Gross signs and histopathology of Ostrea puelchana infected by a Bonamia exitiosa-like parasite (Haplosporidia)

Abstract

Haplosporidian microcells belonging to the genus Bonamia parasitise various species of oysters around the world. In Argentina, Bonamia sp. was the causative agent of mass mortality among Ostrea puelchana cultured in San Antonio Bay (San Matías Gulf), and it was detected in natural beds inside San Matías Gulf. In order to describe the gross and histopathological signs caused by Bonamia sp. in O. puelchana, cultured and wild oysters were sampled and analysed by traditional techniques including heart imprints and histology. Cells of Bonamia sp. were observed in connective tissue, free or within haemocytes, in gills and around the digestive gland, stomach, intestine and gonad. Gross signs, histopathological alterations in O. puelchana, and Bonamia sp. cytological morphology resemble those reported for B. exitiosa. However, I propose to treat the Argentinean species as B. exitiosa-like until more molecular and ultrastructural studies are conducted to determine the correct taxonomy.

Analysis of large-scale spatio-temporal trends of Ostrea puelchana beds in Northern Patagonian gulfs, Argentina

“…The protozoan parasite B. exitiosa (Phylum Haplosporidia) was identified as the cause of mass mortality (Kroeck and Montes, 2005;Kroeck, 2010). As it infected several oyster beds located close to San Antonio Bay (Kroeck et al, 2008), it was defined as an epizootic (disease affecting many animals within a given area at the same time; widely diffused and rapidly spreading) (FAO)http://www.fao.org/fi/ glossary/aquaculture/.…”

A Status Assessment of Perkinsiosis, Bonamiosis, and Mateiliosis in Commercial Marine Bivalves from Southern Brazil

“…The puelche oyster, Ostrea puelchana, is found in the waters of southern Brazil, has been reported to be a host of Bonamia spp. based on collections made in Northern Argentina (Kroeck & Montes 2005, Kroeck 2010. Bonamia spp.…”

Detection of Bonamia exitiosa (Haplosporidia) in European flat oysters Ostrea edulis cultivated in mainland Britain

“…Therefore, the presumption is that the infection must have originated in the Fal itself. Several routes of transmission could be considered, including the release of ballast water or the movement of a vector species into the estuary, either deliberately or accidentally (Culloty et al 1999, Lynch et al 2006, 2010, although the current study design precludes the possibility of determining the source of infection.…”

“…With the exception of B. perspora, these normally occur within haemocytes of the host (Cochennec-Laureau et al 2003); B. perspora occurs within connective tissues of its host Ostreola equestris (Carnegie et al 2006). A number of unidentified Bonamia-like parasites have also been reported in both northern and southern hemisphere bivalves (Cochennec et al 1998, Burreson & Ford 2004, Audemard et al 2008, Lohrmann et al 2009, Hill et al 2010, Kroeck 2010. Some authors have suggested that B. ostreae was accidentally transferred from the Pacific coast of the USA to Europe through the movement of infected oyster seed from California (Elston et al 1986, Cigarria & Elston 1997, Abollo et al 2008.…”