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The pattern of sensory papillae, chaetotaxy, of the cercaria of Clonorchis sinensis was observed. The chaetotaxy was as follows; 5-6 Ci l, 4-5 Ci 2, 5-6 Ci 3 at lst row, 4 Cii 1, 2 Cii 2, 4 Cii 3, 5-6 Cii 4 at 2nd row, 3-4 Ciii 1, 2-3 Ciii 2 at 3rd row, and 2 Civ 1, 2-3 Civ 2, 2-3 Civ 3, at 4th row, in cephalic region; 2 AiV, l AiD, 2 AiiV, 1 AiiD, 2 AiiiV, 2 AiiiD, 1 AivV, 1 AivD, 1 PiiD, l PiiiD, in ventral(V) and dorsal(D) portions of body. Caudal region revealed 2-2-2-2 formula.

The present study was designed to elucidate the recent prevalence of the intestinal protozoa and to demonstrate the relationship on prevalence of the surveyed population with their academic career and living conditions. During the period from May to July 1981, total 2,735 fecal specimens were collected from the inhabitants of 11 areas in Gyeong-gi Do (province) near by Seoul City, and 6 areas in Jeonra Bug Do, southwestern part of Korea. The samples were fixed with SAF solution and were examined by formalin-ether sedimentation technique. The results are summarized as follows: Overall positive rate of intestinal protozoa was 11.1 %: Gyeong-gi Do, 10.7 %; Jeonra Bug Do, 11.7 %. Five species of intestinal protozoa were detected: Entamoeba histolytica 0.69 %, Entamoeba coli 5.52 percent, Endolimax nana 2.71 %, Giardia lamblia 2.23 %, Iodamoeba butschlii 0.l8 %. Highest positive rates among the examined areas were recognized: Incheon City of Gyeong-gi Do, 26.7 %; Im-sil Gun(county) of Jeonra Bug Do, 19.9 %. By species, E. nana showed the highest prevalence rate (13.74 %) in Incheon City, and E. histolytica (2.37 %) and E. coli (9.95 %) in Im-sil Gun. Prevalence of E. histolytica in rural areas was higher than in urban areas. No significant difference in the prevalence rate by sex and age was recognized, although the group under 10 years and over 60 years were lower than in other age groups. The highest positive rate of E. histolytica was observed in pauper group and significant linearity of prevalence rate of E. histolytica by monthly income was observed. The inhabitants who used conventional latrine showed higher prevalence, 11.5 %, than the group of inhabitants who used modified privy. Although no significant difference of positive rate was recognized by academic career, but the lowest prevalence rate was observed in college graduates. Over half of the surveyed population, 64.8 % has no experience on anthelmintic practice. Number of anthelmintic application resulted no difference in prevalence. In conclusion, prevalences of intestinal protozoa in Gyeong-gi Do and Jeonra Bug Do decreased remarkably in comparison with those of one decade before. However, economic level, academic career and anthelmintic administration seemed no essential reasons for such declination.

The present study has been designed as a basic study on laboratory diagnosis of giardiasis and to demonstrate a more effective method for the detection of Giardia lamblia cyst with the inherent advantages of minimizing both the number of stool examinations required and the interval of stool collections for estimating the real state of prevalence in the shortest time possible. There were 3 subject groups of 75 children each currently residing in an orphanage in Gunsan city, Jeonbuk province from which stool specimens were collected every day, every other day, and every 3 days. The procedure is as follows: Resuspend the fixed sample after fixation with SAF solution. Centrifuge the sediment for 1 min. at 2,000 rpm after straining through gauze into a tube. Divide the sediment into 3 parts and use them for direct fecal smear, formalin-ether concentration (MGL) and zinc sulfate (ZnSO(4)) floatation techniques. The results are summarized as follows: Overall infection rate after 10 trials showed a 60 percent positive indication. The positive rate among children under 4 years old was significantly higher than the rate in children over 4 years old. No significant difference in rate by sex was observed. The results of examinations by direct fecal smear and MGL techniques appeared more accurate than that obtained by ZnSO(4) floatation method as indicated by a higher positive rate. Of all three methods concerned, combinations of two demonstrated a higher positive rate than that shown by any one alone. In three consecutive examinations under varying conditions such as different days, the cyst detection rate by MGL technique indicated 83 percent. In 5 examinations under the same varying conditions, the indicated rate was 94 percent. The interval of stool collection proved to be insignificant for the cyst detection rate. In conclusion, both MGL method and modified fecal direct smear can provide a good cyst detection rate of G. lamblia provided that more than 3 consecutive examinations of stool under varying conditions are carried out.

