2 71

Cited 0 times in

Paragonimus westermani의 폐장에 이르는 이동경로 및 태도에 관한 연구

Other Titles
 Experimental studies on the route of larval migration of Paragonimus westermani 
Issue Date
[영문] Yokogawa (1915) and several other workers reported that the excysted larvae of Paragonimus westermani in intestine reached the lungs via intestinal wall, peritoneal cavity, diaphragm and pleural cavity. Although Nakagawa (1951) and Ando (1915) found the presence of Paragonimus larvae in the abdominal wall muscle of experimental animals, they considered those findings were as one of the heterotopic parasitism. However, recently Yokogawa et al (1962) conducted more detailed experiments on the migration routes of Paragonimus westermani in cats and rats, and they found the larvae in peritoneal cavity migrated into abdominal muscle as a normal route. Yokogawa (1957) and Takizawa (1964) reported that the migration routes varied according to the species of host: favorable or unfavorable. Recently Yokogawa (1957) found that the larvae in the abdominal muscle of favorable hosts returned to the peritoneal cavity before taking the route to the lungs, but not always in unfavorable hosts. Especially in unfavorable hosts there were no reliable reports concerning the further route of the larvae from the abdominal muscle, although some of them reached the lungs. The present studies were designed to clarify which was the normal route of larval migration of Paragonimus westermani and secondly to confirm whether the lungs were the favorite site for the development of the parasites among organs of the host, specially in the unfavorable ones. Materials and methods The metacercariae of Paragonimus westermani were obtained from naturally infected fresh water crabs, Eriocheir japonicus, in the endemic area of Koheung. 20∼50 metacercariae were fed to rats, rabbits, cats and dogs by means of a syringe. 0.3% of Evans-blue(Merk) solution was injected into veins of rats with 15cc/kg and of rabbits with 10cc/kg. 15 minutes after the injection of Evans-blue solution, the animals were sacrificed by bleeding from the carotid arteries, and the larvae were detected in muscle and other tissues at the Evans-blue spots. Migration route of the larva in the muscle could be observed along stained lines. In another series, the larvae which were collected from abdominal muscles of the rabbits were introduced into vascular, muscular and nervous systems of the experimental animals which were sacrificed 10-83 days after the inoculation. External jugular vein, carotid artery, splenius muscle, spinal lumen and hemisulcus of large brain were selected as the injection parts of the larvae. Morphological studies of the larvae in various developmental stages from various tissues were conducted as follows: worms were fixed in A.F.A. fixatives and 2-3 worms in each group were stained with Semichon's carmin, for microscopical studies. Results Ⅰ. Migration route of Paragonimus westermani to lungs in unfavorable hosts. A. Location and number of worms recovered in rabbits and rats at various times after feeding the metacercariae of Paragonimus westermani. Number of worms were recovered only in abdominal muscles 3 days after the feeding of metacercariae, and they were found in the diaphragm, thoracic muscles and thigh regions of the rabbits from 6 days after the feeding. Among rats, none of the excysted larvae were found in any other part except the abdominal wall on the 6th day after the feeding of metacercariae. It was considered that majority of the worms migrated through abdominal muscles to diaphragm and thoracic muscles, and they did not return to the peritoneal cavity from the abdominal wall contrary to the report by Yokogawa (1957) in favorable hosts. B. Intermuscular migration of the larvae in abdominal wall of rabbits and rats. In this observation the abdominal wall was divided into four regions on each side of the abdomen, and the presence of the worms were calculated by timed observation. Majority of the worms in the abdominal muscle showed the direction of migration to diaphragm and backward up to psoas muscle. C. The migration route and the direction of muscle fiber of abdominal wall. 57.1-82.4% of the larvae which were recovered in the abdominal muscle of rabbits showed upward migration parralelling the muscle fiber direction and 6.3-15.0% of the larvae showed downward migration. The larvae which migrated across the muscle fiber were only 6.7-28.6% and 0-6.3% of the larvae did not migrate in direction. D. Migrating distance and growth rate of the larvae in abdominal muscle, thoracic muscle and pleural cavity. At 10 days after the feeding of the metacercariae, the migrating distance was 6.3cm in average among the larvae which migrated into abdominal wall, 9.5cm among the larvae that migrated from abdominal muscle to diaphragm, and 13.4cm from abdominal muscle to thoracic muscle. The differences of migration distances of the worm observed at various times, 3,6,10 days after the feeding of the metacercariae were considered significant. However, the significant differences could not be observed in migration distances 10 and 15 days after the feeding. It was assumed that the disappearance of hemorrhagic line and migrating route were due to natural healing mechanism in the muscle. The size (body length) of the larvae collected 3 days after the feeding was 0.73mm and it was, as a standard, used in comparison with the size and growth rate of the larvae at various times and regions. 