Scientists at the Indian Council of Medical Research’s National Institute of Virology on Tuesday said at least 21 lions in Gujarat’s Gir sanctuary have been infected with the canine distemper virus. As many as 23 lions have died at the sanctuary over the last month.

The National Institute of Virology in Pune had received a total of 80 samples of nasal, ocular and rectal swabs, from 27 lions in Gir forest who had taken ill.

“There is active disease transmission among the lions,” Indian Council of Medical Research Director General Balram Bhargava told The Indian Express. “The animals should be immediately vaccinated for the canine distemper virus. At present, most of the available vaccines are made up of CDV American genotypes. These vaccines have been used in a number of countries and have been found to be effective.”

“Since there is a hint of active disease transmission, we have directed that the lions be given vaccine shots and kept in different geographical locations,” he told the Hindustan Times.

Indian Council of Medical Research officials have recommended that healthy lions from Gir should be shifted to other, possibly two or three, sanctuaries. “There are no papers about the mortality rate due to the CDV in lions,” an unidentified official said. “However, CDV infection once found can kill 50% of infected dogs and 80% of infected puppies.”