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

A status survey on Metagonimus yokogawai infection along the Tamjin River basin, South Cholla Do, Korea was conducted from September to November 1977. The snail intermediate host, Semisulcospira sp., the fish host, Plecoglossus altivelis and the inhabitants in three villages in Jangheung and Kangjin Guns were examined for detection of this trematode infection respectively. The results could be summarized as follows: Out of 452 snails, Semisulcospira sp., 105 (23.2%) were found positive for rediae and/or cercariae of M. yokogawai in Jangheung Gun. All of 20 sweetfishes, P. altivelis were infected with metacercariae of M. yokogawai and the mean number per fish was 15,688 and per gram of fish muscle, 234. Out of 606 inhabitants in three villages, 160(26.4%) persons were found infected with M. yokogawai and the mean E.P.G counts per infected cases were 2,078. Sixty cases (9.8%) were positive for ova of Clonorchis sinensis with mean E.P.G., 846, frequently mixed-infected with M. yokogawai. From the above results, it was turned out that the Tamjin River basin is one of the endimic foci of metagonimiasis in Korea. The relatively low infection rate of human host in spite of much higher infection of intermediate hosts were considered to be due to the less population of sweetfishes in the Tamjin River than in the Sumjin River basin.
parasitology-helminth-trematoda ; Metagonimus yokogawai ; epidemiolgy

This study was undertaken to figure out the basic patterns of the frequency distribution of Ascaris lumbricoides in rural Koreans and to find out the effects of changing endemicity on the frequency distribution pattern. Total 853 cases in 6 areas were surveyed from November 1975 to February 1978. The mean ova positive rate was 33.1% and in the range from 23.9 to 66.7% by the surveyed unit. From the analyses of the collected data, the following results were obtained. The overdispersion pattern of worm burden per case was mathematically fitted both to the theoretical values of the negative binomial and Poly-Eggenberger distributions. However, when "0" and lower burden cases were considered, the better fitness was observed in the negative binomial than in Polya-Eggenberger distribution. Although the endemicity of Ascaris is changed, the relative frequency of the lower burden cases is rather constant. The false negative rate of stool examination and unfertilized ova passers in the population were not changed significantly according to the endemicity. And the rate of unfertilized ova passers in infected cases was increased when the endemicity was lowered. From the above results, it is concluded that the overdispersed frequency distribution pattern of Ascaris in an endiemic area is changed by the relatively rapid decrease of heavy burden cases and increase of non-infected cases according to the lowered endemicity due to the impact of the control.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; egg ; epidemiology ; frequency distribution

In Ascaris lumbricoides infection, the faecal examination, undertaking for ova detection, is not always diagnostic. It is just because some of the infected cases has Ascaris worm(s) which do not produce eggs. In the present study, the authors attempted to analyse quantitatively the egg discharging patterns in Ascaris infected cases with low worm burden. The following results were obtained: In 1,861 Ascaris worms collected from 853 cases, the sex ratio was 1: 0.74 (female: male). Sex combinations in each burden of case were always fitted with theoretical values from the binomial distribution; (m+f)(n)= (0.426+0.574)(n). In each worm burden, their sex combination indicated different egg discharging patterns; false negative cases, unfertilized ova passers and fertilized ova passers. When the relative frequency of the above three egg discharging patterns was plotted to worm burden per case, a definite relationship was found. The cases with six or more worms have nil probability to be false negative case or unfertilized ova passer. Out of 853 cases, we found 129 false negative cases. The collected worms from 125 cases were morphologically analysed. It was found that 52% of them were infected with only male worm(s) and 24% were infected with young female worm(s). And in 8.8%, old female(s) with empty uterus were infected. The cause of 15.2% was remained unexplained, even though the collected worms were scrutinized.
parasitology-helminth-nematoda ; Ascaris lumbricoides ; egg ; epidemiology

