Overview: Fish Parasites Cause Massive Losses Worldwide
Fish farmers around the world are battling a growing threat—deadly parasitic infections caused by Myxozoa, microscopic parasites wreaking havoc on aquaculture industries. These parasites infect commercially important fish species such as salmon and trout, causing diseases that result in annual losses exceeding £50 million across the global fish farming sector.
Amazon Basin: A Hotspot for Fish Parasite Research
To combat this crisis, a team of international researchers has turned to the Amazon basin, home to the world’s richest diversity of freshwater fish species. Led by King’s College London and Universidade Federal de São Paulo (UNIFESP), scientists have discovered that over 50% of the fish examined in this region are infected with parasitic organisms.
This alarming discovery has implications not only for aquaculture but also for biodiversity conservation and recreational fishing. In the western United States, for example, up to 90% of native trout populations have been wiped out in some streams due to similar infections.
Cutting-Edge Research: A Floating Laboratory in the Amazon
In an innovative approach, researchers established a mobile laboratory aboard a boat navigating the Amazon River near Santarém in the Brazilian state of Pará. The team includes experts from:
- King’s College London (UK)
- UNIFESP (Brazil)
- Federal University of Western Pará (Brazil)
- University of Zagreb (Croatia)
- University of Cambridge (UK)
- Natural History Museum, London (UK)
The findings were published in the scientific journal GigaScience.
New Gene Regulation Discoveries Offer Hope for Fish Farmers
One of the study’s most groundbreaking discoveries involves a previously unknown method of gene regulation in Myxozoa. Understanding how these parasites turn genes on and off could lead to the development of gene-based vaccines to control the spread of infection in fish farms.
Professor Paul Long, a marine biotechnology expert from King’s College London, emphasized the importance of this research, saying:
“Fish farming is essential to global food security. Our findings offer a potential pathway to create new genetic treatments or vaccines to protect fish from devastating parasitic infections.”
Epigenetics and Climate Change: A New Frontier in Parasitology
Professor Edson Adriano, a parasitologist from UNIFESP, noted the importance of understanding epigenetic processes in myxozoans. These genetic mechanisms could explain how parasites adapt to changing environments throughout their complex life cycles—an area of study that’s particularly relevant as climate change alters aquatic ecosystems.
Industry Insight: Veterinarians Support the Research
Dr. Santiago Benites de Pádua, veterinarian and manager at a Brazilian fish company, reinforced the practical value of this research:
“Studies like this are crucial for developing effective parasite control strategies to safeguard the health and productivity of farmed fish.”
Published Study Reference:
Starcevic, A., et al. (2025). Long-read metagenomic sequencing negates inferred loss of cytosine methylation in Myxosporea (Cnidaria: Myxozoa). GigaScience. DOI: 10.1093/gigascience/giaf014