Studies on the Lungfluke Paragonimus iloktsuenensis Chen, 1940

Abstract

During the period of August, 1970 to February, '1971, 52 rodent hosts (Rattus noruegicus, Rattus rattus and Apodemus agrariusy collected from the two areas at the estuaries of the Nakdong and the Sumjin Rivers, South Kyongsang Do, Korea were examined to prove the presence of P. iloktsuenensis of which metacercariae have already been found in the crab hosts (Sesarma dehaani) at the one of the above two areas. The results of this survey are as follows: Five rats, Rattus noruegicus (12.5%) were found to be infected with the adult worms was obtained. These worms are enclosed singly in the worm capsules in the right lobe of the lung. The detailed study on the morphology of the adult worms collected was made for the specific diagnosis and the comparative observation with the worms obtained from albino rats experimentally infected with the metacercariae of P. iloktsuenensis, were also conducted for the definite identification. The following structural characteristics are recognized; the cuticular spines are mostly grouped in single rows, indicating those of ohirai-iloktsuenensis type by Miyazaki (1965). The feature of ovary branched into a coral appearence closely coincides with the Chen's original description of P. iloktsuenensis. The average ratio of the size of the testis to the ovary is 2. 62: 1. The average ratio of body length to the distance between the anterior end and the middle of the acetabulum is 2. 76: 1. The shape of eggs is subspindle (67%). The maximum width of eggs is noticed on the middle of the egg (77%). These observations are closely resembled to those described on the known specimens of P. iloktsuenensis by Isshiki (1962) and Tornimura (1959). From the above observations, it is certainly assumed that the present specimen is identical with Paragonimus iloktsuenensis Chen, 1940. Therefore, this is the first account of the occurrence of P. iloktsuenensis in the natural final host, Rattus noroegicus in Korea.