Aedes aegypti, the dengue fever mosquito in Mexico City. Early invasion and its potential risks.

Introduction Mexico City has no endemic presence of Aedes aegypti, and it is therefore free of vector-borne diseases, such as dengue fever, Zika and chikungunya. However, evidence has shown the presence of Aedes aegypti eggs in the city since 2015. Objective To report the constant and increasing presence of Aedes aegypti eggs in Mexico City from 2015 to 2018. Methods Surveillance was carried out using ovitraps. Eggs were counted and hatched in order to determine the species. Results From 2015 to 2018, 378 organisms were identified as Ae. aegypti. In total, 76 Aedes aegypti-positive ovitraps were collected at 50 different places in 11 boroughs of the city. Northeastern Mexico City was the area with the highest number of positive traps. Conclusions The results may be indicating a period of early colonization and the probable existence of cryptic colonies of the mosquito; Mexico City could be at risk of experiencing vector-borne epidemics.