Caligus rogercresseyi infestation is associated with Piscirickettsia salmonis-attributed mortalities in farmed salmonids in Chile

Arriagada, Gabriel; Hamilton‐West, Christopher; Nekouei, Omid; Foerster, Claudia; Müller-Sepúlveda, Andrea; Lara, Marcela; Gallardo‐Escárate, Cristian

doi:10.1016/j.prevetmed.2019.104771

Cited by 19 publications

(10 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sea lice are among the most common parasites for the global salmon industry, with a prevalence of up to 100% in some farms ( 46 , 47 ). Moreover, in unvaccinated fish, the infestation of salmonids with sea lice can cause lethal or sublethal effects such as stress, loss of appetite, decreased growth, skin damage, depression of the immune system, and flesh quality detriment ( 32 , 45 , 48 – 50 ). Nevertheless, it has been established that the sea louse maintains only a transient association that does not last more than one hour, so it is not considered a biological or mechanical vector of P. salmonis ( 51 ).…”

Section: Why Vaccines Fail Against Piscirickettsiosis?mentioning

confidence: 99%

“…Under laboratory conditions, coinfection with these parasites reduces the survival and growth of vaccinated fish, increasing the bacterial load and pathological signs of disease, leading to acute SRS infections ( 44 ). Similarly, in field conditions where a high percentage of fish are vaccinated against P. salmonis , it has been observed that a high prevalence of adult sea lice is significantly associated with Piscirickettsiosis cumulative mortality, suggesting that the two diseases have a synergistic relationship ( 50 ). Thus, sea-lice coinfection with other pathogens could partly explain the low vaccine efficacy in field conditions.…”

Section: Why Vaccines Fail Against Piscirickettsiosis?mentioning

confidence: 99%

See 1 more Smart Citation

Why vaccines fail against Piscirickettsiosis in farmed salmon and trout and how to avoid it: A review

et al. 2022

View full text Add to dashboard Cite

Piscirickettsiosis is the most severe, persistent, and damaging disease that has affected the Chilean salmon industry since its origins in the 1980s. As a preventive strategy for this disease, different vaccines have been developed and used over the last 30 years. However, vaccinated salmon and trout frequently die in the sea cages and the use of antibiotics is still high demonstrating the low efficiency of the available vaccines. The reasons why the vaccines fail so often are still debated, but it could involve different extrinsic and intrinsic factors. Among the extrinsic factors, mainly associated with chronic stress, we can distinguish: 1) biotic including coinfection with sea lice, sealions attacks or harmful algal blooms; 2) abiotic including low oxygen or high temperature; and 3) farm-management factors including overcrowding or chemical delousing treatments. Among the intrinsic factors, we can distinguish: 1) fish-related factors including host’s genetic variability (species, population and individual), sex or age; 2) pathogen-related factors including their variability and ability to evade host immune responses; and 3) vaccine-related factors including low immunogenicity and poor matches with the circulating pathogen strain. Based on the available evidence, in order to improve the development and the efficacy of vaccines against P. salmonis we recommend: a) Do not perform efficacy evaluations by intraperitoneal injection of pathogens because they generate an artificial protective immune response, instead cohabitation or immersion challenges must be used; b) Evaluate the diversity of pathogen strains in the field and ensure a good antigenic match with the vaccines; c) Investigate whether host genetic diversity could be improved, e.g. through selection, in favor of better and longer responses to vaccination; d) To reduce the stressful effects at the cage level, controlling the co-infection of pathogens and avoiding fish overcrowding. To date, we do not know the immunological mechanisms by which the vaccines against P. salmonis may or may not generate protection. More studies are required to identify what type of response, cellular or molecular, is required to develop effective vaccines.

show abstract

Section: Why Vaccines Fail Against Piscirickettsiosis?mentioning

confidence: 99%

Section: Why Vaccines Fail Against Piscirickettsiosis?mentioning

confidence: 99%

Why vaccines fail against Piscirickettsiosis in farmed salmon and trout and how to avoid it: A review

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Annually the salmon farming industry accounts $480 million in losses associated with sea lice, representing 10% of production costs [3][4][5] . The parasitism on farmed fish causes skin damage, immunosuppression, and co-infection of opportunistic pathogenic bacteria [6][7][8] . Like all ectoparasites, lice spend a large part of their life cycle on a fish host, displaying specific mechanisms for evading the host's immune response [9][10][11] .…”

