Mysterious death of polar bear Knut solved
His life was very short and his death tragic. Now, a team of researchers may finally have to answer to what killed Knut. Posthumously, the famous polar bear contributes to the research of neurodegenerative diseases.
A heartbreaking story
Knut was born in 2006 in the Berlin Zoo. The cuddly pup quickly captured the hearts of thousands, drawing crowds to the zoo and becoming world famous. In 2011, when Knut was four years old, the fan community was shocked when the polar bear suffered an epileptic attack, fell into a water ditch and drowned.
Two more celebrity deaths
What made Knut's death even more tragic was that his zookeeper Thomas Dörflein, who had nursed Knut from a puppy into polar bear adolescence, also suddenly died of a heart attack in 2008. At that time Dörflein's fluffy foster child was two years old, and not quite so cuddly anymore. Together with Knut, Dörflein had also become a celebrity.
Uncertain diagnosis
Initially, there was much speculation as to what might have triggered the attack: Was it Knut's mourning over the death of his foster-parent? Was he stressed out after being mobbed by other adolescent polar bears? The Leibniz Institute for the Research of Zoo and Wild Animals (IZW) investigated the circumstances and determined Knut probably contracted an infection that developed into encephalitis.
Research continued
However, researchers were not fully satisfied with their conclusion, and the real cause of the disease remained in the dark - until now. Finally, the speculations have come to an end: In an article in the journal "Scientific Reports," published on August 27th 2015, researchers revealed Knut had an autoimmune disease.
A case for biologists and neuroscientists
The paper reveals a new discovery: A disease called "anti-NMDA-receptor encephalitis," which until now was thought to only affect humans. This is the first proof that also animals can suffer from a version of the same disease. The research as made possible through cooperation between the IZW and the German Center for Neurodegenerative Diseases (DZNE).
Overactive Defense System
"The defense system of the body goes out of control. It starts producing antibodies which turn against the body's own nerve cells rather than fighting infections," DZNE scientist Harald Prüß explains. The possible symptoms of anti-NMDA-receptor encephalitis include epileptic attacks, hallucinations and dementia.
Only recently discovered
The mechanism was discovered in humans just a few years ago. That's why IZW researcher Alex Greenwood considers these new findings "pretty remarkable." The treatment for humans could now be adapted for zoo animals.
Knut's contribution to research
"Autoimmune diseases of the nervous system could be more common among humans and animals than we have previously thought," Greenwood suggests. It is possible that inflammations triggered by an autoimmune response are often overlooked when doctors are treating people with psychoses or lack of memory. In the future, routine tests could be done to get the diagnosis right.