This has been confirmed after a PCR test done on the male lion named "Thor '' which was brought to Sri Lanka from South Korea in 2012.
The animal has been suffering from cough and throat pain for a few days and the authorities of the zoo have then decided to do a PCR test on it.
The tests have been done at the Veterinary Teaching Hospital at Peradeniya.
Sources say the zoo authorities have taken steps to quarantine three employees who were on duty at the lions' cage.
A zebra calf and a hippopotamus have also fallen sick and died during the time lion tested positive, but it is learnt that these two have not been subjected to any PC tests.
However, WildLife Minister Wimalaweera Dissanayaka said there can be errors in the PCR tests done on animals and therefore, he has decided to seek help from India to conduct an accurate test on the lion.