Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Vaccination of salmonids against viral haemorrhagic septicaemia

The feasibility of a vaccine against the viral haemorrhagic septicaemia (VHS) of salmonids was explored. The following 3 types of vaccines were evaluated with respect to efficacy and safety: a killed virus, an attenuated live virus and recombinant subunit viral protein.

The live attenuated strain always provided a good protection at the challenge but it was established that the safety of this vaccine was not sufficient.
At the other extreme, the killed vaccine was very safe but the potency was not always consistent. This was due to the sensitivity of the protective antigen to the inactivator. A reliable inactivation procedure had to be set up.

The development of a recombinant subunit vaccine based on the G protein of the VHS virus was a very difficult task since it had to comply with 2 conflicting requirements: low cost for a product for use on the aquaculture market and high performance production system to synthesize a membrane anchored glycoprotein. More than 50 vaccine candidates were produced and tested. Mediocre results were obtained with vaccine produced in bacteria or yeast. An insect cell product was efficient but not cost effective because of the use of the cell culture technology.
Finally 2 new vaccines were produced in yeast. They were potent when administered by injection. One of these candidates is currently under field trials in Italy, France and Belgium. The good availability of the vaccine produced in yeast will probably allow the rapid development of a formulation effective by bath.

Reported by

EUROGENTEC S.A.
Parc de Recherche de la Cense Rouge 14 rue Bois Saint Jean
4102 Seraing
Belgium
See on map