KAMPALA, Sept. 7 (Xinhuanet) -- The death toll of hippos in Queen Elizabeth National Park in western Uganda has reached 60 and is still on the rise, while the cause remains a mystery, local media reported on Tuesday.

    The Uganda Wildlife Authority (UWA) dispatched a expert team inmid-August to the park after about 25 hippos died from a strange disease there.

    Chief warden of the park John Bosco Nuwe said "a quick discovery of the cause is needed to stem it before it runs out of hand."

    However, he said the 4,000-5,000 strong hippos population was not under serious threat although the incidents are very disturbing.

    He said the recent dry weather led to turning of the water in Kazinga channel, lakes Edward and George to a blue-green color, a process now being suspected to be toxic.

    Hippos are ranked the 4th in tourist attraction for the park after lions, elephants and buffaloes. They live in water most of daytime, and come out in the evening to graze.

    "First we suspected anthrax. But Uganda Wildlife Authority veterinary experts have ruled this out because it should have affected even human beings and other animals," Nuwe said, adding that "we're now suspect the change in the state of the water to bea possible cause." Enditem