In the present study, the effect of primary infection to reinfection with Ascaris suum larvae was experimented in mouse model. Mice were challenged with l,000 infective stage eggs of Ascaris suum. The embryonated eggs were directly introduced into stomach of mice. Reinfection was performed at 50 days after the primary infection with same method as primary infection. Mice were sacrificed 3, 5, 7, 10, 15 and 20 days after infection in both groups respectively. Larvae collected from livers and lungs with Baermann's apparatus were enumerated and measured after sacrifice. Sera of mice were also collected at same time. The results of the experiment were as follows: With antigen prepared from coelomic fluid of adult Ascaris suum and sera collected from mice before reinfection, the production of antibody in experimental mice was confirmed by the gel-diffusion technique. In the livers of reinfected mice, the larvae were recovered up to 10 days after challenge, otherwhile in the primary infected mice, the larvae were observed up to 7 days. The maximum number of larvae were observed in the lungs of primary infected mice on 10 days after inoculation. In the lungs of reinfected mice, maximum number of larvae were recovered on 7 days after, only few larvae were recovered on 10 days after reinfection. As regards the growth of the larvae, the third stage larvae, over 500 micrometer in length, appeared in livers at 5 days after reinfection, but it couldn't be found on 7 days and 10 days after challenge. The third stage larvae continuously developed were observed in lungs of mice from 5 days after reinfection. In conclusion, it was found that development of larvae in livers of immune mice were probably repressed by the immune mechanisms being rised in livers and defence mechanism is also acting by interfering with the process of larval penetration into the lung from the liver.

A number of studies on the papillae of cercariae of trematodes reported that the papillar patterns (or chaetotaxy) of cercariae might be an excellent method to attain better understanding of the digenetic trematodes (Richard, 1971; Short and Cartrett, 1973; Bayssade-Dufour, 1979). The present study was aimed to determine the number, distribution pattern and structure of the sensory papillae of Metagonimus yokogawai cercariae, and to elucidate the chaetotaxy of this digenetic trematode. M. yokogawai cercariae were pipetted from a vial in which infected snails (Semisulcospira libertica) had been kept for 3 hours. The snails were collected from an endemic area of M. yokogawai, Boseong river in west-southern part of Korea. Observations of papillae were based on light microscopy of those stained with silver nitrate, and on scanning electron microscopy. The results are summarized as follows: All papillae observed were uniciliated. Cilia in anterior tip were shorter than the others in other portions. The body papillae were arranged in essentially symmetrical patterns. Total number of the papillae was 126(63 pairs) in average; anterior tip 40(20 pairs), ventral 20(10 pairs), lateral 42(21 pairs), and caudal 8(4 pairs). The chaetotaxy of M. yokogawai cercaria was; C(I) cycle (3+3C(I)V, 2+2C(I)L, 2+3C(I)D), C(II) cycle(2C(II)V, 1C(II)L, 2C(II)D), C(III) cycle (1+lC(III)V, 1C(III)L), C(IV) cycle (1C(IV)V, 1C(IV)L) in cephalic region: A(I)(lA(I)V, l+2A(I)L, 1A(I)D), A(II)(1A(II)V, 1+3A(II)L, lA(II)D), A(III) {lA(III)V, l+lA(III)L, lA(III)D) and A(IV)(lA(IV)V, 2A(IV)L) in antacetabular region: 1M(I)V and 2M(I)L in median: 1+lP(I)L, 1P(II)L, lP(II)D lP(III)L, lP(IV)L and 1P(IV)D in postacetabular region: 2-2-2-2 in caudal region.

This paper deals with the 11th case of human thelaziasis in Korea. The patient was a 25-year-old woman with complaints of foreign body and itching sensation of rihgt eye, who had lived in Seoul. The slender milky-white nematodes extracted from lower conjunctival sac, one male and one female in respect, were confirmed as Thelazia callipaeda Railliet and Henry, 1910.

A case of Strongyloides stercoralis infection wss experienced in a 73-year old Korean female patient, was hospitalized with relapse of cholecystitis. The patient developed cough and dyspnea 17 days after the admission. On the 27th hospitalized day, diarrhoea, nausea, vomiting and abdominal pain started. A number of parasitic larvae were incubated at 25 degrees C for 2 days. Typical fork tailed filariform larvae of S. stercoralis (Bavay, 1876) Stiles and Hassall, 1902, were identified after cultivation. There was no improvement of diarrhoea after the medication with mebendazole. After the administration of thiabendazole, however, diarrhoea was stopped. On the 6th day of medication, S. stercoralis larvae were no more detected, and thereafter no larva was observed by repeated stool examinations upto 2 months after chemotherapy. The patient had the history of administration of steroid for articular rheumatism. Therefore this case seems to be a hyperinfection of S. stercoralis due to an autoinfection and to be the first report on the hyperinfected strongyloidiasis in Korea. Related literature was briefly reviewed.