Smell of Infection: A Novel, Noninvasive Method for Detection of Fish Excretory-Secretory Proteins

Abstract

Chemical signals are produced by aquatic organisms following predatory attacks or perturbations such as parasitic infection. Ectoparasites feeding on fish hosts are likely to cause release of similar alarm cues into the environment due to the stress, wounding, and immune response stimulated upon infection. Alarm cues are often released in the form of proteins, antimicrobial peptides, and immunoglobulins that provide important insights into bodily function and infection status. Here we outline a noninvasive method to identify potential chemical cues associated with infection in fish by extracting, purifying, and characterizing proteins from water samples from cultured fish. Gel free proteomic methods were deemed the most suitable for protein detection in saline water samples. It was confirmed that teleost proteins can be characterized from water and that variation in protein profiles could be detected between infected and uninfected individuals and fish and parasite only water samples. Our novel assay provides a noninvasive method for assessing the health condition of both wild and farmed aquatic organisms. Similar to environmental DNA monitoring methods, these proteomic techniques could provide an important tool in applied ecology and aquatic biology.

Identification of factors associated with Fasciola hepatica infection risk areas on pastures via an environmental DNA survey of Galba truncatula distribution using droplet digital and quantitative real‐time PCR assays

“…However, major practical challenges are associated with screening non‐liquid matrices such as plants and soil for eDNA, which include limited sample volume capacity per extraction and the presence of PCR inhibitors (Cuthill, 2020; Thomsen & Willerslev, 2015). Considering that water is the optimal screening matrix for eDNA, other molecular markers also present in water and that may be specific for distinct F. hepatica life stages, such as protein or RNA (Pawluk et al, 2018; Veilleux et al, 2021), could be targeted in future environmental water‐based surveys, although substantial research would need to be undertaken initially to characterize proteins and/or RNA markers that are specific to each F. hepatica life cycle stage (Cwiklinski & Dalton, 2018).…”

Moving towards improved surveillance and earlier diagnosis of aquatic pathogens: From traditional methods to emerging technologies

“…Biochemical methods for diagnostics encompass a variety of techniques all of which utilise some form of biochemical signal to conduct the diagnosis. These techniques vary from those which detect chemical signals (volatile organic compounds, or VOCs) released during infection (e.g., Pawluk et al 100 who identified chemical cues from infected and uninfected fish), to biosensors that use biochemical reactions to detect (optical, volatile, electrochemical or mass‐sensitive) chemical compounds. When considering their application to aquatic diagnostics, the information gained from these health parameters is currently too general for diagnostics, especially in a preventative context, and the benefits would not outweigh the costs.…”

Bacterial MgrB peptide activates chemoreceptor Fpr3 in mouse accessory olfactory system and drives avoidance behaviour

“…Avoidance mechanisms are based on the remote sensing of pathogen-associated metabolites 1 that activate the olfactory and/or other chemosensory systems in the body. In fact, there is now increasing evidence from nematodes 3 and fruitflies 4 to fishes 5 , rodents 6,7 and humans 8,9 that chemosensory cues associated with harmful microbes or inflammation and reduced fitness can be detected and avoided by conspecifics. In the mouse, interest has focused on the vomeronasal organ (VNO), a chemosensory organ that provides sensory input to the accessory olfactory bulb (AOB) in the olfactory forebrain 10–12 .…”