Conservations for India's Gir National Park in the country's western region of Gujurat announced on Tuesday that 21 Asiatic lions had died in the park in the past three weeks. At least four of them were confirmed to be carrying a virus that killed 1,000 lions in Tanzania in the 1990s.
The virus is called canine distemper virus (CDV), and can easily spread from dogs in the wild to other animals.
"A team of experts is working to ascertain the reason for the viral infection. Since all 21 lions have died in one Sarasiya grassland, it is a matter of concern," said park official Dushyant Vasavada.
Another 31 lions from the same part of the sanctuary are currently under observation, though they have shown no sign of the disease thus far.
Gir National Park is home to all the world's remaining Asiastic lions, of which there are about 520.
es/msh (AFP, dpa)