The present study was undertaken to observe the morphological changes of Clonorchis sinensis obtained from experimentally infected rats treated with praziquantel (Biltricide) which is a new anthelmintic agent with high activity against a broad spectrum of cestode and trematode species. For this study, the rats were infected experimentally with about 50 metacercariae of C. sinensis and were given praziquantel a single dose of 600 mg per kg of body weight at 5 weeks after infection. The Clonorchis worms were isolated from the bile ducts of the rats which were autopsied on the 4th day after treatment. After isolation the parasites were observed their shape and motility in the medium of 37 C physiological saline solution, and then the fine structure of the tegument of C. sinensis was studied by means of light, scanning and transmission electron microscope. The findings of the observation were compared with those of untreated parasites. The results are as follows: All the isolated worms moved actively in the medium of physiological saline solution (37 C). A majority of the parasites obtained from the treated rats showed a large balloon shaped structure on the surface between oral and ventral suckers. But such structure has never seen in the parasites obtained from control rats. By the scanning electron microscopic observation, the regular pattern of the tegumental ridges was significantly changed on the outer surfaces of parasites obtained from the treated rats as compared with those of the control rats. By the transmission electron microscopic observation, the numerous mitochondriae in the syncytial tegumental layer of the treated parasites appeared to be degenerated and formed small vacuoles, and the tegumental ridges were also degenerated and showed somewhat flattened. In the parasites obtained from the treated rats, a different size of vacuoles interspersed in the distal part of the syncytial tegument and also in subepithelial region of the urinary bladder. These vacuoles are fused each other and lead to the disruption of the apical region of syncytial tegument along the basement layer. Finally the basement layer was dislocated. So that the tegumental layer appeared as a large balloon.
parasitology-helminth-trematoda ; Clonorchis sinensis ; chemotherapy

A total of 60 patients with Hymenolepis nana infection were treated with a single oral dose of praziquantel in two different dose levels. Twenty-nine cases treated with praziquantel in a single dose of 15 mg/kg body weight produced a 100% cure rate. On the otehr hand, 30 out of 31 patients who received a single dose of 25 mg/kg body weight cured completely, but only one case had counts of 200 EPG of feces in each tests on the 20th and 21st days after treatment. The cure rate was 96.8% and the mean egg reduction rate of 99.8 per cent was obtained. Side effects were mild and transitory. In a few cases, abdominal pain, vertigo, headache and diarrhea were complained in a few hours after medication. Clinial hematology, serum biochemistry and urinalysis were performed immediately before and the next day after treatment in all cases. There were no significant abnormalities detected in these tests.
parasitology-helminth-cestoda ; Hymenolepis nana ; chemotherapy-praziquantel

Ten cases infected with Taenia saginata were treated with Bithionol, 2, 2' thiobis (4,6-dichlorophenol) which is well known as an excellent anthelminthhic against paragonimiasis and their follow-up studies were carried on within 3 to 12 months after treatment. Bithionol, 50 mg dose per kg of body weight was divided into two equal dose and administered orally in 30 minutes intervals. Three hours later, this was followed with a sodium sulfate or magnesium sulfate purge. The strobilas without scolices were found in the stools after the medication and the follow-up studies have shown the complete deworming in all cases. It is well tolerated, toxic effects being uncommon and when present, limited to mild gastro-intestinal disturbances.
parasitology ; helminth ; cestoda ; Taenia saginata ; chemotherapy ; bithionol

The phamacological and anthelmintic action of Lysimachia clethroides were examined. Upon examining the action of water, ether, alcohol and acetone extrcts of the root on smooth muscle, it was found that the active principle was weakened by heating. Water and ether extracts inhibited the dehydrogenase of the worm. In 50 percent of 8 areas studied, Taenia were completely eliminated with 2.5-4.0 gm doses of the ether extracts, and no toxic effect was observed by the administration of the above-mentioned doses.
parasitology-chemotherapy ; Taenia sp. ; Lysimachia clethroides

