Pathological study of oysters Crassostrea gigas from culture and C. rhizophorae from natural stock of Santa Catarina Island, SC, Brazil

Parasites of economically important bivalves from the southern coast of Bahia State, Brazil

“…Regarding Ancistrocoma sp., the low infection intensity and the apparent lack of damage to the host are in line with previous observations of Sabry et al (2011) on C. rhizophorae and C. gigas from Santa Catarina, but with prevalences of up to 40%. As for Sphenophrya, according to Bower et al (1994), these ciliates are found in a variety of bivalve species, in which they may cause xenoma.…”

“…With respect to the RLOs found in both species, the site of infection in the host (the digestive gland), the localized effect, and the absence of a hemocyte response converge with results from recent studies conducted by Da Silva et al (2011) and Sabry et al (2011) on C. rhizophorae and C. gigas (Thunberg, 1793) in Santa Catarina state, and by Boehs et al (2010) and Ceuta and Boehs (2012) on M. guyanensis in Bahia state. Except for the study by Sabry et al (2011), who identified prevalences of up to 30% for C. gigas (coinciding with the results of this study for M. guyanensis collected at Canavieiras, in February 2010), other studies have indicated a low prevalence of these bacteria. Other studies have also found a significant lack of damage, as seen in this study.…”

“…In turn, in C. virginica (Gmelin, 1791), Winstead et al (2004) observed xenoma formation in all oysters containing this protist. As observed in this study, the prevalence levels seen by these authors were low; still, the study conducted by Sabry et al (2011) showed a prevalence of up to 70% for C. gigas, at one locality in Santa Catarina.…”

“…Other studies of Brazilian coastal mollusks have also reported the occurrence of Sphenophrya sp. in oysters, but without xenoma formation (NASCIMENTO et al, 1986;SABRY et al, 2011). In turn, in C. virginica (Gmelin, 1791), Winstead et al (2004) observed xenoma formation in all oysters containing this protist.…”

“…Other studies have also found a significant lack of damage, as seen in this study. Yet, Sabry et al (2011), who observed RLOs in the stomach of one C. rhizophorae specimen, noted gastric-epithelium changes caused by these organisms.…”