To relate the results of repeatedly undertaken anal swabs to worm burden of Enterobius vermicularis in a highly endemic community, 193 rural schoolchildren, divided into 4 groups, were examined daily by Scotch-tape anal swab method, 1, 2, 3 and 4 times respectively. All of the schoolchildren were treated with pyrantel pamoate 10 mg/kg body weight exactly after the last anal swab in each group disregard the results. And all of the expelled E. vermicularis were collected and counted. It was found that 68.8% of total anal swabs were positive and the collection rate of E. vermicularis was 90.7% with average worm burden, 17.0, in surveyed children. From the analyses of the obtained data, following three inferences were derived. The consecutive postive findings of anal swabs could not reduce the possibilities of detecting light worm burden cases when the anal swabs were undertaken daily up to 4 times. The possibilities of detecting the heavy infection cases were found in consecutively positive categories of anal swab and the presence of negative result(s) of anal swab during the consecutive examinations did denote the reduced possibilities of detection heavy infection. The consecutive negative findings in anal swab have tendenicies reducing the possibilities of detecting heavy worm burden cases. Above results were highly suggestive that the processes of infection loss in E. vermicularis were taken place continuously, allowing daily small allotments of discharge of fully gravid worms in heavy infection cases and massive discharge in a very short period of time is practically rare event.
parasitology-helminth-nematoda-Enterobius vermicularis ; pyrantel pamoate-chemotherapy ; enterobiasis ; worm burdern ; pyrantel pamoate

To evaluate the efficacy of anthelmintic treatment of Enterobius vermicularis in highly endemic population, total 82 children in two orphanage institutes were divided into 4 groups and treated with placebo, 5 mg/kg of pyrvinium pamoate, 100 mg of mebendazole and 10 mg/kg of pyrantel pamoate respectively. Total 4 anal swabs were taken from each child before treatment and the even distributions of positive rate and consecutive results between groups were considered. Follow-up swabs were taken 8 times up to the 40th day after treatment. After remarkable and significant reduction of positive rates up to 19-27th day after treatment in respective groups, the remarkable egg positive conversions were observed 3-4 weeks after treatment. The positive conversion was the earliest and the most remarkable in pyrantel-treated children and the slowest and the least remarkable in mebendazole-treated cases. Also found was that the figures of negative conversion were different with statistical significance between two categories of cases, consecutively positive and alternately positive cases of pre-treatment swabs. This means that the conventional indices of cure rate in E. vermicularis infection may be variable by the selection of subjected cases. Above results mean that the spectrum of susceptible pinworms according to the developmental stages are different between currently available drugs, and the ability to remove pinworms completely in certain developmental stage are also different between chemotherapeutics. These results suggest the need of interval chemotherapy of Enterobius vermicularis infection in heavily infected cases of in highly endemic population to achieve the complete eradication of whole range of pinworms in intestine.
parasitology-helminth-nematoda ; Enterobius vermicularis ; chemotherapy- mebendazole ; pyrantel pamoate ; enterobiasis

The significance of Scotch-tape anal swab technique was evaluated in three communities of Korea, one in orphanage institute and two in rural populations, from November to December, 1975. Based on the epidemiological concept that the prevalence rate of Enterobius vermicularis infection in a community as "the proportion in the population who harboured E. vermicularis at certain point of time", the present authors treated the whole surveyed population with pyrantel pamoate disregard to the results of Scotch-tape anal swab and collected pinworms expelled in stool specimens during 2 consecutive days after the chemotherapy. Although the present authors could not collect the younger adult worms less than 3.54 mm in length after chemotherapy, the positive rates of pinworm collection in three surveyed communities were 80.6%, 92.5% and 91.4% respectively whereas the positive rates of single Scotch-tape anal swab were 52.4%, 53.6% and 57.1% respectively. These results denote that results of single anal swab do not represent the prevalence rate of Enterobius infection in a community. The results of successive two anal swabs and estimation of positivity in a population using Neyman's "Best asymptotically normal estimate" revealed 62.9% in the third trial group of this study and probability of finding eggs in single slide was 0.869. Comparing with the pinworm collection rate after the chemotherapy in this group the estimated positive rate was by far lower than that of pinworm collection(89.3%). The positive results of single anal swab did not correspond to the pinworm collection in average 9.1% of anal swab positive cases and the negative results did not correspond to pinworm collection in 81.3% of anal swab negative cases, when the data from three surveyed communities were amalgamated. These results must come from the principle of anal swab that detect the terminated parasitism. With rare exceptions, the anal swab negative cases harbour relatively fewer number of Enterobius than those of positive cases. And the mean number of E. vermicularis collected from anal swab negative cases was 9.1 whereas the number in anal swab positive cases was 31.5. By analyzing the data on the relationship between bathing interval and anal swab positive conversion, it was assumed that the positive rate of anal swab in a community represent the rate of appearance of gravid female Enterobius vermicularis through anus during approximately past two days prior to examination.
parasitology-helminth-nematoda ; Enterobius vermicularis ; chemotherapy ; pyrantel pamoate ; diagnosis

