Lone Madsen research on fish diseases

Diseases in fish and molluscs

The focus is on diseases in fish and molluscs. The research primarily focuses on the prevention of diseases and on bacterial diseases in fish.

The fight against rainbow trout fry syndrome

The research is centered on the fish pathogenic bacterium Flavobacterium psychrophilum, which is the cause of rainbow trout fry syndrome (RTFS) in rainbow trout on Danish fish farms.

The areas of interest are characterization of virulence using biochemical, serological, genotyping and infection methods. The research focuses on the mechanisms by which the bacterium causes disease in rainbow trout, i.e. the pathogenesis (how the disease is progressing), the transmission (transfer to and between fish), and the survival of the bacteria, e.g. on as well as inside fish.

The researchers are involved in several projects on the bacterium Flavobacterium psychrophilum, amongst others the EMIDA project Pathofish where the objectives are to develop rapid methods for the detection of RTFS as well as vaccines. The researchers are furthermore involved in a project supported by the Danish AgriFish Agency - an agency under the Ministry of Food, Agriculture and Fisheries – that focuses on the use of bacteriophages for controlling bacterial pathogens in aquaculture.


Regarding diseases in molluscs the focus is primarily on the diseasesbonamiosis and marteiliosis in oysters and mussels, which are caused by the parasites Bonamia ostreae and Marteilia refringens, respectively.

The National Veterinary Institute DTU is appointed national reference laboratory for diseases molluscs, and the laboratory is responsible, amongst other duties, for screening the European flat oysters from the Danish fjord Limfjorden and mussels from the Danish waters outside Limfjorden’ for the two above-mentioned diseases using histology and other methods.

Feed and health

Another area of ​​research is the impact of feed on health in rainbow trout as well as on the intestinal microbiota. The National Veterinary Institute DTU is heading  a project with an organic scope called "Influence of probiotics and feed on organic rainbow trout health – OPTIFISH”, which aims to improve the health of rainbow trout fry, i.e. ultimately resulting in a higher production of organic rainbow trout.

International posts

Senior Researcher Lone Madsen has been a member of WGPDMO (Working Group on Pathology and Diseases of Marine Organisms), an ICES (International Council for the Exploration of the Sea) working group  since 2002.

Since 2007, Lone Madsen has been a member of the European Association of Fish Pathologists (EAFP), where she is appointed General Secretary. Furthermore, she is Branch Officer for the EAFP in Denmark.

Senior Researcher

Lone Madsen
Senior Research Scientist
DTU Aqua
+45 35 88 68 26
18 OCTOBER 2018