On Wednesday, 6 January, two gorillas from the troupe began coughing, which prompted zoo staff to test fecal matter for the virus.
On 8 January, it was found the gorillas had become infected with the coronavirus.
The US Department of Agriculture Veterinary Services Laboratory confirmed the positive test on 11 January.
Lisa Peterson, the executive director of the San Diego Zoo, told The Associated Press the gorillas were doing well, all things considered.
“This is wildlife, and they have their own resiliency and can heal differently than we do,” Ms Peterson said. “Aside from some congestion and coughing, the gorillas are doing well.”
She said the park's main concern was keeping the gorillas "healthy and thriving".
This is the first known transmission of the virus to gorillas, although other wildlife have become infected with the virus.
Cats, dogs, mink, tigers and other animals have been infected with the virus as well.
The gorillas at the San Diego Zoo are western lowland gorillas, which are extremely endangered.
United States, the Netherlands, France, Spain, Italy, Sweden, Canada, Greece and Lithuania have all reported mink with coronavirus infections, according to the World Organisation for Animal Health.
Unlike other animals that have become infected with the virus, mink are the only confirmed creatures other than humans that can become severely ill and die as a result of the virus.
In Denmark, mink farming has been banned for 2021 over fears the mink could pass the virus along to humans.
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