The yellow fever mosquito (Aedes aegypti) is closely related to the tiger mosquito (they are from the same genera, but they are not the same species). The yellow fever mosquito can be a vector of the diseases Zika, dengue, Chikungunya, and yellow fever. In Spain, this mosquito has not been present for the past 75 years (the last time it was detected was in Barcelona in 1939 by the ecologist Ramon Margalef), but it could arrive to Europe once again due to globalization and the increase in global mean temperatures. Using the Mosquito Alert app, citizens will be able to report when they believe they have seen one of these mosquitos, and if confirmed the pertinent authorities will be notified.