Domestic Infection of Hepatitis E in Japan

In most cases of hepatitis E in Japan, patients acquire the viral infection abroad in countries where hepatitis E is endemic. However, in Nagano Prefecture, Japan, we encountered a patient with hepatitis E who had never been abroad. The diagnosis was made on finding hepatitis E viral RNA and antibodies against the virus in the serum. Prompt normalization of liver function test occurred without medication. The nucleotide sequence of the virus isolated from this patient was closely related to the sequence of previously isolated viruses of genotype III. The source of infection could not be identified.