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

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

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 present study was undertaken to determine whether an analysis of the collected worms after chemotherapy with pyrantel pamoate could be used as a method measuring the amount of reinfection of Ascaris lumbricoides in a given population. A total of 398 cases from two villages and one primary school were treated with pyrantel pamoate with dose of 10 mg/kg of body weight. The whole two-day stool specimens after treatment were examined. Out of 279 followed cases, 110 cases (39.4%) were found infected with A. lumbricoides. A total of 527 worms were collected, they were in the range of 1.2 to 32.5 cm in length and 0.0004 to 7.424 gm in weight. The measurements were made on the specimens fixed with 10% formalin. The relationship between the number of worms per positive case(X) and the total weight of worms(Y) showed the positive linear regression; this was expressed by the equation, Y= 2.012X + 1.135 (Sy=4.84, r=0.92). From the above results, it seems that worms of small size may not be considered as a product of crowding effect in heavy infections. The relation between the weight(Y) and length(X) of collected A. lumbricoides was expressed as an equation, Log(e)Y=3.032 log(e)X-8.2903(S.E. of reg. coeff.= 0.040, r=0.957). In the intestinal phase of development, the first increase of the length of the worm, up to 10-12 cm was observed and this followed by the well marked increase of weight from 13 cm upto 32.5 cm in the sexually maturing phase. A total of 285 schoolchildren were treated by pyrantel pamoate, 10 mg/kg of body weight three times each in two months interval. After the second and third treatment, thirteen and fifty-four worms were collected respectively. They were measured in length and weight and were all in the range of 1.2 to 13.2 cm in length and 0.0006 to 0.436 gm in weight except 3 fully matured adults. It is assumed that these young worms, defined as those less than 0.5 gm in weight and less than 13 cm in length should be regarded as those having reinfected during the previous two months period. From this observation, it was possible to calculate the reinfected number of young worms. Therefore, it is suggested that the average number of Ascaris per month per person means the reinfection amount in a certain period of time in an endemic area of A. lumbricoides. In other words, reinfection amount may be expressed by the calculated figure of young worms reinfected in a certain period of time in a population.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; ascariasis ; epidemiology-reinfection ; pyrantel pamoate

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

Dirofilaria (D.) immitis is an important canine parasitic nematode in dogs. D. immitis parasitizes the right ventricle and pulmonary artery of dogs. An ivermectin and pyrantel pamoate compound (IPPC) was administered to dogs naturally infected with this parasite. IPPC is composed of 68.0, 136.0 and 272.0 microg of ivermectin and 57.0, 114.0 and 227.0 mg pyrantel pamoate for small, middle, and large animals. Ivermectin has activity against nematodes and ectoparasites in dogs. Pyrantel pamoate is also effective against nematodes in dogs. Our results showed that this drug combination has good efficacy in D. immitis infected dogs.
Animals ; Dirofilaria ; Dirofilaria immitis ; Dogs ; Heart Ventricles ; Ivermectin ; Parasites ; Pulmonary Artery ; Pyrantel ; Pyrantel Pamoate

Toxocara (T.) canis and Trichuris (T.) vulpis are very important canine parasitic nematodes. T. canis parasitize in small intestine and T. vulpis parasitize in large intestine. In order to control of these nematodes, ivermectin and pyrantel pamoate compound was applied to the dogs infected with these parasites naturally and artificially. This drug was composed of 68.0 microg of ivermectin and 57.0 mg of pyrantel pamoate for small animal, 136.0 microg of ivermectin and 114.0 mg of pyrantel pamoate for middle animal, and 272.0 microg of ivermectin and 227.0 mg of pyrantel pamoate for large animal. Ivermectin in this drug is activity to nematodes and ectoparisites. Pyrantel pamoate in this drug is also activity to nematodes. In this experiment, this drug had a good efficacy against T. canis and T. vulpis in the infected dogs.
Animals ; Dogs ; Intestine, Large ; Intestine, Small ; Ivermectin ; Parasites ; Pyrantel ; Pyrantel Pamoate ; Toxocara ; Toxocara canis ; Trichuris