Challenges and Solutions to Viral Diseases of Finfish in Marine Aquaculture

Abstract

Aquaculture is the fastest food-producing sector in the world, accounting for one-third of global food production. As is the case with all intensive farming systems, increase in infectious diseases has adversely impacted the growth of marine fish farming worldwide. Viral diseases cause high economic losses in marine aquaculture. We provide an overview of the major challenges limiting the control and prevention of viral diseases in marine fish farming, as well as highlight potential solutions. The major challenges include increase in the number of emerging viral diseases, wild reservoirs, migratory species, anthropogenic activities, limitations in diagnostic tools and expertise, transportation of virus contaminated ballast water, and international trade. The proposed solutions to these problems include developing biosecurity policies at global and national levels, implementation of biosecurity measures, vaccine development, use of antiviral drugs and probiotics to combat viral infections, selective breeding of disease-resistant fish, use of improved diagnostic tools, disease surveillance, as well as promoting the use of good husbandry and management practices. A multifaceted approach combining several control strategies would provide more effective long-lasting solutions to reduction in viral infections in marine aquaculture than using a single disease control approach like vaccination alone.

Genomic Epidemiology of Salmonid Alphavirus in Norwegian Aquaculture Reveals Recent Subtype-2 Transmission Dynamics and Novel Subtype-3 Lineages

“…Viral whole-genome sequencing has become a routine and cost-effective scientific approach that has gained much prominence during the human COVID-19 pandemic. Considering the extensive commercial importance of salmon aquaculture, balanced against the scale of financial, welfare, and reputational costs caused by viral diseases, we argue that efforts are required to develop and sustain routine viral genomic surveillance programs as part of the 'toolbox' to limit viral disease outbreaks [8]. Data such as that reported here, ideally expanded in spatial and temporal resolution, can be used by producers and regulating authorities to support a range of actions aimed at disease control.…”

“…Viral pathogens pose a particular challenge due to limited effective treatment options, coupled with the fact that outbreaks are highly damaging financially and in terms of animal welfare. A range of approaches are available to prevent and control viral disease in aquaculture [8], including selective breeding [9] and vaccination for finfish [10]. While it is recognized that genomic epidemiology can deliver much to support disease control efforts in aquaculture [11] and other sectors [12], large-scale genomic sequencing to monitor aquaculture pathogens is not a widespread practice, even for high-value species.…”

Current status and development prospects of aquatic vaccines

“…Inactivated viral vaccines are safe and won’t cause any infections because the virus has lost its activity, many inactivated aquatic viral vaccines have been reported in studies ( Table 5 ). However, the immune response is lessened or the duration of immunity is reduced since the virus is only a fragment and not an intact virus ( 173 ). It has been reported that the infectious hematopoietic necrosis virus (IHNV) vaccine inactivated by 1.5 mmol/L Beinylating agents can significantly improve the survival rate of rainbow trout ( 155 ).…”

The Role of Anti-Viral Effector Molecules in Mollusc Hemolymph

“…Pathogens pose extreme risks to abalone and other molluscs, offsetting aquaculture production as a result, which accounts for one third of global food production [9][10][11]. It is estimated that $2B US of aquaculture production is lost per year, with viruses being a major contributor to this figure [9][10][11]13]. Specifically, 10% of reared aquaculture species are lost due to pathogens each year, 90% of which pertain to viruses or bacteria [14].…”