Epidemiology and Health

Volume 14 (1); June 1992

An Epidemiologic Study on the Leptospiral Infection in the Period of an Anticipated Epidemic: Bo Youl Choi, Dae Eun Chung, Soo Jin Lee, Hung-Bae Park, Jeoung Bae Park, Kyung Hee Lee, Jeong Soon Kim; Korean J Epidemiol. 1992;14(1):91-101. Published online June 30, 1992

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A large epidemic of leptospirosis was anticipated in September 1990 because flood has resulted the heavy rain for 4 consecutive days from the 8th of September, 1990, in the Yang-pyeung Gun (Country), a farm area of Central Korea. Actually, patients were already appearing sporadically soon after the flood. Soldiers of ROK Army units stationed in this area were under the higher risk since many of them participated in field works (such as tieing rice plant fallen by the flood) as a part of Civil Aid Plan. The objectives of this study were 1) to detect infected ones at early stage 2) to estimate the attack rates of infection and apparent infection through serologic examinations, 3) to estimate pathogenecity and case-fatality rate and 4) to compare the rates of infection by the type of work and the use of protective devices. All of those with febrile episode were interviewed and the leptospiral antibody was examined during the one month period after the field work. Serologic examinations (including the interview) were done twice with 1 week interval (first on 8th to 10th of October, about 4 weeks following the days of field work) for 446 soldiers belong to three companies stationed in the country area. The serologic test (Microscopic agglutination test) were performed with 4 strains. Icterohemorrhagiae lai and Canicola canicola Hond Utrecht IV as standard strains, and 6P-049-1 and YP-35-1 as strains isolated in Korea in 1986, in accordance with WHO guideline. The results are as follows. 1. Among 57 febrile, suspected cases, 37 had serological tests twice and, 20 of them (54.1%) were serologically confirmed to be infected whereas among other 20 subjects who had single serological test, only 2 persons (10.0%) were serologically positive. 2. The dates of onset of fever in confirmed cases were clustered in 10 to 20 days from late September to early October, which coincided well with the duration of exposure (Sep. 13-18). 3. The attack rate of infection and apparent infection were estimated to be 11.2% (95% C. I. ; 8.3-14.1%), 1.8% (95% C. I. ; 0.7-3.1%). Pathogenecity and case-fatality rate were estimated to be 16.0% (95% C. I. ; 6.0-26.0%) and 0%, respectively. 4. The attack rate of infection of persons who worked in rice paddy for 3-6 days, for 1-2 days and participated in other field work were 3.5, 2.7 and 2.1 time high respectively as high as that of persons who did not join in field work (p<0.05). 5. The effectiveness of protective devices shown in this study was rater poor; perhaps the preparation of the protective devices was not sufficient because the mobilization of army is usually a sudden order. For more satisfactory prevention in the future, a complete clothing (including glove and boots) and chemoprophyaxis (with doxycycline) are recommended.; Summary

Original Articles

A seroepidemiological study on leptospiral infection in a ruralcommunity.: Soon Jin Lee, Seok Yong Lee, Bo Youl Choi, Ung Ring Ko, Sae Jung Oh, Joung Soon Kim; Korean J Epidemiol. 1992;14(1):79-90.

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A seroepidemiological follow-up survey for antibody to Leptospirae was undertaken twice, the first one in Oct.-Dec. 1988 and the second in Dec. 1989-Mar. 1990 among adult inhabitants of over 20 years of age in Yang-pyeong Gun, Kyeong-ki Do. The sera of 480 persons in 1988 and 328 persons in 1989 were tested for Leptospirae by microscopic agglutination test (MAT) and interview was used for additional inforamtion. The serologic test was performed against 4 strains, which were Icterohemorrhagiae lai and Canicola canicola Hond Utrecht IV as standard strains, and 6P-049-1 and YP-35-1 as strains isolated in 1986 in Korea, in accordance with WHO guideline. The results of the test showed that 106 of 480 sera(22.1%) in 1988, and 84 of 328 sera(25.6%) in 1989 turned out to be positive to Leptospirae. The seropositive rates for Leptospirae by district in 1988 and 1989 were 12.9~33.3% and 15.0~42.2% respectively and the difference was statistically significant. One district, mainly a commercial area was newly added in 1989. The seropositive rate of that district was 15% and it was significantly low when compared with 32.8% of seropositive rate of the other rural districts. No difference was observed among age groups of 20~30, 40~50 and over 60 years as well as among sexes. The seropositive rate of farmers and non-farmers were 23.0% versus 10.0% in 1988 and 31.1% versus 17.7% in 1989 showing higher rate among farmers. A total of 143 persons were followed up 14 months and it was observed that 37.0% (10/27) of seropositive subjects remained positive, and 31.9%(37/116) of seronegatives were converted to seropositive. The duration of persistent antibody titer over 1 : 80 against Leptospirae that be calculated by formula(prevalence=incidence*duration) was 8.3 months. As for the seropositive reaction with or without febril illness, 29.3% (17/58) of subjects with febrile illness and 24.7 (66/267) of subjects without febrile illness turned out to be positive, showing no significant difference between them.; Summary

