hfectivity of a rickettsia isolated from coho salmon Oncorhynchus kisutch

Garces, L.H.; Larenas, J.; Smith, Pamela; Sandino, Sayonara; Lannan, C. N.; Fryer, J. L.

doi:10.3354/dao011093

Cited by 68 publications

(72 citation statements)

References 2 publications

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“…7,12 In the present work, the hepatic lesions observed were milder than those described in natural outbreaks. 1,7 Differences in the severity of the lesions may be due to variations in the host species, age, mode of infection, chronicity of the infections, and water temperature.…”

Section: Discussionmentioning

confidence: 48%

“…5 Previously, histological changes in SRS have often been classified in the broad category of necrosis and inflammation. 1,12 Commonly affected organs are liver, spleen, intestine and hematopoietic tissue of the kidney. 12 Specific lesions in these organs include multifocal to diffuse coagulative necrosis, presence of fibrin thrombi within small blood vessels with necrosis of the endothelium, and infiltration by inflammatory cells.…”

Section: Discussionmentioning

confidence: 99%

“…1,12 Commonly affected organs are liver, spleen, intestine and hematopoietic tissue of the kidney. 12 Specific lesions in these organs include multifocal to diffuse coagulative necrosis, presence of fibrin thrombi within small blood vessels with necrosis of the endothelium, and infiltration by inflammatory cells. 1,7 These histologic lesions correlate well with some gross lesions such as skin ulceration and widespread hemorrhage observed in the abdominal serosal surfaces in SRS.…”

Section: Discussionmentioning

confidence: 99%

“…1,7 The disease has been experimentally reproduced in coho and Atlantic salmon by intraperitoneal inoculation. 7,12 The objective of this work was to study the pathogenesis of hepatic lesions associated with experimental inoculation of juvenile Atlantic salmon with P. salmonis using 3 routes of infection.…”

mentioning

confidence: 99%

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Pathogenesis of Liver Lesions Caused by Experimental Infection with Piscirickettsia Salmonis in Juvenile Atlantic Salmon, Salmo Salar L

2000

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Abstract. Piscirickettsia salmonis, the etiologic agent of salmonid rickettsial septicemia (SRS), or piscirickettsiosis, causes substantial economic losses to the salmon industry. The pathogenesis of the disease has not been fully characterized. The aim of this study is to describe the hepatic lesions associated with experimental P. salmonis infection in Atlantic salmon juveniles. Fish were maintained in fresh water and inoculated intraperitoneally (IP), orally, or on the gill surface with P. salmonis. A group of uninfected fish was kept as control. Liver samples from 5 fish in each inoculated group and 3 controls were collected weekly and processed for histological and immunohistochemical examination. Thickening of the liver capsule by inflammatory cells was a characteristic histologic feature of IP inoculated fish. Three weeks post-IP inoculation, 8 fish had died and 2 fish were sampled. Histological changes at this time consisted of vasculitis, presence of fibrin thrombi, vacuolated hepatocytes and focal areas of necrosis. Leukocytes containing intracytoplasmic basophilic microorganisms were seen within hepatic sinusoids. Vasculitis and intracytoplasmic vacuoles were prominent features in fish inoculated orally and on the gill surface. The presence of P. salmonis within hepatocellular vacuoles, endothelial cells, and leucocytes was confirmed by immunohistochemistry. The intracellular location of P. salmonis and the vascular damage seen in infected fish are characteristic of rickettsial infections. Histological lesions induced by experimental infection with P. salmonis using the oral and gill surface routes were similar to those observed in natural outbreaks of piscirickettsiosis. The tropism of P. salmonis for endothelial cells explains the vascular lesions observed in SRS, whereas hepatic lesions are due to ischemic necrosis and direct injury by intracytoplasmic organisms.

