A total of 860 cellotape anal swab specimens from 326 school children of urban area, 243 of rura1 farm village and 291 of rural fishing village was submitted for Enterobius vermicularis egg detection from September through November 1985. Each specimen was collected in the morning. Among the total 860 children's submitting specimens, 316 (36.7 per cent) were positive for E. vermicularis eggs. Of the 326 children in the urban area, E. vermicularis eggs were detected in the 45 (13.8 per cent). This detection rate was lower significantly as compared with 143 (55.6 per cent) of 243 children in the farm village or 136 (46.7 per cent) of 291 children in the fishing village. The egg detection rate in the male children was lower remarkably than that in the female children.
parasitology-helminth-nematoda ; Enterobius vermicularis ; epidemiology

Metacercariae were found from 6 samples among 4,382 Parlemon nipponensis which were caught at Podu, Kohung, Korea. The metacercaria was inclined as a larval stage of Paragonimus westermani by following reason: Semisulcospira libertina was the only one species which lives in Podu area. No other metacercaria except Paragonimus westermani were found from the craw or cray fish which were caught in the endemic aera. Metacercariae, ovary, testes and cuticular spines resmbled the characteristics of Paragonimus westermani, which have been described by previous workers.
parasitology ; helminth ; trematoda ; Paragonimus westermani ; metacercaria ; epidemiology

The epidemiological status of ascariasis was analyzed in 8 rural villages in Korea, through observation of its epidemiological parameters such as prevalence, worm burden and basic reproductive rate. Total 978 inhabitants were subjected to stool examination and recovery of worms after chemotherapy with pyrantel pamoate. The results were as follows: The worm positive rate in each village was 16.5-79.5%, while the egg positive rate was 9-18% lower, 3.3-66.7%. The average worm burden(among all inhabitants) ranged from 0.21 to 8.44 by villages and the frequency of cases with each worm burden showed negative binomial distributions with 'k' values of 0.38-0.54. The prevalence rates (worm) in each village was almost identical with the theoretical ones from Anderson and May's equation; p=1-(1+M(*)/k)**(-k), where 'p' is worm prevalence and 'M(*)' equilibrium average worm burden. The basic reproductive rate 'R' was calculated from 1.03 to 2.11. It is suggested that, although 'R' in lower endemic areas is approaching to the breakpoint of reinfection (R=1), control programs of ascariasis in Korea should be continued until it becomes below the level nationwidely.
parasitology-helminth-nematoda ; epidemiology ; Ascaris lumbricoides

Prevalence study of Metagonimus yokogawai infection, survey of intermediate hosts of Metagonimus yokogawai and food habits of raw sweetfish among inhabitants along Boseong river (120 km), Jeonra Nam Do (province) were carried out. The results are summarized as follows: Among 360 examined, the egg positive case were 128(35.6 percent); male 112(46.7 percent), female 16(13.3 percent). The prevalence rates were different by geographical areas; 42.4 percent in down stream, 49.4 percent in middle stream and 13.3 percent in upper stream. By ages, highest rate, 53.6-59.1 percent was observed among 30-49 group (male 69.6-73.0 percent, female 15.8-35.5 percent). Eggs per gram of feces were 2,084 (200-12,280) in average; down stream 1,708, middle stream 2,590, upper stream l,550. By social strata, the prevalence showed differences; 24.8 percent in primary schoolchildren, 78.4 percent in school teacher and local officers, 30.6 percent in general inhabitants. Clonorchis sinensis infected cases in the areas were 21(5.8 percent) out of 360 examined, and 90.5 percent of them showed mixed infection with Metagonimus yokogawai. Cercariae of Metagonimus yokogawai from the lst intermediate host, Semisulcospira sp., in down and middle streams were detected from 32 snails (5.9 percent) out of 545 examined. All the 22 Plecoglossus altivelis which were caught from the down stream were infected with metacercariae of Metagonimus yokogawai. The number of the metacercariae detected was 22,650 per fish in average, and the number increased from August to October. Experiences of raw sweetfish intake of the inhabitants were found in 208(58.4%) among 356 interviewed by questionaire form (male 76.7 percent, female 20.7 percent). Means of acquisition of the sweetfish were mostly by purchase 68.8 percent, and seasonally in summer. Reason of the raw sweetfish intake was due to the flavor, 83.2 percent. The fish were mixed in soy sause with vinegar before the intake.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; metagonimiasis ; epidemiology

