At least 18 of the 20 gorillas in the Atlanta zoo have now tested positive for COVID-19, an outbreak that began just days before the zoo had hoped to get a veterinary vaccine for the primates, officials said on Tuesday.
Zoo Atlanta had announced the first positive tests among the western lowland gorillas on Friday after employees noticed that the gorillas had coughed, had runny noses and shown changes in appetite. A veterinary laboratory at the University of Georgia returned positive tests for the respiratory disease.
Zoo Atlanta says that the National Veterinary Services Laboratories in Ames, Iowa, confirm that at least four of the gorilla samples so far have tested positive for the delta variant of the virus.
The zoo says it uses monoclonal antibodies to treat gorillas that are at risk of developing complications of the virus.
Officials say there is no evidence that gorillas can transmit the virus to humans and visitors are too far away to be infected by gorillas.
Since the gorillas live close to each other in four troops, zoo officials say it is impossible to keep infected animals isolated.
Zoo officials say they believe an asymptomatic employee who cares about the gorillas transmitted the virus. The employee had been completely vaccinated and was wearing protective equipment such as a mask and gloves.
“According to our guidelines for animal care personnel, they should stay home if they have the slightest symptoms of a cold,” says Dr. Sam Rivera, the zoo’s director of animal health.
“It so happens that the animal care team member, the following day, she developed signs that she suspected may be compatible with COVID and were tested and were positive.”
Senior Animal Health Manager at Zoo Atlanta Sam Rivera said the zoo will vaccinate the gorillas with a veterinary vaccine that had been on the waiting list before the gorillas’ positive tests.
Eight gorillas at the San Diego Zoo Safari Park were treated for the virus in January. A silverback in San Diego received an experimental antibody treatment and everyone recovered.