Health assessment of the oyster Crassostrea rhizophorae on the southern coast of Bahia, northeastern Brazil Avaliação da saúde da ostra Crassostrea rhizophorae no Litoral Sul da Bahia, nordeste do Brasil

This study investigated the health of natural stocks of the oyster Crassostrea rhizophorae on the southern coast of Bahia in northeastern Brazil, during summer and winter 2010, at three localities (sampling points) in the estuaries of the Mara&#250; (Camamu Bay) and Graciosa rivers. A total of 180 oysters (30/sampling point/season) were examined macroscopically for the presence of pathogens and anatomical changes. The specimens were subsequently fixed in Davidson solution, processed for paraffin embedding, sectioned and stained with Harris' hematoxylin and eosin. Histological analysis revealed the presence of Rickettsia-like organisms (RLOs), Ancistrocoma, Trichodina, Sphenophrya, Nematopsis, Urastoma, Bucephalus in the sporocyst phase, a nonspecific metacercaria, and a metacestode of genus Tylocephalum. The prevalence of infection was low except for parasitism by Nematopsis sp. which also caused histopathological changes. The presence of Bucephalus sp. caused parasitic castration. These two pathogens significantly affect the health of C. rhizophorae.<br>Este estudo investigou a sa&#250;de de ostras da esp&#233;cie Crassostrea rhizophorae de estoques naturais do Litoral Sul do Estado da Bahia, Nordeste do Brasil, durante o ver&#227;o e o inverno de 2010, em tr&#234;s pontos amostrais distribu&#237;dos nos estu&#225;rios dos rios Mara&#250; (Ba&#237;a de Camamu) e Graciosa. Um total de 180 ostras (30/ponto amostral/per&#237;odo) foram examinadas macroscopicamente para a presen&#231;a de pat&#243;genos e altera&#231;&#245;es anat&#244;micas e posteriormente fixadas em solu&#231;&#227;o de Davidson, processadas para inclus&#227;o em parafina, seccionadas e coradas com hematoxilina de Harris e eosina. A an&#225;lise histol&#243;gica evidenciou a presen&#231;a de organismos com caracter&#237;sticas similares a Rickettsia (RLOs), Ancistrocoma, Trichodina, Sphenophrya, Nematopsis, Urastoma, Bucephalus em fase esporoc&#237;stica, metacerc&#225;ria inespec&#237;fica e metacest&#243;ide de Tylocephalum. As preval&#234;ncias de infec&#231;&#227;o foram baixas, com exce&#231;&#227;o do parasitismo por Nematopsis sp., o qual tamb&#233;m causou altera&#231;&#245;es histopatol&#243;gicas. A presen&#231;a de Bucephalus sp. causou castra&#231;&#227;o parasit&#225;ria. Esses dois pat&#243;genos t&#234;m interfer&#234;ncia significativa na sa&#250;de de C. rhizophorae.