Abstract

The present study was carried out in Chiloe island (Chile) in a period between late autumn and early summer in 1997. From a total of 167 specimens histologically analysed, there were two oysters with a haemocytic hyperplasic response in the mantle, gills and digestive gland. The parasited haemocytes contain in the citoplasm a variable number of spherically shapped parasites similar to the protozoan Bonamia. The genus Bonamia has been described in Tiostrea chilensis from aquaculture farms in New Zealand, which indicates the susceptibility of the Chilean oyster to this parasite.