Adult zebrafish enteritis induced by an infection with Listonella anguillarum: a new experimental model for gut diseases

Listonella anguillarum is the etiological agent of a fatal hemorrhagic disease known as vibriosis that affects a wide range of fish species causing severe economic losses. In this view, numerous investigations have been carried out to elucidate the virulence mechanisms of this pathogen and to develop rapid detection techniques and effective disease-prevention strategies. The aim of this paper is to choose the best way for reproduce in vivo a mild enteritis in a fish model, looking at the interaction between zebrafish and L. anguillarum. Experimental challenges were carried out using different ways of delivery of a known strain of L. anguillarum serotype O1 to adults zebrafish: via Artemia nauplii (oral infection), via intra-peritoneal and via intra-anal injection. Results showed that the intra-peritoneal and intra-anal infections are too strong for the fish due to their systemic involvement. The effect of both infections was evident 24 h after the challenge day showing a cumulative mortality of 70% and 100% respectively, within 5th day after challenge, with severe histo-pathological changes. On the contrary, the oral infection via Artemia shows a mild enteritis with no evident clinical signs. So the last proposed model appears to be most useful tool to reproduce a mild enteritis with a local inflammatory response.