Sea lice, myxozoans and invisible threats: the parasite front in global aquaculture – Sea lice, intestinal worms, protozoa, cestodes, myxozoa. The list of parasites affecting fish reared in the world’s seas and rivers is long and constantly updated. The coexistence of intensive aquaculture and pathogens has long since passed the threshold of the exception: today it represents one of the structural challenges for the health and economic sustainability of the industry.
The Amazon fish parasite, recently identified by an international scientific team, fits into this complex scenario. It is a myxozoan, a microscopic but potentially devastating parasite, already responsible for major losses in other areas of the planet. The novelty? Its surprising spread in Amazon basins and the discovery of novel genetic control mechanisms.
Myxozoa and emerging infections: a global risk
To date, Atlantic salmon remains one of the emblems of parasitic infections with direct economic impacts. In Norway and Scotland, sea lice (Lepeophtheirus salmonis) cost the industry hundreds of millions of Euros per year. Similarly, in the United States, some trout populations have seen collapses of up to 90% due to infections with Tetracapsuloides bryosalmonae, another member of the myxozoan family.
In the Amazon basin, where fish biodiversity is among the highest in the world, scientists have found that more than 50% of the fish sampled carry these parasites. This is not just an environmental problem: Brazil’s booming aquaculture now risks being hampered by an invisible but tenacious enemy.
Joint work by King’s College London, UNIFESP and other European and South American scientific institutions has revealed that these Amazonian myxozoans use sophisticated epigenetic mechanisms to adapt to their host and environment. An evolutionary behaviour that complicates diagnosis and makes prevention a race against time.
Epigenetics opens new avenues for prevention
The researchers set up a mobile laboratory on a boat in the heart of the Amazon basin, near the confluence of the Tapajós and Amazon rivers. The aim: to observe parasites in situ, throughout their life cycle and in the presence of an extreme variety of host species.
The most promising insight concerns the activation and deactivation of genes in myxozoa depending on environmental conditions. This epigenetic mechanism, which has never before been so clearly documented, could become the key to the development of genetic vaccines or targeted treatments.
For those responsible for animal health and biosecurity in aquaculture, this is a real opportunity to anticipate infections. The future adoption of protocols based on parasite gene expression reading could complement existing surveillance systems and improve animal welfare.
Strategic implications for the European supply chain
If the Amazon is a natural laboratory for studying parasites, the implications are far from remote for the European fishing industry. Intensified trade flows, climate change and increasing pressure on intensive facilities make farming systems vulnerable to the introduction of new pathogens.
Knowing the dynamics of emerging myxozoans and other pests means anticipating risks and protecting value throughout the supply chain. The resilience of fish production also depends on this: the ability to translate scientific innovation into sustainable operational tools and preventive measures.
The Amazon fish parasite is just the latest warning light on a vulnerability that the sector can no longer ignore. Investing in research, updating protocols and building more aware supply chains is a strategy for survival, even before growth.
Sea lice, myxozoans and invisible threats: the parasite front in global aquaculture
