scholarly journals Enterocytozoon schreckii n. sp. Infects the Enterocytes of Adult Chinook Salmon ( Oncorhynchus tshawytscha ) and May Be a Sentinel of Immunosenescence

mSphere ◽  
2022 ◽  
Author(s):  
Claire E. Couch ◽  
Michael L. Kent ◽  
Louis M. Weiss ◽  
Peter M. Takvorian ◽  
Stephanie Nervino ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Opportunistic Pathogen ◽  
Enterocytozoon Bieneusi ◽  
Aids Patients ◽  
Content Type ◽  
Microsporidian Species

In this work, we describe a new microsporidian species that infects the enterocytes of Chinook salmon. This novel pathogen is closely related to Enterocytozoon bieneusi , an opportunistic pathogen commonly found in AIDS patients and other severely immunocompromised humans.

scholarly journals First Isolation of a Novel Aquatic Flavivirus from Chinook Salmon (Oncorhynchus tshawytscha) and Its In Vivo Replication in a Piscine Animal Model

2020 ◽  
Vol 94 (15) ◽  
Author(s):  
Esteban Soto ◽  
Alvin Camus ◽  
Susan Yun ◽  
Tomofumi Kurobe ◽  
John H. Leary ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Habitat Degradation ◽  
Infection Model ◽  
Fish Cell ◽  
Pathogenic Potential ◽  
Content Type ◽  
Reading Frame ◽  
Rapid Amplification

ABSTRACT The first isolation of a flavivirus from fish was made from moribund Chinook salmon (Oncorhynchus tshawytscha) from the Eel River, California, USA. Following the observation of cytopathic effect in a striped-snakehead fish cell line, 35-nm virions with flaviviral morphology were visualized using electron microcopy. Next-generation sequencing and rapid amplification of cDNA ends obtained the complete genome. Reverse transcriptase quantitative PCR (RT-qPCR) confirmed the presence of viral RNA in formalin-fixed tissues from the wild salmon. For the first time, in vivo replication of an aquatic flavivirus was demonstrated following intracoelomic injection in a Chinook salmon model of infection. RT-qPCR demonstrated viral replication in salmon brains up to 15 days postinjection. Infectious virus was then reisolated in culture, fulfilling Rivers’ postulates. Only limited replication occurred in the kidneys of Chinook salmon or in tissues of rainbow trout (Oncorhynchus mykiss). The proposed salmon flavivirus (SFV) has a 10.3-kb genome that encodes a rare dual open reading frame, a feature uncharacteristic of classical flaviviruses. Phylogenetic analysis places SFV in a basal position among a new subgroup of recently recognized aquatic and bat flaviviruses distinct from the established mosquito-borne, tick-borne, insect-only, and unknown-vector flavivirus groups. While the pathogenic potential of the virus remains to be fully elucidated, its basal phylogeny and the in vivo infection model will allow SFV to serve as a prototype for aquatic flaviviruses. Ongoing field and laboratory studies will facilitate better understanding of the potential impacts of SFV infection on ecologically and economically important salmonid species. IMPORTANCE Chinook salmon are a keystone fish species of great ecological and commercial significance in their native northern Pacific range and in regions to which they have been introduced. Threats to salmon populations include habitat degradation, climate change, and infectious agents, including viruses. While the first isolation of a flavivirus from wild migrating salmon may indicate an emerging disease threat, characterization of the genome provides insights into the ecology and long evolutionary history of this important group of viruses affecting humans and other animals and into an expanding group of recently discovered aquatic flaviviruses.

scholarly journals High Prevalence of Enterocytozoon bieneusi in Asymptomatic Pigs and Assessment of Zoonotic Risk at the Genotype Level

2014 ◽  
Vol 80 (12) ◽  
pp. 3699-3707 ◽  
Author(s):  
Wei Zhao ◽  
Weizhe Zhang ◽  
Fengkun Yang ◽  
Jianping Cao ◽  
Hua Liu ◽  
...  
Keyword(s):  
Opportunistic Pathogen ◽  
Small Subunit ◽  
Enterocytozoon Bieneusi ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Content Type ◽  
Zoonotic Risk ◽  
High Prevalence ◽  
Life Threatening ◽  
Clinically Significant

