Zebrafish Models for Pathogenic Vibrios

Abstract

Vibrio is a large and diverse genus of bacteria, most of which are non-pathogenic species found in the aquatic environment. However, a subset of the Vibrio genus includes several species that are highly pathogenic, either to humans or to aquatic animals. In recent years, Danio rerio, commonly known as the zebrafish, has emerged as a major animal model used for studying nearly every aspect of biology, including infectious diseases. Zebrafish are especially useful because the embryos are transparent, larvae are small and facilitate imaging studies, and numerous transgenic fish strains have been constructed. Zebrafish models for several pathogenic Vibrio species have been described, and indeed a fish model is highly relevant for the study of aquatic bacterial pathogens. Here, we summarize the zebrafish models that have been used to study pathogenic Vibrio species to date.

Neutrophil-associated responses to Vibrio cholerae infection in a natural host model

“…Use of the zebrafish model in studying V. cholerae infection is still relatively novel compared to other more commonly used mammalian animal models, however its advantages are numerous. Among them are the availability of transgenic animals, transparent embryos, and relatively lost cost, as well as several others (3). The work done here continues to strengthen the evidence of using this model in studying V. cholerae infection.…”

“…Zebrafish have previously been shown to be an effective model system for the study of V. cholerae infection, having many advantages over more commonly used mammalian animal models (3, 22-24). Among these advantages is that teleosts are a natural reservoir for V. cholerae species (25), the model is relatively inexpensive, easy to use, and recapitulates the characteristic diarrheal symptoms and transmission dynamics seen in humans (24).…”

“…The O1 serogroup can be further divided into classical and El Tor biotypes. While classical strains caused the first six pandemics, El Tor strains have caused the current pandemic, ongoing since 1961 (3).…”

“…CP can also have downstream effects leading to the activation of a positive feedback loop of inflammation. Presence of CP can act as a cytokine and chemokine, can activate anti-and proinflammatory responses, and can also bind to receptors such as toll-like receptor 4 (TLR4) to activate a signaling cascade of inflammation through the transcription factor NF-κB (32,33) Zebrafish have previously been shown to be an effective model system for the study of V. cholerae infection, having many advantages over more commonly used mammalian animal models (3,(22)(23)(24). Among these advantages is that teleosts are a natural reservoir for V. cholerae species (25), the model is relatively inexpensive, easy to use, and recapitulates the characteristic diarrheal symptoms and transmission dynamics seen in humans (24).…”

Secretion Systems in Gram-Negative Bacterial Fish Pathogens

“…Fish pathogens can infect both edible and ornamental fish species. Some ornamental fish such as zebrafish are used as host model organisms to understand the virulence mechanisms of pathogens in fish in general ( Rowe et al, 2014 ; Nag et al, 2020 ). This review mainly covers virulence mechanisms of Gram-negative pathogens that target common edible fish.…”