In 2019, an outbreak of hepatitis A was reported in South Korea due to the ingestion of salted shellfish contaminated with hepatitis A virus. In a survey of the contamination of salted shellfish, hepatitis A virus (HAV) type IA was detected, and it was confirmed that it originated from clams produced in one of the clam farms located in the western parts of the country. The aim of this study was to determine the cycle of human infection by HAV contaminating the water flowing into the environment. We selected a clam farm that is one of the largest producers of clams in South Korea and tested for the presence of HAV in the river water flowing directly into the vicinity of that farm. An HAV detection test was performed on river water collected from 15 points in three areas of the selected clam farm. HAV was detected in one sample of the collected river water, and its genotype was confirmed as IA, which is the most common genotype causing infection in humans and the same genotype that is prevalent in South Korea. We confirmed that the HAV released via infection in humans contaminated the tidal flats through the river. This result might be a good example of the cycle of infection of HAV in the environment.