20 days after the feeding of the metacercariae, the worms in the pleural cavity showed 4.4mm of growth rate, while the larvae in abdominal muscle and thoracic muscle showed only 2.4 and 2.3mm respectively. It was found that the larvae staying in muscle showed low growth rate. Ⅱ. Migration route of Paragonimus larvae which were introduced into various systems of the final hosts. A. External jugular vein. The migration figures of the larvae which were introduced into the vein showed same tendency with the group of oral administration. The larvae in abdominal muscle migrated to the pleural cavity and lungs and they developed to matured stage. B. Carotid artery. Although migration figures were similar to the larvae introduced into the external jugular vein it was considered that one third of the larvae were found in peritoneal cavity even 40 days and 52 days after the larvae were introduced. The larval migration to thoracic muscles could not be recognized in the cases introduced into the external jugular vein, but in the group of carotid artery injection, 17% of the larvae were found in the thoracic muscle. Most of the worms migrated to the lungs, and none of the worms remaind in the central nervous system. C. Splenius muscle in cervical region. The migration of larvae to biceps and triceps muscle were observed coinciding with the direction of muscle fiber and it was observed that the migration route was from thoracic muscle to pleural cavity along the direction of muscle fibers of the external oblique muscle. The development of the worms in muscle could not be recognized except slight development of the suckers and guts. However the development of general morphology were observed in the worms found in the pleural cavity at 50 days in rabbits and 30 days in dogs. D. The excysted larvae which were introduced into the spinal lumen or hemisulcus of large brain of rabbits or rats. The introduced larvae did not stay, nor develop in the cerebrospinal system 50 days after the infection. However, in cats 60% of the matured worm were found in lung and thoracic cavity 80 days after the infection. Summary The metacercariae or young worms of Paragonimus westermani were fed orally to cats and dogs as favorable hosts, and rats and rabbits as unfavorable hosts. The excysted larvae or young worms of the same parasite were introduced into vein, muscle or nervous system of the above animals. 1. The locations of the young worms in unfavorable hosts at various times after the feeding of the metacercariae of Paragonimus westermani was as follows: a. In rabbits larvae were found in abdominal muscle on the 3rd day, in the diaphragm on the 6th day and in the thoracic cavity on the 20th day after the feeding of the metacercariae. b. In rats larvae were found only in abdominal muscle on the 4th day, in the diaphragm on the 6th day and in the thoracic cavity on the 18th day after the feeding. 2. The larvae reached to the abdominal muscles of unfavorable hosts did not return to the peritoneal cavity except for a few cases. 3. Larvae in the abdominal muscles generally migrated upward along the muscle fibers to diaphragm and thorax. 4. The larvae stationed in muscles developed poorly compared to the worms which migrated into the pleural cavity. 5. The larvae which were introduced into the carotid artery, jugular vein, intermuscular layer in neck portion or central nervous system showed the tendency to gather in lungs regardless the unfavorable hosts (rats and rabbits) and favorable hosts (cats and dogs). Through the present study, it is concluded that the larvae in the abdominal muscle do not return to the peritoneal cavity, but migrate upward along the muscle fibers. All the worms inoculated into various parts of the body showed the tendency to migrate toward the thoracic cavity regardless of the type of host.
Appears in Collections:
2. Thesis / Dissertation (학위논문) > 1. College of Medicine (의과대학) > Ph.D. (박사)
사서에게 알리기
Full Text
Files in This Item:
제한공개 원문입니다.
RIS (EndNote)
XLS (Excel)


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.