Zoo officials say they believe a vaccinated employees who cares for the gorillas passed on the virus while asymptomatic. The employee was wearing protective equipment such as a mask and gloves.
The zoo says there is is no evidence that the gorillas can pass the virus back to humans and says visitors are too far away to be infected by gorillas.
Zoo Atlanta says at least 13 western lowland gorillas have tested positive for COVID-19, including their oldest male gorilla in captivity - a 60-year-old named Ozzie
Experts are now testing all 20 of Zoo Atlanta's gorillas, who live in four troops
Zookeepers are now treating the gorillas at risk of developing complications with monoclonal antibodies. They are testing all 20 of Zoo Atlanta's gorillas, who live in four troops.
'We are very concerned that these infections occurred, especially given that our safety protocols when working with great apes and other susceptible animal species are, and throughout the pandemic have been, extremely rigorous,' Dr. Sam Rivera, the zoo's senior director of animal health, said in a statement.