Detection of Bonamia ostreae and B. exitiosa (Haplosporidia) in Ostrea edulis from the Adriatic Sea (Italy)

Abstract

The flat oyster Ostrea edulis L. is widespread along the Italian coasts. In particular, the Manfredonia Gulf (Adriatic Sea) represents an important site where natural beds subsist. Previous monitoring conducted in 1990 by light microscopy and ultrastructural studies revealed the presence of Bonamia-like microcell parasites in some flat oysters: following this observation, a new sampling of O. edulis was carried out at this location in 2007. Of 750 oysters collected, 3 showed the presence of uninucleated microcells (2 to 3 µm diameter) free or inside the haemocyte cytoplasm by cytology and histopathology. Molecular analysis confirmed that the microcells in 2 oysters were B. exitiosa, whereas in the third oyster the microcells were B. ostreae. Moreover, molecular studies were carried out to confirm the existence of Bonamia sp. in archived samples, confirming the presence of B. ostreae in the Manfredonia Gulf since 1990. KEY WORDS: Bonamia spp. · Ostrea edulis · Molecular analysis · Electron microscopy Resale or republication not permitted without written consent of the publisherDis Aquat Org 89: [79][80][81][82][83][84][85] 2010 Bonamia exitiosa infects Ostrea chilensis in New Zealand (Hine et al. 2001) and O. angasi in Australia (Corbeil et al. 2006) and has been recently reported in O. edulis in Spain (Abollo et al. 2008). B. roughleyi, previously called Mikrocytos roughleyi, infects Saccostrea glomerata in southeast Australia (Farley et al. 1988). B. perspora is a newly described protozoan species found in Ostreola equestris (North Carolina, USA) and represents the first Bonamia species producing a typical haplosporidian spore (Carnegie et al. 2006). Other B. exitiosa-like organisms have been described in O. chilensis from Chile (Kern 1993, Campalans et al. 2000, O. puelchana from Argentina (Kroeck & Montes 2005), and Crassostrea ariakensis from North Carolina ); these organisms have been subsequently declared B. exitiosa (Lopez-Flores et al. 2007).Previous studies have reported by microscopic and ultrastrustural means the occurrence in Italy of small parasites similar to Bonamia sp. in flat oysters collected from the southern (Tiscar et al. 1991) and northern Adriatic Sea (Tiscar et al. 2002). A small number of molluscs appeared infected by the parasites (1/161 from the southern and 8/600 from the northern Adriatic Sea, respectively). Nevertheless all the infected oysters showed high infection level of the haemocytes with the presence of numerous protozoans per cell (Tiscar et al. 1991(Tiscar et al. , 2002.Taking into account these previous reports, the aim of the present study was to investigate by cytology and histology the occurrence of microcell parasites in flat oysters Ostrea edulis newly collected from natural beds in the southern Adriatic Sea and to characterize the recovered parasites by molecular and ultrastructural analyses as well as to confirm and characterize the presence of Bonamia sp. in one positive sample collected during 1990 from the Manfredonia Gulf (Tiscar et al. 1991). MAT...

Lineage-specific molecular probing reveals novel diversity and ecological partitioning of haplosporidians

“…Lack of spore stages suggests that infection may be by direct transmission (Elston et al, 1987). We detected only one Bonamia SSU-type (probably B. exitiosa, Figure 1a) in water column/sediment samples from Naples (Italy; (BioMarks DNA)) which has also been reported from oysters in the Adriatic coastline of Italy in 2010 (Nardsi et al, 2011).…”

Species-specific diagnostic assays for Bonamia ostreae and B. exitiosa in European flat oyster Ostrea edulis: conventional, real-time and multiplex PCR

“…Two species of Bonamia, B. ostreae (Pichot et al 1980) and B. exitiosa (Hine et al 2001), are highly pathogenic and are widespread, the former in the northern hemisphere and the latter in both northern and southern hemispheres. B. ostreae has been reported infecting flat oyster Ostrea edulis of the Pacific (Katkansky et al 1969, Elston et al 1986, Friedman et al 1989 and Atlantic coasts (Friedman & Perkins 1994, Zabaleta & Barber 1996 of the USA, as well as in Canada (Marty et al 2006), France (Pichot et al 1980), Spain (Polanco et al 1984), the UK (Hudson & Hill 1991), The Netherlands (van Banning 1991), Ireland (Culloty & Mulcahy 2001), Italy (Narcisi et al 2010) and Morocco (Belhsen et al 2008). B. exitiosa was first reported infecting O. chilensis in New Zealand (Hine 1991, Doonan et al 1994, Cranfield et al 2005.…”

Interlaboratory variability in screening for Bonamia ostreae, a protistan parasite of the European flat oyster Ostrea edulis

“…Heart imprints are economical and rapid to make in comparison to the other techniques commonly used (Zabaleta & Barber 1996, O'Neill et al 1998, Carnegie et al 2000, Culloty et al 2003, Culloty & Mulcahy 2007, Lallias & Arzul 2008. The major disadvantages to the use of heart imprints is that Bonamia ostreae, due to its small size (2−5 µm), may go undetected when the infection is light or in its latent period (Carnegie et al 2000, Culloty et al 2003, Da Silva & Villalba 2004, Lynch et al 2008, Bower 2011 and that B. ostreae may be confused with other morphologically similar parasites, such as Mikrocytos mackini and B. exitiosa (Marty et al 2006, Narcisi et al 2010.…”

“…Heart imprints are economical and rapid to make in comparison to the other techniques commonly used (Zabaleta & Barber 1996, O'Neill et al 1998, Carnegie et al 2000, Culloty et al 2003, Culloty & Mulcahy 2007, Lallias & Arzul 2008. The major disadvantages to the use of heart imprints is that Bonamia ostreae, due to its small size (2−5 µm), may go undetected when the infection is light or in its latent period (Carnegie et al 2000, Culloty et al 2003, Da Silva & Villalba 2004, Lynch et al 2008, Bower 2011 and that B. ostreae may be confused with other morphologically similar parasites, such as Mikrocytos mackini and B. exitiosa (Marty et al 2006, Narcisi et al 2010.The main advantage of histology over heart im prints is the ability to make observations on the overall health and physiological status of the oyster (Diggles et al 2003, Balseiro et al 2006, Culloty & Mulcahy 2007, Lynch et al 2008. The primary disadvantages of histology are low sensitivity, misidentification of certain pathogens, difficulty in screening larvae and spat and the length of preparation time (Cochennec et al 1992, Carnegie et al 2000, Diggles et al 2003, Balseiro et al 2006, Marty et al 2006.…”