All issues > Volume 10(4); 1967

Original Article

J Korean Pediatr Soc. 1967;10(4):219-230. Published online April 30, 1967.

Environmental studies on Paragonimiasis

Duk Jin Yun¹, Ki Yung Lee¹, Yung Kyum Ahn¹, Yoon Ho Lee¹

¹Department of Pediatrics,Yonsei University College of Medicine

Abstract

Environmental studies regarding Paragonimiasis have been done in Sulak-Myun, Kapyung-Goon, Yongmoon-Myun, Yangpyung-Goon, both of which are considered wactive” endemic areas and in Byukje-Myun, Koyang-Goon, an arrested area. 1. Paragonimiasis is still active in the Uhmso-river, Sulak-Myun, Kapyung-Goon where 49% of crayfish contained Paragonimus metacercaria and snails which is the first intermediate host of Paragonimus westermani were moderately present. In the Oonke-river, Yongmoon-Myun, Yang-pyung-Goon, crayfish which is the second intermediate host of Paragonimus westermani, were caught in every areas of the river, but snails were not caught in any areas of both branches of the river and were caught in areas which were located below the junction. In the Daeja-river, Byukje-Myun, Koyang-Goon crayfish were caught only in the upper stream of the river and snails were not caught in any areas of the river. 2.The results described above are attributed to the fact that snails, which have minimal mobility and vitality, were completely obliterated by the long unprecedented drought in 1965 contrasted to crayfish with strong mobility and vitality which survived Thus without the snail, the life cycle of Paragonimus westermani become incomplete and the clinical disease, obsolete. 3.Rainfall is very important to maintain water flow in the river, a necessary factor for the life cycle of Paragonimus westermani, therefore, we have charted the amount of rainfall in the Seoul and Choonchun areas in 1965 compared to the average of the past 30 years in order to ascertain the degree of drought which influenced the Paragonimus westermani hosts and cohabitants. 4.The geographic conditoin which is also very important in maintaining water flow in the small rivers was investigated and the conclusion drawn, that a long river has a superior advantage to a short during the drought; a tortuous river provides a better opportunity for miracidia of Paragoni-mus westermani eggs to migrate to snails and Paragonimus cercaria to invade crayfish than a str-aight rapidly flowing river. 5.We must conclude that man may ingest Paragonimus metacercaria by drinking water frcxn shallow wells and streams in the endemic areas of Paragonimiasis when we note that one crayfish of four caught in shallow wells of Kapyung-Goon contained many Paragonimus metacercaria. 6.The increase of traffic due to the expanding population in Korean farm areas; the increase in the use of farm chemicals which seep into the river and reduce the number of snails, crayfish and crabs available as potential hosts. 7.In recent years, the wild vertebrata in the mountains, one of the important terminal hosts of Paragonimus westermani are remarkably reduced in number, which may have contributed in decreasing Paragonimiasis as directly infective to man. 8.Health education on Paragonimiasis informing the people of the dangers of eating raw or inadequatly cooked crayfish and carbs or those soaked less than 10 days in soysauce and drinking the water from shallow wells and streams, is demonstrated to have decreased the incidence of this disease. 9.Because of the preceding facts, Paragonimiasis in Kyunggi-Province is being decreased.

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