Lactococcus garvieae outbreaks in Brazilian farms Lactococcosis in Pseudoplatystoma sp. - development of an autogenous vaccine as a control strategy.

This study evaluated the control of streptococcosis outbreaks in Brazil, isolated from diseased sorubim and identified as Lactococcus garvieae by genetic sequencing. This report determined the potential for lactococcosis control in sorubim Pseudoplatystoma sp. with two vaccines: an aqueous-based, whole-cell inactivated vaccine (bacterin) and an oil-adjuvanted bacterin. Their efficacy was evaluated at 30 days post-vaccination (d.p.v.) by challenge with L. garvieae, and the antibody production response at 15, 30 and 60 d.p.v. and the non-specific immune response were compared amongst treatments. High protection levels (P < 0.05) were achieved with the oil-adjuvanted vaccine with a relative percentage survival value of 81.7% at 30 d.p.v. Additionally, the oil-adjuvanted vaccine increased the immunogenicity of the bacterin as indicated by greater agglutination antibody titres from 15 until 60 d.p.v. This is the first report of a positive effect of vaccine administration on the specific immunity of sorubim, and the study showed that a specific antibody plays an important role in sorubim defence against lactococcosis because the innate immune responses were similar in all of the studied animals. These results demonstrated that oil-adjuvanted vaccine can be an effective alternative for the protection of sorubim from L. garvieae disease.

Detection of white spot syndrome virus in Brazil using negative staining, immunoelectron microscopy and immunocytochemistry techniques / Detección del virus del síndrome de mancha blanca en el Brasil utilizando inmunomicroscopía e inmunomarcación con partículas de oro coloidal

In this study thirty shrimp samples from commercial marine shrimp (L. vannamei) farms of southern region of Brazil were obtained. Hepatopancreas and shell scrapings fragments collected in these animals were processed by transmission electron microscopy using negative staining (rapid preparation), immunoelectron microscopy and immunocytochemistry (immunolabelling with colloidal gold particles) techniques. On the transmission electron microscopy a great number of white spot virus particles, ovoid or bacilliform-to-ellipsoid, measured 230-290 nm in length and 80-160 nm in diameter with intra-nuclear projections were visualized by the negative staining technique in 27 (90 percent) out of 30 samples examined. Using immunoelectron microscopy technique, the anti-VP 664 serum agllutinated a large number of particles formed by antigen-antibody interaction. In the immunocytochemistry technique, the antigen-antibody reaction was styrongly marked by the particles of colloidal gold over the virus. Notably, this is the first report, to our knowledge, describing use of these microscopy techniques to study Brazilian L. vannamei marine shrimp samples; moreover, this methodology also appears to be a viable complementary tool for diagnosing the presence of the white spot virus within shrimp tissues. Importantly, these are the first photoelectron micrographs of the WSSV in Brazil.

Se obtuvieron para el estudio 30 muestras de camarones marinos comerciales (L. vannamei) de las granjas de la región sur de Brasil. Fueron procesados fragmentos de hepatopáncreas y raspados internos del cefalotórax recogidos en estos animales por microscopía electrónica de transmisión con tinción negativa (preparación rápida), inmunomicroscopía y técnicas de inmunocitoquímica (inmunomarcación con partículas de oro coloidal). En la microscopía electrónica de transmisión de un gran número de partículas de virus de la mancha blanca, ovoide o elipsoidal a baciliformes, medían 230-290 nm de longitud y 80-160 nm de diámetro. En 27 (90 por ciento) de las 30 muestras examinadas intra-nuclear proyecciones se visualizaron mediante la técnica de tinción negativa. Utilizando una técnica de inmunomicroscopía electrónica, el anti-suero VP 664 reunió a un gran número de partículas formadas por la interacción antígeno-anticuerpo. En la técnica de inmunocitoquímica, la reacción antígeno-anticuerpo fue fuertemente reforzada por las partículas de oro coloidal en los virus. En particular, en Brasil este es el primer informe, a nuestro entender, que describe el uso de estas técnicas de microscopía en muestras de camarón marino L. vanamei. Además, esta metodología también parece ser una herramienta complementaria viable para diagnosticar la presencia del virus de la mancha blanca en tejidos de camarón. Es importante destacar que estas son las primeras fotos en microscopia electrónica del WSSV obtenidas en Brasil.

Morphocytochemical, immunohistochemical and ultrastructural characterization of the head kidney of fat snook Centropomus parallelus.

This study characterized the structure and the morphocytochemical, immunohistochemical and ultrastructural aspects of the head kidney (HK) of the fat snook Centropomus parallelus. The HK is enclosed by a thin capsule of connective tissue, from which fine trabeculae originate and branch into the interior of organ. In the parenchyma, there are aggregates of lymphoid cells containing populations of lymphocytes T immunopositive for CDRO45, in a nodular arrangement, around blood vessels and melano-macrophage centres. Among the cells that constituted these aggregates and surrounded them, were macrophages and monocytes, and their precursors, with strong immunopositivity for CD68, along with cells of the granulocytic lineage in various phases of maturation positive for lysozyme and PAS. Macrophages and chromaffin and interrenal cells are also present. Ultrastructurally, the HK comprises a reticulum-endothelial stroma consisting of endothelial cells, reticulocytes of the fibroblast type and macrophage type and a parenchyma with increased cellularity, principally blood cells of the erythrocytic, granulocytic, lymphocytic, monocytic and thrombocytic series.

