Associate Professor Inger Dalsgaard

Bacterial fish diseases

The research includes the following bacteria: Flavobacterium psychrophilum, Yersinia ruckeri, Vibrio anguillarum, and Aeromonas salmonicida.

In addition to traditional bacteriology we work with molecular microbiological methods and antibiotic resistance. Using fish as an animal model research is done on virulence, pathogenesis, vaccines, and on strategies for treatment of diseases.

Vaccine for rainbow trout

A significant part of the research is about the freshwater bacterium Flavobacterium psychrophilum causing high mortality in rainbow trout. The objective of this project is to control infections caused by this bacterium, which might be achieved with vaccines - but currently no commercial vaccines are available. Today, the disease is treated with antibiotics, even though it is a non-sustainable treatment. In addition, it is difficult and time consuming to diagnose the cause of the infection, which is why we focus on developing new diagnostic tools. The DNA sequence of the bacterial genome is examined for genes and proteins,  which are relevant for the development of diagnostic tools and effective vaccines (see PathoFish).

Bacteriophages against bacteria

Another project deals with the treatment of the same disease using bacteriophages isolated from freshwater aquaculture. We have shown that F. psychrophilum phages can be multiplied, stored, and are able to reach the infected organs of the fish. The research focus is on factors that affect the phages’ potential to treat the infection, primarily in fry.

Prevention and vaccination

Prevention of disease in farmed fish is a key area, where the focus is to clarify the optimal strategies for vaccination in order to achieve better health as well as environmentally and economically sustainable production of rainbow trout. Enteric Red Mouth disease in fish caused by the bacterium Yersinia ruckeri produces considerable losses in Danish freshwater fish farms, if it is not treated with antibiotics. Commercial vaccines against the disease are available, but to optimize protection from the vaccines, new vaccination strategies are being tested.

Marine aquaculture

Another collaborative project on the development and testing of vaccines has focus on the bacterium Aeromonas salmonicida; a freshwater bacterium that is a major problem in marine aquaculture farms with rainbow trout. Previous studies have shown that existing commercially available vaccines do not provide adequate protection against the Danish strains of Aeromonas salmonicida. Our part of the project is on epidemiology and characterization of Aeromonas salmonicida (see ProFish).

Senior Researcher

Inger Dalsgaard
Associate Professor
DTU Vet
+45 35 88 68 78