Two Sumatran tigers at an Indonesian zoo are recovering after testing positive for coronavirus.Officials at Ragunan Zoo in Jakarta have launched an investigation into how Tino, who is nine years old, and Hari, 12, became infected.Both tigers had displayed flu-type symptoms, experienced difficulty breathing and had lost their appetite after they tested positive for COVID-19 in mid-July.Following about 10 to 12 days of treatment under close observation, officials said the tigers were showing signs of recovery.Jakarta's head of the Parks and City Forest Office, Suzi Marsitawati, said: "Their appetites have returned and they are back to being active."She confirmed the authorities were trying to find out how the tigers became infected.