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

According to the Vietnam News Agency (VNA), the mammals 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.

According to test results from the National Centre for Animal Health Diagnosis, the animals died "because of H5N1 type A virus," VNA said.

The report noted that no zoo staff members were in close contact with the animals that contracted the disease.

FIRST CASE OF HUMAN BIRD FLU DIAGNOSED WITHOUT EXPOSURE TO INFECTED ANIMALS, CDC SAYS

The World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) have said that there has been an increase in outbreaks among mammals caused by influenza viruses, including avian influenza A (H5).

In the U.S., a patient in Missouri was diagnosed with bird flu in September.

The patient, who had underlying medical conditions, was successfully treated with antiviral medications at the hospital and has since been discharged, according to the Missouri Department of Health and Senior Services (DHSS).

This marks the 14th person (in three states) to contract bird flu in the U.S. this year — and the first infection to occur without any reported exposure to sick or infected animals, the CDC alert stated.

The prior 13 cases came after exposure to dairy cows or poultry.

Fox News' Melissa Rudy contributed to this report.