The therapeutic effect of praziquantel on Fibricola seoulensis infection were studied by experimental infection of albino rats with the metacercariae obtained from the snakes. Total 51 albino rats were infected each with 500 or 1,000 metacercariae in number through intragastric tubes. One or four weeks later the rats were treated with 1, 5, 10 or 20 mg/kg sigle dose of praziquantel and sacrificed after 3 days or 10-120 minutes to search for the worms in their small intestine. The worms recovery rate at 3 days after the treatment was 10.7% in 1 mg/kg does group and 0.03-0.2% in 5, 10 and 20 mg/kg group, while that of untreated control was 51.3%. The minimum effective dose to treat F. seoulensis infection in the rats is considered to be 5 mg/kg in sigle dose. By observing the distribution pattern of worms in the small intestine after the treatment, dislodgment of the worms froms the duodenum, thier normal habitat, to the lower portion was recognizable within as early as 10 minutes. The majority of worms was found to have descended to the ileo-caecal portion after 60-120 minutes.
parasitology-helminth-trematoda ; Fibricola seoulensis ; chemotherapy-praziquantel

The efficacy of reduced single doses of mebendazole against Ascaris lumbricoides infection was evaluated by cellophane thick smear and egg counting techinques, in two rural populations from December 1977 to March 1978. Total 191 infected cases were divided into five dose groups; 100 mg single dose, 200 mg single dose, 300 mg single dose, 400 mg and 600 mg in repeated doses. The cure rate of mebendazole in the treatment of Ascaris infection was remarkably high and satisfactory in every dose groups. The egg reduction rates were all over 98 percent in every dose groups. Side effects were observed during the treatment, mainly mild and transient gastrointestinal troubles, and not exacerbated by the increase of doses upto 300 mg in single dose. Above results confirmed that in case of mass chemotherapy of Ascaris infection, 100 mg or 200 mg of single dose treatment is sufficient to achieve the economic and acceptable method of treatment.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; chemotherapy-mebendazole

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 authors carried out two series of field test to determine the basic lines of DDT and Dieldrin susceptibility of Anopheles sinensis at Andong(1961) and Yoju(1962), where malaria endemicity is relatively high in Korea. Tests were performed in accordance with the standard method established by the World Health Oraganization(1960). The results were summarized as follows: The LC-50 of DDT for A. sinensis caught at Andong as 1.5 %, while for the same species in Yoju was 1.3 %. The LC-50 of Dieldrin for A. sinensis caught at Andong was 0.075 %, while the LC-50 for the same species at Yoju was 0.07 %. These results therefore indicate Anopheles sinensis, as the malaria vector species in Korea, is susceptible to DDT and Dieldrin.
parasitology-protozoa-Plasmodium vivax ; chemotherapy-malaria ; Anopheles sinensis ; DDT ; Dieldrin

The following results were obtained in the present study concerning the effectiveness of thiabendazole upon the larvae of the migrating stages. In the early observation group: The average number of larvae of the group treated with single dose and the group treated with three doses were reduced in proportion of 52.2%, 58.5 % respectively compared with control group. In the late observation group: The reduction rate in the group treated with singel dose and group treated with three doses were 59.3 % and 63.2 % respectively compared with control group. The reduction rates of larvae from liver and lungs in the early drug administration group were 72.9 % and 59.7 % respectively, and 14.9 % and 54.8 % in the delayed drug administration group. In the group of drug given before and after infection, the number of recovered larvae were reduced 42.2 % and 31.1 % respectively compared with the control group. The peak number in organs was delayed 1 to 2 days in the treated group than that of control group. The survival period of the infected mouse was prolonged by the drug administration. The pathological changes were reduced by the administration of the drug. Through above results, it was concluded that thiabendazole reduced the number of migrating larvae and delayed the normal migration of the larvae in tissues and reduced the pathological changes in the tissues.
parasitology-helminth--nematode-Ascaris lumbricoides ; chemotherapy-thiabendazole ; migration ; thiabendazole