Chikungunya is a viral infection which mainly affects Africa, islands in the Indian Ocean, and Asia. It is usually transmitted by the tiger mosquitoes Aedes aegypti and Aedes albopictus. An infection may be inapparent. Major symptoms lasting up to 10 days are flu- or dengue-like, including high fever, severe back pain, joint pain (sometimes for months), rash on the trunk and limbs, vomiting, and mild hemorrhaging (in children). In the recent outbreak of chikungunya on the island of Réunion, some cases of meningoencephalitis have been observed. There is no vaccination or specific treatment. Therefore, only the symptoms can be treated.

The first epidemic of Chikungunya was observed in East Africa in the beginning of the 1950s. Since then, the virus has caused several epidemics in Asia, including the Philippines, Thailand, Cambodia, Vietnam, India, Burma, and Sri Lanka.

In 2005/2006, the island of Réunion experinced a severe outbreak of the disease. Other islands in the Indian ocean (Mayotte, Mauritius and the Seychelles) were struck as well, with the number of cases waning later in 2006. Since April 2006, the disease spreads in India. An outbreak on Sri Lanka is also being reported (November 2006).

There are also imported cases of travellers returning to Europe and the United States from Africa, the Indian Ocean and Asia. Cases like this pose a threat for European and American regions where Aedes albopictus and other potential vectors of the disease are present .