Detecting eggs from feces and/or sputum is probably closely associated with many factors such as degree or intensity of infection, physiological status of the host(age, eating habit and duration of residence in the area), the duration of infection for the parasite (age and reproductive activity of flukes), and methods of collecting specimens and technique of examination. Neverthless, it is difficult to determine which factor plays the most inportant role in detecting eggs except comparison of factual result obtained by standardized techniques. The purpose of the study was to find out which method would give better result for detection of eggs, and to estimate what proportion of patients would be missed when the method selected is used. On a single examination of both specimens, stool and sputum, collected from the same person, sputum examination was found to be superior to stool examination for detection of eggs; 37 of 40 egg positives had eggs in sputum whereas only 21 of 40 in stool. Repeated sputum examination on the same subject in spaced time gave higher overall egg detection rate; in the first examination for all skin reaction positives, the detection rate was 36.8%, in the second examination on those who had negative results in the first examination, it was 11.6% among 602 persons examined, and 5.3 percent of 95 persons who were negative in previous two examinations. Thus, repeated sputum examinations (three times) increased the overall detection rate to 48.5% from 36.8%. According to the result obtained through this study, it would be worthwhile to recommend repeated sputum examinations at least three times on the same subject even if collecting second and third sputum is quite difficult problem in mass survey; about 12% of total patients who can be detected as positive by three times repeated examinations shall be missed if only a single sputum examination is done.
parasitology-trematode-Paragonimus westermani ; diagnosis ; sputum examination ; stool examination skin test

An ecologic study on Paragonimus in Malaysia was attempted from May to September 1967. Seven streams located in various directions and distances from Kuala Lumpur were surveyed for the study of intermediate hosts, snail and crab. One Malayan village and one aborigine village where infected crabs were found, and two tuberculosis hospitals in K.L. were surveyed for the study of human population. Intradermal tests along with sputum or stool examination to detect human infection by Paragonimus were employed. Wild animals, only a few, were shot in the vicinity of the aborigine village and several domestic cats from the Malayan village were bought. These animals were autopsied and examined for adult Paragonimus. Among five species of crab collected from the study areas, only two species, Potamon jahorenes and Parathelphusa maculata were found to be infected with Paragonimus. P. maculata seemed to be better crab host for the Paragonimus because this species had higher infection rate and metacercarial density than the other in the very same area. Three out of seven streams had infected crabs and the infection rate as well as the infection intensity varied from one stream to another. Only avilable snail in the streams was identified as Brotia costula. The infection rate of the snail was very low, six snails out of 11,898, which is about the same rate reported from other countries. Infected snail, however, had thousands of rediae uncountable containing about twelve microcercocercariae in each redia, sufficient enough to maintain the life cycle of the parasite even with only a few infected snail, the amplifier. This is the first confirmed report on the snail host of Paragonimus from Malaysia where the existence of Paragonimus had been reported in 1923. The first trial to study human population by means of intradermal test, sputum and/or stool examinations in Malaysia showed no evidence of human infection of Paragonimus. The number of animals, wild and domestic, examined for natural infection was too small to draw any statement. These examined animals were all negative for adult Paragonimus. Even though more extensive studies on wild animals and human population may be necessary for the definite conclusion, the facts that infected crabs from jungle stream where human contacts are extreamely rare, and also highly infected crabs from the area where none of humans or domestic animals were infected, strongly suggest the life cycle of Paragonimus in this area may be maintained by wild animal hosts rather than by human host. The morphology of all stages of the parasite, the pattern of penetrating glands, flame cells and excretroy bladder of cercaria, lancet shaped single cuticular spines and 6 branched ovary of adult worm obtained from experimentally infected cat, and the shape of egg including all measurements agree well with the characteristics of Paragonimus westermani.
parasitology-helminth-trematoda ; Paragonimus westermani ; epidemiology-paragonimiasis ; crab ; Potamon jahorenes ; Parathelphusa maculata ; cat

