Chikungunya Causes and Risks: What causes Chikungunya fever? Chikungunya is a fever which is caused by the bite of a mosquito of the type – Aedes and the main cause of spread of Chikungunya is stagnated water. Presence of stagnated water in and around human inhabitation is one of the main causes of increased Aedes mosquito population. This in turn causes a large number of mosquito bites leading to the rapid spread of Chikungunya virus. Know how Chikungunya virus spreads and transmitted?