B hepatitis is considered as one of the most serious health issues in Korea because of its high prevalence and incidence rates and its close relationships with liver cirrhosis and primary hepatic carcinoma. It was once believed that parenteral transmission was only possible mode of hepatitis B virus infection until its serologic markers could have been identified. However, non-parenteral route was also recognized as important as parenteral one and its mode was classified into vertical and horizontal types. The familial. clustering of B hepatitis was well documented by many authors, and some portion of non-parenteral transmission in family, unit was discoverd by many clinical and epidemiological studies.
This study were carried out in a rural community of Korea to discover the degree of familial clustering and possible non-parenteral transmission route. Susceptibles, infected before 1985, the incidence cases between June, 1985 and April, 1986, and chronic carriers had been identified as index cases by the twice examinations of serologic markers (HBsAg; RPHA, Anti-HBs;PHA). The examination of serologic markers to index cases and their family members was done in June, 1987.
The major results are summarized as followings.
1. HBsAg positive rate in family members with susceptible was 3.12%, and the ratio of HBsAg positive rate in family members with infected before 1985, incidence case and chronic carrier upon susceptible was 4.27, 3.51 and 11.65 respectively. This result imply a strong familial clustering of hepatitis B virus infection and it was strongest in families with chronic carriers.
2. The degree of clustering in familial relationship was observed to increase in order
of with siblings, mother and father. This result suggests the horizontal transmis-
sion between siblings is strong, but the vertical transmision from mother to her
offspings should also be considered as related to clustering in siblings.
From the results of this study, it is recommended that all family members with HBsAg carriers should be examined on the serologic markers of hepatitis B virus infection and to take the appropriate measures.
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