by Joly Ghanawi, Editorial Contributor, International Aquafeed, UK
Shrimp aquaculture has expanded at extraordinary speed over the past three decades, transforming from scattered coastal ponds into a globally interconnected food-production system. Yet this rapid expansion has not been matched by equivalent growth in disease-control capacity.
As a result, the industry faces recurring cycles of viral outbreaks, bacterial surges and microbiome disruptions that are often treated as isolated biological incidents, even though they reflect underlying ecological instability. Several recent scientific reviews, which examine global viral epidemiology, vibriosis ecology, gut microbial dynamics and nanotechnology-based diagnostics, converge on the same conclusion: shrimp disease does not arise simply because pathogens appear. It emerges when the relationships among host physiology, pond chemistry, microbial communities and management practices begin to break down.
Viral threats and globalised systems
Bhassu and colleagues, in their 2024 review, describe how globalised broodstock traffic, shared water flows and interconnected trade networks have created conditions in which viruses such as white spot syndrome virus and yellow head virus behave like transboundary pandemics. These viruses travel quickly, cross borders with ease and can cause catastrophic mortality within hours.
The review argues that traditional responses, like emergency harvests, post-outbreak treatments and pond disinfection, no longer address the central vulnerability of modern systems. Instead, the authors highlight the shift towards earlier visibility: the ability to detect pathogens before they cause irreversible damage. This includes pond-side molecular diagnostics, portable PCR instruments, phage-based biosensors, RNA-interference-enabled detection systems and nanotechnology-enhanced signal amplification.
However, the authors stress that even the most advanced tools are ineffective without governance structures that allow early information to influence decision-making. They point to frameworks such as the Food and Agriculture Organization’s progressive aquaculture biosecurity system, which links farm-level detection with coordinated national responses.
Vibriosis: an ecological challenge
While Bhassu’s work focuses on viruses, the analysis by El-Saadony and co-authors in 2022 turns to the ecology of vibriosis. Their review emphasises that the true cause of vibriosis is not merely the presence of Vibrio species.
Instead, environmental conditions, excessive organic matter, ammonia accumulation, low oxygen levels, high stocking density and chronic stress, create ecological niches that favour the rapid expansion of opportunistic Vibrio populations. Under these conditions, prophylactic antibiotics may provide brief relief, yet they fail to correct the environmental processes that allowed Vibrio to flourish in the first place.
Moreover, antibiotics introduce additional problems, including resistance, residues in shrimp tissues, disruption of beneficial microbiota and contamination of surrounding ecosystems. The authors do not argue against antibiotics entirely; rather, they caution that relying on them as routine management is fundamentally flawed, because it attempts to suppress symptoms while leaving the underlying ecological imbalance unaddressed.
Probiotics as ecological tools
Within this framework, probiotics emerge not as nutritional supplements but as active environmental agents. El-Saadony’s team explains that probiotic microorganisms compete with pathogens for adhesion sites, produce antagonistic metabolites, modulate non-specific immune responses, improve digestive efficiency and, importantly, participate in the biotransformation of nitrogenous waste.
Through these combined functions, probiotics help shift pond microbial dynamics away from Vibrio-dominated states and towards more stable, low-stress equilibria. In this sense, probiotics function as tools for ecological engineering rather than as dietary additions.
Gut health and disease prevention
The importance of environmental engineering becomes even clearer in the 2024 review by Murugan and colleagues, which focuses on the shrimp gut as an immune and metabolic centre. The authors describe how healthy shrimp maintain gut communities dominated by Proteobacteria, particularly beneficial Gammaproteobacteria, with additional roles played by Bacteroidetes and Actinobacteria.
These microbes produce metabolites, especially short-chain fatty acids, that strengthen epithelial barriers, regulate immune tone and support metabolic pathways. Because gut communities are highly responsive to external stress, even relatively small changes in pH, ammonia, nitrite, sulphide, temperature or salinity can restructure microbial composition. This restructuring often leads to reduced diversity, declines in beneficial short-chain-fatty-acid producers, blooms of opportunistic taxa such as Vibrionaceae and weakening of the mucosal barrier.
Murugan’s review argues that dysbiosis is not merely associated with disease; in many cases, it actively increases susceptibility by lowering the threshold for pathogen adhesion and virulence expression. From this perspective, the principal role of functional feeds is to maintain microbiome stability, acting as a form of preventive immunology rather than simple nutrition.
Early detection and nanotechnology
The ecological perspective is applied to a specific case in the 2025 review by Hassan and collaborators, who examine Acute Hepatopancreatic Necrosis Disease, one of the most damaging conditions affecting shrimp farming. Their analysis shows that recent progress has been driven less by pharmaceuticals than by improvements in diagnostics. The transition from the AP3 PCR assay to the more sensitive AP4 assay increased detection capacity by two orders of magnitude, enabling farmers to identify the disease during subclinical colonisation rather than after extensive tissue destruction.
Hassan’s team further demonstrates that metallic nanoparticles, particularly gold nanoparticles, significantly enhance lateral-flow and isothermal amplification assays, allowing reliable pond-side detection. Although certain nanoparticles display antimicrobial activity against Vibrio species, the authors caution that this activity depends on particle chemistry, geometry and the characteristics of specific bacterial strains. Nanotechnology is therefore best understood as a precision tool rather than a broad-spectrum antimicrobial solution.
Building resilient systems
Taken together, these reviews present a coherent scientific position. Long-term disease resilience in shrimp aquaculture will depend less on eliminating microbes and more on cultivating environments in which opportunistic pathogens cannot easily dominate.
Achieving this will require stabilising gut microbial communities, maintaining water chemistry within low-stress ranges, reducing organic loading and managing stocking density with greater precision. It will also require the use of probiotics to reinforce desired ecological states, the deployment of rapid molecular diagnostics during early, reversible phases of infection and the careful application of advanced tools, including RNA-interference-based detectors and nanotechnology-enhanced assays, only when ecological stabilisation is insufficient.
Rethinking disease prevention
This wider ecological approach reframes disease as the consequence of systemic instability rather than pathogen aggression. If shrimp aquaculture is to achieve long-term stability, the pond environment itself must be treated as the primary mechanism of prevention. In this view, microbes are not simply threats to be eliminated but participants in an ecological network that determines whether disease remains a rare event or becomes an enduring constraint on production.
