gorillas are believed to have caught Covid from a US zoo keeper in the first known case of it passing from humans to apes. San Diego Zoo Safari Park confirmed one of the critically endangered animals tested positive for the killer bug on Monday.Officials said three of the western lowland gorillas have been coughing but all are expected to make a full recovery.It is not known if the infected troop of five females and three males including beloved 45-year-old "silverback" Winston will suffer long term or additional symptoms.Lisa Peterson, executive director of the San Diego Zoo Safari Park, said: "Aside from some congestion and coughing, the gorillas are doing well."The troop remains quarantined together and are eating and drinking.