No abstract available.
Korea*

An evaluation of intradermal test in screening paragonimiasis was attempted by comparing antigens, filtered through Sephadex G 50, fractionated by DEAE Sephadex A 25, and V.B.S.(crude extract of adult worms) antigen on 402 school children. The sensitivity and false negative rates were compared with one another on results of two examinations for eggs, one with sputum and the other with stool. The purified antigens showed more intense skin reaction than the crude extract. The crude extrct(V.B.S.) appeared to have lower false negative rate than the purified even though the difference was not statistically significant. Intradermal test with V.B.S. antigen on 12,000 subjects was analysed to find some characteristics of the reaction. Three size groups were classified by egg detection rate; negative reaction, 20-50 mm(2) size group of which egg detection rate was 3.5% among 118 persons, intermediate, 60-100 mm(2) with 26.8% among 1,078, and positive reaction, larger than 100 mm(2) with 45.7% among 2,098 subjects. The distribution of wheal size by age for total population surveyed revealed that younger ages had smaller wheal sizes with larger proportion of negative reaction, which decreased when the age increased. Skin sensitization in a population seemed to occur gradually to and reached a maximum by the age of 13 year. The egg detection rate increased proportionately to wheal size for the intermediate group, however, it did not vary much by size for positive group(larger than 100 mm(2)). When the wheal size distributions were compared in three groups, egg positives, egg negatives, and the group whose sputa were not examined, curves of the two groups, egg positive and negative, did not show clear separation. This fact seems to indicate that there is a low sensitivity and specificity in both tests(sputum and skin). The stability of the intradermal test measured by a second survey done one year after the primary survey revealed that the intermediate size group had more marked unstability than the other groups, and the treated group had tendency to decrease in wheal size. The purification of antigen for intradermal test did not add any better means of screening for paragonimiasis, probably due to the nature of skin sensitization evoked by many elements of the parasite but not by a few selected components. The V.B.S. antigen may be valuable for screening a large population, yet the diagnosis can not be dependent entirely upon the test. The final diagnosis should be made by repeated sputum examinations in spaced time with careful history taking aided by CF test and X-ray examination if necessary.
parasitology-helminth-trematoda ; Paragonimus westermani ; epidemiology ; diagnosis ; skin test ; specificity ; sensitivity

Among 11,005 inhabitants(61% of total population) surveyed in 13 villages of Che Ju Island in 1964, were identified as paragonimiasis patients, of these 1,355 were treated with 40 mg/kg body weight of bithionol for 10-15 doses. The purpose of the study was to test whether mass chemotherapy of the human host may provie an answer for the control of paragonimiasis in an area where the human host is main source of infection to the intermediate hosts. The efficacy of the mass chemotherapy as control program was measured by the acceptance of the survey and treatment by the inhabitants, the efficacy and the toxicity of the drug applied, and the influence of the infection rates of the intermediate hosts. The acceptance of the survey and the treatment was not entirely satisfactory: an estimate based on data suggests that only fifty to sixty percent of all cases infected were detected, and 93% of detected cases were treated in the primary program. All cases detected during the follow up survey, which could not cover whole population, were treated. The efficacy of bithionol was excellent when the treatment was completed. 40 mg/kg body weight for 10-15 doses was sufficient to turn the sputum egg-negative except in a few cases infected heavily that needed 20 doses. Side reactions were generally mild; the most frequent reaction was gastrointestinal; which spontaneously subsided within a few to several days. The infection rate of intermediate hosts started to decrease from the third year of the mass treatment with a pattern of gradual drop. Follow up studies on general population in three and four years of the mass treatment also showed markedly decreased prevalence of paragonimiasis by intradermal test and sputum examination. It is concluded that a complete mass chemotherapy with bithionol in an area where human is the main source of infection to the intermediate hosts can be the answer for control of paragonimiasis.
parasitology-helminth-trematoda ; Paragonimus westermani ; epidemiology ; chemotherapy ; bithionol

No abstract available.
Bioterrorism*

A study on the infection status of intermediate hosts of Paragonimus, snail and crab, was conducted on Che Ju Island for four years to understand ecology of Paragonimus in the area and to evalute the control program by mass chemotherapy The infection rate of the first intermediate host of Paragonimus, snail, showed higher rate in the area where human association was more frequent and had higher human infection rate compared with the area with lower human infection and less contact by people. Larger snails were infected more frequently than smaller ones. After the mass treatment on human population, the infection rate of snail dropped markedly in four years. The infection rate and the intensity of infection of crabs were influenced by many factors:by frequency of human association, by prevalence of paragonimiasis in the population and volume of water flow, dilution effect. The distribution of metacercariae in infected crabs varied by body sites; the most frequently in gill, next in legs, internal organs and thoracic muscle in order. If crabs were examined for existence of metacercariae only gills, about 6% of infected crabs of may be missed as negative. The infection status of the crabs was not different by distance from the actual site of pollution. Also seasonal fluctuation of crab infection was not remakable. The crab infection by size showed time sequence of exposure; smaller crabs had lower infection rate and metacercaria density reaching to the maximum by 3 cm of size. As shown in the snail infection, the crab infection remarkably decreased after the control measure of human paragonimiasis, mass chemotherapy, in four years.
parasitology-helminth-trematoda ; paragonimiasis ; Paragonimus westermani ; metacercaria ; epidemiology ; snail ; crab ; host ; chemotherapy

