Publications by authors named "Nellie Gagne"

Mosquitoes are important vectors for human and animal diseases. Genetic markers, like the mitochondrial COI gene, can facilitate the taxonomic classification of disease vectors, vector-borne disease surveillance, and prevention. Within the control region (CR) of the mitochondrial genome, there exists a highly variable and poorly studied non-coding AT-rich area that contains the origin of replication.

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Sea lice () are ectoparasitic copepods that cause significant economic loss in marine salmoniculture. In commercial salmon farms, infestation with sea lice can enhance susceptibility to other significant pathogens, such as the highly contagious infectious salmon anemia virus (ISAv). In this study, transcriptomic analysis was used to evaluate the impact of four experimental functional feeds (i.

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The sole member of the genus (family ) is cutthroat trout virus (CTV) but recent metatranscriptomic studies have identified numerous fish hepevirus sequences including CTV-2. In the current study, viruses with sequences resembling both CTV and CTV-2 were isolated from salmonids in eastern and western Canada. Phylogenetic analysis of eight full genomes delineated the Canadian CTV isolates into two genotypes (CTV-1 and CTV-2) within the genus.

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Transformative advances in metagenomics are providing an unprecedented ability to characterize the enormous diversity of microorganisms and invertebrates sustaining soil health and water quality. These advances are enabling a better recognition of the ecological linkages between soil and water, and the biodiversity exchanges between these two reservoirs. They are also providing new perspectives for understanding microorganisms and invertebrates as part of interacting communities (i.

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The infectious salmon anaemia virus (ISAV) is capable of causing a significant disease in Atlantic salmon, which has resulted in considerable financial losses for salmon farmers around the world. Since the first detection of ISAV in Canada in 1996, it has been a high priority for aquatic animal health management and surveillance programmes have led to the identification of many genetically distinct ISAV isolates of variable virulence. In this study, we evaluated the virulence of three ISAV isolates detected in Atlantic Canada in 2012 by doing in vivo-controlled disease challenges with two sources of Atlantic salmon.

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Fitness for purpose and validation are increasingly becoming a benchmark in the development of test methods for the diagnosis of infectious diseases in aquatic animals. The design of the evaluation and the analysis of data are critical to demonstrate test method performance characteristics and fitness for purpose, as stated in the World Organization for Animal Health pathway for test validation. Three test methods for the detection of the oyster parasite Haplosporidium nelsoni were selected for the validation study described herein: histology, end-point polymerase chain reaction (PCR), and real-time PCR (qPCR).

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In the absence of a reference standard, a latent class model (LCM) was used in this study to assess diagnostic sensitivity (DSe) and specificity (DSp) of a recently developed reverse-transcription polymerase chain reaction (RT-PCR) for infectious salmon anaemia virus (ISAV). The study included 4 populations of Atlantic salmon, and to ensure the identifiability of the LCM, four additional detection methods were used in parallel including real-time RT-PCR (qRT-PCR), virus isolation (VI), indirect fluorescent antibody test (IFAT), and a lateral flow immunoassay (LFI). While a conventional LCM assumes DSe and DSp to be constant across the populations, Nérette et al.

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Conventional studies on the precision of diagnostic tests with binary outcomes report single descriptive estimates of agreement for a particular pool of samples. However, agreement for binary tests is intrinsically associated with the assay operating characteristics that are influenced by population and laboratory covariate factors. Therefore, reporting agreement estimates under various conditions may be more appropriate for diagnostic test comprehension.

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Diagnostic laboratories frequently select a subjective cutoff value for real-time amplification assays, above which a threshold cycle (Ct) value is deemed false. Commonly, higher Ct values are interpreted as amplification or fluorescence artifacts, or cross contaminations. Although the implementation of Ct cutoff might be reasonable, its justification and selection should be based on evidence.

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As a component of diagnostic test evaluation, the estimation of repeatability and reproducibility of an assay is necessary to assess the robustness and the transferability of the method among laboratories. Respectively defined as the agreement within and between laboratories, repeatability and reproducibility of a qualitative diagnostic test are traditionally reported using observed proportion of agreement or Kappa values. Applied to a recently designed RT-PCR assay for the detection of infectious salmon anaemia virus, repeatability only within a national reference laboratory and reproducibility with two additional independent regional laboratories were investigated.

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The infectious salmon anemia (ISA) virus causes lethargy, anemia, hemorrhage of the internal organs, and death in farmed Atlantic salmon Salmo salar. It has been a cause of disease in Norwegian farmed Atlantic salmon since 1984 and has since been identified in Canada, Scotland, the United States, and the Faroe Islands. Wild fish have been proposed as a viral reservoir because they are capable of close contact with farmed salmon.

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