Dozens of tigers have died in zoos in south Vietnam after a bird flu outbreak, according to state media.
Three lions and a panther were also reported to have died of the virus alongside 47 tigers since August.
The H5N1 outbreak hit the Vuon Xoai zoo near Ho Chi Minh City and the My Quynh safari park in neighbouring Long An province.
An official told Reuters news agency that the animals had likely fallen ill after being fed meat from chickens which had been infected.
The Vietnamese ministry of health said two samples taken from dead tigers tested positive for bird flu, and officials are "tracking the source of the chicken to determine the cause".
The zoos declined to comment when contacted by AFP news agency.
Advice on the World Health Organization (WHO) website warns against consuming raw or undercooked meat and eggs from regions experiencing bird flu outbreaks due to the high risk of infection.
The H5N1 strain of the virus primarily infects animals, and the WHO says almost all cases of human infection arise from close contact with infected live or dead birds, or contaminated environments.
Since 2022, there have been increasing reports of deadly outbreaks among mammals caused by influenza viruses, including H5N1.
Close to 900 human infections have been reported since 2003, of which more than half were fatal.