The prevalence of hepatitis B surface antigen among Korean byliterature review.: Byung Yeol Chun, Mi Kyeong Lee, Yun Kyeong Rho; Korean J Epidemiol. 1992;14(1):70-78.

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This study was carried out to estimate the prevalence of HBsAg in Korea by systematic reviewing the literature on HBsAg prevalence, published during the period of 1980-1989. We analyzed the result of 74 studies by serologic tests, age, sex, and characteristics of study subjects and summarized. The average prevalence rate of HBsAg was 7.95±2.97% or 7.25% considering the size of the study population. The prevalence rate of HBsAg in male (9.11%) was higher than that in female(7.13%). The prevalence of HBsAg was 6.21% in the age group of 0-9 years, 7.00% in the age group of 10-19 years, 8.69% in twenties, 8.83% in thirties, 8.34% in forties, 5.81% in fifties, and 4.39% in sixties or over. The prevalence of HBsAg was increased with age at a peak in thirties and was decreased thereafter. The prevalence of HBsAg was 5.67% in students, 6.57% in pregnant women, 8.83% in the population of community, and 16.62 % in the high risk children such as orphans and mentally retarded children.; Summary

A study on the health status of the inhabitants exposed to cementdust.: Hae Kwan Cheong, Joung Soon Kim, Byung Soon Choi, Chung Bum Kim, Sung Il Cho, Yun Mi Song, Hyun Sul Lim; Korean J Epidemiol. 1992;14(1):59-69.

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A health impact of environmental cement dust exposure among inhabitants around a cement factory was carried out with special emphasis on finding bronchial asthma cases in this area. Questionnaire survey and physical examination were done on 437 persons in two villages located within 1km distance from the cement factory. On the basis of questionnaire survey and physical examination, 56 persons with suspicion of bronchial asthma were screened, who were further examined to establish diagnosis by physical examination, pulmonary function test and bronchodilator test.
Results
are as follows : 1. Inhabitants in surveyed area had high prevalence of acute and chronic diseases, particularly respiratory diseases and dermatologic diseases. 2. Respiratory symptoms complained were sputum(23.9%), cough(23.0%), dyspnea(19.1%), chest tightness(14.6%), and wheezy breath sound(13.1%). On physical examination, pterygium(29.5%), decreased breath sound(3.0%), wheezing(3.3%), and rales(2.7%) were found. 3. On diagnostic examination, 32 cases (prevalence rate 7.3%) of bronchial asthma and 10 current cases (prevalence rate 2.3%) of bronchial asthma were confirmed. Thus it is postulated that high prevalence of bronchial asthma and respiratory diseases in this area may be related to environmental exposure to the cement dust. Further study, however, such as bronchial provocation test may be necessary to establish definite conclusion on causal relationship between bronchial asthma and environmental cement dust exposure.; Summary

A study on the relationship between HBeAg and hepatitis B virus DNAamong healthy HBsAg carries.: Yoo Sik Hahm, Hai Rim Shin, Hyung Jong Park, Sung Ryul Kim; Korean J Epidemiol. 1992;14(1):48-58.