Mortality and morbidity caused by accidents among Koreans have been increasing steadily and more strikingly from motor vehicle traffic accidents since 1980's, when owning and driving car became a fashionable and ubiquitous life style among Koreans. The proportion of deaths from accidents among all deaths was 9. 5% in 1983 and increased to 14. 8% in 1993. Moreover the mortality rate from the motor vehicle traffic accident increased more than three folds along with eight folds increased number of vehicles during the same period.
Accidents, Traffic* ; Epidemiologic Studies* ; Korea* ; Life Style ; Mortality ; Motor Vehicles ; Public Health*

In order to understand the epidemiologic characteristics and trends of Leptespirosis in Korea, year book of acute infectious disease and literatures published were thoroughly reviewed. The results obtained are as follows: 1. The outbreak of Leptospirosis in Korea has decreased during recent years. Most of the patients occured in Semptember, October, and November. Seventy nine percent of reported patients occured in north Choongchung, south Choongchung, and Kyunggi province in 1987-1991. 2. Leptospires isolation rates were ranged from 0.2% to 16.0% among normal healthy person, higher in rural residents than military personnels. 3. Total of 92 strains were isolated from human in six years from 1984 to 1990. Its main serogroups were Icterhaemorrhagiae and Canicola, predominantly consisted of serovar lai, copenhageni and canicola. Eighteen strains of Biflexa were also isolated from healthy persons and patients. 4. The proportion of Leptospirosis among patients with acute febrile episode has decreased since 1985. Sero-positive rate of male among patients with acute febrile episode is higher than that of female. Sixty percent of sero-positive patients with acute febrile episode was older than 40-year of age. The seropositive rates were consistently the highest in harvest season than other seasons. Residents of north Choongchung, north Chunlla, south Chunlla, Kyunggi, and north Choongchung provinces showed higher seropositive rates than those of other ones. Main serogroups positive to most sera of Koreans were Icterohaemorrhagiae and Canicola. 5. The sero-positive rate of normal healthy persons ranged from 2.0 to 25. 6% ; the sero-positive rate of rural area was 4 to 8 times higher than that of healthy urban people. Little difference was observed in sero-positive rate by age group among above 40 years old people, although it was higher in male by sex, in farmers by occupation and in some provinces by area.
Adult ; Communicable Diseases ; Female ; Gyeonggi-do ; Humans ; Korea* ; Leptospirosis* ; Male ; Military Personnel ; Occupations ; Seasons

In the survey of l1,005 subjects in l3 villages of Che Ju lsland, 1,450 persons were egg-positive by repeated sputum examinations. The response rate to intradermal test ranged 50-80 per cent of the population and to sputum examination for skin positive 60-70 per cent in the first survey done in l964. 93 per cent of all egg-positive was treated with 40 mg/kg body weight of bithionol on alternate days for 10-15 doses in l965. Follow-up studies were carried out in one year, three-year, five-year, and eight year after the mass treatment. The one year follow-up study covered 86.5 per cent of all treated cases in all villages but only a part of the population of a few villages in further follow-up studies. In this paper only the result obtained from the age group of 7-18 years, the common population studied in every follow-up for the purpose of comparison, is presented. Intermediate hosts of P. westermani were examined at the same time. In one year follow-up it was found that 91 per cent of egg-positive treated became negative. Three parameters, skin reaction, sputum examination, and infection status of intermediate hosts by area and year were used for comparison. Skin positive rate showed gradual decrease with more marked drop in Kang Chung where more thorough survey and mass treatment (about 43 per cent of all infected persons estimated among whole population) were carried out than other areas (only 20-30 per cent). The proportion of intermediate skin reation (60-100 mm(3) wheal size) increased markedly indicating decreased dose of infection which corresponds to the dropped infection rate and average number of metacercaria in crabs. Egg-positive rate in sputum examination done for skin positive reactors also presented similar pattern to skin reaction although it should be taken account that the result of 1964 was from repeated sputum examinations but that of other years from a single examination. Increased proportion of intermediate skin reaction which has much lower egg-positive rate probably played major role in decreased egg-positive rate. The infection rate of snail started to drop about one year earlier than crab; crab infection rate and intensity started to drop about four year after the mass treatment. The duration needed to show the change of infection status in intermediate hosts after the mass chemotherapy may correspond to the duration of survival of the parasite in the intermediate hosts. With the data available presently, it is difficult to determine on what point of the curve the present status is situated (on decreasing phase or increasing phase?), how far the rate will go down if it is on decreasing phase, and how long would it take in returning to the original status without further management. The result of follow-up study, however, strongly indicate that continous and intense chemotherapy may be able to put the paragonimiasis under control. Further follow-up study on total population including survey on changes of environment and eating habits is planned.
parasitology-helminth-trematoda-Paragonimus westermani ; chemotherapy ; control ; bithionol