Mode of infection and spread of Vibrio anguillarum in turbot Scophthalmus maximus larvae after oral challenge through live feed

Abstract

The infection route of the inanne fish pathogen Vibrio anguillarum was studied after oral challenge of juvenile turbot Scophthalmus maximus L. through a live feed. Artemia nauplii were incubated In a suspension of V anguillarum cells, and subsequently fed twice to the fish. All challenged fish died within 4 d after the first challenge, whde no mortality occurred in the non-challenged controls The results of an immunohistochemical examination of the sectioned f~s h samples clearly demonstrated that V anguillarum cells were ingested by the Artemia and that the latter were ingested by the fish. Bacteria were released from the Arternia mainly In the anterior part of the intestine. Most challenged fish started to show disease slgns 24 h after the second challenge and died 2 d later. A histopathological analysis of monbund fish showed the development of septicaemia. Moreover, the sequential sampling, allowed the reconstruction of the infection route after oral challenge. Our results show that V anguillarum was transported through the intestinal epithelium by endocytosis, after which the bactenum was released in the lamina propna. From there the bactenum was transported by the blood to the different organs, eventually leading to septicaemia and mortality.

Screening and characterisation of potentially pathogenic bacteria associated with Atlantic codGadus morhualarvae: bath challenge trials using a multidish system

“…Our results suggest that a route of entry other than bath-challenge alone is required or, alternatively, that a combination of both bath and oral exposure is needed. Experiments that deliver challenges via live feed have been performed on turbot Scophthalmus maximus larvae (Grisez et al 1996, Planas et al 2005 but to the best of our knowledge no such experiments have been performed on cod larvae. Another explanation for the lack of pathogenicity is the possibility of quorum sensing.…”

Biodiversity of Vibrios

“…Grisez et al (145) showed that infection of turbot (Scophthalmus maximus) larvae by V. anguillarum occurs in the intestinal epithelium, where the pathogen invades the bloodstream and spreads to different organs, culminating in death of the fish. More recently, Ringo et al (326) detected bacterial endocytosis in the pyloric ceca and midgut of arctic charr (Salvelinus alpinus L.) adults and suggested that the whole gastrointestinal tract of fish may be subject to infection.…”

Deep-sea hydrothermal vent bacteria related to human pathogenic Vibrio species

“…Several culturedependent and -independent studies have confirmed the ubiquity of vibrios, and suggested Vibrio populations generally comprise approximately 1% (by molecular techniques) of the total bacterioplankton in estuaries (19), in contrast to culture-based studies demonstrating that vibrios can comprise up to 10% of culturable marine bacteria (20). Clearly, vibrios are ubiquitous and abundant in the aquatic environment on a global scale, including both seawater and sediment (19,(21)(22)(23)(24)(25), and repeatedly shown to be present in high densities in and on marine organisms, such as corals (26), fish (27)(28)(29), mollusks (30), seagrass, sponges, shrimp (28,31), and zooplankton (16,17,28,32,33).…”