Scientists explain the death of Knut

Exact cause of death of the popular polar bear from Berlin finally clear
Eisbär Knut was after his birth in 2006 as a crowd puller in Berlin Zoo and was accompanied by countless fans from childhood. But at just four, the animal died of a brain infection, but the exact cause remained unknown. Now researchers have apparently cleared the death of the bear and published the results of their study in the journal "Scientific Reports".

First polar bear birth in Berlin Zoo for more than 30 years
The birth of little Knut in 2006 was the first polar bear birth in the Zoologischer Garten in Berlin for more than 30 years for an immense regional and even international media interest. The little bear with the bright white coat quickly became a "star" in the capital's zoo, mainly because the caretaker Thomas Dörflein cared for the animal that had been rejected by the mother and opened it up with a bottle. However, at the age of four, after an epileptic attack, the ice bar had fallen into a moat in his enclosure and drowned. At the time, the cause of death was encephalitis, although its exact cause could not be determined.

The cause of death of the polar bear Knut was a special autoimmune disease. (Image: Hüttenhölscher / fotolia.com)

Autoimmune disease first detected in the animal kingdom
However, researchers were able to solve the mystery of the death of the young polar bear. As the Berlin Zoo reports in a press release, a team of scientists from the German Center for Neurodegenerative Diseases (DZNE), the Leibniz Institute for Zoo and Wildlife Research (IZW) and the Charité-Universitätsmedizin Berlin have been able to make the diagnosis more precise. According to this, Knut had suffered from a non-infectious autoimmune disease of the brain (anti-NMDAReceptor encephalitis), which had now been detected in the animal kingdom for the first time.

"This autoimmune disease was previously only known by humans. The body's defense system shoots over the target in a sense. It liberates antibodies that damage one's own nerve cells instead of combating pathogens. " Harald Prüß from the DZNE. As a result, according to Prüß the occurrence of various symptoms is possible, such as epileptic seizures, hallucinations and dementia.

Mechanisms of autoimmune disease have only been known for a few years
Researchers had discovered the autoimmune disease by examining brain samples from the bear, which Prüß carried out in collaboration with IZW's director of wildlife diseases, Alex Greenwood. The analysis showed that Knut was suffering from "anti-NMDA receptor encephalitis" because the researchers were able to detect typical antibodies in the tissue samples, the message continues. The mechanisms of this disease, however, were discovered only a few years ago, and accordingly, previous cases of meningitis in humans often could not be completely dissected.

Number of unexplained brain inflammations dropped significantly
"Meanwhile, the number of unexplained cases has dropped significantly. Since 2010, we know that most patients with inflammation of the brain without pathogens are ill with anti-NMDAReceptor encephalitis, "Prüß is quoted in the communication. According to IZW researcher Greenwood, the researchers had "quite impressed" the new findings about Knut's disease, because it is now known that the autoimmune disease may also occur in other mammals. "We are relieved to have finally solved the mystery of Knut's illness. Especially since these findings could have practical significance. In humans, this disease is treatable. If we succeed in delivering these therapies, we may be able to successfully treat brain infections in zoo animals and avoid deaths, "says Greenwood. (No)