Forty-seven tigers, three lions and a panther have died in zoos in South Vietnam due to the H5N1 bird flu virus, state media said on Wednesday.

The deaths occurred in August and September at the private My Quynh Safari Park in Long An Province and the Vuon Xoai Zoo in Dong Nai, near Ho Chi Minh City, the official Vietnam News Agency (VNA) reported.

According to test results from the National Centre for Animal Health Diagnosis, the animals died “because of H5N1 type A virus”, VNA said. The zoos declined to comment when contacted by AFP. No zoo staff members in close contact with the animals had experienced respiratory symptoms, the VNA report added.

Education for Nature Vietnam (ENV), an NGO that focuses on wildlife conservation, said there were a total of 385 tigers living in captivity in Vietnam at the end of 2023. About 310 are kept at 16 privately owned farms and zoos, while the rest are in state-owned facilities.

The World Health Organisation (WHO) says that since 2022, there have been increasing reports of deadly outbreaks among mammals caused by influenza viruses, including H5N1. It also says H5N1 infections can range from mild to severe in humans, and in some cases can even be fatal.

Vietnam notified the WHO about a human fatality from the virus in March.

In 2004, dozens of tigers died from bird flu or were culled at the world’s largest breeding farm in Thailand.