The content originally appeared on: CNN (CNN)More than 20 Covid-19 cases have been identified aboard an Australian navy ship sailing to disaster-hit Tonga, complicating aid efforts to the virus-free Pacific island nation as Japan halted its relief mission due to a separate outbreak among crew members. Tonga has only reported a single coronavirus case since the start of the pandemic and is making every effort - including insisting on contactless delivery - to keep Covid-19 out as it receives aid […]