scholarly journals The Nasal Epithelium as a Route of Infection and Clinical Signs Changes, in Rainbow Trout (Oncorhynchus mykiss) Fingerlings Infected with Aeromonas spp

2021 ◽  
Vol 11 (19) ◽  
pp. 9159
Author(s):  
Fabián Ricardo Gómez de Anda ◽  
Vicente Vega-Sánchez ◽  
Nydia Edith Reyes-Rodríguez ◽  
Víctor Manuel Martínez-Juárez ◽  
Juan Carlos Ángeles-Hernández ◽  
...  
Keyword(s):  
Nervous System ◽  
Rainbow Trout ◽  
Olfactory Epithelium ◽  
Nervous Tissue ◽  
Clinical Signs ◽  
Infected Fish ◽  
Behavioral Changes ◽  
Aeromonas Species ◽  
Histopathological Findings ◽  
Rainbow Trout Oncorhynchus Mykiss

The genus Aeromonas is a group of bacteria that is widely distributed in water bodies and belongs to the normal intestinal microbiota of aquatic and terrestrial animals. In the present work, rainbow trout fingerlings were experimentally infected by an immersion bath with different Aeromonas species. Subsequently, the behavior of the infected groups was observed and recorded. Infected fingerlings were evaluated by histopathology. The highest percentages of hyperpigmentation (18.88%) and inappetence (47.7%) were observed in fish infected with A. salmonicida, while abnormal swimming (83.33%) was recorded in fish infected with A. bestiarum. In histopathological findings, the highest percentages were observed in the olfactory epithelium (50.0%) for A. lusitana and A. salmonicida (41.1%)-infected fish. While, in the nervous system, the cerebral hemispheres (31.1%) in A. media-infected fish and the oblongata medulla (40.0%) in the A. bestiarum-infected fish presented the highest percentages. Meanwhile, A. salmonicida and A. bestiarum have the highest pathogenicity and virulence based on the histopathological findings in the olfactory epithelium and nervous system. Due to the proximity of the olfactory epithelium with the nervous tissue, it is possible that the infection generated by the Aeromonas species and the histopathological findings in the nervous tissue are reflected in different behavioral changes that suggest differences in the pathogenicity and virulence of the bacteria.

Susceptibility of pike Esox lucius to VHSV and IHNV and potential transmission to rainbow trout Oncorhynchus mykiss

2020 ◽  
Vol 139 ◽  
pp. 175-187
Author(s):  
J Cabon ◽  
F Almeras ◽  
M Baud ◽  
L Pallandre ◽  
T Morin ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Horizontal Transmission ◽  
Clinical Signs ◽  
Esox Lucius ◽  
Infected Fish ◽  
Control Measures ◽  
Viral Hemorrhagic Septicemia Virus ◽  
Fish Farms ◽  
Rainbow Trout Oncorhynchus Mykiss

Determining the origin of recurrent outbreaks of fish diseases occurring on fish farms is essential for disease prevention and control measures. In this study, we investigated the potential reservoir role of wild fish species living near salmonid farms which were regularly found to be positive for viral hemorrhagic septicemia virus (VHSV). In addition to VHSV, infectious hematopoietic necrosis virus (IHNV) was also isolated from several pike Esox lucius samples collected from a pond near the salmonid farms of interest. All isolates of VHSV and IHNV analyzed had 100% identical partial glycoprotein gene sequences. VHSV pike strain OO128-25 belonged to the Ia genotype and shared 99.1 to 99.5% nucleotide identity with strains recently isolated from the farms. IHNV pike strain OO121-8, European genotype, appeared to be different from strains from France characterized since the first isolation in 1987. Isolates representative of both viral species were highly virulent in rainbow trout Oncorhynchus mykiss. OO128-25 induced 65% mortality in pike fingerlings, whereas only weak mortality was observed with OO121-8, despite characteristic symptoms in infected fish. High levels of specific antibodies to VHSV and IHNV were detected in adult pike in the absence of clinical signs. Infection of rainbow trout in contact with experimentally VHSV- or IHNV-infected pike fingerlings indicates possible horizontal transmission. These results suggest that pike could act as a reservoir for VHSV and IHNV in the wild, providing additional evidence to explain viral persistence and resurgence in certain areas.

