With the help of citizens, Mosquito Alert will allow scientists to monitor the spread of these insects, which can transmit viral diseases such as dengue, chikungunya, West Nile fever and Japanese encephalitis. It is produced by the European network AIM-COST Action and the Versatile Emerging infectious disease Observatory (VEO). Through the app, people can take pictures of mosquitoes and try to identify mosquitoes that they see. The information is passed along to a team of more than 50 international expert entomologists across Europe, who validate the observations. Mosquito Alert has been used in Spain for five years, where volunteers have reported more than 18,300 mosquito sightings. These observations have been used to monitor the expansion of the Asian tiger mosquito (Aedes albopictus), a species originally from South Asia that can transmit dengue, chikungunya and Zika. The new version of the app allows users to report mosquitoes of five different species of concern in Europe: the Asian tiger mosquito (Aedes albopictus), the yellow fever mosquito (Aedes aegypti), the Asian bush mosquito (Aedes japonicus), Aedes koreicus and the common house mosquito (Culex pipiens). Mosquito Alert aims to reproduce the Spanish success across Europe, and to create local communities of citizen scientist volunteers. Scientists stress that Mosquito Alert does not aim to replace traditional surveillance methods, but rather to complement them.