In 2011, more than four years ago, Knut – the polar bear form a zoo in Berlin, suffered a seizure and drowned.

After this event, lots of theories and questions followed on what killed this superstar polar bear. The main questions was: “How could this 4-years-vbal of fur suddenly drop dead?” an autopsy decided that his death was determined by an inflammation of the brain, but what caused this inflammation?

Now, experts have the answer.

What caused this inflammation of the brain?

Knut’s inflammation of the brain was a result of an autoimmune disease of the brain. This disease is known as anti-NMDA receptor encephalitis.

One of the immune system’s job is to destroy and seed out foreign cells or organisms that cause disease, such as a virus. Sometimes, the immune system will launch an attack on the body’s own cells. In case of anti-NMDA receptor encephalitis, the immune system will attack nerve cells instead of disease-causing cells. Until Knut’s cases, this disease was never been detected in animals. So, this is what makes his case a rarity.

Knut – a Zoo superstar polar bear

After he was abandoned by his mother at Zoo Berlin after birth in 2007, a zookeeper took care of Knut because he wasn’t old enough to fend for himself. This zoo and his caretaker, who slept just next to his crate became instant celebrities and attracted a lots of fans the zoo.

Knut was such a popular polar bear and his presence to zoo meant the most profitable period in its 163-year history.

Unfortunately. Knut died in March 2011 after he collapsed in a pool in his enclosure.