Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The virus detectives: The secret of brown trout dying uncovered

28.11.2018

Every summer in Southern Germany, Austria and Switzerland, tons of brown trout perish. An interdisciplinary team from the Technical University of Munich (TUM) has now discovered the culprit of the mysterious dying afflicting brown trout. It is triggered by a previously unknown virus.

The setting is always in the same river sections. And the victims are always brown trout. Within a matter of days, their skin turns dark and the animals perish. Researchers and authorities have been hunting down the cause of this mysterious mass mortality for decades – unsuccessfully, until now.


Dr. Jens-Eike Täubert examining a trout.

Chair of Zoology / TUM

Using cutting-edge analysis methods, Prof. Ralph Kühn and a research team from the Technical University of Munich have now identified the pathogen that triggers the proliferative darkening syndrome (PDS) in brown trout.

From the Iller to the lab

"The biggest challenge was identifying a pathogen nobody knew. At the outset, it was not even clear whether it was a bacterium, a virus, a parasite or an environmental toxin," recalls the biologist.

Ten years of scientific detective work followed. The researchers set up two experimental stations at the Iller river – one in the headwaters, near Obersdorf, where the fish disease had never been observed; a second one in the lower course near Kempten, where brown trout die every summer.

At both stations, the researchers set up aquariums fed with river water. From May to September they observed the fish in the aquariums and took tissue samples that were frozen and sent to the TUM laboratory for analysis.

Searching for clues with next generation technology

The observations indicated that PDS advances in three phases. Initially, the fish look healthy. Then changes in internal organs such as the liver and kidneys appear. In the third phase, the brown trout skin turns dark and the animals die shortly thereafter. "The progression of the disease quickly led us to suspect that PDS was a viral disease,” says Kühn.

To detect the virus in the samples, the researchers deployed a set of modern molecular genetic procedures, known as next generation technology. Genomes can be analyzed rigorously using these procedures.

First, the progression of the disease in the fish was characterized at the gene response level. Subsequently, the researchers looked at animals with a similar immune response to determine the nucleotide sequence of all inherited genetic material – of the fish and its possible pathogens.

The needle in a genetic haystack

The researchers deployed computer programs to pinpoint the pathogenic virus in this mountain of genetic data. Using deep bioinformatic processing, they successfully identified parts of the pathogen’s genetic profile and compared them to the profiles of known viruses.

Extended, virus-specific sequencing led to the determination of the viral genome. The result: The culprit behind the demise of the brown trout is a piscine reovirus. It is related to the virus that infects salmon in the North Atlantic and the Pacific, where it causes significant economic damage.

In the next step, the researchers hope to grow the virus in the laboratory and investigate why it only occurs in certain sections of the Alpine rivers and to what extent global fish trade facilitates its spread.


Further information:

The project of the TUM consortium Brown Trout Dying (Department of Zoology, Department of Aquatic Systems Biology, Department of Animal Physiology & Immunology) was funded by the Bavarian State Office for the Environment and the Bavarian State Ministry of Food, Agriculture and Forestry. Another co-operation partner was the Advisory Service for Fishery Lower Bavaria in Landshut (Bavaria).

Wissenschaftliche Ansprechpartner:

Prof. Dr. Ralph Kühn
Technical University of Munich
Chair of Zoology
Hans-Carl-von-Carlowitz-Platz 2
85354 Freising, Germany
Phone: +49 8161 71 4608
E-mail: kuehn@wzw.tum.de

Originalpublikation:

Identification of a piscine reovirus-related pathogen in Proliferative Darkening Syndrome (PDS) infected brown trout (Salmo trutta fario) using a next-generation technology detection pipeline
Ralph Kühn, Bernhard C. Stoeckle, Marc Young,, Lisa Popp, Jens-Eike Taeubert, Michael W. Pfaffl, Jürgen Geist
PLOS ONE, 22.10.2018 – DOI: 10.1371/journal.pone.0206164

Weitere Informationen:

https://www.tum.de/nc/en/about-tum/news/press-releases/detail/article/35106/ Press release on TUM-website
https://mediatum.ub.tum.de/1464488 High resolution images
https://de.m.wikipedia.org/wiki/Datei:Salmo_trutta.jpg Image of a brown trout
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0206164 Original publication
http://www.zoologie.wzw.tum.de/index.php?id=107&L=1 Website of the Chair of Zoology

Dr. Ulrich Marsch | Technische Universität München

More articles from Life Sciences:

nachricht Chip-based optical sensor detects cancer biomarker in urine
06.12.2019 | The Optical Society

nachricht Scientist identify new marker for insecticide resistance in malaria mosquitoes
06.12.2019 | Liverpool School of Tropical Medicine

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Developing a digital twin

University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making

In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...

Im Focus: The coldest reaction

With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction

The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...

Im Focus: How do scars form? Fascia function as a repository of mobile scar tissue

Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.

Fibroblasts kit - ready to heal wounds

Im Focus: McMaster researcher warns plastic pollution in Great Lakes growing concern to ecosystem

Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.

In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...

Im Focus: Machine learning microscope adapts lighting to improve diagnosis

Prototype microscope teaches itself the best illumination settings for diagnosing malaria

Engineers at Duke University have developed a microscope that adapts its lighting angles, colors and patterns while teaching itself the optimal...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

Solving the mystery of carbon on ocean floor

06.12.2019 | Earth Sciences

Chip-based optical sensor detects cancer biomarker in urine

06.12.2019 | Life Sciences

A platform for stable quantum computing, a playground for exotic physics

06.12.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>