Xenomas in Crassostrea rhizophorae (Ostreidae) from Camamu Bay, Bahia, Brazil

et al. 2015

Parasites in the mangrove oyster Crassostrea rhizophorae cultivated in the estuary of the Graciosa River in Taperoá, BahiaParasitos na ostra-do-mangue Crassostrea rhizophorae cultivada no estuário do rio Graciosa em Taperoá, Bahia AbstractIn this work, parasites associated with the mangrove oyster Crassostrea rhizophorae were studied at a cultivation unit in the estuary of the Graciosa River in Taperoá, Bahia. On a monthly basis, between April 2011 and March 2012, 20 oysters were collected, measured and fixed in 10% formaldehyde. In order to identify the parasites, routine histological techniques were used. The specimens were embedded in paraffin and sections, 7 µm thick, were cut. These were then stained with Harris hematoxylin and eosin and were examined using an optical microscope. The parameters analyzed to investigate water quality showed that the temperature ranged from 23.9 °C to 29.3 °C, water salinity from 0.4 to 24.2 Practical Salinity Units PSU and recorded rainfall from 80 mm to 406.4 mm/month. During the parasitological analyses, infestation of the polychaete Neanthes succinea was observed in 41% of the oysters. Through histological techniques, the following parasites were identified: colonies of Rickettsia-like organisms (RLOs); the protozoa Nematopsis sp. and Ancistrocoma sp.; the turbellarian Urastoma sp.; the metacestode Tylocephalum sp. and an unidentified tapeworm. The data collected showed that there was low-intensity infection with and prevalence of parasites, except for Nematopsis sp., thus attesting that these cultivated oysters were in a healthy condition.Keywords: Histology, protozoa, Nematopsis sp., Neanthes succinea, bivalves. ResumoNo presente trabalho, parasitos associados à ostra-do-mangue Crassostrea rhizophorae foram estudados em uma unidade de cultivo no estuário do rio Graciosa em Taperoá, Bahia. Mensalmente, entre abril de 2011 e março de 2012, 20 ostras foram coletadas, mensuradas e fixadas em formol a 10%. Para a identificação dos parasitos, foram utilizadas técnicas histológicas de rotina, com inclusão em parafina e obtenção de cortes com 7µm, corados com hematoxilina de Harris e eosina e examinados em microscopia de luz. Os parâmetros analisados para a qualidade da água mostraram que a temperatura variou de 23,9 °C a 29,3 °C, a salinidade de 0,4 a 24,2 PSU e a pluviometria de 80 mm a 406,4 mm/mês. Nas análises parasitológicas foram observadas infestações do poliqueta Neanthes succinea em 41% das ostras. A partir das técnicas histológicas foram identificados os seguintes parasitos: colônias de organismos assemelhados a Rickettsiae (RLOs); os protozoários Nematopsis sp. e Ancistrocoma sp.; o turbelário Urastoma sp.; o metacestóide Tylocephalum sp. e um platelminto não identificado. Os dados obtidos mostraram baixa intensidade de infecção e prevalência de parasitos, exceto para Nematopsis sp., atestando a boa condição de saúde das ostras no cultivo.

Section: Discussionsupporting

confidence: 83%

Parasites in the mangrove oyster Crassostrea rhizophorae cultivated in the estuary of the Graciosa River in Taperoá, Bahia

Cova

Júnior

et al. 2015

“…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. This lesion was previously observed by Boehs et al (2009) for C. rhizophorae at Baía de Camamu. Other studies of Brazilian coastal mollusks have also reported the occurrence of Sphenophrya sp.…”

Section: Discussionsupporting

confidence: 76%

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

Zeidan

Luz

2012

This study investigated the parasites of three commercially important bivalve species (Crassostrea rhizophorae, Mytella guyanensis and Lucina pectinata) from the southern coast of Bahia, Brazil. A total of 540 specimens were collected in August 2009 and February 2010, at three localities. The bivalve specimens were measured on their longest axis, opened, and macroscopically examined for the presence of parasites or signs of disease. They were then fixed in Davidson' solution and subjected to routine histological processing, with paraffin embedding and H&E staining; next, the specimens were examined under a light microscope. . Nematopsis sp. ocorreu em alta prevalência, porém, aparentemente, não causou danos aos bivalves. Bucephalus sp. causou destruição de tecidos, com castração, mas foi pouco prevalente. Os demais parasitos ocorreram em baixa prevalência e intensidade de infecção e sem causar danos.

“…Specifically, Sphenophrya can cause a tumor called xenoma, i.e., a hypertrophy of the infected cell, including its nucleus (BOWER et al, 1994). The first report of xenoma formation in C. rhizophorae was by Boehs et al (2009) in Camamu Bay in an area close to points 1 and 2 of this study, and was associated with this ciliate by the authors. As in this study, the authors reported a low prevalence.…”

Section: Discussionmentioning

confidence: 53%

Health assessment of the oyster Crassostrea rhizophorae on the southern coast of Bahia, northeastern Brazil

Brandão

Silva

2013

Health assessment of the oyster AbstractThis 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 Maraú (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.Keywords: Oysters, parasitism, pathogen, Bucephalus, Nematopsis, Bahia -Brazil. ResumoEste estudo investigou a saúde de ostras da espécie Crassostrea rhizophorae de estoques naturais do Litoral Sul do Estado da Bahia, Nordeste do Brasil, durante o verão e o inverno de 2010, em três pontos amostrais distribuídos nos estuários dos rios Maraú (Baía de Camamu) e Graciosa. Um total de 180 ostras (30/ponto amostral/período) foram examinadas macroscopicamente para a presença de patógenos e alterações anatômicas e posteriormente fixadas em solução de Davidson, processadas para inclusão em parafina, seccionadas e coradas com hematoxilina de Harris e eosina. A análise histológica evidenciou a presença de organismos com características similares a Rickettsia (RLOs), Ancistrocoma, Trichodina, Sphenophrya, Nematopsis, Urastoma, Bucephalus em fase esporocística, metacercária inespecífica e metacestóide de Tylocephalum. As prevalências de infecção foram baixas, com exceção do parasitismo por Nematopsis sp., o qual também causou alterações histopatológicas. A presença de Bucephalus sp. causou castração parasitária. Esses dois patógenos têm interferência significativa na saúde de C. rhizophorae.