Vancouver Aquarium's beluga Aurora remains under 24-hour care

Experts continue to search for the cause of a mysterious illness affecting the Vancouver Aquarium's beluga whale Aurora, after her health appeared to take a turn for the worse on Sunday night.

Officials have said the 29-year-old animal isn't eating and appears to be suffering from cramps and inflammation, though the cause of her illness is unclear.

The facility says in a news release that Aurora showed signs of improvement over the weekend but then her abdominal discomfort increased on Sunday night.

Deana Lancaster, a spokesperson for the aquarium, said in an email that Aurora is being given fluids and medication every three hours.

"Many of [our team] are putting in extra time," Lancaster wrote. "Our head vet, the head of the marine mammal team and our general manager have been on site almost 24 hours a day."

The whale's 21-year-old calf Qila had the same symptoms and died last week, leaving Aurora as the aquarium's lone beluga.

The aquarium's head veterinarian Dr. Martin Haulena has adjusted Aurora's treatment, but is increasingly concerned about her health.

Lab tests have been sent to veterinary experts around the world and a marine mammal team is monitoring the animal around the clock.