Section: Background and Summarymentioning

confidence: 99%

Chromosome-scale genome assembly of the sea louse Caligus rogercresseyi by SMRT sequencing and Hi-C analysis

et al. 2021

Self Cite

View full text Add to dashboard Cite

Caligus rogercresseyi, commonly known as sea louse, is an ectoparasite copepod that impacts the salmon aquaculture in Chile, causing losses of hundreds of million dollars per year. In this study, we report a chromosome-scale assembly of the sea louse (C. rogercresseyi) genome based on single-molecule real-time sequencing (SMRT) and proximity ligation (Hi-C) analysis. Coding RNAs and non-coding RNAs, and specifically long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) were identified through whole transcriptome sequencing from different life stages. A total of 23,686 protein-coding genes and 12,558 non-coding RNAs were annotated. In addition, 6,308 lncRNAs and 5,774 miRNAs were found to be transcriptionally active from larvae to adult stages. Taken together, this genomic resource for C. rogercresseyi represents a valuable tool to develop sustainable control strategies in the salmon aquaculture industry.

show abstract

“…For instance, L. salmonis and Moritella viscosa –a Gram-negative bacterium causing winter ulcer disease in salmonids– co-infection hindered Atlantic salmon skin’s ability to heal and increased mortality rates compared with individuals infected with M. viscosa alone ( 14 ). The co-infection of Caligus rogercresseyi –the most prevalent parasitic copepod in Chile– and Piscirickettsia salmonis –a Gram-negative bacterium causing salmonid rickettsial septicemia (SRS)– is highly frequent in Chilean salmon farms and seems to be non-competitive ( 15 ), which may have severe implications in vaccines’ efficacy, and salmons’ performance and survival ( 16 , 17 ).…”

Section: Introductionmentioning

confidence: 99%

Interacting Effects of Sea Louse (Lepeophtheirus salmonis) Infection and Formalin-Killed Aeromonas salmonicida on Atlantic Salmon Skin Transcriptome

et al. 2022

View full text Add to dashboard Cite

Lepeophtheirus salmonis (sea lice) and bacterial co-infection threatens wild and farmed Atlantic salmon performance and welfare. In the present study, pre-adult L. salmonis-infected and non-infected salmon were intraperitoneally injected with either formalin-killed Aeromonas salmonicida bacterin (ASAL) or phosphate-buffered saline (PBS). Dorsal skin samples from each injection/infection group (PBS/no lice, PBS/lice, ASAL/no lice, and ASAL/lice) were collected at 24 h post-injection and used for transcriptome profiling using a 44K salmonid microarray platform. Microarray results showed no clear inflammation gene expression signatures and revealed extensive gene repression effects by pre-adult lice (2,189 down and 345 up-regulated probes) in the PBS-injected salmon (PBS/lice vs. PBS/no lice), which involved basic cellular (e.g., RNA and protein metabolism) processes. Lice repressive effects were not observed within the group of ASAL-injected salmon (ASAL/lice vs. ASAL/no lice); on the contrary, the observed skin transcriptome changes –albeit of lesser magnitude (82 up and 1 down-regulated probes)– suggested the activation in key immune and wound healing processes (e.g., neutrophil degranulation, keratinocyte differentiation). The molecular skin response to ASAL was more intense in the lice-infected (ASAL/lice vs. PBS/lice; 272 up and 11 down-regulated probes) than in the non-infected fish (ASAL/no lice vs. PBS/no lice; 27 up-regulated probes). Regardless of lice infection, the skin’s response to ASAL was characterized by the putative activation of both antibacterial and wound healing pathways. The transcriptomic changes prompted by ASAL+lice co-stimulation (ASAL/lice vs. PBS/no lice; 1878 up and 3120 down-regulated probes) confirmed partial mitigation of lice repressive effects on fundamental cellular processes and the activation of pathways involved in innate (e.g., neutrophil degranulation) and adaptive immunity (e.g., antibody formation), as well as endothelial cell migration. The qPCR analyses evidenced immune-relevant genes co-stimulated by ASAL and lice in an additive (e.g., mbl2b, bcl6) and synergistic (e.g., hampa, il4r) manner. These results provided insight on the physiological response of the skin of L. salmonis-infected salmon 24 h after ASAL stimulation, which revealed immunostimulatory properties by the bacterin with potential applications in anti-lice treatments for aquaculture. As a simulated co-infection model, the present study also serves as a source of candidate gene biomarkers for sea lice and bacterial co-infection.

show abstract

Caligus rogercresseyi infestation is associated with Piscirickettsia salmonis-attributed mortalities in farmed salmonids in Chile

Cited by 19 publications

References 14 publications

Why vaccines fail against Piscirickettsiosis in farmed salmon and trout and how to avoid it: A review

Why vaccines fail against Piscirickettsiosis in farmed salmon and trout and how to avoid it: A review

Chromosome-scale genome assembly of the sea louse Caligus rogercresseyi by SMRT sequencing and Hi-C analysis

Interacting Effects of Sea Louse (Lepeophtheirus salmonis) Infection and Formalin-Killed Aeromonas salmonicida on Atlantic Salmon Skin Transcriptome

Contact Info

Product

Resources

About