An Outbreak of Hepatitis A in South Korean Military Personnel: A Clinical and Epidemiologic Study / 대한간학회지

BACKGROUND/AIMS: Increasing the susceptibility of young populations to HAV infection could result in an outbreak in a high-risk group. The author investigated the characteristics of hepatitis A outbreaks among Korean military personnel to obtain the fundamental data for determining the necessity for selective HAV vaccination. METHODS: A case was defined as a person who had an onset of an illness compatible with acute viral hepatitis A between 4 February and 6 April 1998. RESULTS: A widespread outbreak of hepatitis A affected 102 military personnel. The epidemic curve indicated a common-source exposure in the initial stage. At the end of the first month of the initial onset, the occurrence was specific to the location of the military post. Investigation suggested that contamination most likely occurred prior to the local distribution of food. The mean age was 23 years. The overall attack rate was 91 cases per 10000 persons at risk. All cases were jaundiced. The most frequently reported symptoms included icteric sclerae, dark urine, anorexia, malaise and fatigue, nausea, fever, abdominal pain, headache, upper respiratory symptoms, vomiting, itching, diarrhea, light-colored stools, myalgia, arthralgia, and skin rash. The laboratory test showed the serum total bilirubin of 5.5 mg/dL, AST of 344 IU/L, and ALT of 868 IU/L (mean value). CONCLUSION: All patients were clinically apparently diseased with jaundice and were completely recovered. The outbreak was food borne common-source exposure. The changing epidemiology hepatitis A in Korea calls for the economic evaluation of costs and benefits for selective HAV vaccination in high risk adult groups including military personnel.

Molecular Epidemiology of Korean Strains of Hepatitis A Virus / 대한간학회지

BACKGROUND/AIMS: Studies of genotypes and changes in nucleotide and amino acid sequences of hepatitis A virus (HAV) may provide valuable information on the epidemiological aspects of a particular region. In Korea the prevalence of anti-HAV in the 1 - 20 year age group declined from 60% in 1980 to 9% in 1995. As a result this age group has a high risk of HAV infection. Actually over 1,500 cases of clinically overt hepatitis A occurred in 1998 while few cases of clinical hepatitis A had been reported until the early 1990s. The aims of this study are to determine the genotypes of HAV which have been circulating in Korea and to define the phylogenetic relationships of geographically defined isolates. METHOD: From 1994 - 1998 a total of 18 serum specimens was obtained from patients in Korea with sporadic form acute hepatitis A. The HAV nucleic acid from serum specimens was subjected to genomic sequence analysis following viral RNA extraction, reverse transcription and amplification of the cDNA by PCR. DNA sequencing was performed in both directions of each PCR product. RESULTS: All isolates clustered within the subgenotype IA irrespective of the geographic locations and timing of the clinical hepatitis. Among 18 Korean isolates, 9 isolates had 2 amino acid sequence changes and 2 isolates had 1 amino acid sequence change. These changes in the amino acid sequences are unique and have never been reported in HAV subgenotype IA. CONCLUSIONS: All isolated HAV had genotype (IA). Eleven of 18 isolates had unique changes in amino acid sequences. These data indicate that the endemic HAV has been circulating in Korea over a long period of time.