Chikungunya (pronounced chick-un-goon-ya) virus is spread to people by Aedes aegypti and Ae. albopictus (commonly known as the Asian tiger mosquito), the same insects that introduced us to dengue fever. Identified by the WHO as "serious," it causes fever and severe, sometimes debilitating joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash. Most patients eventually recover, but often joint pain can persist for months and even years.
Disease outbreaks have occurred in Africa, Asia, Europe, and the Indian and Pacific Oceans, reports the CDC. In late 2013, the chikungunya virus was found for the first time in the Americas on islands in the Caribbean and has since been reported in the U.S. There is no vaccine or treatment.