ABSTRACTEnterocytozoon bieneusiis an emerging and clinically significant enteric parasite infecting humans and animals and can cause life-threatening diarrhea in immunocompromised people. Pigs are considered to be one of the main reservoir hosts ofE. bieneusibased on their high prevalence rates and zoonotic genotypes in pigs. As an opportunistic pathogen,E. bieneusiinfection of pigs can be inapparent, which leads to neglect in detecting this parasite in pigs and assessing the epidemiological role of pigs in the transmission of human microsporidiosis. In the present study, 95 healthy pigs aged 2 or 3 months were randomly selected from three areas in Heilongjiang Province, China.E. bieneusiisolates were identified and genotyped based on the small-subunit (SSU) rRNA and internal transcribed spacer (ITS) regions of the rRNA gene by PCR and sequencing. A high prevalence ofE. bieneusiwas observed, 83.2% (79/95) at the SSU rRNA locus versus 89.5% (85/95) at the ITS locus. Ten ITS genotypes were obtained, comprising six known genotypes—EbpA (n= 30), D (n= 19), H (n= 18), O (n= 11), CS-1 (n= 1), and LW1 (n= 1)—and four novel genotypes named HLJ-I to HLJ-IV; 70.6% (60/85) ofE. bieneusigenotypes were zoonotic (genotypes EbpA, D, and O). The findings of a high prevalence ofE. bieneusiin pigs and a large percentage of zoonotic genotypes indicate that pigs may play a role in the transmission ofE. bieneusito humans and may become an important source of water contamination in our investigated areas.

Flavobacterium spartansii sp. nov., a pathogen of fishes, and emended descriptions of Flavobacterium aquidurense and Flavobacterium araucananum

2014 ◽  
Vol 64 (Pt_2) ◽  
pp. 406-412 ◽  
Author(s):  
Thomas P. Loch ◽  
Mohamed Faisal
Keyword(s):  
Fatty Acid ◽  
Chinook Salmon ◽  
Type Species ◽  
Oncorhynchus Tshawytscha ◽  
Phylogenetic Analyses ◽  
Acid Methyl Ester ◽  
Gliding Motility ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type

Two strains (T16T and S12) of a Gram-reaction-negative, rod-shaped, yellow-pigmented bacterium were recovered from kidneys of feral spawning adult Chinook salmon (Oncorhynchus tshawytscha) and the gills of captive-reared Chinook salmon fingerlings suffering a mortality episode, respectively. Polyphasic characterization revealed that these strains possessed gliding motility, contained a flexirubin-type pigment, proteolysed multiple substrates (i.e. gelatin, casein and elastin), and had a mean DNA G+C content of 35.6 mol%. Sequencing of the 16S rRNA gene demonstrated that strains T16T and S12 were nearly identical to one another (>99 % similarity) and were placed within the genus Flavobacterium , with Flavobacterium aquidurense CCUG 59847T (98.3 %), Flavobaterium araucananum CCUG 61031T (98.2 %) and Flavobacterium frigidimaris (AB183888, 98.1 %) being their closest relatives. Subsequent phylogenetic analyses using neighbour-joining, maximum-parsimony and Bayesian methodologies demonstrated that strains T16T and S12 formed a well-supported clade within the genus Flavobacterium that was distinct from other Flavobacterium species. The major fatty acid constituents of strains T16T and S12 were iso-C15 : 0, C16 : 1ω6c and/or C16 : 1ω7c, iso-C17 : 0 3-OH, and iso-C15 : 0 3-OH according to fatty acid methyl ester analysis. The mean level of DNA–DNA relatedness between strain T16T and F. aquidurense CCUG 59847T and F. araucananum CCUG 61031T was 23 and 29 %, respectively. Thus, the data accumulated in this study support the suggestion that strains T16T and S12 represent a novel species of the genus Flavobacterium , for which the name Flavobacterium spartansii sp. nov. is proposed. The type strain is T16T ( = LMG 27337T = ATCC BAA-2541T). Emended descriptions of F. aquidurense and F. araucananum are also proposed.

Systematic hexamitid (Protozoa: Diplomonadida) Infection in seawater pen-reared Chinook salmon Oncorhynchus tshawytscha

1992 ◽  
Vol 14 ◽  
pp. 81-89 ◽  
Author(s):  
ML Kent ◽  
J Ellis ◽  
JW Fournie ◽  
SC Dawe ◽  
JW Bagshaw ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha

scholarly journals Managed Wetlands Can Benefit Juvenile Chinook Salmon in a Tidal Marsh

2021 ◽  
Author(s):  
Nicole M. Aha ◽  
Peter B. Moyle ◽  
Nann A. Fangue ◽  
Andrew L. Rypel ◽  
John R. Durand
Keyword(s):  
San Francisco ◽  
Growth Rates ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Nursery Habitat ◽  
San Francisco Estuary ◽  
Rice Fields ◽  
Fish Growth ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

