The deaths have been reported at the My Quynh Safari Park in Duc Hoa District, Long An Province and the Vuon Xoai Tourist Park in Biên Hoà City, Dong Nai, Vietnam News Agency (VNA) reported on Wednesday.
My Quynh Safari Park said at least 27 tigers and tree lions have died during the period while Vuon Xoai zoo reported 20 tiger deaths.
The animals exhibited symptoms of illness and fatigue prior to their deaths. The tests conducted by the National Centre for Animal Health Diagnosis returned positive for the “H5N1 type A virus” among the animals, VNA reported.
At the safari park in Long An Province, at least three animal caregivers were identified as having close contact with the infected animals while some 30 employees at Dong Nai were in close contact with the animals, reported Tuoi Tre (Youth) newspaper.
However, none of the staff members have reported respiratory symptoms, VNA said.
The H5N1 is a type of influenza A virus that is commonly known as avian influenza or "bird flu" and has been detected in birds and some mammals.
The World Health Organisation has said a variant of the virus has caused “unprecedented numbers of deaths in wild birds and poultry in many countries in Africa, Asia and Europe” since 2020. It says while the cases of transmission in humans are rare but can cause severe disease with a high mortality rate.
In March 2024, Vietnam reported its first human case of the virus to WHO. The 21-year-old patient, a student who had gone for wild bird trapping, died from contracting the virus.
In June, India also confirmed the first human case of avian influenza H9N2 in five years. It was the second case of a human infected with bird flu that India has notified WHO about. The first was in 2019.Dozens of tigers, three lions and a panther have died in zoos in southern Vietnam, with subsequent tests detecting cases of bird flu.
The country’s Ministry of Health said in a statement on Thursday that two samples taken from dead tigers at Mango Garden Resort in Dong Nai province tested positive for the H5N1 strain of bird flu.
Since early last month, 20 tigers died at the resort after being fed chicken, said Phan Van Phuc, an official of Dong Nai province’s Centre for Disease Control, in the statement.
“It’s likely that the tigers had been infected from sick chicken, and the authorities are tracking the source of the chicken to determine the cause,” said Phan.
State media had previously said a total of 47 tigers, three lions and a panther died at the private My Quynh safari park in Long An province and the Vuon Xoai zoo in Dong Nai, near Ho Chi Minh City, in August and September.
The animals died “because of H5N1 type A virus”, according to test results from the National Centre for Animal Health Diagnosis reported by the official Vietnam News Agency (VNA) on Wednesday.
No zoo staff members in contact with the animals had experienced respiratory symptoms, the VNA report added.
Education for Nature Vietnam (ENV), an NGO focused on wildlife conservation, said there were 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.
The organisation says H5N1 infections can range from mild to severe in humans, and in some cases can be fatal.Vietnam notified the WHO about a human death from the virus in March.
In Thailand, dozens of tigers died from bird flu or were culled at the world’s largest breeding farm in 2004.
