The norovirus that accumulates in oysters is taken in from seawater. Previously, a human sewage-derived model was considered in which virus particles excreted by norovirus food poisoning patients flow into coastal waters through toilets and sewage and accumulate in oysters. However, since incineration of sewage sludge is common in developed countries, the explanation seemed insufficient.

　Therefore, the research team proposed an animal-derived model in which norovirus originates from animals that live in coastal waters. For verification purposes, we collected seawater during the edible oyster season in Matsushima Bay, Miyagi Prefecture, a major oyster production area, and conducted an ``environmental DNA analysis'' that comprehensively examined animal-derived DNA in the seawater to detect norovirus. We investigated the animal species that appear in synchrony.
The results of several analyzes suggest that norovirus tends to be detected in some edible oysters that are landed about a month after migratory birds such as blue-winged ducks and swans arrive on the Sanriku coast. . A crow and a domestic cat were also identified, but their eco-epidemiological interpretation is unclear and will be the subject of future investigation.

　In the future, the challenge will be to detect norovirus from the intestinal tract and feces of birds in order to directly prove animal-derived models. In addition, this animal-derived model explains the origin of norovirus before human infection, which is upstream from the infection cycle assumed by the sewage-derived model, and has the potential to complement the sewage-derived model and deepen our understanding of the infection cycle. It is said that there is.

Paper information:[Journal of Freshwater Ecology] Animal-sourced model of human norovirus infection predicted using environmental DNA metabarcoding analysis