The Gir forest has lost 21 lions since September 12, the Gujarat government said on Monday after seven lions died while undergoing treatment. The state said some of the deaths were because of a virus but officials are yet to identify what virus it is, PTI reported. At least four of the dead lions were found to have been affected by a virus, and six were infected by a protozoa spread by ticks.

Last month, officials had found carcasses of 11 lions in the Gir forest, prompting the state government to order an inquiry. Officials had said, however, that the deaths appeared to be caused by infighting. All the carcasses were found in Gir (east) division, mainly in Dalkhaniya range.

After the carcasses were found, the forest department launched a screening operation in Dalkhaniya range to identify sick lions. They found three more dead lions during the operation, and rescued others.

The forest department said the virus was found in the blood and tissue samples of the rescued and the dead lions. The samples were analysed in the National Institute of Virology in Pune, the Junagadh Veterinary College and the Forensic Science Laboratory.

“The death toll now stands at 21, as seven more lions who were rescued from Gir forest have died while undergoing treatment at a rescue centre,” said DT Vasavada, the chief conservator of forests in Junagadh Circle. “Though the presence of virus was also found, it will take some more time to identify the exact type of virus.”

Thirty-one lions rescued from the forest are under observation at a rescue centre. They do not appear to be infected, the forest department said. The government will get specialised medicines and vaccines from the United States as a precautionary measure.

Meanwhile, the forest department found during the screening drive that there are 600 lions in the forest now, up from 523 in the last census of 2015.