Studies On Intestinal Trematodes In Korea: VII. Growth, Development And Recovery Of Fibricola Seoulensis From Experimentally Infected Rats And Mice.

This study was carried out to observe the growth and development of Fibricola seoulensis in experimentally infected rats and mice. The metacercariae were obtained from naturally infected Natrix tigrina lateralis which were collected in Hoengseong Gun, Gangweon Do, in August 1982. The results were summarized as follows. 1. Growth and development of worm were not different between the rat and mouse. Body growth was attained within a week in both hosts. The testes differentiated first on the 2nd day after infection, and then ovary on the 3rd day, vitelline follicles on the 4th day, vitelline reservoir on the 5th day. A few eggs appeared in uterus on the 5th day and in feces on the 6th day. The body length grew almost linearly for the first 7 days after infection. The growth of posterior body was more remarkable, and the ratio of posterior body length to that of anterior body increased to 1.099 until 4 weeks after infection. 2. The worms of 4weeks age in rats measured 1.10~1.92 mm long and 0.511~0.696 mm wide. The morphological characteristics of adult worms were identical to the original description of F. seoulensis, though dimensions varied in wider range. 3. The worms were recovered from the rats 12.5% on the day after infecion, and the rate ranged 21.0~59.0% up to 6th day. One week after infection, the rates were 42.6%, 60.9% and 43.9% respectively by the metacercarial group of 200, 1,000 and 2,000 and the rates decreased to 16.2%, 29.1% and 3.1% respectively by the group on the 4th week after infection. Most of the worms were recovered from duodenum, and a part of worms were found in jejunum or ileum in heavily infected rats. 4. The worms of 23.5~63.5% were recovered from mice from 3 to 10 days after infection. A great majority of them was found in duodenum, too.