Several gorillas at the San Diego Zoo Safari Park have tested positive for Covid-19 in what is believed to be the first known cases among non-human primates in the US and possibly the world. The park’s executive director, Lisa Peterson, on Monday said eight gorillas that live together at the park are believed to have the virus and several have been coughing. It appears that the infection came from a member of the park’s wildlife care team who also tested positive for the virus, but was asymptomatic and wore a mask at all times around the gorillas. The park has been closed to the public since December 6 as part of California’s efforts to curb coronavirus cases. Veterinarians are closely monitoring the gorillas and they will remain in their habitat at the park, which is north of San Diego, Ms Peterson said. For now, they are being given vitamins, fluid and food, but no specific treatment for the virus. “Aside from some congestion and coughing, the gorillas are doing well,” Ms Peterson said. While wildlife including minks and tigers have caught the coronavirus, this is the first known instance of transmission to the apes and it is unknown if they will have any serious reaction. Wildlife experts have expressed concern about the coronavirus infecting gorillas, an endangered species that share 98.4 per cent of their DNA with humans and are social animals. The gorillas infected at the San Diego park are western lowland gorillas, the population of which has declined by more than 60 per cent over the past two decades because of poaching and disease, the World Wildlife Fund said. The safari park tested the faeces of the troop of gorillas after two apes began coughing on January 6. Positive test results were confirmed by the US Department of Agriculture National Veterinary Services Laboratories in three gorillas. Faeces from all eight members of the troop will also be tested. Zoo officials are co-ordinating with experts on coronavirus treatment in humans in case the animals develop more severe symptoms. The gorillas will remain together as separating them could be harmful because they live in tight-knit social groups. “This is wildlife, and they have their own resiliency and can heal differently than we do,” Ms Peterson said. The safari park on Monday added more safety measures for its staff, including face shields and eye goggles when working with the animals. The confirmation that gorillas are susceptible to the coronavirus contributes to information on how the pandemic may affect these species in their native habitats if they come into contact with humans and human material, the park officials said. San Diego Zoo Safari Park plans to share what it learns with health officials, conservationists and scientists to develop steps to protect gorillas in the forests of Africa.