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

: A clinical trial of Korean Patent mebendazole was undertaken upon some intestinal helminthic infections in 288 rural Koreans residing in Pochun and Jinyang Gun, from November to December, 1976. They were examined by the cellophane thick smear technique, Stoll's egg counting technique and/or Scotch-tape anal swab before and 3 weeks after the treatment. The administered dose of mebendazole was 600 mg, divided by 100 mg, twice daily for 3 consecutive days disregarding the body weight and the age of the cases. It was confirmed that mebendazole is very effective, broad-spectrum anthelmintic, especially against Ascaris, Ancylostoma, Trichostrongylus and Enterobius infections. Their negative conversion rate and egg reduction rate were respectively; 94.0 and 99.6 per cent in Ascaris, 71.4 and 97.3 per cent in Ancylostoma and 95.0 and 100 per cent in Trichostrongylus. The negative conversion rate in Enterobius was 92.3 per cent. The anthelmintic efficacy against T. trichiura infection was not satisfactory in spite of low worm burden (negative conversion rate, 27.3%, egg reduction rate, 65.5%).
parasitology-helminth-nematoda ; Ascaris lumbricoides ; Ancylostoma duodenale ; Trichostrongylus orientalis ; Trichuris trichiura ; chemotherapy-mebendazole ; Enterobius vermiculariss

This paper is described on the development of KOTRON-13 and recent status of PET cyclotron by commercial cyclotron companies. KIRAMS has developed medical cyclotron which is KIRAMS-13. Samyoung Unitech produces KOTRON-13 with transfered technology by KIRAMS. As a part of Regional Cyclotron Installation Project, KOTRON-13 cyclotrons and [18F]FDG production modules are being installed at regional cyclotron centers in Korea. The medical concern with radiation technology has been growing for the last several years. Early cancer diagnosis through the cyclotron and PET-CT have been brought to public attention by commercial cyclotron models in the world. The new commercial cyclotron models are introduced compact low energy cyclotrons developed by CTI, GE, Sumitomo in recent. It produces different short-lived radioisotopes, such as [18F], [11C], [13N] and [15O]. For the better reliability acceleration particle is proton only. The characteristics of new model cyclotrons are changed to lower energy corresponding to less 13 MeV. New models have self-shielding and low power consumption. Design criteria for the different types of commercial cyclotrons are described with reference to hospital demands.
Acceleration ; Cyclotrons* ; Diagnosis ; Korea ; Protons ; Radioisotopes

Horace N. Allen, an American physician, was a Presbyterian missionary to Korea. In 1886, he wrote the annual report of the Korean government hospital, summarizing patient statistics according to outpatient and inpatient classification for the first ever in Korean history. In the report, he speculated that hemoptysis cases of outpatient might have been mainly caused by distoma. Allen’s conjecture was noteworthy because only a few years lapsed since the first scientific report of paragonimiasis. However, he was not sure of his assumption either because it was not evidently supported by proper microscopic or post-mortem examinations. In this letter, we thus revisit his assumption with our parasitological data recently obtained from Joseon period mummies.
Autopsy ; Classification ; Hemoptysis ; Humans ; Inpatients ; Korea ; Missionaries ; Mummies ; Outpatients ; Paragonimiasis ; Prevalence ; Protestantism

The present study was undertaken to know the infection status of Cryptosporidium parvum among the residents of Chorwon-gun, Kangwon-do in 1993. Total 461 fecal samples were collected from the inhabitants residing in Chorwon-gun during the period of August 12 to September 14, 1993. Fecal smears were prepared by formalin-ether sedimentation, and examined after modified acid fast staining. Of the 461 fecal samples, 9 (1.9%) were positive for C. parvum oocysts. The positive cases were limited to thirties (4) patients, forties (3), and sixties (2), and no oocyst was detected in other age groups. The oocyst positive rate for male was 1.4% and that of female was 2.6%.
Adolescent ; Adult ; Age Factors ; Aged ; Animals ; Child ; Cryptosporidiosis/*epidemiology/parasitology ; Cryptosporidium parvum/isolation & purification ; Feces/parasitology ; Female ; Human ; Korea/epidemiology ; Male ; Middle Aged ; Parasite Egg Count ; Sex Factors

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