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

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

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

With a purpose to find out natural transition of endemicity of Malayan filariasis in inland Korea, a survey was conducted in June 1980 in Isan-Myeon of Yongpung-Gun (former Yongju-Gun) where an epidemiological investigation had been carried out in 1973 without any control activities such as chemotherapy. Five sample villages were surveyed for microfilaremia by 20 microliter night blood examination among inhabitants and the results of the surveys conducted in 1973 and 1980 were compared to determine natural transition of the endemicity of malayan filariasis during the period of the last 7 years. The current microfilaria rate among inhabitants in the 5 villages was 2.2 percent on the average (male: 1.6 percent, female: 2.8 percent) from 370 persons examined. By village, the rates were 5.9 percent (number of persons examined: 34) in Baranggol, 0 percent (30) in Guitonggl, 4.2 percent (72) in Alseonggol, 0 percent(65) in Jangjagol and 1.8 percent (169) in Saehae. Extremely low microfilaria rate was noted in young age groups. By age group, no positive case was found in those age groups below 30-39 years except 10-14 age group in which 2 positives (4.4 percent) were found. Two positives each were found in the respective age groups of 40-49(3.2 percent), 50-59 (4.4 percent) and over 60 (3.4 percent). In evaluation of the natural transition of the endemicity during the period of the last 7 years, the microfilaria rate turned out from 13.1 percent in 1973 to 2.2 percent in 1980. The difference in the microfilaria rate was 10.9 percent and the natural reduction rate per year was 1.6 percent on the average. From the examination of 35 cases which had revealed microfilaremia 7 years ago, 85.7 percent(30) of them were found to have converted to microfilaria negatives. On the other hand, from the 151 cases which had revealed no microfilaria in 1973, only 0.7 percent (1) of them was found to have converted to microfilaria positive. In the intensity of microfilaremia, the number of microfilaria/20 microliter blood per positive case was 11.0 in 1973 and 9.1 in 1980. The number of microfilaria/20 microliter per examinee was 1.4 in 1973 and 0.2 in 1980, thus reduced to 1/7 during the period of the 7 years. The retarding endemicity of malayan filariasis in inland Korea was considered to be resulted in by the gradual increase of environmental factors in relation to ecology of vector mosquitoes, which adversely affect to the transmission of malayan filariasis. Followings are suggested to be the factors which control the transmission of the malayan filariasis in this area: Inhabitants are the only natural final host of Brugia malayi infection in this area, gradual elevation of living standards of the inhabitants, gradual awakening of consciousness and behavior among inhabitants to protect themselves from mosquito biting using such as mosquito nets and insecticide sprays, preference of animal bait of vector mosquitoes, Anopheles sinensis, increase in number of domestic animals and fowls being raised in the village areas which play a major part of blood donors to vector mosquitoes, and relatively short (3-4 months) period of mosquito season in a year.
parasitology-helminth-nematoda ; Brugia malayi ; epidemiology

The effect of transferred immune serum and IgG on the response of recipient mice to concurrent infections with larvae has been investigated. Following one infection, recipient mice harboured fewer worms than control mice, the worms were stunted and thier fecundities were greatly reduced. Four concurrent infections was found to reduce worm burden and worm fecundity, and induce an increase of serum antibody titers in no-treatment and normal serum given mice. On the other hand the transferred immune serum and IgG appeared to adversely affect the protective immune response in recipient mice. In recipient mice, worm fecundity was consistently increased throughout experiment and harboured more worms after four infections than control mice. Serum anti-N. dubius antibody titers of mice made passively immune by transfer of immune serum and IgG were not significant difference between one infection and four infections. Thus, transferred immune serum and IgG may debilitate host antibody production.
parasitology-helminth-nematoda ; Nematospiroides dubius ; immunology ; mouse

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.
parasitology-helminth-nematoda ; immunology ; Ascaris lumbricoides ; mouse

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

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 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.
parasitology-helminth-nematoda ; Strongyloides stercoralis ; case report