Detection of Virus Level in Tissues of Rainbow Trout, Oncoryhinchus mykiss in Clinical Stage of Viral Hemorrhagic Septicemia

In order to detecting VHS virus titer in various tissues in clinical stage of VHS disease, rainbow trout,Oncorhynchus mykiss, were exposed to virus by bath. The experiments were carried out with 140 fish obtained fromrainbow trout farm. The fish were divided into two equal groups in 120 Liter tanks containing 70 fish. Group one wasconsidered as control and group two infected by bath challenge with 103 TCID50 ml-1 of a VHS virus strain serologicallysimilar to reference strain F1 with high pathogenicity in rainbow trout. At days 12, 13 and 14 post infection the organsincluding kidney, spleen, heart, skin, liver, pyloric caeca and brain were sampled from dead fish with appropriate clinicalsigns of VHS separately. Each sample was placed in vials adding 1 ml transport medium to assess virus titer in varioustissues. Results of the study, showed that significant difference between virus loads in various organs (p≤ 0.05). Thehighest virus titer belongs to the heart while it is in minimum amount in the skin. According to the virus quantity theexperimental tissues can be divided in three categories, respectively. Heart and kidney performed the highest amount ofvirus quantities while liver, gill, pyloric caeca and skin showed the lowest with brain and spleen lying in between. Theseresults point out that the significant levels of VHS virus found in rainbow trout tissues are relevant for the biosecurity inVHS-free areas mainly when fish are displayed and retained as whole fish.

Detection of Virus Level in Tissues of Rainbow Trout, Oncoryhinchus mykiss in Clinical Stage of Viral Hemorrhagic Septicemia

In order to detecting VHS virus titer in various tissues in clinical stage of VHS disease, rainbow trout,Oncorhynchus mykiss, were exposed to virus by bath. The experiments were carried out with 140 fish obtained fromrainbow trout farm. The fish were divided into two equal groups in 120 Liter tanks containing 70 fish. Group one wasconsidered as control and group two infected by bath challenge with 103 TCID50 ml-1 of a VHS virus strain serologicallysimilar to reference strain F1 with high pathogenicity in rainbow trout. At days 12, 13 and 14 post infection the organsincluding kidney, spleen, heart, skin, liver, pyloric caeca and brain were sampled from dead fish with appropriate clinicalsigns of VHS separately. Each sample was placed in vials adding 1 ml transport medium to assess virus titer in varioustissues. Results of the study, showed that significant difference between virus loads in various organs (p≤ 0.05). Thehighest virus titer belongs to the heart while it is in minimum amount in the skin. According to the virus quantity theexperimental tissues can be divided in three categories, respectively. Heart and kidney performed the highest amount ofvirus quantities while liver, gill, pyloric caeca and skin showed the lowest with brain and spleen lying in between. Theseresults point out that the significant levels of VHS virus found in rainbow trout tissues are relevant for the biosecurity inVHS-free areas mainly when fish are displayed and retained as whole fish.(AU)

Isolation, Characterization and Pathology of Citrobacter freundii Infection in Native Brazilian Catfish Pseudoplatystoma

Bacterial diseases are responsible for important economic losses in aquaculture over the world, and South American catfishes are susceptible to Gram negative bacteria causative of haemorrhagic septicemia. This study registers the biochemical characteristics, antimicrobial resistance and pathological effects of Citrobacter freundii infection in cachara Pseudoplatystoma reticulatum. Moribund juvenile fish with non-specific clinical signs were used for bacteriological and parasitological diagnosis. No parasitic infections were found in examined fish, but two isolate obtained from the kidney and encephalon was characterized by Gram negative bacilli, catalase positive and oxidase negative. Isolates were submitted to biochemical identification by a commercial API 20E. Susceptibility analysis to 15 drugs was performed by the diffusion method in Agar Muller Hinton discs. Experimental assay was also made to confirm the Kock postulate. The isolates showed biochemical profile corresponding to Citrobacter freundii. A multiresistance at 66.7% of the antibiotic molecules tested was observed. In experimental infection haemorrhagic septicaemia, severe enteritis and important lesions in kidney and gills are described.

Isolation, Characterization and Pathology of Citrobacter freundii Infection in Native Brazilian Catfish Pseudoplatystoma

Bacterial diseases are responsible for important economic losses in aquaculture over the world, and South American catfishes are susceptible to Gram negative bacteria causative of haemorrhagic septicemia. This study registers the biochemical characteristics, antimicrobial resistance and pathological effects of Citrobacter freundii infection in cachara Pseudoplatystoma reticulatum. Moribund juvenile fish with non-specific clinical signs were used for bacteriological and parasitological diagnosis. No parasitic infections were found in examined fish, but two isolate obtained from the kidney and encephalon was characterized by Gram negative bacilli, catalase positive and oxidase negative. Isolates were submitted to biochemical identification by a commercial API 20E. Susceptibility analysis to 15 drugs was performed by the diffusion method in Agar Muller Hinton discs. Experimental assay was also made to confirm the Kock postulate. The isolates showed biochemical profile corresponding to Citrobacter freundii. A multiresistance at 66.7% of the antibiotic molecules tested was observed. In experimental infection haemorrhagic septicaemia, severe enteritis and important lesions in kidney and gills are described.(AU)

