ORLANDO, Fla. -- Tilikum, the killer whale that became infamous for battering and drowning a SeaWorld Orlando trainer, has an apparent lung infection that could kill him.
SeaWorld announced Tilikum's illness Tuesday on social media. The orca, estimated to be 35 years old, has become increasingly lethargic over the past few weeks.
"I wish I could say I was tremendously optimistic about Tilikum and his future, but he has a disease which is chronic and progressive and at some point might cause his death," veterinarian Scott Gearhart said on a video.
SeaWorld said the bacterium that has infected Tilikum is found in a variety of species including wild cetaceans. Trainers are giving him a variety of antibiotics and antifungal medications in his fish.
"What I know is that every day that I'm here and every day that these amazing veterinarians are here, he will receive the best care," said Kelly Flaherty Clark, SeaWorld's director of animal training.
SeaWorld said Tilikum has not lost any significant weight. The fact he is still eating is generally a good sign, said Naomi Rose, a marine mammal scientist with the Animal Welfare Institute.
Tilikum is in SeaWorld's medical pool. Asked if he was still performing, a SeaWorld spokeswoman pointed to the company's online video -- in which animal care supervisor Daniel Richardville says, "If he's ready to go out and do a show and get people wet, I'm excited to do that with him."
Animal advocates say that Tilikum's life is a sad example of why whales should not be kept in captivity.
"The sickness at SeaWorld is with its management, which has deliberately caused Tilikum ... to suffer immensely by confining him to a small concrete tank for decades, causing him to succumb to mental illness that has resulted in aggression and now to some incurable illness," People for the Ethical Treatment of Animals said in a statement.
Tilikum came to SeaWorld 23 years ago from the now-defunct Sealand of the Pacific in Victoria, British Columbia. SeaWorld acquired him to breed with female orcas. Tilikum has sired more than a dozen whales for SeaWorld. But he has also been a public relations problem for the park.
He has been involved in three human deaths. He was one of three whales that drowned a trainer at Sealand. In 1999, he was involved in a second incident when the naked body of a man who had apparently sneaked in after hours to swim with the whales was found draped dead across his back.
After Tilikum killed trainer Dawn Brancheau in 2010, his life became the focus of the 2013 documentary "Blackfish." That movie suggested the stress of his captivity made him lash out and kill Brancheau. SeaWorld is still grappling with the fallout from that film: It has lost corporate sponsorships, attendance and revenue while spending more money on public relations and fending off lawsuits.
In the video released this week, SeaWorld animal care workers talked lovingly of Tilikum getting back rubs and playing with his favorite toys.
Richardville said Tilikum "has had some ups and downs health-wise." Those include what SeaWorld calls "chronic teeth issues."