KSE
Articles
- Page Path
- HOME > Epidemiol Health > Volume 6(1); 1984 > Article
- Special edition An analytic epidemiological study to test the hypothesis, Leptospirosis as the cause of epidemic pulmonary hemorrhagic fever in Korea
- J.S Kim, C.W Lee, D.K Oh, S.D In, Y.H Lee, W.H Cho, W.Y Lee, S.O Kim
-
Epidemiol Health 1984;6(1):8-15
DOI: https://doi.org/
- 4,802 Views
- 58 Download
- 0 Crossref
- 0 Scopus
Abstract
This study was carried out to test the causal hypothesis, leptospirosis, of the epidemic pulmonary hemorrhagic fever on the outbreak occurred from the middle of September, 1984 in Korea. The outbreak has occurred right after the group work to tie the fallen rice plants following flood just like the one that had occurred in 1975. This particular disease characterized by fever, chill, malaise and nausea/vomiting in the begining of the onset and chest pain, hemoptysis, and dyspnea in the later stage of the illness, had been reported frequently since 1975 as a disease of unknown etiology. The disease has been occurred predominantly among farmers during the harvest season, particularly among those who worked in wet rice paddies located in montainous area without protection for abraised skin injuries. The fatality rate reported ranged from 5 to over 50%, the direct cause of death being asphyxia due to the massive pulmonary hemorrhage. Despite the continuous research the etiologic agent of the disease has been remained unknown. The objective of this study was to test the specific hypothesis, leptospiral infection, which was derived from the literature review on the papers published ; the clinical, pathological and epidemiological features of the disease was considered to be fitting mostly well among others to that of leptospirosis. The patients who were admitted or have been admitted to hospital with diagnosis of epidemic pulmonary hemorrhagic fever were matched with their family members, villagers, and fellow soldiers who did not have the disease but worked in the same environment. Both groups were interviewed with a structured questionnaire and paired blood and urine specimens were collected. In order to increase the test validity one batch of the specimen was sent to KNIH laboratory and the other to the Dept. of Microbiology of Yonsei Medical School blindly for the laboratory works. Environmental survey was also carried out on rice paddies located at mountainous site in an endemic area where the source of water for cultivation was spring water. There were innumerable rodent holes along the paddy banks with assively accumulated ears of rice plant. From these paddies about three liters of water was collected for laboratory work. Also forty five wild rodents were trapped from two endemic areas for the study. These specimens were primarily inoculated to guinea pigs and mice for culture and then in a specific media to utilize for the serological test. The results obtained from the study are as followings: 1. Letospiral organisms were isolated from nine patients, the water collected from rice paddies of endemic area, and seven wild rodents, all of which strains made the Koch’s postulate satisfactory. 2. The incidence rate of the disease among military service men was 2.7/1,000 person-day exposed and showed a cumulative effect of exposure; longer the duration of exposure, higher the incidence. 3. The incubation period calculated from the military service men ranged from 3-11 days and 8 days of mean incubation period when estimated from the epidemic curve. 4. KNIH laboratory reported the spiral organisms isolated were all fitted well to the description of L. interrogans icterohemorrhagiae with specific serological reaction to the known antigen, whereas the spital organisms isolated by the Dept. of Microbiology, Yonsei Medical School have left-handed tight coils even though other characteristics fits well to the description of L. interrogans. The problem involved in the discrepancy on taxonomical aspect of the leptospiral organisms isolated between two laboratories may be settled down when the on-going studies are completed. This is the first report on leptospirosis epidemic identified bacteriologically in Korea.
Cite
