Knut the polar bear was a beloved animal at the Berlin Zoo when he died four years ago. His sudden death puzzled veterinarians who were anxious to keep other animals from suffering the same fate. But what they found out about what killed Knut may help raise public awareness to a similar condition that affects humans, and possibly save human lives.
Knut was 4 when he died in March 2011. He suffered what looked like a seizure and collapsed into the pool in his enclosure at the zoo in front of hundreds of visitors. A necropsy determined that Knut suffered from a swelling of the brain. Initially, scientists thought the inflammation had been caused by an infection, but that theory was later discounted.
Researchers at the Leibniz Institute for Zoo and Wildlife Research, which led much of the initial research into Knut's death, put the matter to the side, believing that it might take decades to figure out why Knut died.
But then they got a call from a neurologist at Berlin's Charite hospital named Harald Pruess who is also a researcher at the German Center for Neurodegenerative Diseases. He noted that Knut's case showed similarities to human patients with a condition called anti-NMDA receptor encephalitis. It is an autoimmune disorder where the body attacks its own brain cells. This encephalitis was discovered in humans 8 years ago and had never been seen in animals. Knut turned out to have anti-NMDA receptor encephalitis.
If zookeepers had known what Knut had, they could have treated him with cortisone, a drug that suppresses the immune system, and is what is used to treat people with anti-NMDA receptor encephalitis. People with the condition are usually able to return to normal life after treatment, though some have memory problems and difficulty concentrating. Knut might have been more likely to survive if he had not fallen into the pool when he had seizures.
The disease is still relatively unknown in humans; Knut's case may help raise awareness of it. It affects at least one in 200,000 people each year. Symptoms include sudden behavioral changes.
The research was published in the journal Nature Scientific Reports.
