Aedes aegypti mosquito after feeding. This female mosquito has fed on blood from a vertebrate animal, which can be a mammal, reptile, bird or amphibian. The blood fills the abdomen which becomes enlarged due to its blood meal contents. A. aegypti is found throughout tropical Africa and in parts of South America. It is a vector for the transmission of yellow fever, chikungunya, dengue fever and zika viruses to humans. Photographed in a research laboratory.