Los Angeles Times, Dec. 29, 2007 An unusual virus known as chikungunya sickened at least 200 people and contributed to the death of a man in northeastern Italy this year, marking the first time the tropical virus has caused a disease outbreak in a temperate climate, researchers reported this month. Chikungunya has expanded its range in the last few years because the virus has mutated to transmit easily through the Asian tiger mosquito, Aedes albopictus, said Stephen Higgs, a vector biologist at UTMB.