AbstractLoss of estuarine and coastal habitats worldwide has reduced nursery habitat and function for diverse fishes, including juvenile Chinook salmon (Oncorhynchus tshawytscha). Underutilized off-channel habitats such as flooded rice fields and managed ponds present opportunities for improving rearing conditions and increasing habitat diversity along migratory corridors. While experiments in rice fields have shown enhanced growth rates of juvenile fishes, managed ponds are less studied. To evaluate the potential of these ponds as a nursery habitat, juvenile Chinook salmon (~ 2.8 g, 63 mm FL) were reared in cages in four contrasting locations within Suisun Marsh, a large wetland in the San Francisco Estuary. The locations included a natural tidal slough, a leveed tidal slough, and the inlet and outlet of a tidally muted managed pond established for waterfowl hunting. Fish growth rates differed significantly among locations, with the fastest growth occurring near the outlet in the managed pond. High zooplankton biomass at the managed pond outlet was the best correlate of salmon growth. Water temperatures in the managed pond were also cooler and less variable compared to sloughs, reducing thermal stress. The stress of low dissolved oxygen concentrations within the managed pond was likely mediated by high concentrations of zooplankton and favorable temperatures. Our findings suggest that muted tidal habitats in the San Francisco Estuary and elsewhere could be managed to promote growth and survival of juvenile salmon and other native fishes.

Analysis of straying variation in Alaskan hatchery chinook salmon (Oncorhynchus tshawytscha) following transplantation

1999 ◽  
Vol 56 (4) ◽  
pp. 578-589 ◽  
Author(s):  
Jeffrey J Hard ◽  
William R Heard
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Release Site ◽  
Substantial Variation

In 1976 chinook salmon (Oncorhynchus tshawytscha) gametes from the Chickamin and Unuk rivers in southeastern Alaska were transplanted 250 km to establish hatchery runs at Little Port Walter (LPW), Baranof Island. From 1977 to 1989, 1 862 058 marked smolts from 12 broods were released from LPW. Homing and straying were estimated from adult recoveries at 25 locations in Alaska and British Columbia between 1981 and 1989. Of 22 198 LPW fish recovered over this period, 21 934 (98.8%) were collected at LPW. Of 264 fish recovered elsewhere, 38.3% were within 7 km of LPW; 64.4% were within 25 km of LPW. No LPW fish were recovered from the ancestral rivers, but nine fish were recovered from rivers supporting wild chinook salmon. Straying declined with distance from the release site but varied between hatcheries and streams. Straying declined with increasing age and run size. Straying was similar between the populations but varied among broods, and analysis of straying in experimental groups provided evidence for a heritable component. Males strayed more often than females. Population, gender, run size, and recovery age interacted to produce substantial variation in straying, indicating that run composition can produce complex straying responses.

Route selection in a large river during the homing migration of Chinook salmon (Oncorhynchus tshawytscha)

2006 ◽  
Vol 63 (8) ◽  
pp. 1752-1762 ◽  
Author(s):  
Matthew L Keefer ◽  
Christopher C Caudill ◽  
Christopher A Peery ◽  
Theodore C Bjornn
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Columbia River ◽  
Large River ◽  
Migration Route ◽  
Route Selection ◽  
Behavioral Differences ◽  
Long Distance ◽  
Selection Decisions ◽  
Efficient Route

Upstream-migrating adult salmon must make a series of correct navigation and route-selection decisions to successfully locate natal streams. In this field study, we examined factors influencing migration route selections early in the migration of 4361 radio-tagged adult Chinook salmon (Oncorhynchus tshawytscha) as they moved upstream past dams in the large (~1 km wide) Columbia River. Substantial behavioral differences were observed among 11 conspecific populations, despite largely concurrent migrations. At dams, Chinook salmon generally preferred ladder passage routes adjacent to the shoreline where their natal tributaries entered, and the degree of preference increased as salmon proximity to natal tributaries increased. Columbia River discharge also influenced route choices, explaining some route selection variability. We suggest that salmon detect lateral gradients in orientation cues across the Columbia River channel that are entrained within tributary plumes and that these gradients in cues can persist downstream for tens to hundreds of kilometres. Detection of tributary plumes in large river systems, using olfactory or other navigation cues, may facilitate efficient route selection and optimize energy conservation by long-distance migrants.

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