 41.7 per cent, male: none), on the other hand, no worm was found in young frogs(less than 10 gms). Distribution of sparganum in the frogs was recorded and 82.6 per cent of worms were distributed in the femoral intermuscular connective tissues of the hind legs. Among those infected frogs, number of worm burden was one to five worms, and 53.3 per cent of frogs were infected by only one worm.
parasitology-helminth-cestoda ; Spirometra sp. ; sparganum ; sparganosis ; epidemiology ; frog ; Rana nigromaculata

A total of 220 tadpoles was captured in 6 areas and total 117 frogs, Rana nigromaculata, were collected in 11 areas in Korea. They were examined for their infecion status by the metacercariae of Fibricola seoulensis by peptic digestion technique and by histological observation with hematoxylin-eosin staining. This study was carried out from August 1983 to September 1984. Followings are the results. The tadpoles of R. nigromaculata were positive for the metacercariae from 3.3 percent to 100 percent by area. The number of metacercariae per infected tadpole ranged from 1 to 584, and the mean number per tadpole ranged from 7.6 to 221 by area. The metacercariae from 16 tadpoles were counted by the body portion. A great majority of the metacercariae was collected from abdominal cavity, 98.3 percent of 484 counted larvae. And 6(1.2 percent) larvae were from proximal tail and 2(0.4 percent) from trunk. Histological sections of tadpoles showed many metacercariae in abdominal cavity but none in other parts. The larvae were free in the spaces among intestinal loops or around primitive liver. A few larvae were in duct-like tissues near trunk wall. There was little infiltration of inflammatory cells. The metacercarial infection rates of frogs ranged from 0 percent to 100 percent by area. The larval burden was 1 to 470 by infected frogs, and mean number ranged from 1 to 175.6 by area. By above results, it is suggested that the cercariae of F. seoulensis may infect R. nigromaculata already in the stage of tadpole. Almost all of the metacercariae were concentrated in abdominal cavity of tadpoles. According to the infection status of frogs, this fluke is prevalent almost nation-widely in rice paddies in Korea.
parasitology-helminth-trematoda ; Fibricola seoulensis ; epidemiology ; metacercaria ; frog ; tadpole ; Rana nigromaculata

The life cycle of Fibricola seoulensis was studied in the laboratory and in the field, with special interests in the larval developments within the eggs and in the intermediate hosts. The first emergence of miracidia after incubation of eggs in 26C water began on the ninth day. The miracidia, elongate and cylindrical shape, had epidermal plates in the formula of 6, 9, 4 and 3, with two pairs of flame cells and lateral processes. A kind of fresh water snail, Hippeutis (H.) cantori, was found to shed furcocercous cercariae from the 13th day after experimental challenge with miracidia while Physa acuta failed to shed. The same kind of snail collected from the field also shed the same cercariae. The cercariae were equipped with 2 pairs of penetration glands and 5 pairs of flame cells. The tadpoles of Rana nigromaculata were found susceptible to experimental infection with the cercariae. The same kind of tadpoles collected from various areas were also found naturally infected. The metacercariae in the tadpoles which were infected experimentally became infective to the definitive host in 21 days. The metacercariae were located free in the body cavity of tadpoles, and attained sexual maturity in rats in 7 days. The present study successfully followed the complete life cycle of F. seoulenis and found that it is possible to maintain the life cycle in the laboratory.
parasitology-helminth-termatoda ; Fibricola seoulensis ; biology ; rat ; Hippeutis cantori ; Rana nigromaculata ; Physa acuta ; intermediate host

This study was carried out to confirm the infection source of the human case of Fibricola seoulensis, and to reveal out a part of its life cycle in Korea. Also the morphological characteristics of the metacercaria were described. The results were summarized as follows: Rana nigromaculata and Natrix tigrina lateralis were found to be infected naturally by the metacercariae(diplostomula) of F. seoulensis. The metacercarial capsule was round to elliptical in tissue of the intermediate hosts with a long diameter 0.232 - 0.385 mm. Liberated metacercariae were ovoid with small conical posterior body. Body length measured 0.199 - 0.312 mm and width 0.153 - 0.252 mm. The infection rate of R. nigromaculata by the metacercariae ranged from 87% to 100% by area, and the number of the larvae ranged from 3 to 390 by frog. The metacercariae were found in skeletal muscle of frogs, from head to hindlegs. All examined N. t. lateralis were found to be infected by the metacercariae with the range of numbers frome 3 to 35,918. The larvae were collected from all viscera and body segments except for the head of the snakes. However, a great majority of the metacercariae were collected from the stomach. Hematoxylin-eosin stained preparations of frog skeletal muscle and snakes stomach revealed that the metacercariae had no cyst wall of worm origin, but encapsulated by the host tissue. Some of them were found in dilated lymphatic vessels. The larval infection was associated with slight or severe inflammatory reaction even with granuloma formation. By above results, it was concluded that the frog, Rana nigromaculata, was the second intermediate host, and the snake Natrix tigrina lateralis was a paratenic host of F. seoulensis in nature in Korea.
parasitology-helminth-trematoda ; Fibricola seoulensis ; metacercaria ; host ; frog ; Rana nigromaculata ; Rana rugosa ; Natrix tigrina lateralis ; Elaphae dione ; Dinodon rufozonatum rufozonatum ; Agkistrodon blomhoffi brevicaudus ; epidemiology

An investigation on the trematodes of Korean amphibians was carried out during the period from April to September of 1976. A total of 883 amphibians of 6 species were examined. These frogs, toads and salamanders were collected in the areas of the Han river side. And also these amphibians comprised 775 Rana nigromaculata, 53 Rana rugosa, 21 Hyla arborea japonica, 2 Bufo bufo gargarizans, 2 Gallula tornieri and 30 Hynobius leechi. Out of the results of this work, 7 species of trematodes belonging to 2 orders were found as follows: Monogenea: Diplorchis ranae Ozaki, 1931. Digenea: Diplodiscus japonicus (Yamaguti , 1936), Gorgodera japonica Yamaguti, 1936, Haematoloechus sibiricus japonicus(Yamaguti, 1936) , Mesocoelium brevicaecum Ochi, 1929, Loxogenes liberum Seno,1980, Pleurogenoides japonicus (Yamaguti, 1936).
parasitology-helminth-trematoda ; monogenea ; digenea ; epidemiology ; frog ; Rana nigromaculata ; Rana rugosa ; Hyla arborea japonica ; Bufo bufo gargarizans ; Gallula tornieri ; Hynobius leechi ; Diplorchis ranae ; Diplodiscus japonicus ; Gorgodera japonica ; Haematoloechus sibiricus japonicus ; Mesocoelium brevicaecum ; Loxogenes liberum ; Pleurogenoides japonicus