This survey was undertaken to determine the recent prevalence of lung fluke, Paragonimus westermani, in the three localities of Wiseong county, Kyungpook Province, Korea and to compare the prevalence among the residents in the same areas between 1924 and 1980. The three localities, Ku-seong, Sam-chun, and Um-ji villages (dong) have been known as the endemic areas of Paragonimus westermani. The surveys were made on the general population. They were examined using intradermal test with Paragonimus westermani antigen, and the diagnosis of paragonimiasis was made depending on the positive intradermal reaction. The sputum examination could not be performed beacause the residents were inaccessible. The prevalence of Paragonimus westermani among the residents in the three communities varied from 1.4 percent to 7.9 per cent, with an average of 4.0 per cent. Whereas, the average reported by Ichinomiya in 1924 was 4.7 percent. There are no significant differences in the sex and age specific rates of infection between 1924 and 1980. With the abundant density of Semisulcospira snails and crayfish in Sam-chun stream and the high rate of infection with Paragonimus westermani among the residents in the village, it is found that Sam-chun village, one of the three localitied in Wiseong county, where Ichinomiya (1924) surveyed, was still the endemic focus of Paragonimus westermani.
parasitology-helminth-trematoda ; Paragonimus westermani ; paragonimiasis ; epidemiology

In order to determine the epidemiological patten of the liver fluke, Clonorchis sinensis, the locality where the snail, Parafossarulus manchouricus, is abundant, the infestation rates for the cercarial and metacercarial larvae of digenetic trematodes in the snail and fish hosts, and the prevalence of Clonorchis sinensis among the residents in the vicinity of river Taewha, Kyungnam Province, Korea were studied from March 1979 to September 1980. Four snail habitats were found in the river Taewha. The population density of the snail per square meter of the habits ranged from 10 to 500, with an average of 150. Among the 4 snail habitats, three, Baek-cheon, Sa-yeon and Taewha had snails infected with the cercaria of Clonorchis sinensis, and the proportion of infested snails in the three habitats was very low, the average being 0.59 per thousand. Four species of fresh-water fish, the bullhead, Coreobagrus brevicorpus, the Korean shiner, Gnathopogon atromaculatus, the flat bitterling, Paracheilognathus rhombea, and the striped shiner, Pungtungia herzi among ten species of fish examined harbored the metacercaria of Clonorchis sinensis. The intensity of infestation with the cyst of Clonorchis sinensis in the four species of fish was low. The approximate number of the cysts per gram of flesh was between 3.5 in Paracheilognathus rhombea and 21.5 in Gnathopogon atromaculatus. Seven kinds of laval tremathodes, Clonorchis sinensis, Cyathocotyle orientalis, Echinochasmus species, Exorchis oviformis, Metacercaria hasegawai, Metagonimus yokogawai and Metorchis orientalis were found from ten species of fish examined. In general, the infestation rates for the encysted larvae of digenetic trematodes varied from fish to fish. The infection rate for Clonorchis sinensis among the residents in the vicinity of river Taewha was relatively high, 22.2 percent by the formalin-ether sedimentation technique, and the difference in the rate of infection between males and females found to be siginificant(t>2). Of these, the rate was 12.4 per cent in 483 elementary school children and 17.7 percent in 761 middle and high school students. The results obtained in the present study indicate that endemic foci of Clonorchis sinensis exist in the river Taewha and the prevalence of the liver fluke among the residents is still high.
parasitology-helminth-trematoda ; Clonorchis sinensis ; epidemiology

An epidemiological study on brugian filariasis was carried out in endemic areas including Cheju Island in Korea, with a brief review of literatures.The results showed that the incidence among residents has remarkably decreased in Cheju Island, which was the main endemic area. Reviewing available informations on the prevalence of filariasis reported in recent years and also judging from the present socio-economic conditions which enable people to practice personal protection against mosquitos, it can be said with confidence that filariasis has almost disappeared from Cheju Island and inland areas. The disease is considered to remain at a low level of endemicity in Hugsan Islands. Certainly mass diethylcarbamazine (DEC) treatment carried out in Cheju Island in the 1960s and 1970s and remarkable economic growth followed by improved living standard and altered life-style of inhabitants could all have combined effects on the disappearance of this mosquito-borne diseae in this island. If the present trends go on, the possibility of resurgence of filariasis in Cheju Island is hardly postulated.
parasitology-helminth-nematoda ; Brugia malayi ; filariasis ; epidemiology

