Katsuo Okada

To the Editor-As was reported in the Journal, by Takahashi et al. Zoonotic risks have been suggested for sporadic HEV infections, particularly in industrialized countries We hereby report our recent experience in Japan, which may support the zoonosis hypothesis.

To evaluate mortality reduction from gastric cancer by endoscopic screening, we undertook a population-based cohort study in which both radiographic and endoscopic screenings for gastric cancer have been carried out. The subjects were selected from the participants of gastric cancer screening in two cities in Japan, Tottori and Yonago, from 2007 to 2008. The subjects were defined as participants aged 40-79 years who had no gastric cancer screening in the previous year. Follow-up of mortality was continued from the date of the first screening to the date of death or up to December 31, 2013. A Cox proportional hazards model was used to estimate the relative risk (RR) of gastric cancer incidence, gastric cancer death, all cancer deaths except gastric cancer death, and all-causes death except gastric cancer death. The number of subjects selected for endoscopic screening was 9950 and that for radiographic screening was 4324. The subjects screened by endoscopy showed a 67% reduction of gastric cancer compared with the subjects screened by radiography (adjusted RR by sex, age group, and resident city = 0.327; 95% confidence interval [CI], 0.118-0.908). The adjusted RR of endoscopic screening was 0.968 (95%CI, 0.675-1.387) for all cancer deaths except gastric cancer death, and 0.929 (95%CI, 0.740-1.168) for all-causes death except gastric cancer death. This study indicates that endoscopic screening can reduce gastric cancer mortality by 67% compared with radiographic screening. This is consistent with previous studies showing that endoscopic screening reduces gastric cancer mortality.

A 72-year-old Japanese man displayed asymptomatic eosinophilia for 4 months. Computed tomography showed multiple space-occupying lesions in the liver. Zoonotic liver flukes were suspected based on occupational exposure to cattle, serological and radiological findings. Immunological examination was helpful in diagnosing the disease and laparoscopy was crucial in confirming Fasciola hepatica and excluding the possibility of malignant hepatic tumors. Human fascioliasis was finally diagnosed and praziquantel administered. Blood eosinophilia resolved within 4 months and liver tumors almost disappeared within 12 months. From our experience, laparoscopy with liver biopsy is very important for diagnosing human fascioliasis, particularly for asymptomatic fascioliasis.

2006年開催の第85回日本消化器病学会中国支部例会では，シンポジウム「急性肝炎の疫学的変遷」が行われ，最近の中国地方における急性肝炎の発生動向が報告された．その結果，最近5∼25年間の総計1,815症例の報告では，ウイルス性急性肝炎が約52%で，薬物性肝炎14%，自己免疫性1%，原因不明33%であった．また，山陰地域ではA型急性肝炎が，山陽地域ではC型急性肝炎や薬物性肝炎がより多く発生した．一方，最近の10年間では，急性肝炎は発生総数として約15%減少し，その要因はA型急性肝炎の減少であった．また，原因不明の急性肝炎が増え，薬物性肝炎も増加する傾向にあった．この間のウイルス性肝炎は，成因別にA型急性肝炎に代わりB型急性肝炎の割合が一位となり，C型急性肝炎の割合は変化なかった．すなわち，最近5年間に発生したウイルス性急性肝炎の割合は，HBVが約45%，HAV 25%，HCV 15%，HEV 1%，EBVとCMVとは併せて15%であった．