Co-infestation of gills by different parasite groups in the mullet, Mugil platanus Günther, 1880 (Osteichthyes, Mugilidae): effects on relative condition factor.

This study involved 334 specimens of mullet, Mugil platanus, captured monthly in the estuarine region of Cananéia, São Paulo State, Brazil, from July 1988 to June 1989, and examined for the presence of gill parasites. Parasitological inspections revealed the occurrence of the following groups: Trichodina sp., Monogenoidea, Copepoda, and Hirudinea. Only four mullets were not parasitized. Total weight and total length of all 334 mullet specimens examined were used for adjusting the weight-length relationship curve and calculating the relative condition factor (Kn). The 118 specimens infested with monogenoideans on average had lower weights than expected (Kn < 1.0), and the 81 fish co-infested with Copepoda, Monogenoidea, and Trichodina sp. showed a Kn < 1.0. The other infested and non-infested mullets had a Kn > 1.0. It was possible to infer that gill infestation with monogenoideans alters mullet weight, especially in the presence of co-infestation with Trichodina sp. and copepods.

Co-infestation of gills by different parasite groups in the mullet, Mugil platanus Günther, 1880 (Osteichthyes, Mugilidae): effects on relative condition factor

Foram examinados exemplares de tainha, Mugil platanus, capturados mensalmente na região estuarino-lagunar de Cananéia, SP, entre julho de 1988 e junho de 1989, a fim de verificar a ocorrência de parasitos branquiais. Das 334 tainhas examinadas, apenas quatro não apresentaram nenhum parasito. Nas demais, foram encontrados os seguintes grupos: Trichodina sp., Monogenoidea, Copepoda e Hirudinea. Utilizando os valores de peso total (Wt) e de comprimento total (Lt) de todos os espécimes estudados calculou-se o fator de condição relativo (Kn). Constatou-se que os 118 espécimes infestados por monogenóideos encontravam-se, em média, com peso inferior ao esperado. Os 81 espécimes que tinham, concomitantemente nas brânquias, Trichodina sp., copépodos e monogenóideos apresentaram, em média, peso inferior ao esperado. Os demais espécimes parasitados, assim como os não parasitados, estavam com o peso igual ou acima do esperado. Foi possível constatar que o parasitismo das brânquias por monogenóideos afeta o peso das tainhas, Mugil platanus, da região estuarino-lagunar de Cananéia, SP, especialmente quando co-infestado com Trichodina sp. e copépodos.

Differential leucokocyte counts in dourado, Salminus maxillosus Valenciennes, 1840, from the Mogi-Guaçu River, Pirassununga, SP

From August, 1996 to December, 1997, 293 of ''dourado'' specimens, Salminus maxillosus (Valencienes, 1840), of various sizes, were caught in Mogi-Guaçu River, Emas Falls, for hematologic studies. Total weight (Wt in g) and length (Lt in cm) were taken for each individual animal. Smears were prepared from blood samples and utilized for differential leukocyte counts (lymphocytes, neutrophils, monocytes, eosinophils, special granulocytic cell and immature cells). The mean percentages of leukocytes were determined according to sex and stage of gonadal maturation (immature, in maturation, mature, spent and resting). Significant differences between male and female occurred only for the special granulocytic cell. In analyzing the leukocyte profile during gonadal development, only female showed significant differences in mean percentages of lymphocytes, neutrophils, monocytes and eosinophils.

Morphological and ultrastructural study of the thrombocytes and leukocyte granulocytes of Salminus maxillosus (Characiformes, Characidae).

The thrombocytes and leukocytes of 'dourado' fish Salminus maxilosus peripheral blood were studied by means of light microscopy and transmission electron microscopy techniques. In respect to the morphological and ultrastructural aspects of thrombocytes and granulocytes, the cellular elements that appear with high frequency in the light microscopy preparations stained by the Rosenfeld method, three different types of granulocytes could be differentiated at the electron microscope, based on the ultrastructural aspect of the cytoplasmic elements: type I granulocyte that possibly corresponds to the type I neutrophil described under light microscopy; type II granulocyte is possibly the cell identified as type II neutrophil by the morphological analysis; type III granulocyte is equivalent to the eosinophils described in the samples stained by Rosenfeld methods.

Aspectos morfológicos y citoquímicos de las células sanguíneas de salminus maxillosus: characiformes characidae / Morphological and cytochemistry observation in blood cells of salminus maxillosus: characiformes characidae

Las características morfológicas de sangre periférica del pez Salminus maxillosus fueron descritas usando microscopía de luz. Para demostrar el comportamiento citoquímico de las células sanguíneas del pez en estudio, fueron aplicados métodos específicos para la detección de cuatro tipos básicos de componentes macromoleculares, de naturaleza química diferente: carbohidratos, lípidos. proteínas enzimáticas y estructurales. Fueron observados 6 tipos de células: eritrocitos, trombocitos, monocitos, linfocitos, neutrófilos de los tipos I y II y eosinófilos. Los trombocitos y los neutrófilos de los tipos I y II presentaron glucógeno en el citoplasma. Los neutrófilos del tipo II presentan gránulos sudanófilos y mielloperoxidasa. Además presentan, reacción difusa intensa para proteínas en el citoplasma. Los eosinófilos muestran reacción intensa en sus gránulos