Distribution of Cases of Hepatitis C Virus Infection by Subtypes and Results of Interferon Therapy in the Southern Region of Ibaraki Prefecture

It has been made known that there isn't any significant regional difference in the frequencies of cases of viral hepatitis C by subtypes in our country. In the present study we investigated the subtypes in hepatitis C virus carring patients without blood transfusion history in the southern region of Ibaraki Prefecture to clarify the occurrence ratio of each subtype of the virus. The results of interferon therapy were also examined in those patients with chronic hepatitis C. The frequencies of subtypes 2, 3 and 4 were found to be 71%, 16% and 10%, respectively. Although these ratios were the same as the national average, a significantly high frequency (P>0.01) of subtype 3 was observed in the patients from Tsuchiura in the region, suggesting that there may have existed some particular source of infection other than blood transfusion. The effectiveness of interferon therapy was significantly higher (P>0.01) in the patients with subtype 3 (75%) than in those patients with subtypes 2 and 4 (23% and 43%, raspectively), suggesting that interferon is a remedy specific to subtype 3.