News that scientist Satoshi Omura had won the Nobel Prize came so unexpectedly that many people in Japan, including the winner himself, were stunned by the honor — but delighted as well.

"I was planning to go back home at around 4:30 p.m.," Omura, an 80-year-old professor emeritus at Kitasato University in Tokyo, said at a news conference Monday night to announce that he had been named as one of this year's winners of the Nobel Prize in physiology or medicine. "But my secretary wouldn't let me go home, just telling me to wait and wait. Then, to my surprise, there came a phone call from Sweden."

Omura shared the award with Irish-born William C. Campbell, an 85-year-old research fellow emeritus at Drew University in New Jersey, for discovering the new drug avermectin, derivatives of which have radically lowered the incidence of river blindness and lymphatic filiarisis, commonly known as elephantiasis.