Transmission of Seasonal Outbreak of Childhood Enteroviral Aseptic Meningitis and Hand-foot-mouth Disease

This study was conducted to evaluate the modes of transmission of aseptic meningitis (AM) and hand-foot-mouth disease (HFMD) using a case-control and a case-crossover design. We recruited 205 childhood AM and 116 HFMD cases and 170 non-enteroviral disease controls from three general hospitals in Gyeongju, Pohang, and Seoul between May and August in both 2002 and 2003. For the case-crossover design, we established the hazard and non-hazard periods as week one and week four before admission, respectively. In the case-control design, drinking water that had not been boiled, not using a water purifier, changes in water quality, and contact with AM patients were significantly associated with the risk of AM (odds ratio [OR]=2.8, 2.9, 4.6, and 10.9, respectively), while drinking water that had not been boiled, having a non-water closet toilet, changes in water quality, and contact with HFMD patients were associated with risk of HFMD (OR=3.3, 2.8, 6.9, and 5.0, respectively). In the case-crossover design, many life-style variables such as contact with AM or HFMD patients, visiting a hospital, changes in water quality, presence of a skin wound, eating out, and going shopping were significantly associated with the risk of AM (OR=18.0, 7.0, 8.0, 2.2, 22.3, and 3.0, respectively) and HFMD (OR=9.0, 37.0, 11.0, 12.0, 37.0, and 5.0, respectively). Our findings suggest that person-to-person contact and contaminated water could be the principal modes of transmission of AM and HFMD.

A Study on the Epidemiologic Characteristics of Scrub Typhus in Gyeongsangbuk-do, 1999-2001 / 한국역학회지

ONJECTIVE: This study was carried out to investigate the epidemiologic characteristics and magnitudes of scrub typhus (tsutsugamushi disease) in Gyeongsangbuk-do, Korea. METHODS: Resources of data collected were epidemiologic surveillance report to public health centers on each disease occurrence. The authors reviewed 344 epidemiologic surveillance reports for cases of scrub typhus developed in Gyeongsangbuk-do, Korea from Jan 1, 1999 to Dec 31, 2001. RESULTS: The scrub typhus cases were 376 during three year period, and the incidence was significantly higher in the county area than in the city area. Incidence of scrub typhus was increasing each year. In 344 epidemiologic surveillance reports, the job of the cases was farmer (67.2%), housewife (4.7%), clerk (3.5%). Two hundred ninety eight cases (86.6%) have experienced outdoor activities before development of the scrub typhus. The outdoor places of exposure were dry field (64.8%), rice field (51.7%), hill (12.8), and grass field (9.7%). The symptoms reported were fever (93.3%), headache (83.7%), chill (69.5%), and rash (54.4%). CONCLUSIONS: Incidence of scrub typhus was increasing in Gyeongsangbuk-do, Korea, this phenomenon may be related to change of climate, the reporting rate of disease and outing activities. Good surveillance and adequate analysis of epidemiologic data is a essential for the prevention of the disease. With this result, high risk population was identified and effective intervention should be done to prevent the disease.

Clinical and Virologic Study of Aseptic Meningitis / 소아과

PURPOSE: The cause of aseptic meningitis remains mostly unknown because viral culture and identification is difficult. Thus, we report a study on 123 children with aseptic meningitis in Gyeongju in 2002 to identify the causing virus and the relationship with the clinical manifestation. METHODS: We prospectively investigated the patients, admitted to Dongguk University Hospital, into two groups between April and October 2002. Group 1 included 123 patients diagnosed as aseptic meningitis. Group 2, the adimssion control, included 120 patients, who suffered from none-enteroviral diseases. Specimens of CSF and stool were collected to perform reverse transcription polymerase chain reaction(RT-PCR), and enteroviral culuture was done in RT-PCR positive patients as well. RESULTS: The male to female sex ratio was 2.2:1 and the mean age was 6.2+/-3.7 years. The clinical manifestations were fever, headache and vomiting. The RT-PCR for enterovirus, performed in 58 cases of CSF in group 1, showed 5.2% positive results and negative result in viral culture. The RT-PCR for enterovirus used in stool specimens showed 89.3% and 41.1% of positive results in group 1 and group 2, respectively. Viral culture of stool specimens showed five cases of echovirus 13 and four cases of echovirus 6 in group 1, whereas three cases of echovirus 6 and one case of coxsackie B4 were detected in group 2. CONCLUSION: The etiologic viruses of the aseptic meningitis outbreak in Gyeongju in 2002 is presumed to be echovirus 13 and echovirus 6. Since echovirus 13 firstly appeared with various age distributions, the outbreak may have emerged due to a lack of acquisition of immunity to this virus.

Analysis of Transmission Mode of Confirmed Shigellosis in Gyeongju, Korea / 한국역학회지

PURPOSE: This study was carried out to investigate the sources of infection and modes of transmission of an 107 (54males, 53 females) confirmed shigellosis in Gyeongju from Sept. 24 to Oct. 24, 1998. METHODS: We reviewed hospital records of all confirmed shigellosis. Thirty-two strains of Shigella sonnei isolated were analyzed in order to trace the source of infections by plasmid profile, antimicrobial drug resistance pattern, biotyping and pulsed-field gel electrophoresis (PFGE). RESULTS: The first source of infection was estimated to be contaminated underground water and simple piped water caused by leakage from the cess pool. Antimicrobial drug resistance pattern showed that all strains were multi-resistant. All isolates had the same XbaI and SfiI PFGE patterns, indicating the epidemiological relationship of the outbreaks strains in this area. The major characteristics of diarrhea were watery (84.2%) in nature. The clinical symptoms among the diarrheal cases included abdominal pain (86.1%), fever (83.2%), headache (78.2%), chill (45.5%) and tenesmus (41.6%). Six cases were asymptomatic. From initial manifestation to admission were 6.2+/-1.6 (median 6) days, so it could be transmitted to others in this infective period. Duration of admission were 5.5 +/-2.4 (median 6) days. We can find familial mean secondary attack rate were 38.5%. CONCLUSION: It's transmission to other areas were certified by contaminated water and contact with shigellosis, and unknown cases were estimated to be transmitted by contacts with inapparent infection. By plasmid profile and PFGE, the epidemiological relationship of the outbreaks strains in this area seemed to be the same micro-organisms.