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Section: Discussionmentioning

confidence: 48%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Pathogenesis of Liver Lesions Caused by Experimental Infection with Piscirickettsia Salmonis in Juvenile Atlantic Salmon, Salmo Salar L

2000

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“…An RLO (strain ECR0811) isolated from the experimentally infected salmon multiplied and pi-oduced a characteristic CPE in CHSE cells that was similar to that produced by salmonid RLO from British Columbia, Scotland and Norway (Brocklebank et al 1992, Olsen et al 1993, Grant et al 1996 and by Piscirickettsia salmonis (Garces et al 1991). Cultured ECR0811 was most virulent in Atlantic salmon and less so in other salmonid a n d non-salmonid species.…”

Section: Discussionmentioning

confidence: 99%

Virulence and antigenic characteristics of a cultured Rickettsiales-like organism isolated from farmed Atlantic salmon Salmo salar in eastern Canada

Jones¹,

Markham²,

Groman³

et al. 1998

Dis. Aquat. Org.

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The present study describes culture, virulence and antigenic characteristics of a Rickettsiales-like organism (RLO) associated with mortality in farmed Atlantic salmon in eastern Canada. Clinical disease was reproduced in naive Atlantic salmon parr by intraperitoneal (IP) inoculation with kidney homogenate from naturally infected fish. Pure cultures of RLO were isolated into chinook salmon embryo (CHSE) cells from kidney of experimentally infected fish. The RLO caused cytopathic effect in cultured CHSE-214 typified by coalescing areas of swollen cells that eventually detached from the substrate. Bacteria in infected culture supernatants reacted with Piscirickettsia salmonis-specific polyclonal sera or monoclonal antibody (MAb) in an indirect fluorescent antibody test. IP inoculation with cultured RLO resulted in mortal~ties of 100. 62, 22.5 and 0 % in Atlantic salmon, coho salmon, rainbow trout and common carp, respectively. Cultured RLO were sensitive to chloramphenicol, flumequine, oxytetracycline and oxolinic acid and insensitive to gentamicin and amphotericin B. RLO antigens were compared with those of 3 strains of P, salmonis from Chilean salmon by SDS-PAGE and immunoblotting. A silverstaining band of about 12 kDa was detected in proteinase K (PK) digests of all RLO strains, and a d~ffuse band of about 15 kDa was observed in 2 Chilean strains only. No other silver-stained bands were visible in PK digests of any strain examined. The polyclonal serum recognized 9 protein bands and multiple non-protein bands extending from less than 20 kDa to greater than 95 kDa in all isolates. The MAb reacted with an epitope in PK digests that occurred in all 4 strains on structures of widely ranging molecular masses, resulting in a ladder pattcrn similar to that obtained with polyclonal serum. Treatment of PK digests wlth periodic acid abolished reactivity with MAb and polyclonal serum. CO-elution of 2-keto-3-deoxyoctonate and MAb reactivity following size exclusion chromatography of solubilized P. salmonis suggested that the MAb recognized a lipopolysacchande-associated epitope in all 4 RLO isolates. Cultural, virulence and antigenic similarities among the strains examined in the present study indicate that the eastern Canadian salmonid RLO should be considered a strain of P. salmonis.

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Salmonid Bacterial Diseases

Plumb

Hanson

2010

Health Maintenance and Principal Microbial Diseases of Cultured Fishes

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hfectivity of a rickettsia isolated from coho salmon Oncorhynchus kisutch

Cited by 68 publications

References 2 publications

Pathogenesis of Liver Lesions Caused by Experimental Infection with Piscirickettsia Salmonis in Juvenile Atlantic Salmon, Salmo Salar L

Pathogenesis of Liver Lesions Caused by Experimental Infection with Piscirickettsia Salmonis in Juvenile Atlantic Salmon, Salmo Salar L

Virulence and antigenic characteristics of a cultured Rickettsiales-like organism isolated from farmed Atlantic salmon Salmo salar in eastern Canada

Salmonid Bacterial Diseases

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