Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Knut the polar bear’s medical legacy

03.01.2014
Knut, the polar bear of the Berlin Zoological Garden, drowned in 2011 after suffering seizures and falling into the enclosure pond.

Necropsy and histology at the Leibniz Institute for Zoo and Wildlife Research suggested the cause was encephalitis most likely due to viral infection. After one of the most intensive investigations in veterinary history for a single animal, utilising state-of-the-art pathological techniques and high-throughput next-generation molecular sequencing methods, the conclusions of the investigations are presented.


Polar bear Knut as dermoplastic in the Museum für Naturkunde in Berlin, Germany.
Steven Seet/IZW

Keeping wild animals is an important component of the mission of zoos to educate the public and preserve endangered species. When animals die, tracking the potential cause becomes an investigation of pathogens from around the world. This is because zoo animals are not only potentially exposed to pathogens occurring where the zoo is located, but also to those pathogens harboured by other zoo animals. In other words: the diagnostic challenge is enormous.

In the case of Knut, researchers from the Leibniz Institute for Zoo and Wildlife Research Berlin (IZW), the Freie Universität Berlin, the Friedrich Loeffler Institute – Insel Riems, the Max Delbrück Center for Molecular Medicine in Berlin, the University of California at San Francisco and many others combined their efforts to investigate Knut’s death. Classical pathological, bacteriological, serological, molecular, histological and electron microscopical methods were combined with high throughput microarray and next generation sequencing methods to undertake the most extensive and exhaustive evaluation of the cause of death of any zoo animal to date. The necropsy was headed at the IZW by Dr Claudia Szentiks of the Department of Wildlife Diseases.

“After a detailed necropsy and histology that took several intense days to perform, the results clearly suggested that the underlying cause of Knut’s seizures was a result of encephalitis, most likely of viral origin” says Dr Szentiks.

Encephalitis can be caused by a large number of viruses, bacteria and parasites, and identifying novel pathogens in wild animals is a huge and often insurmountable challenge. In the case of Knut, the team screened gene sequences from plausible causative pathogens from tens of millions of individual DNA sequences.

“The sheer number of experiments undertaken and the sorting of results by many of the top diagnostics groups in Germany and beyond was extremely time consuming but also informative as to what we can and cannot do with current technologies. Many new directions for improvements and novel developments should come from this”, says Professor Alex Greenwood, head of the Department of Wildlife Diseases of the IZW. Although frequently suspected by many to be the likely culprit, the equine herpesviruses found in other polar bears in Germany and elsehwere was not responsible. The analysis of Knut also revealed a novel group of bear retroviruses whose presence was not related to his death. The only pathogen Knut seemed to have been exposed was an influenza A virus, as suggested by the detection of antibodies in his blood. However, it remains unclear and relatively unlikely that the flu was responsible for his death since the actual virus (in the form of viral RNA) could not be detected in his brain.

“After so much hard work, the results appear ultimately sobering. We cannot and therefore should not blame influenza as the source of death” stated Professor Klaus Osterrieder, holder of the chair for Veterinary Virology at the Freie Universität Berlin.

The results illustrate that while great strides in diagnostics have been made over the last decade, wildlife diseases present unique challenges because less is currently known than remains unknown about them. As a case in point, the research on Knut led to the discovery that a herpesvirus of zebras is able to kill polar bears as documented in the Wuppertal Zoo, infecting Knut’s father Lars, who survived the infection, and his partner, Jerka, who died from the infection. This was a surprising result that has developed into an intensive project on herpesvirus transmission in endangered zoo animals.

“It would have been impossible to check for all the suggested culprits without the support by the zoo community which willingly supplied samples from other animals for comparative purposes. This was exemplary. Although it will not help Knut any more, or other bears in the past, because of the new knowledge on pathogens in polar bears the zoos can now begin to develop management strategies to minimise their occurrence”, commented Professor Heribert Hofer, head of the IZW.

Contact:
For press questions:
Steven Seet, +49 30 5168 125, +49 177 857 26 73, seet@izw-berlin.de
Anke Schumann, +49 30 5168 127, schumann@izw-berlin.de
Scientific questions:
Leibniz Institute for Zoo and Wildlife Research (IZW)
in the Forschungsverbund Berlin e.V.
Alfred-Kowalke-Str. 17, 10315 Berlin
Prof Alex Greenwood, +49 30 5168 255, greenwood@izw-berlin.de
Dr Claudia Szentiks, +49 30 5168 213, szentiks@izw-berlin.de
Institut für Virologie
Freie Universität Berlin
Philippstrasse 13, 10115 Berlin
Prof Klaus Osterrieder, +49 30 2093 6564, no34@cornell.edu
Publications:
Szentiks CA, Tsangaras K, Abendroth B, Scheuch M, Stenglein MD, Wohlsein P, Heeger F, Höveler R, Chen W, Sun W, Damiani A, Nikolin V,Gruber AD, Grobbel M, Kalthoff D, Höper D, Czirják GÁ, DeRisi J, Mazzoni CJ, Schüle A, Aue A, East ML, Hofer H, Beer M, Osterrieder K, Greenwood AD (2013): Polar bear encephalitis: Establishment of a comprehensive next-generation pathogen analysis pipeline for captive and free-living wildlife. Journal of Comparative Pathology, doi: 10.1016/j.jcpa.2013.12.005.

Mayer J, Tsangaras K, Heeger F, Avila-Arcos M, Stenglein MD, Chen W, Sun W, Mazzoni CJ, Osterrieder N, Greenwood AD (2013): A novel endogenous betaretrovirus group characterized from polar bears (Ursus maritimus) and giant pandas (Ailuropoda melanoleuca). Virology 443, 1-10. doi: 10.1016/j.virol.2013.05.008.

Greenwood AD, Tsangaras K, Ho SYW, Szentiks CA, Nikolin VM, Ma G, Damiani A, East ML, Lawrenz A, Hofer H, Osterrieder N (2012): A potentially fatal mix of herpes in zoos. Current Biology 22, 1727-1731. http://dx.doi.org/10.1016/j.cub.2012.07.035.

Background Information

The Leibniz Institute for Zoo and Wildlife Research (IZW) investigates the vitality and adaptability of wildlife populations in mammalian and avian species of outstanding ecological interest that face anthropogenic challenges. It studies the adaptive value of traits in the life cycle of wildlife, wildlife diseases and clarifies the biological basis and development of methods for the protection of threatened species. Such knowledge is a precondition for a scientifically based approach to conservation and for the development of concepts for the ecologically sustainable use of natural resources. The IZW is member of the Forschungsverbund Berlin e.V.

Karl-Heinz Karisch | Forschungsverbund Berlin e.V.
Further information:
http://www.izw-berlin.de
http://www.fv-berlin.de
http://www.leibniz-gemeinschaft.de

More articles from Life Sciences:

nachricht Severity of enzyme deficiency central to favism
26.07.2016 | Universität Zürich

nachricht From vision to hand action
26.07.2016 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-assembling nano inks form conductive and transparent grids during imprint

Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.

To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...

Im Focus: The Glowing Brain

A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology

On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...

Im Focus: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

New movie screen allows for glasses-free 3-D

26.07.2016 | Information Technology

Scientists develop painless and inexpensive microneedle system to monitor drugs

26.07.2016 | Health and Medicine

Astronomers discover dizzying spin of the Milky Way galaxy's 'halo'

26.07.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>