0000000000315728
AUTHOR
Rodolfo Barrera
Susceptibility of Nile tilapia (Oreochromis niloticus) to vibriosis due to Vibrio vulnificus biotype 2 (serovar E)
The present study documents the susceptibility of Nile tilapia to the experimental vibriosis caused by Vibrio vulnificus biotype 2 (serovar E) using a reference strain (Spanish Collection of Type Cultures, CECT 4604) selected for its high degree of virulence for eels. The biotype 1 of this species is one of the usual organisms involved in epizootics occurred in tilapia. After intraperitoneal injection, the selected strain developed a haemorrhagic septicaemia similar to eel vibriosis with a LD50 four log units lower than that exhibited by the type strain of the species, which belongs to the biotype 1. The results obtained in waterborne and intubation challenges indicated that water and feed …
Efficacy of oral reimmunisation after immersion vaccination against Vibrio vulnificus in farmed European eels
Abstract Vulnivaccine, a licensed vaccine against Vibrio vulnificus , protects eels against vibriosis after vaccination by triple prolonged immersion at glass eel stage. Protection lasts for at least 6 months, but later, protection decreases, and eels can suffer stress-related vibriosis. The main objective of this work was to design an oral vaccine that can be used for reimmunisation at any developmental eel stage. With this aim, the efficacy of Vulnivaccine mixed with food as an oral booster was tested in an eel farm. The protection and the immune response (innate and acquired) in serum, mucus (from skin and intestine) and bile were evaluated in reimmunised and control animals (non-reimmun…
Vaccination of market-size eels against vibriosis due to Vibrio vulnificus serovar E
Vaccination with Vulnivaccine at eel farms has been previously shown to protect cultured eels against vibriosis caused by Vibrio vulnificus serovar E for more than 1 year. The reported protocol included an initial vaccination by triple prolonged immersion at the glass-eel stage together with one optional oral booster at the elver stage. However, eels at the market-size stage (around 150 g body weight) can suffer stress-related vibriosis after handling and transport to the selling facilities, which implies a serious risk for consumer health. The main objective of this work was therefore to develop an effective re-vaccination procedure, useful for preventing stress-related vibriosis and zoono…
Field testing of a vaccine against eel diseases caused by Vibrio vulnificus
The field results of a vaccination programme against Vibrio vulnificus serovar E (biotype 2) in a Spanish eel farm are reported. A total of 9.5 million glass eels were vaccinated from January 1998 to March 2000 by prolonged immersion followed by 2 subsequent reimmunisations after 12 to 14 and 24 to 28 d, respectively. The acquired protection and the immune response against serovar E were estimated over a period of 6 mo after vaccination. A similar vaccination schedule was conducted with elvers in a Danish eel farm. In this case, the acquired protection and the immune response against serovar E and the new eel-pathogenic serovars, recently described in Denmark, were evaluated over a short te…
The Fish Pathogen Vibrio vulnificus Biotype 2: Epidemiology, Phylogeny, and Virulence Factors Involved in Warm-Water Vibriosis
ABSTRACT Vibrio vulnificus biotype 2 is the etiological agent of warm-water vibriosis, a disease that affects eels and other teleosts, especially in fish farms. Biotype 2 is polyphyletic and probably emerged from aquatic bacteria by acquisition of a transferable virulence plasmid that encodes resistance to innate immunity of eels and other teleosts. Interestingly, biotype 2 comprises a zoonotic clonal complex designated as serovar E that has extended worldwide. One of the most interesting virulence factors produced by serovar E is RtxA1 3 , a multifunctional protein that acts as a lethal factor for fish, an invasion factor for mice, and a survival factor outside the host. Two practically id…