we started to see a rising number of cases, doubling more rapidly than we thought. and particularly if we started to see cases appearing in the local population that seemed to be linked back into the village or vice versa. reporter: so far, that hasn t happened. but for the head of the world health organization, the olympics is a balance. the fess health of a nation versus the mental health of the world. may the message of hope resound, resound there tokyo around the world in every nation, every village. and every heart. reporter: dr. gupta, cnn, tokyo. and you can follow the games with cnn s instant coverage on our website, just point your browser to cnn.com/olympics. and we re standing by for a decision from the unesco world heritage committee on australia s great barrier reef. the marine wonder has been deteriorating for years due to