Female (left) and male (right) Aedes aegypti mosquitoes. The yellow fever mosquito (Aedes aegypti) is a mosquito that can spread dengue fever, chikungunya, Zika fever and yellow fever viruses, and other diseases. The mosquito can be recognized by white markings on its legs and a marking in the form of a lyre on the upper surface of the thorax. The mosquito originated in Africa, but is now found in tropical and subtropical regions throughout the world. Aedes aegypti is a vector for transmitting several tropical fevers. Only the female bites for blood, which she needs to mature her eggs. Zika fever is an infectious disease caused by the Zika virus. Infection during pregnancy causes microcephaly and other brain malformations in some babies.