Distúrbios morfológicos em leucócitos de exemplar de kinguio (Carassius auratus auratus Linnaeus, 1758) com septicemia hemorrágica bacteriana: relato de caso / Morphologic disorders in leukocytes of goldfish sample (Carassius auratus auratus Linnaeus, 1758) with bacterial hemorrhagic septicemia: case report

O presente estudo teve por objetivo relatar um caso sobre as alterações morfológicas em leucócitos de kinguio comsepticemia hemorrágica bacteriana. Um exemplar foi atendido no Laboratório de Patologia de Organismos Aquáticos doCAUNESP, Unesp de Jaboticabal, apresentando apatia, natação errática, anorexia e discreta perda de equilíbrio, buscandoconstantemente a superfície da água. Através de análise visual da superfície corpórea, foram observadas áreas de hemorragiapetequial na base das nadadeiras peitoral, pélvica e caudal, além da órbita bucal, periocular e anal e efusão celomática. Naextensão sanguínea foram observadas a presença de monócitos ativados, hiperativados, e fagócitos mononuclearesrealizando eritrofagocitose e leucofagocitose, neutrófilos com basofilia citoplasmática e com vacuolização citoplasmática,além de imunócitos e leucócitos imaturos com anisocitose e anisocariose. As alterações morfológicas descritas no presenteestudo revelaram parte da patogenia e resposta orgânica de kinguio com septicemia hemorrágica bacteriana. Dessa forma,as análises qualitativas das células sanguíneas devem ser também utilizadas como ferramenta complementar aos estudosdo estado geral da saúde de peixes em cultivo.

The morphological changes in leukocytes of goldfish with bacterial hemorrhagic septicemia were reported. One sample was served at the Laboratory of Pathology of Aquatic Organisms of CAUNESP, Unesp in Jaboticabal. The fish showed lethargy, erratic swimming and without force, slight loss of balance, trying constantly to the water surface. In the body inspection, areas of petechial hemorrhage at the base of the pectoral fins, pelvic fins and caudal fin were observed, beyond the periocular and oral orbitand anal. Blood smears presented hiperactivated monocytes, performing erythrophagocytosis and leukophagocytosis, the cytoplasm of neutrophils presented basophilia and vacuolization, beyond immunocytes, immature leukocytes with anisocytosis and anisokaryosis. The morphological changes described in this study revealed part of the pathogenesis and organic response of Kinguio with bacterial hemorrhagic septicemia. Then, the qualitative analysis of blood cells should also be used as a complementary tool to study the general health status of fish farmed(AU)

Distúrbios morfológicos em leucócitos de exemplar de kinguio (Carassius auratus auratus Linnaeus, 1758) com septicemia hemorrágica bacteriana: relato de caso / Morphologic disorders in leukocytes of goldfish sample (Carassius auratus auratus Linnaeus, 1758) with bacterial hemorrhagic septicemia: case report

O presente estudo teve por objetivo relatar um caso sobre as alterações morfológicas em leucócitos de kinguio comsepticemia hemorrágica bacteriana. Um exemplar foi atendido no Laboratório de Patologia de Organismos Aquáticos doCAUNESP, Unesp de Jaboticabal, apresentando apatia, natação errática, anorexia e discreta perda de equilíbrio, buscandoconstantemente a superfície da água. Através de análise visual da superfície corpórea, foram observadas áreas de hemorragiapetequial na base das nadadeiras peitoral, pélvica e caudal, além da órbita bucal, periocular e anal e efusão celomática. Naextensão sanguínea foram observadas a presença de monócitos ativados, hiperativados, e fagócitos mononuclearesrealizando eritrofagocitose e leucofagocitose, neutrófilos com basofilia citoplasmática e com vacuolização citoplasmática,além de imunócitos e leucócitos imaturos com anisocitose e anisocariose. As alterações morfológicas descritas no presenteestudo revelaram parte da patogenia e resposta orgânica de kinguio com septicemia hemorrágica bacteriana. Dessa forma,as análises qualitativas das células sanguíneas devem ser também utilizadas como ferramenta complementar aos estudosdo estado geral da saúde de peixes em cultivo.

The morphological changes in leukocytes of goldfish with bacterial hemorrhagic septicemia were reported. One sample was served at the Laboratory of Pathology of Aquatic Organisms of CAUNESP, Unesp in Jaboticabal. The fish showed lethargy, erratic swimming and without force, slight loss of balance, trying constantly to the water surface. In the body inspection, areas of petechial hemorrhage at the base of the pectoral fins, pelvic fins and caudal fin were observed, beyond the periocular and oral orbitand anal. Blood smears presented hiperactivated monocytes, performing erythrophagocytosis and leukophagocytosis, the cytoplasm of neutrophils presented basophilia and vacuolization, beyond immunocytes, immature leukocytes with anisocytosis and anisokaryosis. The morphological changes described in this study revealed part of the pathogenesis and organic response of Kinguio with bacterial hemorrhagic septicemia. Then, the qualitative analysis of blood cells should also be used as a complementary tool to study the general health status of fish farmed