National survey of the status of infection surveillance and control programs in acute care hospitals with more than 300 beds in the Republic of Korea.

BACKGROUND: This study was conducted to assess the status of infection surveillance and control programs (ISCPs) and to analyze the trends associated with ISCP implementation since the first program was established in Korea in 1991. METHODS: A questionnaire modified from the Study on the Efficacy of Nosocomial Infection Control was mailed 4 times nationwide to acute care hospitals (n = 164) with more than 300 beds between June and October 2003. Eighty-five hospitals participated (52%). RESULTS: The mean number of beds (649) in the responding hospitals was significantly greater than in nonresponding hospitals. Of the participating hospitals, 92% had educational functions, 40% to 90% used hand hygiene resources, and 100% had infection control committees; 86% had infection control doctors, 98% had infection control nurses (ICNs), 89% employed only 1 ICN, and 59% employed an ICN only part-time; 68% performed surveillance, undertaking 2.7 epidemic investigations per year and 8.4 teaching programs per year; 88% undertook needlestick prevention programs; 58% performed regular air culture; and 64% discarded ineffective ISCPs. Annual trends analysis of ISCPs indicated that accreditation and legislation impact strongly on Korean ISCPs. CONCLUSION: The figures for ISCPs in this study indicate that improvements have been made since the 1990s. Legislation and accreditation have strongly influenced ISCPs. Much consideration should be given to the weaknesses in Korean ISCPs: surveillance, insufficient hand hygiene resources, and shortage of ICNs.

Impact of Agent Orange exposure among Korean Vietnam veterans.

In order to determine whether Agent Orange exposure was associated with increased frequency of medical problems, we conducted a cross-sectional epidemiologic study of Korean veterans during 1995-1996. 1,224 Vietnam and 154 non-Vietnam veterans were included in the study. Exposure to Agent Orange was assessed by structured in-depth interview on the participants' history of service in Vietnam. Health outcomes were assessed by a standardized comprehensive clinical investigation by a group of clinical specialists. The differences in the prevalence of various medical diagnoses were assessed by Cochran-Mantel-Haenszel chi-square tests comparing the exposure levels of Vietnam veterans, adjusting for age. Multiple logistic regression was performed to estimate the effect of "service in Vietnam" adjusting for age, smoking, alcohol, body mass index, education, and marital status. Vietnam veterans had an increased frequency of eczema (odds ratio [OR] = 6.54), radiculopathy (OR = 3.98), diabetes (OR = 2.69), peripheral neuropathy (OR = 2.39), and hypertension (OR = 2.29), compared to non-Vietnam veterans, adjusting for potential confounders. In addition, higher levels of exposure among Vietnam veterans were associated with increased frequency of ischemic heart disease (p < 0.01), valvular heart disease (p < 0.01), and retinopathy (p < 0.01). We conclude that exposure to Agent Orange is associated with various health impacts in Korean Vietnam veterans.

Prevalence and risk factors for enterobiasis among preschool children in a metropolitan city in Korea.

The infection rate of Enterobius vermicularis was investigated in 1,191 preschool children in 25 daycare centers in Seoul, Korea by cellotape anal swab from July to August 1999. Both the directors of the daycare centers and the children's parents were asked to complete questionnaires that inquired about the potential risk factors involved. The overall egg positive rate for E. vermicularis was 9.5%, and the prevalence in the daycare centers ranged from 0 to 31.1%. Children aged 6-7 years showed a significantly higher egg positive rate than younger children, but the infection rate was similar for boys and girls. The socioeconomic status of the family and personal hygiene were not associated with enterobiasis, but anthelmintic medication significantly reduced the infection rate. The daycare centers in residential areas showed significantly lower egg positive rates than those situated near traditional markets. The environment of daycare centers is an important factor in enterobiasis, and the mass screening and treatment of children at high risk is recommended.

An ecological study of Paragonimus in Malaysia.

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.

[Values of intradermal test and multiple sputum examinations for Diagnosis of paragonimiasis]

