Analysis of variance has been applied as a new tool for precise substantiation of taxometric differences between Eustrongylides spinispiculum n. sp. and close species, as indicated by the polythetic divisive classificatory system. A revised key to the species of genus Eustrongylides Jagerskiod (1909) has been presented.
parasitology-helminth-nematoda ; Eustrongylides spinispiculum

The morphological characters of the microfilaria of Brugia malayi collected in Cheju-Do, Korea were described and compared with those or other local strains, already reported from the Malay Archipelago(Brug, 1927), Huchow, South China (Feng, 1933), Hachijo Kojima, Japan (Hayashi, 1951) etc. And it was found that there are no marked difference among these kinds of Microfilaria malayi. The percentage measurements of the fixed points in the Microfilaria malayi from Korea are summarized as follows; B.N.C.: 3.38%(2.90-3.72%), N.R.: 22.64% (17.36-25.81%), E.P.: 32.26% (27.49-36.60%), E.C.: 38.78% (34.90-41.72%), Inn. K. begin: 53.95% (49.50-58.84%) end: 67.87%(63.02-72.97%), G-1: 70.42% (60.22-75.23%), G-2:76.70% (75.10-78.32%), G-3:78.84% (77.81-79.59%), G-4:80.84%(79.82-81.35%), A.P.:82.94%(77.32-89.72%), Length: 193.39(+-12.3 micro-meter)(170.77-233.08 micro-meter), Width: 7.04+-0.37 micro-meter(5.99-7.99 micro-meter), Sheath: 268.48+-17.07 micro-meter(218.72-286.47 micro-meter), Ratio(Cephalic space): 1: 0.78
parasitology-helminth-nematoda ; Brugia malayi ; microfilaria

Epidemiological studies on the reinfection pattern of Ascaris lumbricoides were undertaken by means of blanket mass chemotherapy and worm collection in a rural village in Korea, during 1977~1980. The study objectives were to determine the age(sex)-specific reinfection rate during 2, 4, 6 and 12 months through repeated mass chemotherapy with pyrantel pamoate, and to observe the familial aggregation tendency of the reinfected cases. The results obtained are as follows: The age(sex)-reinfection curve revealed that the reinfection rate is much higher in younger individuals than in olders in all of 4 kinds of interval chemotherapy groups. The highest reinfection rate and the highest burden of reinfected worms were observed in preschool childen, followed by primary school students. Such fluctuation in the age-specific reinfection rates was more pronounced in males than in females. There was noted a significant tendency of familial aggregation among the reinfected cases. It is suggested that reinfection occurs never randomly but preferably to the members of certain household families. From these reinfection analyses, it is inferred that the principal mode of A. lumbricoides transmission in the surveyed rural area is likely to be of 'dooryard type', in which case childen and certain family members are more preferably reinfected. It is also suggested that the preschool childen should be included in the primary targets of mass control programme.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; epidemiology ; reinfection

The epidemiological relationship between the current prevalence and monthly reinfection rate of Ascaris lumbricoides was observed in rural communities in Korea by measns of blanket mass chemotherapy and worm collection for measurement of the prevalence and reinfection rates. During the period from 1975 to 1980, a total of 4,466 inhabitants in 10 different localities were treated with 10 mg/kg of pyrantel pamoate and 2 days' whole stools were collected from 2,547 inhabitants. The stools were examined for the presence of expelled adult and/or young worms, which represent the prevalence and reinfection rates for past 2 months respectively. After then, the obtained rates were correlated each other applying the time-prevalence curve proposed by Hayashi. It was observed that the prevalence (overall worm positive rate) and worm burden per individual ranged by areas from 13.6 to 72.3% and 1.4-10.2 respectively. The calculated monthly reinfection rates (X) (from young worm positive rates) according to areas were in the range, 2.6~16.2%, and clearly correlated with the current prevalence (Y) under the equation, Y=1-(1-X)(7.2) where 7.2 is time in month. The equation means that after one time mass chemotherapy the period needed to attain equilibrium of prevalence again would be about 7~8 months. And it is inferred that the majority of reinfected worms in human host turn over every 7~8 months.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; epidemiology ; reinfection

