Acute hepatitis due to hepatitis A virus subgenotype IA as an imported infectious disease from Indonesia

A 25-year-old Japanese man was admitted with general malaise and fever, which had developed 12 days after coming back to Japan from Indonesia. Blood examination revealed elevated transaminase levels and positivity for the IgM anti-HAV antibody; therefore, he was diagnosed with acute hepatitis A. HAV-RNA was detected in his serum and phylogenetically classified as subgenotype IA. The partial genome in the VP1/P2A region was consistent with the strain recently isolated from Surabaya, which indicated that he had been infected during his stay in Indonesia. Thus, HAV vaccination is recommended before visiting HAV-endemic countries for a long period of time.