This study was undertaken to estimate the reinfection incidence of Ascaris lumbricoides after biannual blanket mass chemotherapy and to figure out the characteristic seasonal fluctuation pattern in a Korean rural village. A total of 612 residents from 4 Ri's of Hwasung Gun, Kyunggi Do, Korea was selected and divided into 6 groups according to hamlets, each of which consisted of about 100 inhabitants. Each group received blanket biannual mass chemotherapy with 10 mg/kg of pyrantel pamoate respectively in each month, during the period from April 1977 to September 1978 (Group A-April and October 1977 and April 1978, Group B-May and November 1977 and May l978, and so on). Beforehand Ascaris infection status was evaluated by examining eggs and worms expelled exactly after the first mass chemotherapy checked during the first 6 months and the reinfection incidences were estimated in follow-up examinations during next l2 months by the above two kinds of methods and by detection of young Ascaris positive cases. Young Ascaris was defined as worm shorter than l3 cm and lighter than 500 mg and considered to have introduced to human host during the period from the previous 2 months to 2 weeks. The results were summarized as follows: Beforehand infection rate with Ascaris were 42.3 percent (34.4-50.6 percent by group) by egg detection and 46.2 percent (36.2-51.9 percent by group) by worm detection methods in average. Number of worms per infected case was 2.7 (1.5-4.2 by group) in average. Reinfection rates estimated by egg detection ranged from 8.0 to 3l.5 percent (l6.9 percent in average) in the first follow-up period and from 14.0 to 20.0 percent (l7.5 percent in average) in the second follow-up. Seasonal fluctuation was found marked and there were roughly two peaks, of which the larger appeared from February to March and the smaller from August to September. Reinfection rates by worm detection method ranged from 20.6 to 34.9 percent(25.7 percent in average) and from 14.3 to 21.9 percent (19.6 percent in average) in respective follow-up examinations. Seasonal fluctuation was also observed and the peak incidence appeared one month earlier than those made by egg positive conversion. Number of worms per infected case decreased to 1.6 in average in both follow-up. Young Ascaris detection rates ranged from 6.0 to 12.9 percent (9.4 percent in average) and from 2.3 to 5.8 percent (3.8 percent in average) in respective follow-up. Seasonal fluctuation was also observed. From January to February, the positive rates were up to 12.9 percent and 12.7 percent respectively, which formed the higher peak. Lower one was observed during July to August. From the above results, the actual time of Ascaris reinfection were November to December for the higher peak and May to June for the lower one in Korean population. Pickled vegetable was suggested as a most probable source of Ascaris reinfection during late autumn to winter season.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; reinfection ; epidemiology

In Ascaris lumbricoides infection, the faecal examination, undertaking for ova detection, is not always diagnostic. It is just because some of the infected cases has Ascaris worm(s) which do not produce eggs. In the present study, the authors attempted to analyse quantitatively the egg discharging patterns in Ascaris infected cases with low worm burden. The following results were obtained: In 1,861 Ascaris worms collected from 853 cases, the sex ratio was 1: 0.74 (female: male). Sex combinations in each burden of case were always fitted with theoretical values from the binomial distribution; (m+f)(n)= (0.426+0.574)(n). In each worm burden, their sex combination indicated different egg discharging patterns; false negative cases, unfertilized ova passers and fertilized ova passers. When the relative frequency of the above three egg discharging patterns was plotted to worm burden per case, a definite relationship was found. The cases with six or more worms have nil probability to be false negative case or unfertilized ova passer. Out of 853 cases, we found 129 false negative cases. The collected worms from 125 cases were morphologically analysed. It was found that 52% of them were infected with only male worm(s) and 24% were infected with young female worm(s). And in 8.8%, old female(s) with empty uterus were infected. The cause of 15.2% was remained unexplained, even though the collected worms were scrutinized.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; egg ; epidemiology

From 1960 through 1965, 39 cases with epileptic seizure caused by the Cystricercus cellulosae were experienced at Kaejong Mental Hospital, Okku-Gun, Chollapukdo province. The present study was carried on at the area of Chollapukdo province where Cysticercus cellulosae cases were frequently reported. Thrity-nine Cystricercus cellulosae cases(35 male and 4 female) with epileptic seizure visited Kaejong Mental Hospital . Okku-Gun, Chollapukdo during the years of 1960-1965 from various Gun(county): Okku-Gun 13, Kimje-Gun 7, and Soonchang-Gun 6. The high incidence was found at the age group of 20-49 years and the distribution of 214 subcutaneous nodules were as follows: Trunk 56.6 percent, upper extremities 26.6 percent, head and neck 9.3 percent, lower extremities 7.5 percent. According to the address of above 39 cases, taenia infestation of the inhabitants in the area was examined by questionaire form. Plain rural area (Maryong-Ri, Okku-Gun); Among 803 persons interviewed, 4.0 percent or 32 complained the output of Taenia segments. The male group showed higher incidence (6.4 percent) than the female(1.5 percent) . The highest incidence was observed at the age group of 30-39 years. Most of the inhabitants of the area had the eating habit of raw beef and pork. Mountainous rural area(Bok-Heung-Myun, Soonchang-Gun); Among 542 persons interviewed, 33 or 6.1 percent complained Taenia infection. The higher incidence was observed in the male group(8.7 percent) than in the female group(3.1 percent) , and also at the age group of 20-49 years. They had eating habit of raw beef and pork. The species of adult worm were identified by morphological examination. Totally 36 adult worms(Taenia saginata 21, T. solium 15) were obtained from 26 cases, and it was experienced that 5 T. solium were eliminated from one person.
parasitology-helminth-cestoda ; Taenia solium ; cysticercus ; epidemiology