This study was undertaken to evaluate the present status of intestinal helminthic infections in Koreans, from April 1967 through May 1969. The nationwidely collected stool specimens and scotch-tape anal swabs from primary schoolchildren, middle school students, draftees to army recruitment camp, soldiers and inhabitants of various parts of Korea were examined. The methods employed were Kato's cellophane thick smear technique and formalin-ether sedimentation technique in 40,581 for the prevalence rate of various intestinal helminths, scotch-tape anal swab technique in 8,585 for the prevalence rate of Enterobius vermicularis and by Stoll's dilution egg counting technique in 1,174 for the evaluation of the worm burden of some helminths. The results are as follows. I. Result of stool examination: 1. The positive rate of intesinal helminthes of any kind was 90.5% among 40,581. In rural people, it was 92.3% in average in contrast to 85.0% in Seoul inhabitants. 2. The infection rate of A. lumbricoides in 40,581 was 58.2%. It was higher in rural people 62.9% than in Seoul inhabitants and highest in 5-9 year-old group by age. 3. The infection of Trichocephalus trichiurus showed the highest prevalence rate in Koreans and it was 74.5%. No remarkable difference was observed between Seoul inhabitants(72.2%) and rural people(75.2%). The tendency of higher prevalence rate with the older age group was observed. 4. The infection rates of hookworm and Trichostrongylus orientalis in 40,581 examinations by cellophane thick smear were 5.1% and 5.8% respectively. But in 4,949 examinations for which refined cellophane thick smear technique and formalin-ether sedimentation technique were employed, the infection rates were turned out 17.6% in hookworm and 15.9% in T. orientalis. Although rural people showed higher infection rate of hookworm(18.8%) than Seoul inhabitants(13.8%), the reverse was true in T. orientalis infection rate(14.5% : 20.3%). Both kinds of infections were tend to be higher with the increase of age. 5. The infection rates of Clonorchis sinensis and Metagonimus yokogawai were 4.7% and 0.4% respectively. In both kinds of infections male showed higher infection rates than female and the tendencies of higher infection rate in the older age group were observed. The provinces which showed the higher infection rate of C. sinensis were South and North Kyongsang Do and North Cholla Do, all of which are provinces of southern part of Korea. Some endemic foci of M. yokogawai were noticed in South Kyongsang Do and South Cholla Do. 6. The infection rate of Taenia spp. by applying only the stool examination was 0.7% throughout the survey. No sex difference in infection rate of Taenia spp. was noticed, but in older age group it was increased. Cheju Do, the island of extreme southern part of Korea seemed the most endemic area and South and North Cholla Do were next in ranking of Taenia infection rate. The ova of Hymenolepis nana were observed in 0.2% and all of them were under the age of 20 except only one caes. The infection rate seem...

Authors carried out the experimental study to investigate whether the Paragonimus westermani would uptake the blood in the parasitic definitive host, and also tried for the amount and distribution of the blood which would be harbored in a worm body, and so on. Experimental animals used in this study were dogs and cats, and they were infected with metacercariae of P. westermani. Several months later of the infection, Cr(51) tagged red blood cells were administered to each animal, and the animals were sacrificed and autopsy was done after 24 or 48 hrs of the administration. One part of the detected P. westermani adult worms of each animal were bred in Tyrode's solution and the others were killed by fixing in formalin solution. By Well-type scintillation counter, the radioactivities were measured for the alive and killed worms and of the blood of each experimental animal which was collected at autopsy. In conclusion, it was found that P. westermani worms uptake blood in parasitic definitive host, and amount of the blood harboring in a worm of 56 infection-days(size of worm; 4 x 3 x 1 mm) was 0.002 ml, 0.004 or 0.005 ml in 103 infection-days(size of worm: 8 x 5 x 3 mm) and 0.011 ml in 217 infection-days(size of worm: 9 x 7 x 4 mm). Almost of the whole blood uptaked in the worms was distributed in intestine. It was observed that the blood uptaked in the worm body was excreted continuously through the excretory pore, so that the radioactivity could not measured almost completely in cases of 24 hrs-breeding worms.

The question of infectivity and prevalence of Clonorchis sinensis in Cheju province (Quelpart Island) was arisen to authors since the several surveys on the endemic diseases were performed in this island. Therefore, authors decided to solute this question. Then the survey on the possible second intermediate host of Clonorchis sinensis was performed and reported already with negative finding. At present time, authors carried out the collection of all kinds of fresh-water snails through all areas of this island, to confirm the presence or not of Parafossarulus manchouricus, the only first intermediate host of Clonorchis sinensis in Korea. And the following results were obtained. 1)The fresh-water snails collected in the survey were Semisulcospira libertina Gould and Lymnaea ollula Gould. 2)Parafossarulus manchouricus Bourguigant was not collected in this island. 3)It is confirmed that the Clonorchis sinensis can not be prevalent in this island.

Authors carried out experimental study on chemotherapy with oral administration of Dithiazanine iodide (D.I.) and Bithionol sulfoxide(B.S.) in rabbit clonorchiasis. And the following result was obtained. 1)In change of the E.P.G (eggs per gram feces) by D.I. administration, it was rather increased in early stage of the administration than prior to administration, and thereafter decreased gradually. 2)In the change of the C.S. worm body by D.I. administration, there was not only prominent change of supporting tissue but also the change of reproductive organ was found. 3)In considering the wormicidal effect of D.I. from detecting rate of survival worms, the effect was slight in group of 100 mg(80 mg/kg) per day dosage, but the effects were very excellent and almost complete by proper times of administration in groups of 200 mg (130 mg/kg) per day or higher dosage. 4)But the side effect and intoxication sign of D.I. were appearent in groups of 200 mg or higher dosage. 5)By B.S. administration, E.P.G. was decreased gradually. 6)In changes of the C.S. worm body by B.S. administration, prominent inhibitory chnnge was seen in egg formation ability. 7)Slight wormicidal effect of B.S. was observed in groups of 140 mg (100 mg/kg) per day or higher dosage. 8)Side effect and intoxication sign of B.S. were found little in groups of 140 mg or lesser dosage.

Authors carried out the survey for human paragonimiasis in Ko-Hoong County, Chun-Nam Province, Korea from July to September 1964 by the use of intradermal screening test with Veronal buffered saline antigen. Eight myuns (village) out of 13 myuns of this county were selected for the survey, regarding balanced selection. The number of 2,916 primary school children of high class and 764 residents of all age groups in these areas were examined (total 3,680; male 1,961; female 1,719). The following results were obtained in this survey. 1) As a whole, 20.1 per cent of the examiners showed positive reaction, with sexual difference of 20.9 per cent in male and 19.1 per cent in female. 2) In regional differences of positive rate, the highest rate(50.1 per cent) was showed at Po-Doo myun and lowest rate(3.6 per cent) was showed at Do-Yang myun. 3) In age group, the highest positive rate was showed in 16 to 20 age group (46.7 per cent). 4) In regional comparison of paragonimiasis infectivity of whole nation (province and county), Ko-Hoong County as nearly same as the Hea-Nam County, Chun-Nam Province follows next of Cheju Province, the highest prevalance area of paragonimiasis in Korea, in concentration of prevalence of paragonimiasis.