To understand the mode of transmission in clonorchiasis, a survey was made in Kim-hae Goon, South Kyong-sang Do (=Province). The mathematical analysis of the age prevalence was done on the egg positive rates. And another analysis for the comparison was also made to the cited data from two areas, North Kyong-sang Do and Ko-yang Goon, Kyong-gi Do. Some catalytic models of H. Muench (1959) were applied to the observed age prevalence. Because the both parameters, such as force of infection(a) and loss of positivity(b) were considered to be constant for a long period in the surveyed area, the two stage catalytic model by Muench was chosen to the analysis. In the surveyed area, Kim-hae Goon where the egg positive rates were 56.2 percent and 61.2 percent (by Kim, 1974), the constant values of 'a' were found to be 0.051 and 0.089 respectively. In other words, the force of infection was 51, 89 per 1,000 susceptibles. The values of 'b' were found to be 0.006 and 0.005. This means that the rates of disappearance from egg positive cases to negative were 6 and 5 per annum per l,000 positive cases in above area. Therefore, the two catalytic curves were expressed by the following equations, y = 1.133 {e(-0.006t) - e(-0.051t)} and y = 1.047 {e(-0.005t) - e(-0.089t)} respectively. In the cases of North Kyong-sang Do and Ko-yang Goon, Kyong-gi Do where the egg positive rates of clonorchis shown as 27.7 percent and 15.2 percent by Shin (1964) and Kim (l974), the curves were expressed by y = 1.769 {e(-0.010t) - e(-0.034t)} and y = 2.857 {e(-0.020t) - e(-0.027t)} respectively. From the above mathematical analyses by age prevalence in clonorchiasis, it was considered that the mode of transmission of clonorchiasis in the surveyed area, Kim-hae Goon presented more rapid pattern than those of North Kyong-sang Do and Ko-yang Goon, Kyong-gi Do.
parasitology-helminth-trematoda ; clonorchiasis-Clnorchis sinensis ; epidemiology ; transmission

The present work was to observe the wormicidal effects of the external mucous substance of Carassius carassius and Pseudorasbora parva on cercaria, metacercaria (liberating) and adult of Clonorchis sinensis. The mucous substance which was extracted by ether was separated into various spots on the silica gel thin layer chromatography and separated into various fractions in the silica gel column chromatography, using petroleum ether(30 percent) and chloroform(70 percent) as solvent. R(f) 0.952 value of the silica gel thin layer chromatography and the first fraction (reddish yellow) frorn the silica gel column chromatography of the ether extracts from C. carassius had the wormicidal effect on all of the developing stages of C. sinensis. Cercaria was killed within 14 minutes, metacercaria within 27 minutes and adult 2.5 hours by the first fraction. But in the normal saline solution (control) and in the other fraction, cercaria and metacercaria were alive more than 24 hours and adult more than 72 hours. The extracts from the mucous substance of P. parva that is well penetrated by cercaria had no wormicidal effect on them.
parasitology-helminth-trematoda ; clonorchiasis-Clnorchis sinensis ; metacercaria ; Carassius carassius ; Pseudorasbora parva ; mucous substance ; chromatography