The Vancouver Aquarium is still struggling to pinpoint what's afflicting Aurora, its last resident beluga whale, and veterinarians haven't ruled out the possibility that someone harmed her on purpose.

Aurora is still exhibiting similar symptoms to the ones suffered by her daughter, Qila, before she died suddenly last week, and the ailing beluga is being kept under round-the-clock care.

Head veterinarian Dr. Martin Haulena hasn't been home in days, instead sleeping on a camping mat laid out in his office.

"It's all hands on deck. It's everything we can do for Aurora," Haulena told CTV News. "She's now a whale in the equivalent of intensive care."

The beluga is receiving medical treatment every three hours, and 54 different biological samples have been sent to various laboratories for testing, some as far away as Spain.

But so far, whatever it is that's making Aurora sick – and is likely responsible for killing her daughter – remains a mystery.

While it's possible the belugas caught a virus, or were exposed to naturally occurring biotoxins, Haulena said the aquarium is also investigating whether the belugas were deliberately harmed.

"Unfortunately yes, that's a possibility," he said. "We're still at that stage where nothing's off the table."

Staff noted there are many groups that consider themselves enemies of the aquarium. Just last Thursday, someone broke into the facility's off-site Marine Mammal Rescue Centre, which is currently housing 42 seal pups that will soon be released back into the wild.

None of the animals were hurt, but the intruders made a mess and drained water from some of the enclosure pools.

Fortunately, though the source of Aurora's illness is still unclear, the beluga's condition appears to be stabilizing and her hydration has improved, the aquarium said. The beluga is also showing signs that she wants to play.

Qila had a brief period of improvement as well the day before she died, however, and her approximately 30-year-old mother has a long way to go before she could be called healthy again.

"Aurora is a whale with a serious health problem, there's no two ways about that," Haulena said.

With a report from CTV Vancouver's St. John Alexander