This study was performed to observe the present status of intestinal parasitic infections in a remote island, Yondo, located in southern part of Jeonranam-do(province), Korea. In February and May 1988, total 1,011 individual stool samples were collected and examined for intestinal helminths and protozoa using formalin-ether centrifugal sedimentation technique. The results are summarized as follows: Of 1,011 ingabitants examined, 398(39.4%) were positive for intestinal parasites. Helminth positives were 372(36.8%), and protozoan cyst positives were 56(5.5%). Ten species of parasites were found. Trichuris trichiura revealed the highest infection rate of 27.5%, Ascaris lumbricoides 17.4%, Taenia sp. 5.8%, Entamoeba coli 3.3%, Giardia lamblia 1.5%, Endolimax nana 0.8%, Hymenolepis nana 0.4%, hookworm 0.2%, Trichostrongylus orientalis 0.2%, and Entamoeba histolytica 0.2%, respectively. The female group showed higher positive rate (44.0%) than males (34.7%). Also, higher positive rates were observed among adults as compared with the group younger than 10 years old. Average value of E.P.G. was 1,876(range 200-17,800) in A. lumbricoides positives, and 327(range 200-1,600) in T. trichiura positive cases. In helminth egg positive cases, single infection was 63.4%, double infection 34.7%, and triple infection 1.9%, respectively. Among protozoan cyst positives, single infection was 94.6%, and double infection was 5.4%. The present study revealed that the prevalence of intestinal parasites among inhabitants in Yondo island is still so high that special control measures should be performed.
parasitology-helminth-trematoda ; cestoda-nematoda-protozoa ; epidemiology ; Ascaris lumbricoides ; Taenia sp. ; Entamoeba coli ; Giardia lamblia ; Endolimax nana ; hookworm ; Trichostrongylus orientalis ; Entamoeba histolytica

Effectiveness of flubendazole, a newly introduced as an anthelmintic in Korea, was evaluated in 28 ascariasis, 28 whipworm infections and 17 pinworm infections in primary school children. All patients were orally given by flubendazole of 500 mg once. Stools for roundworm and whipworm and anal swabs for pinworm infections were examined both before and 25 days after treatment. After flubendazole treatment, all ascariasis and pinworm infected cases were cured. On the other hand, in whipworm infections, the cure rate was 82.1 percent (23 cured of 28 infected), and the egg reduction rate was 67.1 percent, respectively. Headache (one case), dizziness (2 cases) and abdominal pain (3 cases) were noticed as untoward effects, but they were mild and disappeared within 24 hours. These results demonstrate the excellent effectiveness of flubendazole in treating these helminth infections.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; Trichocephalus trichiurus ; Enterobius vermicularis ; chemotherapy ; flubendazole

Total of 2,643 Korean soldiers were examined of their stool for parasitic infections by both cellophane thick smear and formalin-ether concentration techniques from August 1983 to December 1985. Out of them, 73.6% were free from any parasite, 22.6% were ova positive and 4.0% cyst positive. The ova positive rates by species were Ascaris lumbricoides 2.0%, Trichuris trichiura 13.0%, hookworm and Trichostrongylus orientalis 0.08% respectively, Clonorchis sinensis 7.6%, Metagonimus yokogawai 1.1%, Paragonimus westermani 0.08%, Echinostoma hortense 0.04%, Fibricola seoulensis 0.9%, Taenia sp. 0.3%, Hymenolepis nana 0.2% and H. diminuta 0.04%. Most of them (87.3%) were positive by a species, 11.9% by two and 0.8% by 3 species. The cyst positive rates were Entamoeba histolytica 0.6%, E. coli 1.4%, Endolimax nana 1.7%, Iodoameba butschlii 0.04% and Giardia lambla 0.9%. Among the cyst positives, 89.5% were positive by a species, 7.6% by two and 0.5% by 3 species. The intestinal parasite infections among the Korean soldiers decreased distinctly compared with previous data.
parasitology-helminth-nematoda ; trematoda ; cestoda ; protozoa ; epidemiology ; Clonorchis sinensis ; Trichuris trichiura ; Metagonimus yokogawai ; hookworm ; Ascaris lumbricoides ; Diphyllobothrium latum ; Hymenolepis nana ; Entamoeba histolytica ; Giardia lamblia ; Entamoeba coli ; Endolimax nana ; Trichostrongylus orientalis ; Paragonimus westermani ; Echinostoma hortense ; Fibricola seoulensis ; Taenia sp. ; Hymenolepis diminuta

