"Our leopards, Ranney, Everest, and Makalu, were beloved by our entire community inside and outside of the zoo," the zoo said in a Facebook post. "This loss is truly heartbreaking, and we are all grieving together."
Snow leopards are native to mountainous areas in Central Asia and are considered vulnerable, according to the World Wildlife Fund.
Last month, the zoo said that the leopards and its Sumatran tigers tested positive after showing symptoms consistent with the virus. The animals were treated with steroids and antibiotics to prevent secondary infections, the zoo said at the time.
"Sumatran tigers, Axl and Kumar, have made a seemingly full recovery from their illness," zoo officials said on Friday.
Covid-19 has been detected in a number of mammals, including big cats, primates, ferrets and minks, according to the Centers for Disease Control and Prevention.
The zoo remains open "and continues to take every precaution to prevent the spread of COVID-19 to humans and animals," it said on Facebook.
"We will continue following the American Association of Zoo Veterinarians (AAZV) and CDC guidelines to ensure the safety of our animals, staff, and community," the post said.
A snow leopard at the San Diego Zoo tested positive in July and three snow leopards at the Louisville Zoo were infected with the disease last December.