Vaccination plays an important role in large-scale commercial fish farming and has been a key reason for the success of salmon cultivation. In addition to salmon and trout, commercial vaccines are available for channel catfish, European seabass and seabream, Japanese amberjack and yellowtail, tilapia and Atlantic cod. In general, empirically developed vaccines based on inactivated bacterial pathogens have proven to be very efficacious in fish. Fewer commercially available viral vaccines and no parasite vaccines exist. Substantial efficacy data are available for new fish vaccines and advanced technology has been implemented. However, before such vaccines can be successfully commercialized, several hurdles have to be overcome regarding the production of cheap but effective antigens and adjuvants, while bearing in mind environmental and associated regulatory concerns (e.g., those that limit the use of live vaccines). Pharmaceutical companies have performed a considerable amount of research on fish vaccines, however, limited information is available in scientific publications. In addition, salmonids dominate both the literature and commercial focus, despite their relatively small contribution to the total volume of farmed fish in the world. This review provides an overview of the fish vaccines that are currently commercially available and some viewpoints on how the field is likely to evolve in the near future.

Vaccines for fish in aquaculture

In the last decade betanodavirus infections have emerged as major constraints on the culture of marine fish in all parts of the world with the exception of the African continent. The occurrence of these infections appears to be a function of the number of species cultured and the intensity of culture. This has been further complicated by the promiscuous translocation of stock within and between countries. Great strides have been made in defining these agents and producing diagnostic techniques but much more remains to be done. Lack of knowledge of the epidemiology of the diseases caused by nodaviruses, except for vertical transmission of the pathogen in some species, has impeded the development of control measures but, even so, the measures identified to date have not been adequately implemented by producers with the result that catastrophic losses still occur on a regular basis.

Betanodavirus infections of teleost fish: a review

Vaccination trials with Penaeus japonicus to induce resistance to white spot syndrome virus

Understanding the interaction between Betanodavirus and its host for the development of prophylactic measures for viral encephalopathy and retinopathy.

A comparative review on European-farmed finfish RNA viruses and their vaccines

Immunisation by intraperitoneal injection of an oil-emulgated recombinant partial cap- sid protein (rT2) from striped jack nervous necrosis virus (SJNNV) was performed on adult turbot Scophthalmus maximus and Atlantic halibut Hippoglossus hippoglossus. A specific humoral immune response was recorded in both species, and the levels of rT2-specific antibodies increased markedly in all groups during the 20 wk experiment. A challenge model for SJNNV was established by intra- muscular injection of juvenile turbot. The turbot developed viral encephalopathy and retinopathy (VER), also known as viral nervous necrosis (VNN), with cumulative mortality in the range of 25 to 66%, after intramuscular inoculation with SJNNV propagated in the striped snake head cell line (SSN-1). Although neither clinical signs nor mortality were registered, SJNNV was neuroinvasive after bath exposure. The infection after both modes of challenge was verified by means of immuno- histochemistry and RT-PCR, and SJNNV was reisolated in cell culture. The results indicate that SJNNV may have entered the central nervous system (CNS) by axonal transport through motor nerves after intramuscular inoculation. A vaccine efficacy test was performed on juvenile turbot, employing oil emulsified rT2 as a test vaccine and intramuscular inoculation of SJNNV. Significant protection was observed when the challenge was performed 10 wk post-vaccination.

https://www.int-res.com/articles/dao/45/d045p033.pdf

Immune response to a recombinant capsid protein of striped jack nervous necrosis virus (SJNNV) in turbot Scophthalmus maximus and Atlantic halibut Hippoglossus hippoglossus, and evaluation of a vaccine against SJNNV.

Susanna Husgard

Papers

Immune response to a recombinant capsid protein of striped jack nervous necrosis virus (SJNNV) in turbot Scophthalmus maximus and Atlantic halibut Hippoglossus hippoglossus, and evaluation of a vaccine against SJNNV.