Aedes aegypti mosquito and Zika virus. Computer illustration of a female Aedes aegypti mosquito biting a human and transmitting the Zika virus (ZIKV). This species of mosquito is found throughout tropical Africa and parts of South America. The female feeds on human blood and is a vector for the transmission of yellow fever, Chikungunya, Dengue fever and ZIKV to humans. ZIKV is an RNA (ribonucleic acid) virus that causes zika fever, a mild disease with symptoms including rash, joint pain and conjunctivitis. In 2015 a previously unknown connection between Zika infection in pregnant women and microcephaly (small head) in newborns was reported. This can cause miscarriage or death soon after birth, or lead to developmental delays and disorders.