Patógenos em duas espécies de bivalves comercialmente importantes do estuário do Rio Pacoti, Estado do Ceará, Brasil

Abstract

In Ceará State’s estuaries, the mangrove oyster, Crassostrea rhizophorae and the cockle Anomalocardia brasiliana are harvested by local communities, representing a very important socioeconomic activity. Whereas the pathogens can cause mortality in mollusk populations, this study aimed to investigate the occurrence of parasites in C. rhizophorae and in A. brasiliana from Pacoti River estuary, Ceará State. During the period from February, 2008 to January, 2009, samples of cockles and oysters (n = 360 per species) were collected monthly for histopathological analyses. The results in cockles showed bacterial colonies rickettsia-type (7.2%), metazoan possibly bucephalids (35.8%), Tylocephalum (31.7%) and metacercariae of trematodes (0.5%). In oysters, it was observed protozoa of the genera Nematopsis (83%), unidentified protozoans (3.9%), Ancistrocoma (7.2%) and the metazoa: Urastoma (0.8%), bucephalids (0.2%) and Tylocephalum (3%). Despite the high prevalence of Nematopsis in oysters, damage was not observed in the tissues of infected animals. In contrast, the infestation by bucephalids in the gonads caused the castration of the host. The results indicate that those mollusk species must be monitored in their habitat so as to keep pace with the evolution of the prevalence and the appearance of new pathogens.