Featured Research

from universities, journals, and other organizations

Knut the polar bear's medical legacy

Date:
January 3, 2014
Source:
Forschungsverbund Berlin e.V. (FVB)
Summary:
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 harbored by other zoo animals. In other words: the diagnostic challenge is enormous.

Knut the polar bear. "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.
Credit: Forschungsverbund Berlin e.V. (FVB)

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 harbored 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 elsewhere 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 minimize their occurrence," commented Professor Heribert Hofer, head of the IZW.


Story Source:

The above story is based on materials provided by Forschungsverbund Berlin e.V. (FVB). Note: Materials may be edited for content and length.


Journal References:

  1. C.A. Szentiks, K. Tsangaras, B. Abendroth, M. Scheuch, M.D. Stenglein, P. Wohlsein, F. Heeger, R. Höveler, W. Chen, W. Sun, A. Damiani, V. Nikolin, A.D. Gruber, M. Grobbel, D. Kalthoff, D. Höper, G.Á. Czirják, J. DeRisi, C.J. Mazzoni, A. Schüle, A. Aue, M.L. East, H. Hofer, M. Beer, N. Osterrieder, A.D. Greenwood. Polar Bear Encephalitis: Establishment of a Comprehensive Next-generation Pathogen Analysis Pipeline for Captive and Free-living Wildlife. Journal of Comparative Pathology, 2013; DOI: 10.1016/j.jcpa.2013.12.005
  2. Jens Mayer, Kyriakos Tsangaras, Felix Heeger, María Ávila-Arcos, Mark D. Stenglein, Wei Chen, Wei Sun, Camila J. Mazzoni, Nikolaus Osterrieder, Alex D. Greenwood. A novel endogenous betaretrovirus group characterized from polar bears (Ursus maritimus) and giant pandas (Ailuropoda melanoleuca). Virology, 2013; 443 (1): 1 DOI: 10.1016/j.virol.2013.05.008
  3. Alex D. Greenwood, Kyriakos Tsangaras, Simon Y.W. Ho, Claudia A. Szentiks, Veljko M. Nikolin, Guanggang Ma, Armando Damiani, Marion L. East, Arne Lawrenz, Heribert Hofer, Nikolaus Osterrieder. A Potentially Fatal Mix of Herpes in Zoos. Current Biology, 2012; 22 (18): 1727 DOI: 10.1016/j.cub.2012.07.035

Cite This Page:

Forschungsverbund Berlin e.V. (FVB). "Knut the polar bear's medical legacy." ScienceDaily. ScienceDaily, 3 January 2014. <www.sciencedaily.com/releases/2014/01/140103085250.htm>.
Forschungsverbund Berlin e.V. (FVB). (2014, January 3). Knut the polar bear's medical legacy. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2014/01/140103085250.htm
Forschungsverbund Berlin e.V. (FVB). "Knut the polar bear's medical legacy." ScienceDaily. www.sciencedaily.com/releases/2014/01/140103085250.htm (accessed August 1, 2014).

Share This




More Plants & Animals News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) — Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) — With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) — Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins