Studies on Intestinal Trematodes in Korea III. Natural Human Infections of Pygidiopsis sμmma and Heterophyes heterophyes nocens

Abstract

The small intestinal flukes of the family Heterophyidae Ohdner, 1914 are classified into 22 genera (Yamaguti, 1958). Total 8 genera among them, i. e., Heterophyes , Heterophyopsis, Metagonimus, Stellaηtchasmus ， Centrocestus , Haplorchis , Pygidiopsis and Proceroνum had been reported human parasitic (Komiya et Suzuki, 1966). However, human infections other than these genera are supposed to be possible also , because heterophyid fluke infections are one of zoonoses In nature. When they infect human intestines, severe enteritis may occur. And the symptoms caused by them are closely related with the number of infected worms. Really, their infections tend to be passed unnoticed when the worm burden is low. Furthermore, Heterophyes , Stellantchasmus and Haplorchis were reported to cause fatal extraintestinal heterophyidiasis by spreading eggs into the blood stream (Africa et al. , 1940). Among the heterophyid flukes in Korea , Metagoηimus yokogawai is the only species that was proved to be prevalent in inhabitants along several rivers and streams, and its medical im portance has been studied sufficiently until now However, even a human case of heterophyid flukes other than M. yokogawai has not been recorded yet. Only the distribution of some !lukes was recorded by detecting metacercariae from piscine hosts. Heterophyes was reported by Seo et al. (1980) , Stellantchasmus was by Sco et al. (1979) , Ceηtrocestus was by Choi et al. (1964) and Pygidiopsis was by Chun (1963) . The authors found small heterophyid eggs which were very similar to those of Cloηorchis si:ηeηsis but apparently smaller in size , from 8 cases during a stool examination of inhabitants in Okku area , North Cholla Do (Fig. 1) in 1979. And all the cases were proved to be infected with Pygidiopsis summa by obtaining adult worms after treatment with bithionol. And from the most heavily infected case, a few worms of Heterophyes and Metagoηimus were col lected concomitantly. Therefore, this is the first record on human infection cases of Pygidiopsis and Heterophyes in Korea.