Molecular Identification and Virulence Potential of the Genus Aeromonas Isolated from Wild Rainbow Trout (Oncorhynchus mykiss) in Mexico

2019 ◽  
Vol 82 (10) ◽  
pp. 1706-1713 ◽  
Author(s):  
NYDIA E. REYES-RODRÍGUEZ ◽  
CELENE SALGADO-MIRANDA ◽  
IZANAMI T. FLORES-VALLE ◽  
MARICRUZ GONZÁLEZ-GÓMEZ ◽  
EDGARDO SORIANO-VARGAS ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Foodborne Pathogens ◽  
Sequence Similarity ◽  
Aeromonas Species ◽  
Pathogenic Potential ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Worldwide Distribution ◽  
Virulence Potential ◽  
Rpod Gene ◽  
Potential Pathogenicity

ABSTRACT The members of the Aeromonas genus are important foodborne pathogens, with a worldwide distribution. Wild rainbow trout, from the national protected area Santuario del Agua State Park, Corral de Piedra, were analyzed. Species of Aeromonas were isolated from the trout, and their pathogenic potential was analyzed based on different pathogenicity and virulence factors. The isolates were identified as A. allosaccharophila (n = 15), A. sobria (n = 8), A. veronii (n = 3), A. rivipollensis (n = 2), A. piscicola (n = 2), and A. popoffii (n = 1), by RNA polymerase sigma factor (rpoD) gene sequencing. Sequence similarity with the type strain was 92.2 to 99.6% for A. sobria isolates, 97.8 to 98.0% for A. allosaccharophila isolates, 99.2% for the A. popoffii isolate, 99.2 to 100% for A. piscicola isolates, and 98.2 to 99.2% for A. veronii isolates. Notably, isolates A30T2–gills and A30T2–spleen showed sequence similarity of 98.0% with strain A. media CECT 4232T and 99.0% with strain A. rivipollensis P2G1T. Virulence genes were detected by PCR at the following frequencies: fla and serine protease, 96.77%; aerA, 93.54%; aexT, 87.09%; lipases, 74.19%; ascV and ahyB, 67.74%; exu, 61.29%; act, 41.93%; ascF-G, 38.70%; lafA, 32.26%; alt, 6.46%; aopP, 9.67%; and ast, 3.23%. These results indicate that several Aeromonas species had the potential pathogenicity to infect wild rainbow trout in the waterway created by the Corral de Piedra dam, suggesting they could be an emerging zoonotic pathogen.

Effects of Rosyside Dace (Clinostomus funduloides) on Microhabitat Use of Rainbow Trout (Oncorhynchus mykiss)

1991 ◽  
Vol 48 (7) ◽  
pp. 1235-1243 ◽  
Author(s):  
Gary D. Grossman ◽  
Vital Boulé
Keyword(s):  
North Carolina ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Intraspecific Competition ◽  
Behavioral Changes ◽  
Microhabitat Use ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Competition For Space ◽  
Laboratory Results ◽  
Spatial Resources

We experimentally examined the effects of competition for space between rainbow trout (Oncorhynchus mykiss) and rosyside dace (Clinostomus funduloides) in an artificial stream. These species generally do not exhibit statistically significant differences in microhabitat use in Coweeta Creek, North Carolina, USA. Two competition (trout and dace) and two control (trout only) trials were conducted during spring and summer. Microhabitat use data indicated that the presence of dace did not produce microhabitat shifts in trout. Most behavioral changes could be attributed to acclimation effects or intraspecific competition. Based on field and laboratory results, it does not appear that interspecific competition with dace strongly affects the use of spatial resources in rainbow trout.

scholarly journals Weissellosis in rainbow trout in Colombia

2020 ◽  
Vol 13 (3) ◽  
pp. 575-580
Author(s):  
Gersson Vásquez-Machado ◽  
Miguel Rubiano-Garzón ◽  
Jonny Yepes-Blandón ◽  
Daniel Gordillo-González ◽  
Jersson Avila-Coy
Keyword(s):  
Rainbow Trout ◽  
Clinical Signs ◽  
Fish Swimming ◽  
Gram Positive Bacteria ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Ocular Lesions ◽  
Intraocular Hemorrhage ◽  
Trout Farms ◽  
Kidney Liver ◽  
Corneal Rupture

