The death of a young Siberian tiger at Winnipeg's Assiniboine Park Zoo was caused by "severe, sudden onset, bacterial pneumonia."

The zoo released a statement on Tuesday saying its veterinary team has determined Reka, the one-year-old male tiger that was born at the zoo, was stricken by a bacteria commonly found in the mouths of members of the cat family.

“While it is unusual for oral bacteria such as this to result in clinical disease, it can opportunistically cause infections and in this particular case, the bacteria entered Reka’s lungs and resulted in pneumonia,” said Chris Enright, head of veterinary services for the zoo.

“Testing for canine distemper and other viruses came back negative.”

Zoo staff began monitoring Reka on Aug. 26 as he was appearing lethargic, had a reduced appetite and showed a discharge from the eyes.

Reka was scheduled for a full exam and diagnostics but stopped breathing shortly after being tranquilized for the exam.

He went into cardiac arrest, passing away at approximately 9:55 a.m. on Aug 27.

The bacteria involved in Reka’s illness is not likely to result in clinical disease in other feline species at the zoo, stated the news release.

No other animals have shown signs of illness and are being carefully monitored by the zoo’s animal care and veterinary staff.