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The study was carried out at 3 health centers in Ulsan city to investigate the relationship between HBeAg, which is considered to be associated with infectivity, and hepatitis B viral DNA, which seems to be related with viral replication, among those who received health examination. Two hundred of HBsAg carriers, randomly sampled, from populatin 6,408 who have received health examination were examined serological tests including HBeAg, liver function test(AST, ALT and γ-GTP), IgG Anti-HBc, DNA probe(Dot blot hybridization method) to detect HBV DNA and Anti-HCV to investigate coinfection rate with hepatitis C virus simultaneously from December 18, 1991 to April 10, 1992.
Results
are as follows : 1. The prevalence of HBs Antigenemia(HBsAg Positive) was 6.2% (400 persons) and the prevalence of Anti-HBc was 28.1% (1,798 persons) among 6,408 population who are examined by serological test with HBsAg and Anti-HBs. 2. Male to female ratio was 0.9 : 1 and average age was 29.5 in male, 30.9 in female among study subjects. 3. Among 200 HBsAg carriers, HBeAg positive rate was 36% (72 subjects). 4. The result of LFT carried out HBeAg positive 72 subjects was not significant statistically. (ALT : x2=3.64 p>0.05, AST : x2=3.85 p>0.05, γ-GTP：X2=0.12 p=0.73). 5. Among 72 HBeAg carriers, positive rate of IgG Anti-HBc was 88.9% (64 subjects) : it is likely to be chronic hepatitis. 6. Among 200 HBsAg carriers, HBV DNA was detected in 44 HBsAg carriers, 20 in male and 24 in female by using DNA probe(Dot blot hybridization method) : the level of HBV DNA was 31.2 pg/75μl~4.00 pg/75 μl. 7. Among 72 HBeAg carriers-generally repressents hepatitis B viral infectivity, hepatitis B virus(HBV) DNA-marker of hepatitis B virus replication was detected in 37 subjects : HBV DNA level under 500 pg/75 μl was highest frequency(14 subjects). 8. Though the LFT of HBV DNA positive sera was not significant statistically, the lower was level of HBV DNA, the more abnormal was LFT ; it represents chronic active hepatitis. 9. The co-infection rate of HBV and hepatitis C virus(HCV) was 4% (8 subjects) in HBsAg carriers. Consequently, it was general concept that HBeAg is the marker of infectivity in HBsAg carriers but HBV DNA was detected in some HBeAg negative sera, and not detected in some HBeAg positive sera ; because of the gap between HBeAg-marker of infectivity generally, and replication of HBV DNA-actually infective, it is unreasonable to determine the infectivity by HBeAg only. The infectivity of HBV in HBsAg carriers was may be determined by detection of HBV DNA only, not HBeAg in clinical fields and various examinations.; Summary

Compliance in a hypertension clinic in Korea.: Daniel W Jones; Korean J Epidemiol. 1992;14(1):42-47.

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The purpose of this study was to evaluate the compliance rate to long term therapy, the rate of adequate blood pressure control, and to determine the reasons for noncompliance among a group attending a hypertension clinic. This study was a retropective observational study performed by record review. Records of 200 patients were reviewed to assess compliance to clinic attendance, baseline blood pressure, blood pressure after one year of treatment, and cost of treatment including treatment fees, laboratory fees, and medication costs. Noncompliant patients were contacted to determine the reason for noncompliance. Of the 189 hypertensives, 41(22%) failed to keep their first follow-up appointment and 148(78%) began long term treatment. At the end of one year, 112 patients were still attending the clinic on a regular basis and reported compliance to taking medication (59% of the total number of hypertensives evaluated and 76% of those that began long term treatment). Baseline mean blood pressure was 179±25/107±15 mm Hg and blood pressure at one year was 145±21/91±12mm Hg. Of the 112 compliant to long treatment, 72(64%) had a diastolic blood pressure below 95mm Hg at one year. This study demonstrates compliance rates similar to studies in other countries where patient education and other techniques have been applied. Efforts to improve hypertension patient compliance to long term therapy need to continue, especially in Korea and other Asian countries where cerebrovascular disease is a leading cause of morbidity and mortality. Running Head : Compliance in Korea; Summary

Effect of cigarette smoking and alcohol drinking on risk of cancers.: Soo Yong Choi, Kahyo Hiroaki, Yun Sang Shim; Korean J Epidemiol. 1992;14(1):35-41.

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Abstract: Abstract
No abstract available.; Summary

The effect of parent support on cigarette smoking among Korean adolescents.: Joo Hyung Kim, Hee Soon Juon, Jung Ja Nam; Korean J Epidemiol. 1992;14(1):11-22.

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Abstract PDF: Abstract
No abstract available.; Summary

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