Weissellosis is an emergent disease caused by Weissella, a Gram-positive bacteria correlated with hemorrhagic illness and mortality in farm-raised trout in several countries. The current study reports the first outbreaks of weissellosis by Weissella ceti in rainbow trout (Oncorhynchus mykiss), which caused severe mortalities in trout farms in Colombia between May 2016 to June 2019. The disease occurred in several farms irrigated by the same river where temperatures were above 17 °C. Symptoms of the disease were limited almost exclusively to trout above 250 g. The clinical signs consisted of lethargic and anorexic fish, swimming in circles at the surface or against the walls. Pathological findings were mainly ocular lesions like bilateral exophthalmia, periocular and intraocular hemorrhage, lenticular opacity and corneal rupture usually leading to blindness, muscular hemorrhages and necrosis. Microbial isolating from eye, brain, kidney, liver and muscle was performed and W. ceti was confirmed by amplification and sequencing of the 16S rRNA. The aim of this work was to characterize the Weisellosis by Weissella ceti in trouts in Colombia, including microbiological isolating, molecular analysis, gross and microscopic characterization.

scholarly journals Emergence of Rickettsial Infection in Rainbow Trout (Oncorhynchus mykiss) Fry Displaying the Appearance of Red Mark Syndrome in Korea

2019 ◽  
Vol 7 (9) ◽  
pp. 302 ◽  
Author(s):  
Oh ◽  
Giri ◽  
Yun ◽  
Kim ◽  
Kim ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Clinical Signs ◽  
Lateral Side ◽  
Fish Disease ◽  
Rickettsial Infection ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Transmission Electron ◽  
Polymerase Chain ◽  
Distinct Features

Red mark syndrome (RMS) is a fish disease caused by the infection of Rickettsial agents, especially affecting rainbow trout (Oncorhynchus mykiss). The disease is prevalent in many countries in Europe (France, Switzerland, Italy, and Slovenia), South America (Chile), North America (USA), and even Asia (Japan). However, it has not been reported in Korean aquaculture. In February 2019, rainbow trout presenting red spot lesions with swollen features on the lateral side of their body were observed at a hatchery in Korea. Fishes showing those clinical signs were fry weighing 25 ± 5 g. Moreover, the fish showing the red spot lesions were found dead, which suggests an outbreak of a mortality-causing disease. The symptoms were similar to those of RMS, and we identified the presence of Rickettsia-like organisms associated with this disease using polymerase chain reaction (PCR), sequencing, histopathologic examination, and transmission electron microscopy. The distinct features of this infection, compared to that in previous reports, were that RMS occurred in small-sized fish and accompanied mortality. Additionally, the presence of the Rickettsia agent was accompanied with outbreak of the disease. Therefore, this is the first report of RMS outbreak in rainbow trout fisheries in Korea.

scholarly journals Genetic Characterization and Pathological Analysis of a Novel Bacterial Pathogen, Pseudomonas tructae, in Rainbow Trout (Oncorhynchus mykiss)

2019 ◽  
Vol 7 (10) ◽  
pp. 432 ◽  
Author(s):  
Woo Taek Oh ◽  
Ji Hyung Kim ◽  
Jin Woo Jun ◽  
Sib Sankar Giri ◽  
Saekil Yun ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Genome Sequence ◽  
Clinical Symptoms ◽  
Bacterial Species ◽  
Bacterial Pathogen ◽  
Infected Fish ◽  
Fish Pathogens ◽  
Fish Genome ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pseudomonas Species

Pseudomonas species are one of the most prevalent bacterial species globally distributed in forest soil, river water, and human or animal skin. Some species are pathogens or opportunistic pathogens in hospitalized patients, animals, and plants. Various Pseudomonas species, including Pseudomonas putida, P. plecoglossicida, P. aeruginosa, and P. fluorescens, are known fish pathogens; P. fluorescens and P. putida cause severe losses in rainbow trout farming. Therefore, we investigated and isolated the pathogen that is responsible for mortality in a rainbow trout farm in Korea. The isolated bacterium was a strain of P. tructae, which was recently classified in the P. putida group. We performed taxonomical analysis of the bacteria in our previous study. In this study, we investigated the pathogenicity and clinical symptoms of P. tructae and analyzed its genomic characteristics. The pathogenicity of the strain was tested via challenge experiments in healthy rainbow trout and histopathologic analysis of the infected fish. Genome sequence was analyzed to identify the bacterial genes that are involved in antibiotic resistance and virulence. This is the first study reporting P. tructae as an emerging pathogen that is responsible for mortality in rainbow trout fisheries and providing the genome sequence of P. tructae.

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