According to a release by the Ministry of Agriculture, Forestry and Fisheries of Japan, an outbreak of highly pathogenic avian influenza, H5 strain was diagnosed in a caged layer flock located near Mitoyo City in Kagawa Prefecture on the Northeast quadrant of the Island of Shikoku. Rapidly ascending mortality was observed in the flock and exceded ten percent in four days following the emergence of clinical signs.

The Governor of the Prefecture, Keizo Hamada, confirmed that depopulation of the flock of 330,000 hens is in progress using the resources of the Japan Self Defense Force. Restrictions consistent with Word Organization of Animal Health (OIE) are in effect including quarantine, restrictions on movement of poultry and products, surveillance within a two mile zone and monitoring within a six mile zone around the affected farm.  The Chief Cabinet Secretary, Katsunobu Kato, announced that the Cabinet of Japan had discussed the issue and that the Prime Minister, Yoshihide Suga, has encouraged cooperation among state and local officials to restrict spread of virus.

Previous outbreaks of avian influenza have occured in Kagawa Prefecture as it lies on a migratory pathway and the infection was probably introduced by free-living birds.