The present study was undertaken to evaluate the present status of intestinal parasitic infection in Seoul area, Korea. During the period from June 1985 to July 1986, a total of 5,251 stool samples were collected in Department of Clinical Pathology, Hanyang University Hospital and examined by formalin-ether sedimentation technique once for helminth ova and protozoan cysts. The results were summerized as follows: The overall egg positive rate of intestinal helminthes was 2.53 per cent ; and 1.43 per cent for Clonorchis sinensis, 0.7 per cent for Trichuris trichiura, 0.13 per cent for Metagonimus yokogawai, 0.06 per cent for hookworm, and 0.02 per cent for Ascaris lumbricoides, Diphyllobothrium latum and Hymenolepis nana, respectively. The overall cyst positive rate of intestinal protozoa was 1.07 per cent. Cyst positive rate was 0.06 per cent for Entamoeba histolytica and 0.13 per cent for Giardia lamblia, respectively. Higher prevalence of intestinal parasitic infection was observed in male and in 21-50 year-old groups. The highest prevalence of Clonorchis sinensis infection was observed in 40th age group(3.4 per cent), and male (2.3 per cent) was more infected than female (0.7 per cent) in general.
parasitology-helminth-nematoda ; trematoda ; cestoda ; protozoa ; epidemiology ; Clonorchis sinensis ; Trichuris trichiura ; Metagonimus yokogawai ; hookworm ; Ascaris lumbricoides ; Diphyllobothrium latum ; Hymenolepis nana ; Entamoeba histolytica ; Giardia lamblia ; Entamoeba coli ; Endolimax nana

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

In order to estimate the recent pattens of intestinal helminth infections among the residents in Taege City, Korea, a survey based on discovery of helminth eggs by formalin-ether sedimentation and modified Graham's scotch-tape anal swab techniques, were performed during the period from March to September in 1983. A total of 1,697 fecal specimens were collected from 854 male and 843 female residents from 5 villages(Dong), each of whom were selected randomly to represent 1,000 persons referred to the census in 1982. Among the specimens examined, one or more species of helminth parasites were found in 473, revealing the overall positive rate of 27.9 pre cent. Of them, Trichuris trichiura was found most frequently, in 13.2 percent, followed by Enterobius vermicularis in 7.0 per cent. Hookworm was the least prevalent. The sex-specific rate of overall helminth infections was a little higher in females than in males, while in cases of Clonorchis sinensis, Metagonimus yokogawai and Taenia species, the infection rates in males was higher than in females. T.trichiura was most prevalent in the 20~29 age group and showed about the same prevalence in males and females of all age groups. C. sinensis infection rate increased with age while those of Ascaris lumbricoides decreased. Single infections were 82.5 per cent of all positive cases. Of cource, T. trichiura revealed the highest prevalence in 31.7 per cent followed by E. vermicularis in 20.1 per cent and A. lumbricoides in 14.8 per cent. Of the double infections, the percentage of T. trichiura in combination with other intestinal helminths was higher than that of A. lumbricoides. It was concluded that although the infection rates of intestinal helminths among the residents in Taegu City, Korea is still high, eradication of these parasitic diseases seems to be possible with twice-a-year administration of specific anthelmintics, in combination with extensive public health education and improvement of the dietary life.
parasitology-helminth-nematoda-trematoda-cestoda ; epidemiology ; Ascaris lumbricoides ; Clonorchis sinensis ; Enterobius vermicularis ; hookworm ; Megtagonimus yokogawai ; Taenia sp. ; Trichostrongylus sp. ; Trichuris trichiura

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

The present study was undertaken to evaluate the anthelmintic effects of fenbendazole against intestinal nematode; Ascaris lumbricoides, hookworm and Trichuris trichiura, and to compare the efficacy in fenbendazole, oxantel-pyrantel pamoate and placebo by means of double blind method. Out of 114 subjects harbouring Ascaris lumbricoides, hookworm and Trichuris trichiura, 36 cases were treated with single dose of fenbendazole, 38 cases with oxantel-pyrantel pamoate, and the remaining 40 cases had received the placebo. The results were as follows: In the group treated with fenbendazole (30-50 mg/kg), the cure rates were 83.9 percent in 31 subjects with Ascaris lumbricoides and 83.3 percent in 18 subjects with hookworm, and only 28.6 percent in 28 subjects with T. trichiura respectively. In the group treated with a single dose of oxantel-pyrantel pamoate (10 mg/mg), the cure rates were 96.7 percent in 30 subjects with A. lumbricoides, 95.2 percent in 21 subjects with hookworm, and 54.6 percent in 33 subjects with T. trichiura. Egg reduction rate was 85.7 percent in T. trichiura cases. On the other hand, the egg negative conversion rates in placebo group were 9.7, 8.3 and 33.3 percent in Ascaris, Trichuris and hookworm infections respectively. The above results showed that fenbendazole was highly effective against Ascaris and hookworm. However, incomparisom with oxantel-pyrantel pamoate, fenbendazole was less effective in regards of A. lumbricoides, hookworm and T. trichiura infections.
parasitology-helminth-nematoda ; chemotherapy ; Ascaris lumbricoides ; hookworm ; Trichuris trichiura ; fenbendazole ; oxantel-pyrantel pamoate