The chronologic growth patten of Ascaris lumbricoides was made by the maximum length of worms collected from inhabitants after mass chemotherapy with pyrantel pamoate by various interval; 2-month, 4-month, 6-month an 12-month. The results obtained were summarized as follows: When the collected 497 worms were plotted on weight/length chart by treatment interval, there was always size limitation in each group, permitting the idea of maximal growth in a given period of infection. The maximum lengths in each interval treatment, 2, 4, 6 and 12-month were; 12.5, 16.4 , 19.2 and 22.8 cm in male and 14.2, 22.0, 26.2 and 30.8 cm in female respectively. The maximum growth curves were expressed by the equations; Y=9.212 In(X+1)+0.025 in male and Y=11.953 In(X+1)+0.025 in female when X is age in month and Y is length in cm. It was revealed that female grew more rapidly than male. The growth of length was rapid in initial 2~3 months and weigth gain was rapid in later than 2~3 months. The weight seems better than length as an indicator of aging.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; chemotherapy ; pyrantel pamoate ; epidemiology ; growth

Atrial to control reinfection cycle of Ascaris lumbricoides was made in a rural village in Korea by blocking the process of new egg production. Chemotherapy with pyrantel pamoate was repeated bimonthly in three hamlet groups, each consisted of 105~149 inhabitants of whole age group. In one hamlet (2.5 mg/kg dose) blanket mass treatment was repeated for 18 times from June 1977 to May 1980. In other two, 5.0 mg and 10.0 mg/kg dose groups, treatment was undertaken for 10 times from June 1977 until December 1987 and later reinfection patten was observed. Follow-up examination was made by whole-day stool collection for 2 days from each case after every treatment. The samples were examined both for eggs and worms, adult and immature young, of A. lumbricoides. The results obtained are summarized as follows: The pre-treatment egg positive rate in Group A, B and C was 48.1, 45.3 an 37.8% respectively. The lowest dose of pyrantel pamoate, 2.5 mg/kg was equally effective as higher doses in case of repeated use for reinfection control. Among 4,311 pyrantel treatments, only 8 cases complained of side effects such as abdominal pain and diarrhea. When the blanket mass chemotherapy was continued 18 times in Group A, all of the examined inhabitants were free from reinfection and egg production from 28th month (the 15th treatment) until the end of study period, for 8 months. When the mass chemotherapy was stopped after 10 times, the egg positive rate returned gradually up to half of pre-treatment level within one year. From the analysis of total 124 positive cases during the course of follow-up, it was revealed that the mass chemotherapy with 2-month interval was successful for the suppression of fertilized egg production. However, social factors such as infected immigrants or absentees were inevitably encountered and involved in the fertilized egg production. Summarizing the results, at least 28-30 months were needed to eradicate A. lumbricoides in the subjected area of Korea, by repeated blanket mass treatment bimonthly with a quarter dose of pyrantel pamoate. Furthermore, to lessen the social factors as a source of later reinfetion, the project area of control programme should be extended as wide as possible.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; chemotherapy ; pyrantel pamoate ; epidemiology

To observe the effect of various interval mass treatment on Ascaris ova and worm positive rates and worm burden per population, 2-month, 4-month, 6-month and 12-month interval schemes were designed and applied. All of inhabitants in nine villages of Hwasung Gun, Kyunggi Do, Korea were treated from April 1977 to May 1980. Each village consisted of 100-140 people, however, there had been 20-40 drop-outs in every treatment. Pyrantel pamoate was used in dose of 10 mg/kg. Evaluation of schemes was made by examinations both for eggs and for expelled worms. The drop-outs in former treatment was included because they were few in munber. The reults obtained were summerized as follows: The pre-treatment infection status of A. lumbricoides was not significantly different between Groups; 32.5-42.2% and 33.8-46.2% in egg and worm positive rates respectively. The mean worm burdens were in range, 1.6-4.2 per infected and 0.61-1.42 per population. Twelve-month interval treatment was by no means meaningful to be adopted as a strategy of Ascaris control because egg and worm positive rates and worm burden were returned to pretreatment level. The shorter the treatment interval was, the lower the egg/worm positive rates and worm burden were. By repeating biannual, triannual and six-times-in-a-year treatments, the indices of prevalence showed the tendency of further lowering during later 2 years of follow-up. If the mass chemotherapy is adopted as a method of controlling ascariasis in a community, it should be repeated more than two times in a year to expect the gradual lowering of reinfection.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; chemotherapy ; pyrantel pamoate ; epidemiology

