Environmental studies on paragonimiasis in Korea

[Study on the analysis of snails(Semisulcospira libertina), the first intermediate host of Paragonimus westermani in the Haenam area]

Studies of the water analysis of the breeding place of the first intermediate host(Semisulcospira libertina) was carried out. The breeding place of Semisulcospira libertina in the Haenam area were found mainly in pebbly and sandy riverbed of the upper stream and halfway up the Donghae river, but we could not find the habitats of Semisulcospira libertina in the spring, paddyfield and tidal part of flow in which the content of Cl ion, Ca ion, total alkalinity, total hardness and pH were obviously higher than those of the breeding place. The range of physical and chemical characters of the Semisulcospira libertina breeding water were as follows. 0.05-0.7 m/s of optimal flowing velocity of fresh water, 20-50 cm in depth, 7.12+/-0.17 of optimal pH range 19.4+/-4.92(mg/l)in total alkalinity, 9.4+/-2.97(mg/l) of Ca ion, 9.8+/-2.3(mg/l) of Cl ion content, 115.1+/-34.2(mg/l) of total hardness, but there were no remarkable differences between the habitat water and the contrasts in their specific gravities. In the comparison of analytical result of the breeding water at Haenam, the content of Ca ion, Cl ion, total alkalinity, total hardness and pH showed a gradually higher value in the lower reaches of the river than those of the upper stream and halfway up the river.