The Eurasian strain of highly pathogenic avian influenza (HPAI H5N1) was detected in two mountain lions in Mono County in December 2022 and January 2023, according to wildlife health experts with the California Department of Fish and Wildlife. While additional disease testing is being conducted to rule out the possibility of co-infections, HPAI H5N1 is suspected to be the cause of the death for both mountain lions.