To observe the effect of egg-free state in an institute on the endemicity of Enterobius vermicularis, the theoretical condition was made by repeated chemotherapy. Mebendazole or pyrantel pamoate were administered to all orphans and their staffs concomitantly for four times, each 20-day interval. In two low endemic orphanages, in which mean egg positive rates were 18 % and 39 % respectively, the pinworm infection was controlled up to 6-7 months period. And other two highly endemic orphanages, with 70% and 55% of egg positive rates, were controlled up to 90th day after the first treatment. After then up to 7 months, the reinfection occurred, but the endemicity was brought down to about 20 % of egg positivity.
parasitology-helminth-nematoda ; Enterobius vermicularis-chemotherapy ; enterobiasis ; mebendazole ; pyrantel pamoate

A total of 56 subjects with multiple nematode infections with T. trichiura, Ascaris, hookworms and Enterobius were treated with oxantel and pyrantel pamoate mixture in a paratable suspension(50 mg of each per ml). A single dose of 10 mg per kg body weight in each cured 100 per cent of 54 subjects with Ascaris, 97.1 per cent of 35 subjects with hookworms, 77.8 per cent of 36 with Enterobius and 73.2 per cent of 56 subjects with T. trichiura infestation. The mean egg per gram stool reduction rate in T. trichiura infection was 91.9%. Of the 31 subjects infected with Ancylostoma doudenale 96.8% were cured with a single dose and 4 infected with Necator americanus showed a 100% cure rate with a similar daily dose on 3 consecutive days. Side effects were few and mild. There was no clinical or laboratory evidence of drug toxicity. These findings show a single dose of oxantel and pyrantel pamoate mixture to be a highly effective and acceptable treatment for multiple infections with these nematodes.
parasitology-helminth-nematoda ; Trichuris trichiura ; Ascaris lumbricoides ; hookworm ; Enterobius vermicularis ; chemotherapy-oxantel pamoate-pyrantel pamoate

This study was undertaken to observe the fluctuation pattern of E.P.G. (eggs per gram of feces) according to the number of infected worms and developmental status of Ascaris lumbricoides. The cases were selected from 2,109 inhabitants of Hwasung Gun, Kyunggi Do, Korea, who had received pyrantel treatment in dose of 10 mg/kg during April 1977-May 1980 and who were cooperative enough to collect whole-day stool specimens for 2 days. Among them, 602 cases who had been infected with 1-5 worms were subjected to analysis. Egg examination was undertaken by means of cellophane thick smear technique and the amount of produced eggs was checked by Stoll's egg counting technique. The Ascaris worms were collected from stool specimens, counted in number in each case, and each worm was measured by length. The results could be summarized as follows: According to the increase of worm burden per case from l to 5, the egg detection rate increased from 33.4 percent to 95.7 percent. And the same pattern was observed when the only burden was considered. There were ample variations in the individual E.P.G. counts even among the cases with same burden, although the mean E.P.G. counts among the cases were quite proportionately increased from 842 to 3,467 according to the number of female worms, 1-4. However, from the distribution pattern of the number of each grade of E.P.G. count, it was revealed that the lower the number of females the more cases were with low grade of E.P.G. It was observed that the eggs could be detected after the female worm grew longer than 12.6 cm and the amount of eggs increased until the worm became about 25.0 cm, where a plateau was made in E.P.G. 1,300-1,400, and decreased significantly after 27.5 cm. And yet, wide variations in E.P.G. counts were noted even among the worms of similar growth. Accordingly, the E.P.G. value had better be used as a useful index to estimate the intensity of Ascaris infection and to compare the intensity between two communities, rather than be used to estimate the individual worm burden.
parasitology-helminth-nematoda ; Enterobius vermicularis-enterobiasis ; chemotherapy ; pyrantel pamoate ; biology ; morphology

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