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— Research

Zoo Gorillas Test Positive for Coronavirus

UC San Diego Health physicians assist in treatment

Experts say COVID-19 is a zoonotic disease. The virus that causes it — SARS-CoV-2 — jumped from one species, perhaps a bat, to humans. That assumption continues to be investigated, but one thing is clear: COVID-19 is not strictly a human disease.

Though people are its primary victims, there have been SARS-CoV-2-positive cases reported in domestic cats and dogs, minks, ferrets, cougars, lions, leopards and tigers.

In January 2021, western lowland gorillas at the San Diego Zoo Safari Park were added to the list. It became international news, in part because of what it might portend for all life on Earth.

It’s not known exactly how the gorillas became infected. Best guess: They picked up the virus from an infected, but asymptomatic, wildlife care specialist. Nearly half of the pandemic’s spread can be attributed to asymptomatic infections, says the CDC.

“The closer you are on the evolutionary tree, the more likely you are to be susceptible to the same disease. ”

Pascal Gagneux, PhD

Transmission is also easier when species are related. Both humans and gorillas are primates, sharing approximately 98 percent of the same DNA. “The closer you are on the evolutionary tree, the more likely you are to be susceptible to the same disease,” Pascal Gagneux, PhD, associate director of the Center of Academic Research and Training in Anthropogeny at UC San Diego, told The San Diego Union-Tribune.

Two diagnosed gorillas subsequently infected others in the eight-ape troop, but most of the apes experienced only minor symptoms — sneezing, coughing, lethargy and fatigue — and all fully recovered. A 49-year-old silverback named Winston suffered heart issues and pneumonia, but recovered after receiving experimental antibody treatment.

“UC San Diego Health was involved in
consultations with the zoo.”

Jess Mandel, MD

“UC San Diego Health was involved in consultations with the zoo,” said Jess Mandel, MD, chief of the Division of Pulmonary, Critical Care and Sleep Medicine. “We helped review Winston’s chest CT and also advised regarding treating him with monoclonal antibodies and other therapies. It was a unique collaboration that combined UC San Diego Health’s expertise in treating patients with COVID-19 and the zoo’s expertise with nonhuman primates.”

In March, the zoo’s four orangutans and five bonobo chimpanzees were inoculated with an experimental vaccine developed by a veterinary pharmaceutical company.