But was it enough to turn this forest-dwelling mosquito into the fearsome virus-transmitting machine that we know today? How did Aedes aegypti’s intrinsic ability to acquire and transmit viruses evolve during this process? The adaptation of Aedes aegypti to the domestic environment and the increased frequency of encountering humans for blood meals significantly enhanced its vector performance. In contrast, the contemporary African subspecies Aaf remains a generalist and is only found in sub-Saharan Africa. The globally invasive subspecies Aaa thrives in urban habitats across the American and Asian tropics with females taking up to 95% of their blood meals from humans. It consists of two subspecies that are morphologically, ecologically, and genetically distinct: Aedes aegypti aegypti (Aaa) and Aedes aegypti formosus (Aaf) (Figure 1). This shift in its feeding and breeding behavior allowed the domesticated form of Aedes aegypti to escape from Africa 400-500 years ago during the rise of transatlantic trade and colonize the rest of the world over the last centuries.Īedes aegypti is now present throughout the tropics and sub-tropics. Following a domestication process that presumably occurred 5,000-10,000 years ago, a human-adapted Aedes aegypti population with a marked preference for human blood and the inclination to breed in human habitats evolved from the generalist ancestors. Originally, the ancestral populations of Aedes aegypti took blood meals from various vertebrate hosts in sylvan habitats in Africa. Although Aedes aegypti is now well recognized as the most efficient vector (carrier) of viruses and the major cause for their worldwide spread, this was not always the case. Among this very private club, Aedes aegypti, also known as the yellow fever mosquito, is the first pathogen-transmitting mosquito causing human viral diseases. There are approximately 3,500 known mosquito species out there, but contrary to common belief, the ability to transmit viruses to humans is the privilege of only a few of them.
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