This study was conducted on 4,003 inhabitants of six villages, Southern County of Che Ju lsland from April 18 to July 30, 1974 with purpose of studying. Relationship between intradermal reaction and egg detection rate, Egg detection rate by the number of sputum examination on the same subject, Comparison of direct sputum examination method (Whole volume of sputum in vinyl bag pressed between petri dishes) with concentration (2% NaOH) method, Estimation of sensitivity and specificity of the intradermal test in screening paragonimiasis. The results obtained are as follows: 1. Overall positive skin reaction rate was 57.7 % and egg positive rate regardless of skin reaction was 17.1 % the population studied. 2. Egg positive rate for negative skin reactors(wheal size smaller than 70mm(2)) was l0.l %, and that of positive reactors was 22.8 %. 3. Positive skin reaction rate increased as age increased, egg positive rate, however, revealed rather inconsistent distribution by age. 4. The egg positive rate showed a tendency of increase by increase of wheal size, though not so remarkably. 5. 2.9 % of egg positives by direct sputum examination method was negative when re-examined by concentration method; 2.6 % of egg negative sputum by direct method was egg positive by concentration method. It was found that the sputa showing discrepant result by two different methods had only a few eggs in whole sputum collected. 6. Egg positive rate by single sputum examination was 8.l %, by two examinations 14.6 % by three 19.2 %, by four 24.5 %, and by five examinations on the same individual was 20.5 %. 7. The estimated sensitivity and specificity of the skin test were 76.5 % and 42.7 % respectively under the postulation that all infected persons could be detected by four sputum examinations.

[A Follow-Up Study To Evaluate The Efficacy Of Mass Chemotherapy For Control Of Paragonimiasis]

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% of the population and to sputum examination for skin positive 60-70% in the first survey done in l964. 93% 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% 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% 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% of all infected persons estimated among whole population) were carried out than other areas (only 20-30%). 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.

Ecology of filariasis on Che Ju Island.

Study of filariasis to determine important factors involved in its ecology was carried out on Che Ju Island for three consecutive years from 1968 to 1970 in seven villages, three coastal villages and four islets remote from the main island. One village which was located in mountainous area far from the coast was surveyed to serve as control area. About 90% of population inhabiting the study area had at least one blood smear during the three-year period; about one third had three blood smears, and a little over one third had two, and the rest only one examination. Animal and mosquito surveys were carried out at the same period. Followings are the results obtained: 1. All human cases but several had microfilariae identical to the description of B. malayi. The several cases who had morphologically different microfilariae from that of B. malayi need further study for definite conclusion. 2. Five persons randomly sampled from Mf positives and bled every two hours demonstrated nocturnal periodicity between 9 p.m. and 3 a.m. 3. Human is considered to be only reservoir host for human filariasis in the area since animal survey and experimental exposure to the infective larvae of human filaria species showed failure to infect animals. 4. Microfilaria rate, microfilaria density, prevalence of elephantiasis varied by area and age with correlation, which indicated cumulative process of the parasite by repeated exposure and development of host immunity to certain extent. 5. Clinical manifestation of filariasis (symptom complex and elephantiasis ) taken from history and inspection was low in its prevalence with range of 0.9% 11.8% of total population. Only 5.2% of 517 Mf positives had the clinical manifestation. 24.8% of 109 persons with clinical manifestation had microfilaria; 42.9% with symptom complex only, 23.1% with both symptoms and elephantiasis, and none with elephantiasis only were microfilaria positive. 6. Ae. togoi was the only species infected with the filaria. Mosquito infection rate by area showed positive correlation to the Mf rate and density of human population; where the Mf rate and density were high, the mosquito infection rate also high.

Efficacy Of Mass Treatment For Control Of Human Filariasis.

This study was carried out for three years from 1968 to 1970. Three coastal villages and four remote islets of Che Ju Island were surveyed and 90% of all inhabitants were blood smeared. These study areas were grouped into five according to its characteristic for evaluation of mass treatment with diethylcarbamazine citrate (Hetrazan U.S.P.) and insecticide spray in control of human filariasis. To set baseline up for control group, placebo was administered. Followings are the results obtained: 1. 81.1% of all mf positives accepted and completed the mass chemotherapy; main reason for refusal was side reactions told by neighboring villagers who experienced them. 2. 6 mg of hetrazan/kg B.W. X12 doses given every day turned mf postives to mf negative in 92.1%. The patients who had high mf density remained mf positive in 16.5% whereas only 2.1% for low mf density. 3. 73.8% of mf positives after the treatment showed marked decrease in mf density. Most of them to less than 15n mg/20 mm(3) of blood that can not infect mosquito effectively. 4. Mosquito infection rates were also dropped markedly in areas where mf positive were mass treated. 5. Side reaction induced by diethylcarbamazine was frequent(64%-90%) and various. The most frequent symptom was headache and fever. 6. DDT spray did not influence human mf rate and mosquito infection rate.

A Comparison Of Sensitivity On Stool And Sputum Examination For Diagnosis Of Paragonimasis.

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.

A Study On The Infection Status On Intermediate Hosts By Paragonimus On Che Ju Island.

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: 1) by frequency of human association, 2) by prevalence of paragonimiasis in the population and 3) 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.

Mass Chemotherapy In The Control Of Paragonimiasis.

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.

An Evaluation Of Intraderaml Tests For The Screening Of Paragonimiasis By Comparing Antigens Variously Processed.

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.