The Fish Diseases Commission of the Office International des Epizooties has reported an infestation of the parasite bonamia ostreae in oysters in western Ireland.

Routine testing by the republic’s Marine Institute have shown an outbreak in Achill Sound, County Mayo, an area that had previously been considered free of the parasite, which causes lesions in the connective tissues of the gills, mantle, and digestive gland.

It has also been found in the southern Netherlands, Galicia – Spain, France, southern England, and off Maine, California and Washington state – in the USA. Further testing is being carried out on the recent Irish outbreak with a view to clarify the original discovery.