Two baby elephants have died at Chester Zoo after contracting a virus.
The calves fell ill on Monday and vets tried “tirelessly” to save them with “ground-breaking” blood transfusions and anti-viral drugs.
The zoo’s director of animals Mike Jordan said: “Aayu and his half-sister Nandita were wonderful, confident and energetic calves, who loved nothing more than playing with the rest of the family herd – whether in the sand or the pool.
“They will be missed by their young siblings in the herd who will no doubt mourn for a short time.
“To lose them both is also devastating to all of us here who have cared for them day in, day out. We fought for them until the very last moments, but were unable to save them. It is just heart-breaking.”
The virus – elephant endotheliotropic herpesvirus (EEHV) – is carried by almost all Asian elephants in the wild and captivity.
If the virus becomes an illness it is fatal and there is no cure yet, although researchers are trying to find one.
A spokesman for the zoo said: “Despite the exhaustive efforts, their conditions rapidly declined and both calves passed away this morning.”