Five cases infected with Rhabditis sp. were detected in a survey to examine the stool specimen from rural primary school children. A large number of the larvae of Rhabditis sp. detected by the direct cellophane thick smear were cultured by the filter paper method. The examination was carried out in April through June 1980 in Tangjeong-Myon, Ahsan-Gun, and in September 1983 in Sandong-Eup, Yeongwol-Gun. The results obtained in this study were as follows: Prevalence: Out of 925 children, 5(0.54 percent) children were found to be positive. The number of the detected larvae was 110/0.1 gm of feces in case 1, 35 in case 2, 130 in case 3, 86 in case 4 and 62 in case 5. Larvae: The larvae were prepared by means of the direct fecal smear and measured by a micrometer equipped in the microscope. Twelve(12) through 15-day old larvae in culture were 197.1 micrometer long in average, and the maximum size of the matured stage larvae was 884.0 x 25.9 micrometer. However, the length variation was ranged as 173.0 to 884.0 micrometer. Adults: The size of clubbed adult female was 1,357 micrometer(1,176-1,419) in length and 80 micrometer(79-82) in width. Length of buccal cavity was 33 micrometer. A long cylindrical esophagus (273 micrometer) of the worms with a valved posterior cardiac bulb and with median bulbar swelling was morphologically indicated. Distance from mouth to vulva was occupied 58 percent of body length. Male worm was 1,006 micrometer (890-1,148) in length and 49 micrometer(48-49) wide. Caudal alae of bursa and spicules (75 micrometer in length) were well developed. Eggs: The oval shaped eggs in the female uterus, when cultured, were 66 x 56 micrometer in size, and the eggs laid by the adult could not be detected. So, reproduction might be through to be ovoviviparity. The five cases were re-examined during the period from the 1st to the 3rd week after stool examinations, but Rhabditis sp. were detected again in 4 cases in 1st week. When they were examined in 3rd week, larvae could not be detected . So, it was thought that the infection of Rhabditis sp. to humans was facultative.
parasitology-helminth-nematoda ; Rhabditis sp. ; case report

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

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

As the result of a fecal examination performed in October 1978 on 320 middle and high school students of Hapcheon, Korea, we found 2 cases of Rhabditis nematodes in 16-year old high school girls. Rhabditis nematodes isolated from their feces were cultured at 30 C by a filter paper culture method. After careful observation of male and female adults, we confirmed them as Rhabditis elongata Schneider, 1866 on the morphological basis of the male genitalia, and the papillae and measurements of various parts of the worm bodies.
parasitology-helminth-nematoda ; Rhabditis elongata-case report

In order to determine the prevalence of Necator americanus, 182 fecal samples were collected from school children in the Taegu vicinity. These sample were subsequently cultured by the Harada-Mori technique. Necator americanus was differentiated from Ancylostoma duodenale using the bases of morphological characteristics of filariform larvae. Necator americanus was not found in the vicinity of Taegu.
parasitology-helminth-nematoda- Necator americanus ; epidemiology

To investigate the infection status of Enterobius vermicularis the author tried surveys by scotch-tape anal swap on school-children and household environmental factors considered to have influences on the infection were analyzed by an inquiry method with questionnaire. The survey was carried out in October 1986 and 1988 in urban and suburban areas and the results could summarized as follow: The egg positive rate in anal swab was 16.0 per cent (male 14.5 per cent, female 17.6 per cent) out of 2,156 school-children and higher in female group. The egg positive rate in suburban school-children (17.5 per cent out of 1,305 children of two primary school)was a little higher than that of urban school-children(13.6 per cent out of 851 children of one primary schools). The questionnaire analysis on environmental factors showed some significant relations between the egg positive rate and such factors as the number of brothers and sisters, householder's occupation, and avalibility of childroom or bathroom. The result indicate that, although enterobiasis in school-children has shown decreasing tendency in Korea, it is still considerably high in some urban and suburban areas.
parasitology-helminth-nematoda ; Enterobius vermicularis ; enterobiasis ; epidemiology